Podcasts about CD28

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Best podcasts about CD28

Latest podcast episodes about CD28

Uma Arte Longa
TGN 1412: um desastre na ciência.

Uma Arte Longa

Play Episode Listen Later Feb 14, 2023 13:40


O que acontece quando um medicamento nunca antes testado em humanos provoca uma tempestade de citocinas? Como testar medicamentos com segurança? O que foi o escândalo da talidomida? Ficou curioso? Ouça o episódio. Fontes.: ATTARWALA, H. TGN1412: from discovery to disaster. Journal of Young Pharmacists, v. 2, n. 3, p. 332-336, 2010. GOODYEAR, Michael. Learning from the TGN1412 trial. Bmj, v. 332, n. 7543, p. 677, 2006. HANKE, Thomas. Lessons from TGN1412. The Lancet, v. 368, n. 9547, p. 1569-1570, 2006. HORVATH, Christopher et al. Storm forecasting: additional lessons from the CD28 superagonist TGN1412 trial. Nature Reviews Immunology, v. 12, n. 10, p. 740-740, 2012. Imagem da capa: https://www.standard.co.uk/culture/books/the-thalidomide-catastrophe-by-martin-johnson-raymond-g-stokes-and-tobias-arndt-review-a3880221.html --- Send in a voice message: https://podcasters.spotify.com/pod/show/jordanoaraujo/message

ASCO eLearning Weekly Podcasts
Cancer Topics - My Approach to Refractory Diffuse Large B-Cell Lymphoma

ASCO eLearning Weekly Podcasts

Play Episode Listen Later Jan 18, 2023 26:47


Diffuse Large B-Cell Lymphoma or DLBCL is the most common type of lymphoma. Much progress has been made in treatment of the disease lately, particularly with emergence of CAR T-cell therapy, but not all patients are benefiting from it. This episode of Cancer Topics features Drs. Loretta Nastoupil and Chijioke Nze exploring treatment approaches for two cases of refractory DLBCL: a 60-year-old man with no comorbidities (1:30) and a 39-year-old woman with HIV (18:35). The guests also discuss improving patient access to CAR T-cell therapy and managing its toxicities (10:35), as well as emerging therapies for DLBCL (14:30). To learn more about management of refractory DLBCL, check out the ASCO course linked bellow. Guest Disclosures:Loretta Nastoupil, MD: Honoraria – Gilead Sciences, Novartis, Bayer, Janssen Oncology, TG Therapeutics, Bristol-Myers Squibb, ADC Therapeuitcs, Morphosys, Epizyme, Genmab, Takeda, Genentech/Roche; Research Funding – Janssen Biotech, Celgene, Genentech/Roche, Epizyme, Novartis, IgM Biosciences, Caribou Biosciences, Gilead Sciences, Allogene Therapeutics, Takeda Chijioke Nze, MD, MPH: No Relationships to Disclose Resources: ASCO Course: Second-line Therapy for Relapsed/Refractory Diffuse Large B-cell Lymphoma (Free to Full and Allied ASCO Members) ASCO Podcast: Cancer Topics - New Therapies for Lymphoma (Part 1) ASCO Guideline: Management of Immune-Related Adverse Events in Patients Treated With Chimeric Antigen Receptor (CAR) T-Cell Therapy ASCO Article: Navigating the Evolving Treatment Landscape of Diffuse Large B-Cell Lymphoma If you liked this episode, please follow the show. To explore other educational content, including courses, visit education.asco.org. Contact us at education@asco.org.  TRANSCRIPT The disclosures for guests on this podcast can be found in the show notes. Dr. Loretta Nastoupil: So, I do have optimism that as we have more and more treatment options entering into the treatment landscape, we'll have fewer patients that are experiencing a refractory disease, and potentially succumbing to the lymphoma. Hello, my name is Dr. Loretta Nastoupil, I'm an Associate Professor and Deputy Chair of the Department of Lymphoma and Myeloma, at the University of Texas MD Anderson Cancer Center. Welcome to this ASCO Education podcast episode. It's my pleasure to welcome Dr. Chijioke Nze. Dr. Chijioke Nze: Hello, everyone. I'm Dr. Chijioke Nze, a Hematology/Oncology fellow at MD Anderson, I'll be co-hosting this episode with Dr. Nastoupil. Dr. Loretta Nastoupil: We've seen notable advances in diffuse large B-cell lymphoma research lately, with novel treatments including CAR T-cell therapy, offering the prospect of long-term remission for some patients, yet many patients are not even receiving second-line or later therapy, and even fewer are treated beyond the second line. How do you approach a patient with refractory diffuse large B-cell lymphoma? In today's episode, we'll explore strategies for management of refractory diffuse large B-cell lymphoma through two patient cases. So, Dr. Nze, walk us through our first case. Dr. Chijioke Nze: Our first case is Frank. Frank is 60 years old and has no comorbidities. He presented with severe back pain in September 2021, and was evaluated locally. He had a CT scan that showed retroperitoneal mass, prompting further evaluation. He had a biopsy of the left retroperitoneal mass in November 2021, which was consistent with diffuse large B-cell, germinal center B-cell of phenotype Ki-67 of 90%. He had a subsequent PET-CT scan, which showed a large conglomerate, and invasive left retroperitoneal hypermetabolic mass with satellite nodularity and contiguous bulky retroperitoneal adenopathy. He had bulky, FDG-avid metastatic retrocrural and intrathoracic adenopathy as well. He was treated with R-CHOP for six cycles, and at the end, achieved complete remission. He had a PET-CT a year later that showed new and worsening intensely FDG-avid abdominal adenopathy. This was new from a PET scan he'd had in January 2022 of the same year. He had a biopsy of this retroperitoneal adenopathy, which was consistent with relapsed diffuse large B-cell germinal center phenotype, also Ki-67 of 90%. Locally, he was treated with ICE, times five cycles, and had a follow-up CT scan at the end, which showed persistent bulky nodal disease with periaortic regional nodes with double 5, consistent with persistent disease. He also was found to have new and more conspicuous nodes in other areas as well. He presented for his first visit at MD Anderson in September 2022. Dr. Nastoupil, when you see a patient like this coming into your clinic, what's your typical approach? Dr. Loretta Nastoupil: For a diffuse large B-cell lymphoma, we are always hoping for cure with frontline rituximab, containing anthracycline-based chemotherapy. And so, it's always a gross disappointment when patients experience relapse. The timing of that relapse right now informs our current approach. And the reason I mention that, is because there have been three large randomized studies conducted and reported out just in the last year demonstrating that CAR T-cell therapy is the preferred option for patients who experience either primary refractory disease, or relapse within 12 months. And that is because they resulted in better outcomes than standard salvage-based chemotherapy and high-dose therapy autotransplant in the setting of chemosensitive disease. I have to acknowledge, of the three studies that were done, two were positive trials, so that's why currently, we have axi-cel or Axicabtagene ciloleucel, or Lisocabtagene maraleucel, and not tisa-cel or Tisagenlecleucel, as CAR T-cell therapy options. And again, that's because two of the three studies were positive trials. Now, the challenge is why would we have two positive studies in one negative trial? There are a lot of caveats to how those studies were conducted, but I think one of the biggest important lessons to be gained is that if you're going to consider CAR T for these high-risk patients, you want to do it as soon as possible, because that delay from identifying CAR T as a preferred option to actually infusing cells in a disease-- in a case particularly like this, where patients may have bulky, aggressively-behaving disease - that prolonged time may actually have an impact on outcomes. Dr. Chijioke Nze: Excellent. Thank you. So, you've mentioned he had an early relapse. How would you define early relapse in this patient population? Dr. Loretta Nastoupil: Thinking back to how we've been approaching diffuse large B-cell lymphoma over the last two decades, the PARMA study, which was done prior to Rituximab, suggested that for patients who had chemosensitive disease to a platinum-based salvage chemotherapy, which generally, was at least a partial response on CT, if they went on to high-dose therapy autologous stem cell transplant, 50-60% of those patients could anticipate cure. Whereas for the folks who continued on salvage chemotherapy, 10-20% of those patients had favorable outcome. So, we generally do try salvage-based chemotherapy, and for patients with chemosensitive disease, go on to high-dose therapy autotransplant. However, in the modern era where we've approached patients who've had rituximab as part of their frontline therapy, at least two studies - the ORCHARD study, and the CORAL study suggested that only 20% of patients who relapse in the post-rituximab era, particularly within 12 months, were successfully salvaged with platinum-based chemotherapy and high-dose therapy autologous stem cell transplant. Now, fortunately for patients who fail salvage, we have had CAR T-cell therapy as an option based off of three pivotal phase II studies, demonstrating about 40% of patients could anticipate a cure with CAR T-cell therapy. So, it only made sense to try and move that therapy up into second line, and the preferred population was those that had progressed within 12 months of frontline rituximab and anthracycline-based chemo. Now, to qualify for those studies, patients had to be considered fit for the control arm, which was salvage and auto transplant. Nonetheless, I do think for a patient like this, who's 60, without any other significant comorbidities, whose biggest challenge to longevity of life is his aggressive lymphoma, CAR T-cell therapy should be considered as soon as possible for this patient. Dr. Chijioke Nze: Is there still a role for high-dose therapy and autologous transplant in the new era, given the efficacy shown with CAR T-cell therapy? Dr. Loretta Nastoupil: I think there is. And the reason why I say that is, the trials that were done really did focus on the highest-risk patients, which were those with primary refractory disease or those who progress within 12 months of frontline. Now, there are patients that will have later relapse. And so, I do think for those patients, particularly those who are young and otherwise fit, should be approached first with a platinum-based salvage chemotherapy, in the setting of chemosensitive disease, proceed onto high-dose therapy and autologous stem cell transplant. Now, what do we do for those patients who have a late relapse but are otherwise older, or who have comorbidities that would make them suboptimal candidates for the high-dose therapy preceding stem cell transplant? I have a couple other options for those patients - so, there was a trial done with liso-cel for patients who were otherwise older, or not fit for intensive therapy. It's a single-arm phase II without a randomized comparison, but also demonstrated that liso-cel in second-line, later relapsed patients who are not fit for intensive therapy, resulted in comparable outcomes to what we would anticipate on that third-line or later setting. We also have other non-CAR T-cell therapy options, such as tafasitamab, which is a naked CD19 antibody, which has been combined with lenalidomide in the L-MIND study, again, for patients without primary refractory disease and who would not be appropriate candidates for intensive therapy. So, I do think we have alternative options, it's just when we look at the totality of the data right now, my conclusion is that CAR T-cell therapy, particularly for high-risk patients, is the most likely chance to result in cure. Dr. Chijioke Nze: Excellent. In a patient who we are considering CAR T-cell therapy, what are some of the short-term and long-term consequences, or toxicities that we should worry about? Dr. Loretta Nastoupil: One of the challenges right now with CAR T, and why it's still only available in specialized centers, is the acute toxicity, which is really a derivative of its mechanism of action. We take patients' own T-cells, we use a viral vector to introduce extracellular receptor, but also a co-stimulatory molecule. So, once these cells engage their antigen, sort of prime to react to that, and that can lead to pretty rapid T-cell expansion, release of cytokines, recruitment of other inflammatory cells to that tumor bed, and as a result, a large portion of patients can anticipate to experience cytokine release syndrome, which again, is the result of the activation of these T-cells, the expansion and the recruitment of other inflammatory cells. Fortunately, for most patients, this results in fever alone that can be managed with supportive measures. Occasionally, they'll have concomitant hypoxia or hypotension, and unfortunately, few patients will have significant or severe toxicity. The other toxicity that's less easily manageable or less predictable is the neurotoxicity that can vary according to patient-specific characteristics, such as age, and the amount of tumor burden, their performance status going into CAR, but even more importantly, the construct that's utilized, with highest rates of neurotoxicity associated with axi-cel. Again, likely speaking to its construct and the CD28 costimulatory domain that is unique to axi-cel. As a result of these acute toxicities, patients are required to stay within two hours of their treating center for the first four weeks, and they're also discouraged from operating heavy machinery, such as driving, for the first eight weeks following CAR T. So, I do you think this creates some barriers to access to this therapy, particularly the patients that are treated in community settings that may reside long distances from these certified CAR centers. Dr. Chijioke Nze: So, you mentioned that obviously, given the specialized care needed for the CAR T therapy, that they're kind of localized in certain sites. What are some of these issues with access that you're noticing both in the logistics of giving CAR T, and also in patient access? Dr. Loretta Nastoupil: I'm hoping we're going to address one of those issues right now, which is, education and awareness, because we've had these three randomized studies, and two being positive readouts just in the last year. It's important to get the message out that CAR T-cell therapy for high-risk early relapsed refractory large cell lymphoma patients can result in a significant improvement in event-free survival and progression-free survival over the standard of care. And so, being aware that this therapy can result in more favorable outcomes is step one. Step two is, we have to ensure that there are minimal barriers to getting those patients into these treating centers as quickly as possible. So, recognizing who delivers the care - is it your traditional stem cell transplant physician? Is it a lymphoma doctor? What centers are certified? Some of these issues can be addressed with quick internet searches. So, for instance, in our center, we have a 1-800 number for anyone who's interested in CAR T-cell therapy that connects them directly to a CAR T coordinator who can help them understand do they meet the FDA-approved indication? Would they be interested in seeking consult? And we try and prioritize getting those patients in the door as soon as possible since time likely does have an impact on outcomes. And then, partnering with our community oncologist - you're going to be the primary oncologist for these patients leading up to CAR, and then after that four-week window, when we're keeping the patients in close proximity to our centers, we often send them back. And so, making sure that they're comfortable knowing what potential late toxicities to be on the lookout for, which include B-cell aplasia and risk for infection, or prolonged cytopenias, beyond just lymphopenia. And so again, there's a need for education and partnering with our community sites to make sure that there is successful handoff of these patients back after they've completed the monitoring for the acute toxicity. And then, really trying to explore opportunities to utilize some of the better tolerated CAR T, such as liso-cel, in your non-traditional academic centers. Those that are equipped to handle phase I studies or stem cell transplant, for instance, may not be affiliated with the university. So, I think those are all types of strategies that could be employed to try and improve access for patients. Dr. Chijioke Nze: And then, you mentioned the liso-cel, but in some of the toxicities, are there ways of predicting which patients will do better or worse? Are there ways to reduce toxicities? And is there any hope for things such as outpatient administration of CAR T? Dr. Loretta Nastoupil: So, my answer today may improve over time as we get larger numbers and more experience, but what we currently understand is that the patient performance status, their degree of tumor, how quickly that tumor is increasing, LDH and some inflammatory markers such as CRP or ferritin pretreatment can provide some insight into a higher risk of toxicity. And then obviously, the construct that's utilized. Again, axi-cel has higher rates of neurotoxicity. All will have some form of cytokine release syndrome, generally speaking, but rates of grade three or higher are quite infrequent, particularly with liso-cel and tisa-cel. So, it's multifactorial. That then raises the question, can we do anything to alter those modifiable risk factors? Can we reduce the disease burden? Can we improve the performance status? Can we do anything to reduce the inflammatory markers pre-treatment? And so, those are strategies that are being discussed, and I think in general, as we get more effective therapies that enter into the treatment landscape, it's probably some of the best ways to try and reduce some of those risk factors. Dr. Chijioke Nze: Rounding that up, are there any exciting developments or things to look out for, for exciting therapies in the relapse setting? Dr. Loretta Nastoupil: A couple of things beyond CAR T that I think we should all be aware of and anticipate to be in our toolkit relatively soon; probably, one of the most exciting, is the development of the bispecific antibodies. So, another challenge with CAR T is the requirement to collect these patients' own T-cells and send them off to a central manufacturing site, and the turnaround time can be anywhere from 3-4 weeks. And again, in a situation where you have an aggressive disease, that can be a long time to wait. And so, is there any treatments that are more readily available, that again, will be effective at reducing disease burden? And so, by specifics kind of fit those unmet needs to some extent - you have essentially two heads; one head is going to bind the endogenous T-cells that eliminates the need to leukapherese these patients and manufacture, and then the other head is going to generally engage CD20, which we know is an effective targeted antigen, particularly in B-cell lymphomas. And there are a number that are under development. We saw preliminary phase II data with glofitamab, epcoritamab, as well as combination strategies with mosunetuzumab. So, I do have optimism that the bispecific antibodies will potentially enter into the treatment landscape. I anticipate they'll probably be used first post-CAR T, but will likely move their way into earlier lines of therapy. I've already mentioned tafasitamab in combination with lenalidomide, which is an effective non-chemotherapy option. We have antibody-drug conjugates, such as Loncastuximab, which is a CD19 antibody-drug conjugate. It's essentially targeted delivery of chemotherapy, and it looks to have a pretty promising activity as a single agent in that third-line or later space, and then polatuzumab, which is a CD79b antibody drug conjugate, in the relapse setting has been combined with bendamustine and rituximab, but also demonstrated significant improvement in the frontline setting in the POLARIS study where vincristine was replaced with polatuzumab. So, I do have optimism that as we have more and more treatment options entering into the treatment landscape, we'll have fewer patients that are experiencing refractory disease, and potentially succumbing to the lymphoma. Dr. Chijioke Nze: And then, one additional question: How do you approach a patient who is not quite as fit, in thinking about what their options are for later-line therapies? You already mentioned some of these, but which of those would you prioritize in this setting? Dr. Loretta Nastoupil: Again, as we get more experience, we develop skills that help us sort of navigate all these different options. In my practice, if I'm even considering CAR T, I'm going to delay bendamustine until after I've collected those cells. I think that's one caveat that-- we do get nervous about the quality of those autologous CAR Ts if they're generated in someone who's had recent exposure to bendamustine. So, that may help me sequence that later on. We have questions right now about what's the optimal sequencing of CD19-directed therapy because we have several options beyond just CAR T-- As I mentioned, we have Lonca, we've got tafasitamab and lenalidomide. Currently, we don't have prospective data that really informs that question, and there's a number of research studies underway to try and help us understand if there is a preferred sequence, or even if it matters how we handle CD19 targeting. For my older, frailer patients where I'm really worried, they're not going to be able to tolerate something like liso-cel, or they're not going to be able to have that caregiver, and they're uncomfortable relocating to an area where CAR T might be available, my general approach right now is to consider tafasitamab and lenalidomide first in that relapse setting, followed by either Lonca or Pola-BR. Selinexor is another option. It's an oral agent, though again, in my opinion, if we look at the totality of the data, may be less effective than the other options. So, I might reserve that as a last option for someone, again, with relapsed/refractory large cell. Dr. Chijioke Nze: Excellent. Thank you. This has been very helpful. Dr. Loretta Nastoupil: All right. So, Dr. Nze, now I'm going to turn the table and ask you some questions. I'm going to change this up a little bit - she's now a 39-year-old female. She has significant comorbidities. She has HIV, and again, large cell lymphoma. So, let me walk you through her case, and then we'll discuss some of the challenges, again, in a very different scenario, albeit a similar disease. So, our female is, I mentioned 39, pre-existing HIV, she's treated frontline with six cycles of R-CHOP and intrathecal methotrexate for CNS prophylaxis. Because of her comorbidities, again, not well controlled HIV, she also has a poor functional status at the time of relapse. This was a couple years ago, and CAR T was not an option in second line, though she is someone who had a relapse that was beyond 12 months. So, for her second-line approach, because of her comorbidities, she actually receives rituximab in combination with high-dose cytarabine, dexamethasone, and oxaliplatin for three cycles, and actually achieves a chemosensitive disease and is referred to our stem cell transplant colleagues. Unfortunately, at that time, due to comorbidities, she was deemed not to be an appropriate candidate for high-dose therapy, and she's been monitored for signs of relapse. Despite being in the minority, she actually does not have a recurrence of her lymphoma but has a number of other, again, challenges in regards to her comorbidity, including multiple infections, resulting in recurrent hospitalizations. And so, it's always been a challenge for me in being intimately involved in her case, deciding when she's presenting, how alarmed to be about recurrent lymphoma versus infection, and how I might approach her in the setting of relapsed large cell lymphoma. So, what role does prior type and response to therapy play in treatment selection at your next line of treatment? Dr. Chijioke Nze: I think in this patient, it sounds like she got one adequate therapy on and the initial presentation with R-CHOP, and then with IT chemotherapy as well. She looked like she had a good response. I think the fact that she achieved a complete response and the duration of her response, lets me know that she likely has chemosensitive disease. This, in turn, helps me to pick what to do next. As you mentioned previously, we know how efficacious the CAR T therapy is, but in someone like her who had a long duration, trying salvage therapy and proceeding to autologous transplant might make sense. I'd be interested in your thoughts. Dr. Loretta Nastoupil: Yeah, I agree. And I think part of the challenge, particularly when we're facing patients with HIV, they're often excluded from prospective studies. And so, we're often in a scenario where we may not have the wealth of data to inform our treatment decision. But I do think in general, comorbidities play a major role-- we're navigating treatment options. Because again, traditionally, we've used intensive chemotherapy as our mainstay of treatment, and there are clear criteria that patients generally should meet that help us predict how likely they are to have significant or severe toxicity from high-dose therapy. And this is a prime example of even though she was young, her comorbidity made her a poor candidate for intensive therapy. I think the other sort of non-clinical factors that we sometimes take into consideration, because CAR T was approved off of single-arm phase II studies, again, none of which would've included someone like her, because of her HIV status, how do we extrapolate-- for instance, if she had relapsed in that third-line space, and suggesting that she did not have significant infection or other significant comorbidities, do we have experience to proceed with an autologous CAR in that setting? So, again, there've been a few cases where we have case reports where people have reported on their standard of care outcomes, particularly with CAR T in patients with active HIV disease, but one of the concerns I have in these scenarios is very selected. If you have active infection, that can make the acute toxicity with CAR significantly worse. And so again, we're trying to navigate a sort of limited data zone to try and help her and choose the right therapy. Again, you've met this patient with me, you helped care for her for some time, and you have a unique experience of also practicing in a county hospital where comorbidities, particularly, like HIV, can be much more common. What is your perception regarding barriers to accessing CAR T as it pertains to social factors, clinical factors, and again, this is a case that highlights some of those issues. Dr. Chijioke Nze: You mentioned at first that she had uncontrolled HIV. So, I think which, one, speaks to her treatment reference of her non-malignancy-related diseases, and trying to get that under control would be one of the first things I could think about. Thinking about how her care is managed and what kind of support she has are very important for us to think about as well. The other thing that's very important is, a lot of patients who we're seeing in the community may not have access to such specialized centers such as MD Anderson, where patients do have access to clinical trials and CAR T therapy. So, patients who are unlike her, who might qualify, may not actually be able to get these therapies as well. Part of the reason is, it can be insurance status, which is what we see in a lot of our patients. So, a barrier to get into the door. And then too barriers, lack of social support can be a big issue as well. And then there's also a big push in the community to improve the trust and awareness of these novel therapies, as you've mentioned. So, in a lot of the community practice, some of the community practitioners may not be comfortable with these, and a lot of the patients may not have heard of these new technologies, and also want to defer trying new therapies before having other people try new therapies before they consider them themselves. I think all these things present specific significant barriers to patients in the community. One, their ability to adhere to care, two, their insurance and their ability to get care and the financial toxicities associated with that. And then third, really understanding the options that are available. Dr. Loretta Nastoupil: And again, just to try and illustrate a couple other points. You know, we use a case here, which is a real case, with significant comorbidities such as HIV, which again, is something that is not frequently encountered, and will have a large impact on treatment selection. What if I just told you this patient has comorbidities, but she has moderate type-2 diabetes, and as a result, she has mild renal insufficiency, ejection fraction is actually adequate, would you have done anything different in this case? Dr. Chijioke Nze: No. I think in this particular case, I do think the fact that she did have a good response for a long duration of time, and did seem to have chemosensitive disease, I would probably still have tried a salvage therapy and autologous transplant in this patient. In the event that she was refractory, or had early relapse, and in that case, I would consider her to not be chemosensitive and would definitely have sought some more active therapies such as CAR T cell therapy through available products. Dr. Loretta Nastoupil: And then one last question for you: What if we just changed her age and we made her 79, but no other significant comorbidities, how would that have impacted your approach? Dr. Chijioke Nze: I'm going to turn that one over to you, I'm not exactly sure how I would treat with older patient with the same disease. Dr. Loretta Nastoupil: That's fair. So, if you have an older patient who has a late relapse, but not necessarily someone you would consider appropriate for salvage chemotherapy and high-dose therapy, then I think tafasitamab and lenalidomide would be probably my first choice in that setting, just based off of the L-MIND study. Dr. Chijioke Nze: Thank you, Dr. Nastoupil, for a great discussion of the management of diffuse large B-cell lymphoma. And thank you to all our listeners. We appreciate you tuning in to this episode of the ASCO Educational podcast.   The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. Guest statements on the podcast do not express the opinions of ASCO. The mention of any product, service, organization, activity, or therapy, should not be construed as an ASCO endorsement.

Aging-US
Single-Cell Transcriptomics of Peripheral Blood in Aging Mouse

Aging-US

Play Episode Listen Later Jan 16, 2023 3:04


A new research paper was published on the cover of Aging (listed as "Aging (Albany NY)" by Medline/PubMed and "Aging-US" by Web of Science) Volume 15, Issue 1, entitled, “Single-cell transcriptomics of peripheral blood in the aging mouse.” Compositional and transcriptional changes in the hematopoietic system have been used as biomarkers of immunosenescence and aging. In this new study, researchers Yee Voan Teo, Samuel J. Hinthorn, Ashley E. Webb, and Nicola Neretti from Brown University used single-cell RNA-sequencing to study the aging peripheral blood in mice and characterize the changes in cell-type composition and transcriptional profiles associated with age. “Here, we applied scRNA-seq on young and old mice to dissect the transcriptional and cell composition changes of all cell types in the peripheral blood with age.” The team identified 17 clusters from a total of 14,588 single cells. They detected a general upregulation of antigen processing and presentation and chemokine signaling pathways and a downregulation of genes involved in ribosome pathways with age. In old peripheral blood, the researchers also observed an increased percentage of cells expressing senescence markers (Cdkn1a, and Cdkn2a). In addition, a cluster of activated T cells exclusively found in old blood was detected, with lower expression of Cd28 and higher expression of Bcl2 and Cdkn2a, suggesting that the cells are senescent and resistant to apoptosis. “Finally, targeting senescent cells using genetic approaches has been shown to ameliorate the aging phenotype [34, 35]. More recently, senolytics drugs are being identified or developed to target apoptotic pathways because senescent cells are known to be apoptosis-resistant [34]. Therefore, the Bcl2+ old T cells that we identified in old mice can potentially be targeted pharmacologically to ameliorate the phenotypes associated with the aging of the immune system.” DOI: https://doi.org/10.18632/aging.204471 Corresponding Author: Nicola Neretti - nicola_neretti@brown.edu Keywords: aging, single-cell transcriptomics, senescence, peripheral blood Sign up for free Altmetric alerts about this article: https://aging.altmetric.com/details/email_updates?id=10.18632%2Faging.204471 About Aging-US: Launched in 2009, Aging (Aging-US) publishes papers of general interest and biological significance in all fields of aging research and age-related diseases, including cancer—and now, with a special focus on COVID-19 vulnerability as an age-dependent syndrome. Topics in Aging go beyond traditional gerontology, including, but not limited to, cellular and molecular biology, human age-related diseases, pathology in model organisms, signal transduction pathways (e.g., p53, sirtuins, and PI-3K/AKT/mTOR, among others), and approaches to modulating these signaling pathways. Please visit our website at www.Aging-US.com​​ and connect with us: SoundCloud – https://soundcloud.com/Aging-Us Facebook – https://www.facebook.com/AgingUS/ Twitter – https://twitter.com/AgingJrnl Instagram – https://www.instagram.com/agingjrnl/ YouTube – https://www.youtube.com/agingus​ LinkedIn – https://www.linkedin.com/company/aging/ Reddit – https://www.reddit.com/user/AgingUS Pinterest – https://www.pinterest.com/AgingUS/ For media inquiries, please contact media@impactjournals.com.

Translation
Cell Therapies of the Future with Dan Goodman

Translation

Play Episode Listen Later Nov 9, 2022 98:24


Episode SummaryChimeric antigen receptors, or CARs, repurpose the build-in targeting and homing signals of our immune system to direct T cells to find and eliminate cancers. Although CAR-T cells have transformed the care of liquid tumors in the circulating blood, like B cell leukemia and lymphoma, CAR-T therapy has shown limited efficacy against solid tumors. To unlock the full potential of CAR-T therapies, better receptor designs are needed. Unfortunately, the space of potential designs is too large to check one by one. To design better CARs, Dan and his co-author Camillia Azimi developed CAR Pooling, an approach to multiplex CAR designs by testing many at once with different immune costimulatory domains. They select the CARs that exhibit the best anti-tumor response and develop novel CARs that endow the T cells with better anti-tumor properties. Their methods and designs may help us develop therapies for refractory, treatment-resistant cancers, and may enable CAR-T cells to cure infectious diseases, autoimmunity, and beyond.About the AuthorDuring his PhD in George Church's lab at Harvard Medical School, Dan studied interactions between bacterial transcription and translation, built and measured libraries of tunable synthetic biosensors, and constructed a new version of the E. coli genome capable of incorporating new synthetic amino acids into its proteins. He also built a high-throughput microbial genome design and analysis software platform called Millstone.As a Jane Coffin Childs Postdoctoral Fellow at UCSF, Dan is currently applying these high-throughput synthetic approaches to engineer T cells for the treatment of cancer and autoimmune disease. He is also working in the Bluestone, Roybal, and Marson labs.Key TakeawaysBy genetically engineering the chimeric antigen receptor (CAR), T cells can be programmed to target new proteins that are markers of cancer, infectious diseases, and other important disorders.However, to realize this vision, more powerful CARs with better designs are needed - current CAR-T therapies have their restraints, including limited performance against solid tumors and lack of persistence and long-term efficacy in patients.An important part of the CAR response is “costimulation,” which is mediated by the 4-1BB or CD28 intracellular domains in all CARs currently in the clinic. Better designs of costimulatory domains could unlock the next-generation of CAR-T therapies.Since there are so many possibilities for costimulatory domain designs, it's difficult to test them all in the lab.Based on his experience in the Church Lab, Dan has developed tools to “multiplex” biological experiments; that is, to test multiple biological hypotheses in the same experiment and increase the screening power.Dan and his co-author Camillia Azimi developed “CAR Pooling”, a multiplexed approach to test many CAR designs at once.Using CAR Pooling, Dan tested 40 CARs with different costimulatory domains in pooled assays and identified several novel cosignaling domains from the TNF receptor family that enhance persistence or cytotoxicity over FDA-approved CARs.To characterize the different CARs, Dan also used RNA-sequencing.ImpactThe CAR Pooling approach may enable new, potent CAR-T therapies that can change the game for solid tumors and other cancers that are currently tough to treat.Highly multiplexed approaches like CAR Pooling will allow us to build highly complex, programmable systems and design the future of cell engineering beyond CAR-T.In addition to new therapeutics, high-throughput studies will allow us to understand the “design rules” of synthetic receptors and improve our understanding of basic immunology.Paper: Pooled screening of CAR T cells identifies diverse immune signaling domains for next-generation immunotherapies 

This Week in Virology
TWiV 852: Tree man syndrome

This Week in Virology

Play Episode Listen Later Jan 13, 2022 104:27


A TWiV threesome explains the observation that humans with inherited T cell CD28 deficiency are susceptible to severe warts driven by human papilloma virus infection, but are otherwise healthy. Hosts: Vincent Racaniello, Rich Condit, and Brianne Barker Subscribe (free): iTunes, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Vaccine Town Hall (ASV) Travel Award Applications (ASV) CD28 deficiency and severe warts (Cell) Vincent interviews Harald zur Hausen (virology blog) Letters read on TWiV 853 Timestamps by Jolene. Thanks! Weekly Picks Brianne – Every Pore on Your Face Is a Walled Garden Rich – “On Warts” by Lewis Thomas (Pdf) Vincent – Cells at Work Code Black 1 Listener Picks Chris – Ria Lina on the Guilty Feminist podcast Duncan – Meet the green kleptos of the animal kingdom Intro music is by Ronald Jenkees Send your virology questions and comments to twiv@microbe.tv

This Week in Virology
TWiV 852: Tree man syndrome

This Week in Virology

Play Episode Listen Later Jan 13, 2022 104:27


A TWiV threesome explains the observation that humans with inherited T cell CD28 deficiency are susceptible to severe warts driven by human papilloma virus infection, but are otherwise healthy. Hosts: Vincent Racaniello, Rich Condit, and Brianne Barker Subscribe (free): iTunes, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Vaccine Town Hall (ASV) Travel Award Applications (ASV) CD28 deficiency and severe warts (Cell) Vincent interviews Harald zur Hausen (virology blog) Letters read on TWiV 853 Timestamps by Jolene. Thanks! Weekly Picks Brianne – Every Pore on Your Face Is a Walled Garden Rich – “On Warts” by Lewis Thomas (Pdf) Vincent – Cells at Work Code Black 1 Listener Picks Chris – Ria Lina on the Guilty Feminist podcast Duncan – Meet the green kleptos of the animal kingdom Intro music is by Ronald Jenkees Send your virology questions and comments to twiv@microbe.tv

Authentic Biochemistry
T cell receptor signaling kinase dynamics after APC activation. Co-activating CD28 becomes deficient via immunosenescence thus corrupting T cell efficiency in the elderly. 26.10.2021 DJGPhD.

Authentic Biochemistry

Play Episode Listen Later Oct 27, 2021 29:28


The Src-family kinase Lck regulates T-cell development, activation, proliferation, and immune synapse dynamics. These are the initiation phases of TCR signaling. Upon antigen presentation via the APC- TCR immune synapse, Lck phosphorylates tyrosine residues within the immunoreceptor tyrosine-based activation motifs (ITAMs) of the TCR-associated CD3 membrane protein domains. Phosphorylated ITAMs function as a molecular platform for tandem SH2 domains located on the tyrosine kinase Zap-70, initially activated by Lck. Lck kinase activity is regulated at two canonical phosphorylation sites Tyr394 and Tyr505, wherein auto-transphosphorylation of Tyr394 in the kinase domain erupts a relaxed/active conformation but phosphorylation of Tyr505, located at the C-terminus, by the tyrosine kinase Csk results in an inactive enzyme. References Longev Healthspan. 2012; 1: 6 SCIENCE ADVANCES•19 Jun 2019•Vol 5, Issue 6 --- Send in a voice message: https://anchor.fm/dr-daniel-j-guerra/message Support this podcast: https://anchor.fm/dr-daniel-j-guerra/support

ASCO eLearning Weekly Podcasts
Cancer Topics - New Therapies for Lymphoma (Part 1)

ASCO eLearning Weekly Podcasts

Play Episode Listen Later Oct 15, 2021 26:53


In part one of this two-part ASCO Education Podcast episode, Dr. Sonali Smith (University of Chicago Medicine) and Dr. Paolo Strati (MD Anderson Cancer Center) discuss the application of recently approved therapies for diffuse large B-cell lymphoma through examination of challenging patient cases. Subscribe: Apple Podcasts, Google Podcasts | Additional resources: education.asco.org | Contact Us Air Date: 10/20/21   TRANSCRIPT [MUSIC PLAYING] SPEAKER: The purpose of this podcast is to educate and inform. This is not a substitute for medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement. [MUSIC PLAYING] SONALI SMITH: Hello, and welcome to this episode of the ASCO Education Podcast highlighting new therapies for lymphoma. My name is Dr. Sonali Smith, and I'm a hematologist and medical oncologist specializing in lymphoma and clinical investigation in lymphoma. I'm also the Elwood V. Jensen Professor and chief of the hematology/oncology section at the University of Chicago, and very excited to be joined by my colleague, Dr. Paolo Strati. PAOLO STRATI: Good morning to everybody. My name is Paolo Strati. I'm a hematologist and medical oncologist and an assistant professor in the Department of Lymphoma/Myeloma, and in the Department of Translational Molecular Pathology at MD Anderson Cancer Center, Houston, Texas. And I'm also the clinical director for the Lymphma Tissue Bank. In part one of this podcast episode, we will discuss the adoption of recently approved therapies for diffuse large B-cell lymphoma, such as selinexor, tafasitamab, Liso-Cel, and Lonca-T. These therapies have transformed care for patients with this disease. And we'll start our conversation today with a patient case. SONALI SMITH: Great. Well, I'll go ahead and present a patient to you, Paulo. So this is a 78-year-old man with diffuse large B-cell lymphoma that is the germinal center-derived subtype. It is not double expressor, it is not double-hit. He has advanced stage disease with a high IPI, as well as the high CNS IPI. Luckily, his performance status is zero and he has no significant comorbidities or other health conditions. He received frontline dose-adjusted EPOC-R with intrathecal methotrexate for six cycles. But at the end, he had a partial remission. So how do you select your salvage therapy in this situation? Are you concerned about using agents targeting CD19 in the second line, given the potential need to use anti-CD19 cellular therapy, or CAR-T in the third line? PAOLO STRATI: This is a very interesting and unfortunately not uncommon case. And thank you, Sonali, for asking these very important questions. Technically, a platinum-based regimen followed by autologous transplant will be a standard answer and may be feasible. Because as you mentioned, this patient has a good performance status and non-meaningful comorbid health conditions. However, patients who are refractory to a frontline anthracycline-based regimen, such as in this case, with achievement only of partial remission at the end of frontline dose-adjusted EPOC, can potentially experience a suboptimal outcome following the standard approach with a platinum-based second line regimen. And as such, alternative strategies may be needed. To this regard, the combination of tafasitamab that, as you know, is a monoclonal antibody targeting CD19, and lenalidomide, an oral immunomodulatory agent, a combination which is currently approved by the FDA in the United States as a standard second line option for transplant ineligible patients, would be a great option in this case. Data from the three year follow-up of the phase II study that has brought to the FDA approval this combination, the L-MIND had been recently presented and have showed the complete remission rate of 40% and immediate duration of response of 44 months, including patients who received this regimen as a third line or beyond. So there is, of course, a biological concern by targeting CD19 in second line. These may potentially impact a third line use of an autologous anti-CD19 CAR-T, because CD19 downregulation may potentially be a mechanism of escape to tafasitamab. And recent data has shown the CD19 levels are strongly associated with the efficacy of CAR-T cell therapy in patients with large B-cell lymphoma. Small retrospective studies have shown that autologous anti-CD19 CAR-T can be safely and effectively used after antibodies or antibody drug conjugate targeting CD19. But we need a significantly larger and prospective data, including serial tissue biopsy in these patients before considering this combination as a standard practice in patients for whom we plan to use CAR-T as a third line. Until then, I would be cautious in using second line tafasitamab in patients, again, for whom there is a potential plan for anti-CD19 autologous CAR-T in third line. And if necessary, limited to very selective cases. Finally, recent press releases have anticipated the two autologous anti-CD19 CAR-T products, Axi-Cel and Liso-Cel, are superior to autologous settings transplanted in second line. And so in the near future, CAR-T cell therapy may become a standard second line option. And that would be an ideal option in primary chemorefractory patients as the case that you presented here. SONALI SMITH: Yeah, I agree. There are a tremendous number of options. And having anti-CD19 products as well as autologous stem cell transplant, the sequencing will be an evolution. So going back to this patient, he received tafasitamab and lenalidomide for two cycles with no significant toxicity, but unfortunately, he had further progression after two cycles based on a PET/CT scan. So what are your next steps? Would you move directly to an autologous anti-CD19 CAR-T cell therapy now? Would you re-biopsy before that? And how would you select among the three available CAR-T products? PAOLO STRATI: These are not easy questions, particularly the selection of one out of three available CAR-T products. As you said, there are currently three autologous anti-CD19 CAR-T products approved by the FDA in the United States for the treatment of large B-cell lymphoma in third line or beyond. And these are Axi-Cel, Tisa-Cel, and Liso-Cel. For all of them, the best outcome is observed for patients who have a low turmor burden at time of CAR-T infusion. And they need to either select patients with no bulky disease or to decrease it through bridging therapy. And as we define bridging therapy given between leukapharesis and CAR-T infusion. Unfortunately, there is currently no standard bridging therapy and all FDA products approved in third line can potentially be used in this specific scenario that you described, including polatuzumab with bendamustine/rituximab, selinexor, and Lonca-T, of course, beyond tafasitamab and len that has already been used in this case. Of course, when selecting a bridging therapy, there are many disease-related and patient-related factors to take into consideration, including the need to preserve the host immune microenvironment that we all know is crucial for the subsequent activity of CAR-T cells. And also, we need to give into consideration the need to preserve as much as possible, as we discussed previously, in CD19 expression. To this regard, and going back to one of your questions, I strongly recommend to re-biopsy patients if any bridging therapy is used between bridging therapy and CAR-T infusion in order to document CD19 expression before CAR-T infusion. When it comes to CAR-T product selection, as I said, it's a really difficult decision to do. And we don't have at this time randomized trials in third line. And as such, the decision is really left to the treating physician based on multiple factors. But all of the limitations of inter-study comparison, efficacy seems to be pretty much the same for the two products, maybe slightly higher based on the recent second line data. But Axi-Cel and Liso-Cel as compared to Tisa-Cel, and also as suggested by recent press release. However, due to the fact that Liso-Cel and Tisa-Cel have less potent co-stimulatory domain for 1BB instead of CD28, the rate of CRS and ICANS, the two main toxicities associated with CAR-T cell therapy, is usually lower with this to the point that some centers are able to infuse them in the outpatient setting, whereas Axi-Cel is almost always infused in the inpatient setting so the toxicity can be monitored more closely. So with older patients or those who have comorbid health condition, Tisa-Cel and Liso-Cel may be a safer option, though there's a lot of research going on trying to mitigate toxicities associated with Axi-Cel. Finally, it's important to keep in mind manufacturing time. Axi-Cel is manufactured in an average of 17 days, whereas Tisa-Cel and Liso-Cel take typically longer than three to four weeks. This can be itself a determining factor, particularly for patients who are quickly progressing and where immediate treatment is needed. SONALI SMITH: Yeah, I agree. I think there are going to be many patient product and disease-based factors that will impact both the effectiveness as well as the toxicity. And you did a really great job of explaining the role of the co-stimulatory domain potentially in some of that, as well as all of the products that are out there. It's definitely a complicated area. Going back to our patient, so he did undergo leukapharesis for Liso-Cel and received third line polatuzumab and rituximab without bendamustine. The restaging PET/CT after two cycles showed a PR with a significant decrease in tumor burden, and repeated biopsy showed high expression of CD19 by flow cytometry. He then proceeded with Liso-Cel, which was relatively well tolerated. There was only grade 1 cytokine release syndrome and no ICANS, so no neurotoxicity. And his day 30 PET/CT showed a complete remission. Unfortunately, the 90 day PET/CT showed progression. So Dr. Strati what is the outcome for patients who relapse after CAR-T? Do you recommend to re-biopsy? And what are the efficacy data for FDA approved agents for these patients? And I know this is a long question, but is there any role for repeated CAR-T or allogeneic transplant now? PAOLO STRATI: Unfortunately, currently, the outcome of patients with large B-cell lymphoma relapse or progress after autologous anti-CD19 CAR-T is suboptimal, with a life expectancy, unfortunately, shorter than six months. Hence, the need to be creative and customize treatment based on biological data. To this regard, I think it's crucial to repeat a tissue biopsy to guide subsequent therapy. As mentioned previously, there are currently four products approved by the FDA for patients with large B-cell lymphoma in third line and beyond. Two of these target CD19, tafasitamab plus lenalidomide and Lonca-T One targets CD79B, polatuzumab combined with bendamustine and rituximab. And one is an SPO1 inhibitor, selinexor. While we have no data for selinexor in patients who relapse or progress after CAR-T cell therapy, limited prospective data showed that a progression-free survival in the order of weeks is usually observed for patients who receive polatuzumab with or without bendamustine and rituximab after CAR-T cell therapy. So I would not recommend that. However, there's some interesting activity in the post-CAR-T setting for Lonca-T and for tafasitamab/len is limited to patients who still express CD19 in time of relapse. And of course, it needs to be largely and prospectively further investigated before becoming a standard approach for patients who relapse or progress after CAR-T cell therapy. When it comes to cellular therapy, repeated anti-CD19 CAR-T infusion is not shown to be successful in the original registration studies. So it is not currently something that I would recommend and is not definitely a common practice. And very limited retrospective studies have shown the use of allogeneic stem cell transplants in the post-CAR-T setting may be associated with quite elevated treatment-related mortality. So I don't suggest this as a standard practice in large B-cell lymphoma at this time. This is different from B acute lymphoblastic leukemia, where instead, allogeneic stem cell transplant is becoming progressively a standard approach. And we definitely need more data before using this consistently. While we strive to identify the optimal cell batch therapy for large B-cell lymphoma patients who relapse or progress after CAR-T cell therapy. I think the priority should be given to clinical trials, including CAR-T targeting molecules other than CD19, such as CD20, CD22, CD79B, allogeneic CAR-T there are immediately available, so without the need to wait for manufacturing times. And K-CAR, that may be less toxic than CAR-T and other non-cellular therapy biological agents. So definitely, clinical trials are, at this time, the best approach in patients who relapse after CAR-T cell therapy, as the case that you described. SONALI SMITH: Thank you Dr. Strati. As an update, this patient had repeated biopsy showing a CD19 positive relapse. He consented for a clinical trial with a novel NK-CAR targeting CD19, achieving CR which is still ongoing at nine months. And this case really does represent some of the most exciting advances that we've had for this disease for patients who can tolerate aggressive therapies and have access to clinical trials. PAOLO STRATI: Dr. Smith, I'd like to hear your opinion about another patient with diffuse large B-cell lymphoma. This patient is an 81-year-old man with a history of coronary artery disease and well-controlled diabetes mellitus, who noticed a right cervical lymph node while shaving that seemed to have popped up. He was evaluated by his primary care physician and given a course of antimicrobials. 10 days later, the lymphoma seems to be enlarging and he is referred to ENT pharyngeal biopsy. The specimen is small but shows follicular lymphoma in a portion of the sample. However, there is also concern for larger cells and possible transformation. The patient is also beginning to note night sweats and a decreased appetite. And labs are notable for elevated LDH, 500, and thrombocytopenia with a platelet count of 110. So Dr. Smith, in your opinion, is this specimen sufficient to start treatment? Or should treatment be delayed to get a larger and maybe excisional biopsy? SONALI SMITH: Yeah, thank you for this question. I think this is a challenge we have in the clinic all the time, which is what is a sufficient biopsy specimen to make a diagnosis that allows us to subtype lymphoma? As we know, every lymphoma subtype, the treatment is really guided by the histology and not so much the stage or some other factors. So having a needle biopsy is unfortunately often insufficient. In this case, we have a very strong concern for a possible transformation. And as we know, both follicular lymphoma and diffuse large B-cell lymphoma can mark very similarly when it comes to immunophenotype. Certainly, the germinal center type of diffuse large B-cell lymphoma or any transformed follicular lymphoma will be CD20 positive, CD10 positive, and it really requires architecture to be able to tell whether or not there are sheets of large cells. So the ideal outcome for this patient would be to have a biopsy that is done promptly that allows us not only to confirm whether or not there is histologic evidence of transformation, but also to conduct FISH studies to determine if there's acquisition of a MYC rearrangement. At its core, all follicular lymphoma patients essentially have a transformation of 14;18, leading to BCL2 rearrangement and BCL2 overexpression. During the transformation process, there can be an acquisition of a MYC rearrangement, which would then make this a double-hit lymphoma and certainly has a much worse prognosis and may also prompt a change in treatment if the patient can tolerate more intensive therapy. So my recommendation would be to have a biopsy. Now one other aspect is that sometimes, we don't really have the time to proceed with a biopsy, or the lymph node may be in an inaccessible area. And in that case, there are some other criteria that we can use to assume that somebody has a transformation. Symptoms such as profound B symptoms and elevated LDH, and sometimes, a PET scan with multiple areas of very high avidity, can lead you to feel or suggest that this person has a transformation. There is some controversy over the use of PET and we know it does not confirm a diagnosis of transformation. But in my opinion, this is very suggestive if there are many areas of high SUV. PAOLO STRATI: Thank you, Dr. Smith. I agree completely about the importance, when time allows, to perform either a larger core biopsy or an excisional biopsy, because as you very well-outlined, this has not just a mere diagnostic purpose, but can meaningfully affect treatment planning for patients. And actually, in this case, as you suggested, the patient eventually had multiple core biopsy that showed transformed follicular lymphoma with very evident areas of diffuse large B-cell lymphoma. FISH, as expected for follicular lymphoma, was positive for translocation for TN18, but luckily negative for MYC rearrangement. So fortunately, we didn't have to deal with a double-hit lymphoma. The remainder of his staging showed he had diffuse lymphadenopathy. And PET scan, as you mentioned, has a controversial role in the diagnosis of transformation. So there's some areas that had high avidity with an uptake with an SUV of 1215, whereas other areas were less intense with SUV 618. And usually, heterogeneity in SUV actually helps further supporting diagnosis or transformation. While meta-maps showed follicular lymphoma, no large cells. So movement was isolated in the B-cell lymphoma. So Dr. Smith, at this point, based on the provided information, what's your treatment approach in this older patient and also a patient with comorbid health conditions, but with diffuse large B-cell lymphoma? SONALI SMITH: Yes. The goal of treating any aggressive lymphoma is to obtain remission, and if the remission lasts, to hopefully offer cure to the patient. And when somebody has a transformed lymphoma, of course, there is a dual concern, which is that the aggressive component can potentially be put into remission in a durable way achieving cure. But the indolent component will always need to be monitored, although hopefully, will not be life threatening the way the aggressive component can be. Treating an octogenarian is really challenging, particularly due to comorbidities in this age group and the potential toxicity of chemotherapy. So the standard of care for diffuse large B-cell lymphoma is anthracycline-based chemotherapy. But this, of course, can have significant toxicity in older patients. And in addition, the vincristine can aggravate neuropathy. And I've personally found that the high dose steroids that are part of CHOP can also cause toxicity in older patients and patients who are frail. So unfortunately, the literature is somewhat sparse. But we do have several data sets that can guide management in this particular patient situation. The French published, over a decade ago, the development of R mini CHOP, that includes an attenuated dose of cyclophosphamide, doxorubicin, and vincristine, and leads to some durable remissions and cure. Unfortunately, the long-term overall survival is less than 50% with R mini CHOP. And so although this is an appropriate backbone, there's certainly a lot of room for improvement. And there's also toxicity even with R mini CHOP. So in their initial phase II trial, there was actual deaths related to the R mini CHOP, particularly in the first cycle or two, really necessitating some type of pre-phase help ease patients into the chemotherapy. One of the challenges that we face in the clinic is that when we meet an older patient, we both want to maximize our chance for cure, but also minimize the toxicity that is particularly pronounced. And there is very little data in terms of how to guide this at the bedside. I'm excited that SWOG, with the US Intergroup, is conducting a trial, S1918, which prospectively includes a frailty assessment tool that was developed by the Italian group in lymphoma, and then also includes serial comprehensive geriatric assessment so that we can get a better idea about quality of life both during and after treatment. So there is no great standard of care right now, but I would say that R mini CHOP, outside of a trial, is a very reasonable way to proceed. PAOLO STRATI: Dr. Smith, thank you for outlining so well what we can do to minimize toxicity and to better select patients for this type of treatment. And as an Italian practitioner in the United States, I am very excited that the Italian frailty tool will be used in this SWOG trial. Are there any other ways to further improve safety when we use chemo immunotherapy in older patients or patients with comorbid health conditions? In particular, there is a lot of concern about potentially infectious complications in these patients. And so I'm wondering if there's any routine antimicrobial prophylaxis that you recommend. SONALI SMITH: Yes. I think it's really important to maximize supportive care for our older patients with aggressive lymphomas getting intensive therapy. I did mention the pre-phase, and I would just like to mention that one more time because I do think there's data that providing a brief pre-phase can minimize toxicity with the first cycle. And how this pre-phase is given is highly variable. Again, the data is somewhat limited, but it typically includes steroids given for five to seven days with or without a dose of vincristine. And steroids themselves can have toxicity. And the dose of the steroids, I think, is somewhat controversial. In my personal practice, I use somewhere between 40 to 60 milligrams per day for five to seven days. And I do not typically use vincristine, although a prospective French trial recently did and showed that this significantly improved toxicity. Other complications that can occur really are related to infection. And so, of course, all patients should have growth factor support as per ASCO guidelines. But I also routinely give VZV prophylaxis with acyclovir or valacyclovir. And for the first cycle in particular, I have patients come back to clinic after the first dose one week later to ensure that the counts are stable and that they are doing well. This is really where our team of nurses and other providers who are part of the care team are so important and communication is also very important. PAOLO STRATI: So Dr. Smith, as you suggested, also, this patient actually received mini R-CHOP without any complications. And end-of-treatment PET/CT can showed a VL score of 3, so a complete metabolic remission, potentially. How do you interpret these findings? SONALI SMITH: So response criteria in clinical trials, and then of course, extrapolated to the clinic, have evolved in lymphoma. And the Deauville or the International Prognostic Scoring System that has been used typically defines a uptake relative to liver and mediastinal blood pool. And those patients who have a Deauville 1 to 2, which is less than that bar, is considered negative. And 4 to 5 is positive, with five being the emergence of new sites of adenopathy. The interpretation of a Deauville 3 can be somewhat more complicated, but this really outlines the limitations of just using the SUV or the PET scan uptake to measure response. For my patient and for this patient, the lymph nodes all substantially decreased in size. And having some type of combined interpretation of the uptake, as well as the size that has decreased, I think is going to be a very important part of how we approach patients going forward. So for this patient, I opted for close observation after the completion of therapy and felt that his Deauville 3, along with the decrease in the size of the lymph nodes, was very significant. PAOLO STRATI: I completely agree with that. Where PET scan is an extremely helpful tool, particularly for the management of aggressive B-cell lymphoma, can also become a major challenge when it comes to its interpretation for these borderline scenarios. And as you said, it's very important to add into the equation multiple parameters, including CT findings and overall patient performance status symptoms. So that's all we have for today. Thank you, Dr. Smith. This was a great conversation. We have learned and discussed a lot about diffuse large B-cell lymphoma, including novel biological agents, CAR-T cell therapy, management of elderly patients, and patients with comorbid health conditions and interpretation of PET/CT scan. I think this will be very helpful. And the conversation will continue beyond this podcast. In part 2 of this episode, airing in November, we will discuss new therapies for mantle cell lymphoma and for follicular lymphoma. Thank you so much to all the listeners tuning into this episode of the ASCO Educational Podcast. SONALI SMITH: Thank you. It's been a pleasure to speak with you today. [MUSIC PLAYING] SPEAKER: Thank you for listening to this week's episode of the ASCO e-learning weekly podcast. To make us part of your weekly routine, click Subscribe. Let us know what you think by leaving a review. For more information, visit the comprehensive e-learning center at elearning.asco.org.

The Immunology Podcast
Ep. 9: “Lymphocyte Activation” Featuring Dr. Marc Jenkins

The Immunology Podcast

Play Episode Listen Later Jul 20, 2021 75:57


Dr. Marc Jenkins is a Regents and Distinguished McKnight University Professor in the Department of Microbiology and Immunology and the Director of the Center for Immunology at the University of Minnesota. Dr. Jenkins discovered that CD4+ T cells require CD28 as well as TCR to produce IL-2. The Jenkins lab is focused on the basic biology of CD4+ T lymphocytes.

Authentic Biochemistry
T Cell signal transduction involves kinase and transcription factor mediated expression of bioenergetic ensemble gene products. Dr DJ Guerra 23 December 2020

Authentic Biochemistry

Play Episode Listen Later Dec 23, 2020 29:35


T cell agency initiates upon the stimulation of the TCR via presentation of cognate peptide-MHC complexes in associative ligand-mediated membrane co-receptor CD28 with co-stimulatory molecules presented on the surface of the APC: this event is called T cell licensure and essentially quits quiescence. The TCR signals through the ERK/MAPK pathways and calcium flux; where as CD28 signaling activates the PI3K-AKT-mTOR axis, and both pathways synergistically engage the NF-κB organon of pleitropic T lymphocyte agency. Merry Christmas from AUTHENTIC BIOCHEMISTRY! Please subscribe and help promote/produce the podcast by donating 10 dollars each this month! Thank You! --- Support this podcast: https://anchor.fm/dr-daniel-j-guerra/support

La Ciencia Pop
S01E37 | El blues del linfocito

La Ciencia Pop

Play Episode Listen Later Nov 13, 2020 32:37


Se supone que el sistema inmune ha evolucionado para protegernos y, sin embargo, parece que es muy poco lo que puede hacer para combatir a las células cancerosas; células que parecen haberse rebelado contra nuestro cuerpo y que el día de hoy causan alguno de los tantos tipos de cáncer, que se han convertido en una de las causas de muerte más importantes. Durante mucho tiempo se pensó que debido a que las células cancerígenas derivan de células normales, era muy poco lo que el sistema inmune  –que en condiciones normales no ataca a nuestro cuerpo– pudiera hacer algo al respecto y tal vez faltaba encontrar un factor que explicara como se relaciona el sistema inmune con los tumores. A pesar de uno que otro destello en la oscuridad, generaciones de investigadores habían intentado encontrar este factor perdido, pero invariablemente fracasaron. Nadie podía ni siquiera decir con certeza que tal factor existía y hoy les voy a contar la historia de ese descubrimiento, que involucra a un texano amante del blues y que toca la armónica *** La Ciencia Pop es auspiciado por Más Audio, donde cuentan con la tecnología más avanzada y los más cómodos y modernos audífonos de origen alemán. Con los mejores precios del mercado, tecnología de punta y un servicio de primer nivel, en Más Audio te pueden ayudar a ti o un familiar a volver a oír los sonidos que ya no escuchas. Para más información, visita la página www.masaudio.cl o escribe al correo quiero@masaudio.cl. También puedes visitar sus páginas en Facebook o su tienda online en tienda.masaudio.cl y mencionando “La Ciencia Pop”, te darán un 5% de descuento en la compra de audífonos. No te lo pierdas ***Support the show (https://www.patreon.com/LaCienciaPop)

Web Tv Bourse Economie Entreprises's posts
Alexis Peyroles Directeur Général OSE Immunotherapeutics : “Nous avons les moyens d’accélérer si on le souhaite”

Web Tv Bourse Economie Entreprises's posts

Play Episode Listen Later Oct 22, 2020 6:42


OSE Immunotherapeutics est une société de biotechnologie en phase clinique. Elle développe des immunothérapies innovantes, en direct ou via des partenariats, pour l’activation et la régulation immunitaire en immuno-oncologie et dans les maladies auto-immunes. Retour sur les dernières actualités de la biotech. La société a annoncé récemment “l’obtention d’un accord de délivrance par l’Office Européen des Brevets (OEB) pour FR104, un antagoniste first-in-class sélectif du CD28, au stade de développement clinique de phase 2. Ce brevet européen protégera les modalités d’administration innovantes du FR104 jusqu’en 2036 dans la prévention et le traitement des maladies auto-immunes médiées par les lymphocytes T, les maladies inflammatoires, la transplantation et la maladie du greffon contre l’hôte (GVHD, graft-versus-host disease)“. Mon invité est Alexis Peyroles Directeur Général OSE Immunotherapeutics.    Le secteur des biotechnologies vous intéresse, retrouvez toutes les vidéos liées cet univers via ce lien : Vidéos Biotech (https://www.labourseetlavie.com/tag/biotech)   A PROPOS D’OSE IMMUNOTHERAPEUTICS OSE Immunotherapeutics est une société de biotechnologie en phase clinique. Elle développe des immunothérapies innovantes, en direct ou via des partenariats, pour l’activation et la régulation immunitaire en immuno-oncologie et dans les maladies auto-immunes. La société dispose de plusieurs plateformes technologiques et scientifiques : néo-épitopes, anticorps monoclonaux agonistes ou antagonistes, idéalement positionnées pour combattre le cancer et les maladies auto-immunes. Son portefeuille clinique et préclinique de premier plan a un profil de risque diversifié : –        Tedopi® (combinaison innovante de néo-épitopes) : produit le plus avancé de la Société ; résultats positifs de l’étape 1 de la Phase 3 (Atalante 1) dans le cancer du poumon avancé (Non-Small Cell Lung Cancer) chez les patients en échec après traitement par checkpoints inhibiteurs.  En Phase 2 dans le cancer du pancréas (TEDOPaM, promotion GERCOR), en monothérapie et en combinaison avec le checkpoint inhibiteur Opdivo®. –        BI 765063 (OSE-172, anticorps monoclonal anti-SIRP? sur l’axe SIRP?/CD-47): développé en partenariat avec Boehringer Ingelheim ; inhibiteur de point de contrôle myéloïde en Phase 1 dans les tumeurs solides avancées. –        OSE-127 (anticorps monoclonal humanisé ciblant le récepteur IL-7) : développé en partenariat avec Servier ; résultats de Phase 1 positifs ; démarrage prévu au 4ème trimestre 2020 de deux études cliniques de Phase 2 prévues dans la rectocolite hémorragique (promotion OSE Immunotherapeutics) et dans le syndrome de Sjögren (promotion Servier). –        FR104 (anticorps monoclonal anti-CD28) : résultats de Phase 1 positifs ; prêt à entrer en Phase 2 dans les maladies auto-immunes ou la transplantation. –        BiCKI® : plateforme de protéines de fusion bispécifiques construite autour d’une ossature centrale anti-PD-1 (OSE-279) fusionnée à de nouvelles cibles d’immunothérapies ; 2ème génération d’inhibiteurs PD-(L)1 pour augmenter l’efficacité antitumorale. D’autres programmes innovants en recherche. –        CoVepiT : vaccin prophylactique contre le COVID-19 développé à partir de néo-épitopes optimisés du SARS-CoV-2. Résultats positifs en préclinique et ex vivo chez l’homme publiés en août 2020 et phase clinique prévue fin 2020/début 2021. L’article Alexis Peyroles Directeur Général OSE Immunotherapeutics : “Nous avons les moyens d’accélérer si on le souhaite” (https://www.labourseetlavie.com/strategie-et-resultats/alexis-peyroles-directeur-general-ose-immunotherapeutics-nous-avons-les-moyens-daccelerer-si-on-le-souhaite) est apparu en premier sur La Bourse et la Vie TV L'information éco à valeur ajoutée (https://www.labourseetlavie.com) .

ASCO Daily News
How CAR-T Therapies Are Changing the Treatment Landscape for Hematologic Diseases

ASCO Daily News

Play Episode Listen Later Jun 2, 2020 22:04


In today's episode, we hear from Dr. Raghuveer Ranganathan, a clinical instructor in the Division of Hematology and Oncology at the UNC School of Medicine at Chapel Hill. His clinical focus is lymphomas and leukemias, with a specific focus on using cellular immunotherapy to treat patients with hematologic malignancies. Dr. Ranganathan discusses how the treatment landscape has changed with the introduction of CAR-T therapies and other advances in cellular immunotherapy techniques.   Transcript ASCO Daily News: Welcome to the ASCO Daily News Podcast. I'm Geraldine Carol, a reporter for the ASCO Daily News. Today I'm speaking with Dr. Raghuveer Ranganathan, a clinical instructor in the Division of Hematology and Oncology at the University of North Carolina's School of Medicine at Chapel Hill. His clinical focus is lymphomas and leukemias, with a specific emphasis in using cellular immunotherapy to treat patients with hematologic malignancies.   His research on cellular immunotherapy techniques, such as optimized TCR and CAR T-cells, has been published in peer-reviewed journals, and his work has been recognized by the Lymphoma Research Foundation and the American Society of Hematology. Dr. Ranganathan reports no conflicts of interest relevant to this podcast, and full disclosures relating to all Daily News podcasts can be found on our episode pages. Dr. Ranganathan, welcome to the podcast.   Dr. Raghuveer Ranganathan: Hi, Geraldine. Thank you for inviting me and having me on your podcast today.   ASCO Daily News: Dr. Ranganathan, how has the treatment landscape changed with the introduction of CAR T- cell therapies for hematologic diseases? Dr. Raghuveer Ranganathan: The CAR-T therapies have really revolutionized our treatment options in general. Currently, the main pillar of front-line treatment for hematologic malignancies is chemotherapy, with radiation sometimes playing a supportive role, and surgery being a rare adjunct. Now immunotherapy, and specifically cellular immunotherapy, has formed an additional and critical option for these diseases, especially in the relapsed refractory setting.   In particular, CAR T-cell therapy has provided hope in achieving long-term remissions, and maybe even a cure in patients, with these hematological cancers who are chemorefractory, or have exhausted all other treatment modalities due to the persistence of their disease. Interestingly, due to the success in multiple-relapse refractory disease, CAR T-cell therapy is being explored as an option earlier to patients with relapsed refractory disease.   As stated, chemotherapy is still the front-line option for hemotological malignancies. As an example, for diffuse large B-cell lymphoma that is not a double- or triple-hit variant, the standard of care is still R-CHOP as front-line therapy. And if the patient relapses systemically, then the goal is to give salvage chemotherapy, with the hope of proceeding to an autologous stem cell transplant, if they're in CR and transplant-eligible.   CAR-T is approved for a second relapsed disease and beyond in lymphomas. It's thought, though, that patients who have been exposed to high-dose chemotherapy or numerous salvage chemo regimens display less P-cell fitness overall, which subsequently reduces the cytotoxic efficacy of CAR T-cells derived from those patients' regular T-cells. As a result, there are ongoing clinical trials comparing the use of CD19 targeting CAR T-cell therapy with aggressive B-cell lymphoma in first relapsed, and comparing it prospectively against autologous hematopoietic stem cell transplants.   ASCO Daily News: So what are some of the recent FDA drug approvals for CAR T-cell therapy that you are now using when treating lymphoma patients, and what you expect to see approved in 2020?   Dr. Raghuveer Ranganathan: So there are two currently FDA-approved CAR-T products that are now available for commercial use. Both CAR-T products target a CD19 antigen present on B-cell derived hemotological malignancies. One of them is axicabtagene ciloleucel, otherwise known as Axi-Cel, or its trade name of YESCARTA. And it's FDA-approved for use in adult patients who have received two or more lines of therapy for relapsed refractory aggressive B-cell lymphomas, which includes diffuse large B-cell, including high-grade variants, primary mediastinal B-cell, and transform follicular lymphomas.   The other CAR-T product is also CD19-targeting, named tisagenlecleucel, which we will call as Tisa-Cel, its trade name being KYMRIAH. And it has two indications as part of its approval. One is for adults with relapsed refractory diffuse large B-cell lymphoma, including high-grade variants and transport and follicular lymphomas. So in other words, the indication's very similar to Axi-Cel, except with the exclusion of primary mediastinal B-cell lymphoma.   The second indication for Tisa-Cel is for use in children and young adults up to the age of 25 years with B-cell acute lymphoblastic leukemia, or B-cell ALL, that is either refractory to treatment or has relapsed twice or more. The main difference between the two CD19 CAR constructs molecularly is that Axi-Cel has a CD28 intracellular costimulatory domain, while Tisa-Cel uses a 4-1BB costimulatory domain. Axi-Cel had an initial overall response rate and a complete response rate of 82% and 58% respectively, with ongoing complete response rates of about 35% at six months in its ZUMA-1 phase 2 trial.   Tisa-Cel displayed an initial overall and complete response of 53% and 40%, respectively, with ongoing Complete Response, or CR rate, at six months of 30% in its Juliet phase 2 trial in its patients. In both trials, those patients who reached and remained in CR at eight to 10 months displayed a high chance of remaining in complete remission long-term. Several patients in both trials demonstrated conversion of a partial response to a complete response as much as 15 to 18 months after Cartesian infusion, though most of these conversions happened within the first six months.   It's difficult to compare the clinical trials for each of these CD19 CAR-T products with each other because each of the trials were conducted in critically different ways regarding patient selection, disease types, allowing bridging therapy or not, and different dosages of lymphodepletive chemotherapy. How these differences matter clinically is yet unknown and requires more research at this time. However, there were some interesting similarities and results between the two trials.   Patients both below age 65 and above 65 did equally well. Germinal center and non-germinal center lymphomas both responded equally to both CD19 CAR-T products. Both trials include a small number of patients with CD19 negative lymphomas, and some of them responded to CAR-T therapy. Also interestingly, the early use of tocilizumab, which is an aisle 6 receptor-blocking antibody used in cases of Cytokine Release Syndrome, or CRS, did not negatively impact response outcomes, and neither did the early use of corticosteroids for CRS and/or neurotoxicity.   Now, in addition to the Axi-Cel and Tisa-Cel, a third CD19-targeting CAR-T product, lisocabtagene maraleucel, or Liso-Cel cell for short, is supposedly nearing FDA approval for 2020 in relapsed refractory lymphoma. Its distinct feature, compared to the other two products, is that Liso-Cel is formulated as specified CD4, CD8 composition ratio administered at a flat dose. At the recent ASH meeting in December 2019 in Orlando, Liso-Cel showed promising response rates that were comparable to Axi-Cel and tisagenlecleucel in relatively short follow-up time. And the pure publication of the data from its clinical trials is still eagerly awaited.   ASCO Daily News: Right. And what about the use of CAR-T therapy in mantle cell lymphoma?   Dr. Raghuveer Ranganathan: So relapsed mantle cell lymphomas, especially with blastoid or pleomorphic morphologies, have a dismal prognosis with available salvage therapies. And this is where CAR-T can hopefully help. At the recent ASH meeting, the ZUMA-2 clinical trial with Axi-Cel in mantle cell lymphoma showed very promising response rates. An overall response rate of 93%, with 67% CR rate, was seen in 68 patients, with most of these patients having relapsed after autologous hematopoietic cell transplants. And the majority showing refractory disease to BTK inhibition, which is the standard therapy after a first relapse.   The CAR-T therapy results appeared to be agnostic towards the morphology of patients' mantle cell lymphoma. Meaning those with the more aggressive blastoid or premorphic variant morphologies responded as well as those with the classical morphologies. Grade 3 or higher CRS neurotoxicity were seen in 15% and 31% of patients, respectively. And we're waiting for the official publication of these results as well to gauge its full efficacy and safety profile in this disease sub-type for lymphoma.   ASCO Daily News: Let's focus on patients with multiple myeloma for a moment. How does CAR T-cell therapy differ for patients with multiple myeloma?   Dr. Raghuveer Ranganathan: So multiple myeloma tumor cells rarely express CD19. So CD19 is not really regarded as a dependable target for myeloma. B-cell Maturation Antigen, or BCMA for short, is a trans-membrane protein which is expressed on multiple myeloma cells. There have been a handful of phase 1 trials looking at BCMA-targeting CAR T-cells in multiple myeloma.   And the first phase I trial was out of the NCI published in 2015, looking at 12 patients who received anti-BCMA CAR at varying dose levels where they had one stringent CR and two very good partial responses, and one partial response, with response durations lasting between 16 and 30 weeks. But eventually all of the patients relapsed, unfortunately. A follow-up trial by the same group using a different anti-BCMA CAR, with a 4-1BB post-stimulatory domain, instead of the CD28 domain used in the first trial, was used in the multi-center phase I trial with 33 patients enrolled.   Similar to their first trial, the new trial had varying dose levels of the anti-BCMA CAR cells as well, and had slightly higher doses given than seen in CD19 CAR trials. An overall response rate of 85% was seen, with 45% CR or stringent CR. Very good partial response and better were only seen in the higher dose levels of at least 150 million CAR-positive T-cells or higher.   Four of these patients showed ongoing CR or stringent CR of 12-plus months at the time of study publication. In a subset analysis of patients whose myeloma tumor expression of BCMA was less than 50%, and comparing them to patients whose BCMA expression was greater than 50%, there was no difference in response. 16 out of 18 patients who were assessed for MRD negativity were negative at 10 to the minus 4 nucleated cells, and median progression-free survival was 11.8 months.   Another phase 1 trial out of University of Pennsylvania, using a fully-humanized anti-BCMA CAR, was administered to 25 patients, either with or without lymphodepletive conditions prior to CAR-T infusion. In the cohort of 11 patients receiving both lymphodepletion and a higher CAR-T infusion dose, an overall response rate of 64% was seen. Since publication of these studies, unfortunately though, the majority of the study patients have all relapsed with disease.   It is somewhat difficult to pinpoint the reason for this large amount of relapse, but it might have something to do with the nature of the BCMA antigen itself. BCMA is cleaved by an enzyme called gamma secretase and shed off of the surface of myeloma tumor cells normally. High levels of soluble BCMA circulating in the peripheral blood, incidentally, is associated with a poor clinical outcome in general.   While the study showed efficacy in a myeloma tumor whose BCMA expression was less than 50%, there is very likely an expression level below which the CAR T-cells will not be effective in identifying and eliminating a tumor. And since BCMA can be cleaved off the myeloma cell surface, it's basically an escape route for the tumor cells to evade detection from the BCMA-targeting CAR. Interesting data shown at the recent ASH Conference out of the Fred Hutchinson Cancer Center showed the addition of an inhibitor of gamma secretase keeps the BCMA from being cleaved and shed off of the myeloma tumor cell surface, thereby increasing its expression levels and keeping it on the tumor cell surface.   When the gamma secretase inhibitor is combined with anti-BCMA CAR-T cells in patients, it preliminarily showed promising long-standing results in a phase 1 trial with six patients. But further follow-up and additional clinical trials are necessary to validate these findings. Additionally, here at UNC Chapel Hill, we have a clinical trial open that uses CAR T-cells targeting CD138, which is another antigen also expressed on myeloma cells instead of BCMA. We're currently enrolling patients and hope to see an efficacy in myeloma, which would help advance the treatment paradigm from our studies as well.   ASCO Daily News: Excellent. Well, Dr. Ranganathan, I think it's important to address the issue of toxicities. So how are the toxicities unique to CAR-T being addressed? And do you foresee a time when biomarkers will be used to predict toxicity in patients?   Dr. Raghuveer Ranganathan: Sure. The two toxicities uniquely seen with CAR-T therapy are Cytokine Release Syndrome and Neurotoxicity, otherwise known as ICANS. The pathophysiology of these two toxicities is still somewhat unknown, and an area of concerted investigation currently. Cytokine Release Syndrome, or CRS, is a systemic inflammatory response produced by a superphysiologic elevation of cytokines. IL-6, in particular, seems to be a culprit.   Cytokine analyses have shown a relation between higher peak levels of IL-6 and higher grades of CRS in CAR-T patients. It's characterized by a constellation of symptoms, which include fever, malaise, headaches, myalgias, and arthalgias and rigors with fever usually being the first symptom observed with CRS onset. Though it's time of onset can vary from a few hours to more than weeks post CAR-T infusion.   In severe CRS, patients can have life-threatening hemodynamic instability, stemming from capillary leakage, hypoxia, coagulopathy, and organ dysfunction. Risk factors for severe CRS include high tumor burden, higher intensity of lymphodepletive chemotherapy prior to cell infusion, a higher level of administered CAR-T cell dose, and possibly also elevated inflammatory markers at baseline prior to infusion, such as abnormally high C-reactive protein and ferritin. Since high elevations of IL-6 were noted in the early CD19 CAR-T trial patients, administration of tocilizumab, a monoclonal antibody blocking the IL-6 receptor, was noted to demonstrate a rapid de-escalation of CRS symptoms. So now tocilizumab is actually a mainstay of treatment for CRS.   Corticosteroids are also used in the treatment of CRS, especially if tocilizumab is not enough to curtail the symptoms. As I had already mentioned, earlier intervention with tocilizumab and/or corticosteroids did not appear to negatively impact CAR-T efficacy in clinical trials. Now, the second unique toxicity is neurotoxicity, which is now termed as Immune Cell Associated Neural Toxicity Syndrome, or ICANS for short.   It can manifest as a tremor, impaired attention, difficulty writing, expressive aphasia, and confusion, but also can develop into more serious symptoms such as encephalopathy, delirium, stupor, and seizures. In rare cases, diffuse cerebral edema has developed, sometimes as a progressive crescendo, but occasionally also with very little preceding warning or clinical signs. ICANS can happen during CRS, but more commonly occurs after CRS, and can lag behind CRS by up to two weeks.   Expressive aphasia is the most common characteristic symptom that develops first in patients before other symptoms, with the symptom progression taking anywhere from hours to days. Though cytokines leaking through a disruptive blood brain barrier is theorized as a possible cause of ICANS, its pathophysiology really remains largely unknown, and is a hot area of study currently. Unlike with CRS, treatment with tocilizumab does not lead to symptom benefit because tocilizumab does not cross the blood-brain barrier. So corticosteroids are really the only option for treatment of ICANS at this time.   ASCO Daily News: So what's on the horizon for CAR T-cell therapies? Do you think they will be used to treat solid tumors in the future?   Dr. Raghuveer Ranganathan: So far as the horizon and future directions for CAR T-cell therapies, there are already several modifications and upgrades being attempted to improve the current science and technology. One such enhancement is adding additional co-stimulatory intracellular domains to the actual CAR construct, a so-called "third generation" CAR-T. The idea is that by increasing that matter of costimulatory domains in the CAR construct, such as adding a CD28 costimulatory domain to the 4-1BB costimulatory domain that might be already present, there can perhaps be either amplification of signals within the CAR-T cells, and also harnessing of the different properties inherent to each different costimulatory domain, with augmented proliferation tumor cytotoxicity as a result.   Currently, however, third-generation CAR-T constructs have yet to show better tumor cytotoxicity and better long-term remissions clinically, compared to second-generation constructs. Another enhancement is targeting two antigens simultaneously, or dual-targeting CAR0T. One of the purposes of this approach is to minimize tumor escape. Since the current second generation CAR T-cells target one cancer antigen at a time, if tumor cells were to down-regulate the expression of the targeted antigen, it would result in the tumor being able to evade recognition by the CAR T-cells. By targeting two antigens simultaneously, it's thought that the risk for tumor escape is lessened. A spinoff of dual-targeting CAR-T utilizes a sort of Boolean logic-gated approach where the CAR T-cells can be recalibrated to activate in an inducable fashion.   In these logic-gated CAR T-cells, sensing of antigen 1 by a synthetic notch receptor within a modified T-cell then induces transcription and subsequent expression of a CAR receptor, which is specific for antigen number 2. Meaning that without binding of the antigen number 1 by our genetically-modified T cell, there is no expression of the CAR receptor binding to antigen number 2, which could help minimize on-target off-tumor toxicity. Another approach is called T-cells Redirected for Universal Cytokine Killing, or termed somewhat tongue-in-cheek as TRUCK T-cells, a playoff of CAR- T cells. These cells, in addition to direct tumor killing, also produce a pro-inflammatory cytokine, like IL-15 or IL-18, on coming into contact with a tumor, which helps to recruit a second wave of immune cells in a locally-restricted fashion, hopefully, to initiate a secondary attack on cancer cells, and also help enhance its own proliferation, cytotoxicity, and longevity. Now, there are unique obstacles and challenges for CAR-T and solid tumors that make it more difficult when compared to hematologic malignancies. Some of the existing challenges include overcoming the hostile tumor microenvironment, nutrient depletion, hypoxia, and inhibitory checkpoint molecule expression on solid tumors. Now, any one of these impediments would be a strong stumbling block to try and overcome, but when all of these hurdles occur together all at once, it can be very difficult to combat.   In addition, on-target off-tumor toxicity is somewhat of a bigger challenge to overcome in solid tumors. And a likely cause for this is the overlapping antigen expression on epithelial tissues from which most solid tumor types originate. And also the spatial proximity and restriction of critical sites when targeting solid tumors. For example, a few years ago, a patient with metastatic colon cancer who had received CAR T-cell therapy as part of a trial died from acute respiratory distressive failure, with the cause thought to be low-levels of being expressed on lung epithelial cells. That said, I do believe CAR T can become a viable treatment modality in solid tumors with some modifications and improvements. One such method being tested in clinical trials is combining immune checkpoint therapy, such as PD-1 inhibitors, with CAR T-cells. Another possibility is to edit the native inhibitory receptor in CAR T-cells by switching out the inhibitory receptor's intracellular domain for an intercellular domain from a stimulatory receptor. For instance, we take the native PD-1 molecule from a CAR-T cell and edit or switch out the intracellular domain, and put in the intercellular domain from CD28. What you get now is a molecule which has the PD-1 receptor on the outside, but a CD28-signaling mechanism on the inside, so that the net result is actually positive for the CAR-T, which now gets added stimulus instead of inhibition.   Such switch receptors are being incorporated into CAR T-cells to augment their activity and proliferation potential. And as I mentioned before, TRUCK T-cells and logic-based CAR T-cells are also other possible methods to conquering some of these obstacles posed by solid tumors. So while there's still much more investigation to be done in overcoming solid tumors, I do hope that we can make some strong headway in the near future. ASCO Daily News: Well, thank you Dr. Ranganathan for sharing your insights on CAR T-cell therapies with us today. Dr. Raghuveer Ranganathan: My pleasure. Thank you, Geraldine. ASCO Daily News: And to our listeners, thank you for tuning into the ASCO Daily News Podcast. If you're enjoying the content, please rate and review us on Apple Podcasts.   The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement.

Creative Drive
CD28 - Leaving the Outline Behind

Creative Drive

Play Episode Listen Later Feb 21, 2020 10:27


Hi all,Road recording! Lessons from this week about finding an unbeaten path beyond the outline.Much love,jWhen have you veered away from your story outline?Find out more at https://creativedrive.pinecast.co

JACC Podcast
CD28 signaling in vasculitis

JACC Podcast

Play Episode Listen Later Apr 8, 2019 10:06


Commentary by Dr. Valentin Fuster

Carolina Desi Podcast
CD28 Hurry Up and Wait

Carolina Desi Podcast

Play Episode Listen Later Apr 30, 2018 34:38


Time. There’s never enough of it! At least, not for the Carolina Desis. Why is it so hard to come by? Is it a side effect of being an adult? Join them this week as they try to unravel the concept of punctuality and priorities in both the Desi and American cultures. Follow @thecarolinadesi on social media to join the conversation.

Hyperstyles.
Hyperstyles. CD28 | Full-On Fusion | Psytrance Set

Hyperstyles.

Play Episode Listen Later Apr 30, 2017 104:05


Hyperstyles. CD28 | Full-On Fusion | Tracklist can be found at: https://soundcloud.com/lentej/ Enjoy and dance on!

Science Signaling Podcast
Science Signaling Podcast for 13 September 2016: DMF and the immune system

Science Signaling Podcast

Play Episode Listen Later Sep 12, 2016 10:11


Benjamin Cravatt, John Teijaro, and Megan Blewett describe how the immunosuppressive drug DMF affects proteins in human T cells.

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 17/19
Characterization of murine pancreatic carcinoma models regarding immunosuppressive mechanisms and therapy with bifunctional siRNA targeting galectin-1

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 17/19

Play Episode Listen Later Sep 16, 2014


Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive tumor that is characterized by abundant tumor stroma and a potent immunosuppressive microenvironment. Further studies to clarify why T cells infiltrate the tumor but are not able to perform effector functions as well as to find new effective therapies to overcome immunosuppression are urgently needed. The aims of the present study were (1) to characterize different murine PDAC tumor models in regard to their utility for studying novel immunotherapeutic approaches, (2) to assess the therapeutic efficacy of a novel bifunctional ppp-siRNA that combines silencing of the immunosuppressive molecule galectin-1 and RIG-I-mediated immune activation in murine PDAC and (3) to characterize the immunosuppressive mechanisms leading to T cell inhibition in the tumor microenvironment. (1) This study revealed that the pancreatic cancer cell line T110299, which was developed from a primary tumor of the KPC mouse model, is a new valuable tool for studying novel treatment strategies for PDAC. The histological appearance of T110299 tumors reflects in many aspects the primary tumors in KPC mice, which harbor mutations in the Kras oncogene and p53, and the human disease with regard to tumor differentiation, extensive tumor stroma development, poor vascularization and expression of immunosuppressive molecules, like indoleamine 2,3-dioxygenase (IDO) and galectin-1 (Gal-1). In contrast, Panc02 tumors were found to have a sarcomatoid architecture with very little tumor stroma. In Panc02 cells, galectin-1 was strongly expressed by the tumor cells, which differs from the situation found in humans, KPC mice and T110299 tumors, where galectin-1 is preferentially expressed in tumor-associated pancreatic stellate cells (PSC). However, expression of the cytosolic helicase RIG-I was functional in Panc02 cells, but defective in T110299 cells. As RIG-I is expressed in all human PDAC cell lines tested, the Panc02 model appears to be better suited to study RIG-I-based immunotherapies (Ellermeier et al., 2013). Thus, the histological and functional characterization of the tumor models in this thesis will allow selecting the best-suited tumor model for addressing specific aspects of immunotherapy. (2) Treatment studies of PDAC were performed with the 5’ppp-modified siRNA molecule ppp-Gal-1 in the orthotopic Panc02 tumor model. The dual activities of this molecule were confirmed in vitro, leading to (i) reduced galectin-1 expression via RNAi; and (ii) production of CXCL10 and IFN-, MHC-I up-regulation and apoptosis of tumor cells via RIG-I activation. Treatment of mice with orthotopic pancreatic tumors with ppp-Gal-1 significantly prolonged survival, as compared to unmodified OH-Gal-1 or control RNA. In addition, 20% of the mice completely rejected their tumors leading to long-term tumor control. Thus, bifunctional 5’ppp-modified siRNA is a promising treatment strategy for PDAC deserving further pre-clinical evaluation. (3) Pancreatic tumor cells employ multiple mechanisms for suppression of T cell responses. This study identified TGF-β and IDO as two potent mechanisms leading to inhibition of T cell proliferation. Minute amounts of PDAC supernatants effectively blocked T cell proliferation induced by CD3 and CD28 triggering. This could be partially prevented by SD-208, a small molecule inhibitor of TGF-β receptor signaling, or by blocking IDO activity with D-1-MT. Interestingly, tumor supernatants induced up-regulation of IDO mRNA expression in T cells. Furthermore, blocking IDO activity in T cells appeared to be more effective than blocking IDO in tumor cells. This leads to a new hypothesis that factors secreted by the tumor cells induce IDO expression in T cells, which in turn leads to auto-intoxication of the T cells via kynurenine production and eventually T cell apoptosis. Further studies confirming this hypothesis are warranted.

Medizin - Open Access LMU - Teil 20/22
CD160Ig fusion protein targets a novel costimulatory pathway and prolongs allograft survival.

Medizin - Open Access LMU - Teil 20/22

Play Episode Listen Later Jan 1, 2013


CD160 is a cell surface molecule expressed by most NK cells and approximately 50% of CD8(+) cytotoxic T lymphocytes. Engagement of CD160 by MHC class-I directly triggers a costimulatory signal to TCR-induced proliferation, cytokine production and cytotoxic effector functions. The role of CD160 in alloimmunity is unknown. Using a newly generated CD160 fusion protein (CD160Ig) we examined the role of the novel costimulatory molecule CD160 in mediating CD4(+) or CD8(+) T cell driven allograft rejection. CD160Ig inhibits alloreactive CD8(+) T cell proliferation and IFN-γ production in vitro, in particular in the absence of CD28 costimulation. Consequently CD160Ig prolongs fully mismatched cardiac allograft survival in CD4(-/-), CD28(-/-) knockout and CTLA4Ig treated WT recipients, but not in WT or CD8(-/-) knockout recipients. The prolonged cardiac allograft survival is associated with reduced alloreactive CD8(+) T cell proliferation, effector/memory responses and alloreactive IFN-γ production. Thus, CD160 signaling is particularly important in CD28-independent effector/memory CD8(+) alloreactive T cell activation in vivo and therefore may serve as a novel target for prevention of allograft rejection.

Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 04/06
Recognition of renal cell carcinoma by CD8+ and CD4+ TCR-engineered T lymphocytes

Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 04/06

Play Episode Listen Later Feb 21, 2011


Immunotherapy using T cells is a new approach that is being explored for the treatment of metastatic melanoma. For renal cell carcinoma (RCC), adoptive T cell therapy (ATT) is currently hampered by the lack of T cells expressing suitable T cell receptors (TCR). A tumor-infiltrating T cell population (TIL) was identified in our group (TIL-53) that showed a pattern of tumor recognition consistent with the requirements of a TCR applicable for immunotherapy. With the advent of genetic TCR engineering it was possible to further define the TIL specificity which was previously precluded by the failure to cultivate TIL-53. To achieve high expression levels and functionality, the TCR53 required the exchange of the human TCR constant region by the TCR murine constant region (TCR53m). The B3Z T cell hybridoma which stably expressed TCR53m after retroviral transduction was used to analyze a large panel of tumor lines and non-malignant cell cultures for expression of the TCR53 ligand. The analysis included 34 RCC cell lines, 55 tumor cell lines of different histologies and 30 non-tumor cell lines. 65 % of the HLA-A2+ RCC cells and 25 % of other HLA-A2+ tumor lines were recognized by the B3Z-TCR53m cells. Among the non-RCC tumors, the TCR53 ligand was frequently found in malignant B cell lines and EBV-transformed B-lymphoblastoid cell lines (5/13, 38 %). Of 25 HLA-A2+ non-tumor cells only 2 were marginally recognized. The TCR53 ligand expression could be increased with IFN-a but not IFN-g treatment on cell lines that already had some TCR53 ligand expression. De novo induction in cell lines that had no prior expression of the TCR53 ligand was not observed. The B3Z-TCR53m cell line could detect the TCR53 ligand on fresh tumor material and, if used for therapy, B3Z-TCR53m could be used to identify those patients whose tumors are positive for the TCR53 ligand and thus could benefit from the therapy. To achieve high expression levels and functionality of the TCR53m on human PBLs, the TCR53 a and b chain sequences had to be optimized for codon usage. PBLs expressing these recombinant TCR sequences (TCR53mc) showed very low formation of hybrid TCRs between the TCR53mc b chain and endogenous TCR a chains. TCR53mc-expressing T cells of RCC patients and healthy donors showed specific killing of tumor cell lines and had a polyfunctional profile, defined by the detection of T cells that simultaneously secreted cytokines (IFN-g, TNF-a or IL-2) and performed granule exocytosis when recognizing targets. The functional response of TCR53mc-expressing T cells depended on the expression of HLA-A2 on the target cells. Analysis of RCC tumors using multicolor fluorescence immunohistology allowed the detection and localization of CD8+ T cells in relation to blood vessels. The majority of CD8+ T cells were found extra-luminal, indicating strong extravasation of T cells into RCC tumors. The majority of the T cells in the lumen of the blood vessel had perforin (~ 90 %), while T cells that were outside the blood vessels were to a large percentage perforin negative (~ 60 %). Thus, CD8+ T cells apparently arrive at the tumor being perforin-positive and lose perforin when outside the blood vessels. The three-dimensional growth of cells in spheroids was used to mimic the tumor milieu in vitro and to evaluate the functional capacity of T cells with transgenic RCC specific TCR expression. T cells infiltrated the spheroids and preferentially accumulated in the rim of the spheroid (~ 100 μm). The killing capacity of TCR53mcexpressing T cells in the 3-D environment in a 4 h assay was similar to that observed in a standard 4 h chromium release assay with RCC cells in suspension. However, after being cultured for 24 h in the spheroids, the T cells were no longer able to secrete cytokines upon stimulation with target cells and were negative for perforin, granzyme B and CD28. The presence of CD4+ T cells in the spheroids significantly increased the number of CD8+ T cells infiltrating the 3-D tumors. Moreover, the CD8+ T cell response was enhanced with more degranulating T cells and T cells secreting cytokines, which was not seen in the absence of CD4+ T cells. The functional improvement of the CD8+ T cell response required the CD4+ T cells to be activated, as it was not observed when CD4+ T cells were used that lacked TCRs specific for the spheroid tumor cells.

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 10/19
Rolle von T-Zellen bei Ischämie-Reperfusion der Leber

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 10/19

Play Episode Listen Later Jul 16, 2009


Die protektive Wirkung von Immunsuppressiva auf den hepatischen I/R-Schaden deutet darauf hin, dass T-Zellen bei diesem alloantigen-unabhängigen Ereignis eine Rolle spielen. Die Mechanismen der Aktivierung bzw. der mikrovaskulären Rekrutierung von CD4+ T-Zellen bei alloantigen-unabhängiger I/R der Leber sind jedoch weitgehend ungeklärt. Ziele der vorliegenden Arbeit waren daher (1) die Rekrutierung von T-Zell-Subopulationen in den postischämischen hepatischen Mikrogefäßen in vivo zu untersuchen, (2) die Mechanismen einer Interaktion von CD4+ T-Zellen und Thrombozyten während hepatischer I/R zu analysieren, (3) die Rolle von CD4+ T-Zellen an der Ausbildung des hepatischen I/R-Schadens zu beurteilen, (4) zu untersuchen, ob die postischämische Rekrutierung von CD4+ T-Zellen MHC Klasse II-abhängig stattfindet und (5) zu analysieren, ob CD4+ T-Zellen während hepatischer I/R mit Kupffer-Zellen interagieren. In der vorliegenden Studie konnte erstmals in vivo der Typ, die mikrovaskuläre Lokalisation und die Kinetik der Lymphozyten-Endothelzell-Interaktion während hepatischer I/R intravitalmikroskopisch charakterisiert werden. So konnte gezeigt werden, dass insbesondere CD4+ T-Zellen, und nicht CD8+ T-Zellen, während I/R in der hepatischen Mikrozirkulation akkumulieren. Diese Akkumulation tritt hauptsächlich in den Sinusoiden auf, nur zu einem geringeren Teil in den postsinusoidalen Venolen. Bereits nach 30-minütiger Reperfusion ist gegenüber der schein-operierten Gruppe eine signifikante Zunahme der Anzahl akkumulierter CD4+ T-Zellen in den Mikrogefäßen der Leber zu beobachten, die Anzahl emigrierter CD4+ T-Zellen nimmt im Verlauf der Reperfusionszeit signifikant zu. Im Rahmen der Untersuchungen konnte gezeigt werden, dass CD4+ T-Zellen an der Ausbildung des hepatischen I/R-Schadens beteiligt sind. Über CD40L- und CD28-abhängige Signalwege ist die postischämische Akkumulation von Thrombozyten und Leukozyten in der hepatischen Mikrozirkulation von CD4+ T-Zellen abhängig. Darüber hinaus wird die Ausbildung des mikrovaskulären Schadens, gemessen anhand des sinusoidalen Perfusionsdefizites, sowie die Ausbildung des hepatozellulären Schadens, gemessen anhand der hepatischen Transaminasen, CD40L- und CD28-abhängig über CD4+ T-Zellen mediiert. Mittels simultaner Visualisierung zweier Zellpopulationen in vivo konnte in dieser Dissertations¬schrift erstmals nachgewiesen werden, dass CD4+ T-Zellen und Thrombozyten während hepatischer I/R kolokalisieren. Unter Verwendung P-Selektin- und CD40L-defizienter Mäuse konnte in vivo nachgewiesen werden, dass eine feste Adhärenz zwischen Thrombozyten und CD4+ T-Zellen über P-Selektin und PSGL-1 vermittelt wird, während die kostimulatorischen Moleküle CD40 und CD40L eine reziproke Aktivierung unter Thrombozyten und CD4+ T-Zellen bedingen. In einem weiteren Abschnitt dieser Studie konnte unter Verwendung von blockierenden Antikörpern schließlich erstmals in vivo gezeigt werden, dass die im Rahmen der hepatischen I/R stattfindende Aktivierung von CD4+ T-Zellen MHC-Klasse II-unabhängig abläuft. Schließlich wurde in einem weiteren Abschnitt dieser Dissertationsschrift erstmals in vivo nachgewiesen, dass eine reziproke Aktivierung von Kupffer-Zellen und CD4+ T-Zellen während hepatischer I/R vorliegt. Die Anzahl postischämisch akkumulierter CD4+ T-Zellen ist nicht nur nach vollständiger Depletion von Kupffer-Zellen, sondern auch nach selektiver Unterbindung der Signalwege über TNF-α und IL-6 sowie des Abfangens freier Sauerstoffradikaler signifikant vermindert. Vice versa konnte hier Anhand der Untersuchung der Phagozytoseaktivität von Kupffer Zellen mittels Latex-Beads gezeigt werden, dass CD4+ T-Zellen die Aktivität von Kupffer-Zellen beeinflussen. Weitergehende Untersuchungen zur reziproken Aktivierung von Kupffer-Zellen und CD4+ T-Zellen konnten unter Verwendung von Durchflusszytometrie zeigen, dass proinflammatorische Mediatoren wie TNF-α und IL-6, vornehmlich freigesetzt durch Kupffer-Zellen während hepatischer I/R, nicht nur direkt aktivierend auf CD4+ T-Zellen wirken, sondern auch sinusoidale Endothelzellen aktivieren können. Eine Aktivierung der sinusoidalen Endothelzellen mit entsprechender Alteration der Expression von Adhäsionsmolekülen, wie z.B. ICAM-1, VCAM-1 und VAP-1 stellt wiederum einen pathophysiologischen Mechanismus dar, der mit einer konsekutiven Verstärkung der Akkumulation von CD4+ T-Zellen nach I/R verbunden ist. Zusammenfassend weisen diese in vivo Daten darauf hin, dass hepatische I/R die Akkumulation und Emigration von CD4+ T-Zellen, jedoch nicht von CD8+ T-Zellen induziert. Adhärente CD4+ T-Zellen sind in Sinusoiden mit Thrombozyten kolokalisiert; dies lässt eine gegenseitige Aktivierung beider Zelltypen durch direkten Zellkontakt oder über die Aktivierung des Endothels vermuten. Eine CD4 T-Zell-Defizienz geht mit einer Verminderung der postischämischen Thrombozytenakkumulation und mit einer Reduktion des mikrovaskulären I/R-Schadens einher. Die postischämische Rekrutierung von CD4+ T-Zellen in hepatischen Mikrogefäßen wird durch Kupffer-Zellen, wahrscheinlich über die Freisetzung von Sauerstoffradikalen, TNF-α und IL-6, vermittelt.

Videocast Podcasts
Roles of Pathways in the B7:CD28 Family in Regulating T Cell Activation and Tolerance

Videocast Podcasts

Play Episode Listen Later Dec 27, 2007 61:12


Enhanced Video PodcastAired date: 12/19/2007 3:00:00 PM Eastern Time

Videocast Podcasts
Roles of Pathways in the B7:CD28 Family in Regulating T Cell Activation and Tolerance

Videocast Podcasts

Play Episode Listen Later Dec 27, 2007 61:12


Enhanced Audio PodcastAired date: 12/19/2007 3:00:00 PM Eastern Time

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 05/19
Untersuchungen apoptoseinduzierender und costimulatorischer Signalwege im xenogenen System: Wechselwirkungen zwischen porcinen Endothelzellen und humanen Jurkat-Zellen

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 05/19

Play Episode Listen Later Mar 16, 2006


Zielsetzung der Arbeit war es, zu untersuchen ob porciner Fas-Ligand auf nativen aortalen Schweineendothelzellen (PEC) und immortalisierten aortalen Schweineendothelzellen (PEC-A) exprimiert wird und ob dieser mit humanem Fas auf der T-Lymphozytenzelllinie Jurkat interagiert. Unter Einsatz von Matrix-Metalloproteinase-Inhibitoren sowie nach Permeabilisierung und Fixierung der Zellen konnte FasL sowohl auf PEC als auch auf PEC-A in geringem Maße nachgewiesen werden. Die Detektion von FasL erfolgte mit anti-FasL-AK. Bei der Koinkubation von PEC sowie PEC-A mit Jurkat-Zellen in Effektor/Target-Verhältnissen von 4:1, 3:1 und 2:1 konnte weder im APO2.7-Assay noch im Annexin-Assay Apoptose beobachtet werden. Die Auswertung erfolgte mit Hilfe der FACS-Analyse. Der JAM-Test erwies sich in unserem System aus technischen Gründen als nicht geeignet für den Nachweis von Apoptose. Versuche PEC-A mit hFasL zu transfizieren waren mit hoher Zelltoxizität verbunden. Der transfizierte FasL wurde teilweise auch intrazellulär gespeichert. Der costimulatorische Signalweg B7/CD28 kann ein dem Fas/FasL-Signalweg entgegengesetztes Signal vermitteln. Auch nach Blockade der möglichen Interaktion zwischen B7 auf PEC-A und CD28 auf Jurkat-Zellen konnte keine Apotose gezeigt werden.

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 02/19
Phänotypische und funktionelle Charakterisierung lymphozytärer Subpopulationen nach ausgedehnter Verbrennungsverletzung

Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 02/19

Play Episode Listen Later Dec 12, 2003


Die Immunantwort auf ein Verbrennungstrauma beginnt im Moment der Verletzung und resultiert in einer Monozytenaktivierung, die mit einer vermehrten Synthese und Ausschüttung von inflammatorischen Mediatoren einhergeht. Unter physiologischen Bedingungen dient ein ausgewogenes Zusammenspiel von pro- und antiinflammatorischen Zytokinen der Homöostase, wohingegen das Immunsystem nach massivem Trauma mit einer oft exzessiven Freisetzung proinflammatorischer Mediatoren reagiert. Patienten mit schwerer Verbrennungsverletzung sind daher hochgradig gefährdet ein ausgedehntes „systemic inflammatory response syndrome, (SIRS)“, d. h. eine maligne Ganzkörperinflammation, eine Sepsis oder eine Multiorgandysfunktion, assoziiert mit einer hohen Letalität, zu entwickeln. Eine überwiegend antiinflammatorische Immunantwort dagegen manifestiert sich als systemische Immundefizienz und Anergie mit einer signifikant erhöhten Infektionsanfälligkeit. Es besteht eine eindeutige Ursache-Effekt-Beziehung zwischen Trauma und Zytokinsystem. Mechanischer Stress führt zu schweren Störungen der Interaktion von Monozyten und T-Zellen mit der Folge einer schwerwiegenden Immundysfunktion, wobei PGE2 als einer der Hauptmediatoren der traumainduzierten Immundepression angesehen wird. Erhöhte PGE2-Spiegel sind mit einer reduzierten T-Zellmitogenese, IL-2-Produktion und IL-2-Rezeptorexpression korreliert und für eine Verschiebung der T-Helfer-Aktivität in Richtung eines dominierenden TH2 Phänotyps mit erhöhter Synthese der immunsuppressiven Zytokine IL-4 und IL-10 verantwortlich. Zytokine sind für die Kommunikation im Immunsystem, vor allem bei der Koordination einer Immunantwort durch T-Lymphozyten, von entscheidender Bedeutung. Als sezernierte Proteine waren sie bis vor kurzem der durchflusszytometrischen Analyse nur begrenzt zugänglich. Wir konnten sie wie in vorliegender Arbeit beschrieben in fixierten Zellen intrazellulär nachweisen, d. h. vor der Sekretion. Dieses Verfahren erlaubte es uns, die Expression der Zytokingene quantitativ, kinetisch, korreliert mit Oberflächenproteinen und auf die Einzelzelle bezogen analytisch zu erfassen, zumindest bis zur posttranslationalen Ebene. In peripheren mononukleären Blutzellen (PBMC) von 10 Patienten mit schwerer Verbrennungsverletzung (KOF >30%) und 15 gesunden Kontrollpersonen wurde die Zytokinsynthese mit Ionomycin und PMA polyklonal induziert und die Zellen anschließend mit fluorochromkonjugierten monoklonalen Antikörpern gegen IL-2, IL 4 und IFN-g, sowie gegen CD4-, CD8-, CD45RA- und CD45RO-Zelloberflächenantigene in unterschiedlichen Kombinationen gefärbt. Massives Verbrennungstrauma führte nach polyklonaler Stimulation der T Lymphozyten zu teils signifikanten systemischen Veränderungen der Zytokinexpression in den Kulturüberständen. Verglichen mit einer exzessiven IL-4 Freisetzung und stark erhöhter IL-10 Sekretion zeigten die IFN-g- und die IL-2 Synthese eine nur mäßige Steigerung gegenüber den gesunden Kontrollen. Wir sahen somit eine traumatisch induzierte Veränderung des Zytokinprofils in Richtung eines überwiegend TH2-artigen, immunsuppressiven Phänotyps. Diese Verschiebung von einer eher zytotoxischen (TH1) zu einer weitgehend humoralen und daher abgeschwächten Immunantwort ist mit einer erhöhten Infektionsanfälligkeit verbunden. Mit der durchflusszytometrischen Einzelzellanalyse gelang uns dann erstmalig die Identifikation der CD8+ Zelle, die ursächlich für die gesteigerten Syntheseantworten im posttraumatischen Verlauf verantwortlich ist. Die Synthesekapazität der CD4+ T-Helferzellen blieb nahezu unverändert. Eine Ausnahme bildete die prozentuale Abnahme IFN-g positiver Gedächtniszellen (CD45RO+) zugunsten einer zunehmenden Zahl IFN-g produzierender naiver T Helferzellen (CD45RA+). In der CD8+ Subpopulation kam es in der ersten Woche nach Verbrennungsverletzung zu einer signifikanten Steigerung der IL-2, IL-4 und IFN-g de novo Synthese, die interessanterweise bei weiterer, differenzierter Analyse eine positive Korrelation mit dem klinischen Verlauf ergab. Patienten, die verstarben, zeigten im Vergleich zu den Überlebenden signifikant erhöhte IL-4 und IL-2 Syntheseraten der CD8+ Zellen. Betrachtet man die IL-2 Synthese dieser CD8+ Zellen genauer, nahm nur die Zahl IL-2-produzierender CD8+CD45RA+ Zellen signifikant zu, verglichen mit dem Kontrollkollektiv, wobei beide Patientenkollektive an dieser Entwicklung partizipierten. Auch die IFN-g Synthese der CD8+CD45RA+ Subpopulation zeigte an allen Tagen post Trauma eine signifikante Zunahme gegenüber den Kontrollen ohne aber mit der Überlebensrate zu korrelieren. Dagegen war der prozentuale Anteil IFN-g produzierender CD8+ CD45RO+ Zellen von Verstorbenen signifikant gegenüber den Überlebenden reduziert und blieb auch an allen Untersuchungstagen deutlich hinter dem Kontrollniveau zurück, das von den überlebenden Patienten z. T. signifikant übertroffen wurde. Neben der funktionellen Charakterisierung über die Zytokinexpression (intrazellulär) kann der Aktivierungsstatus des Immunsystems durchflusszytometrisch auch über eine Oberflächenphänotypisierung ermittelt werden, ohne aber damit funktionell unterschiedliche Subpopulationen von T Zellen definieren zu können. Einen ersten Hinweis auf die Aktivierung des Immunsystems von Verbrennungspatienten erhielten wir über die signifikante Zunahme von IL-2Ra (CD25) tragenden T-Zellen in der ersten Woche nach Trauma. Aktivierte T-Zellen exprimieren darüberhinaus MHC-Klasse II-Moleküle und verschiedene Adhäsionsmoleküle, denen bei der Wechselwirkung der Zellen entscheidende Bedeutung zukommt. Akzessorische Moleküle erhöhen beispielsweise die Avidität der T-Zell-APC Interaktion und wirken kostimulatorisch. Wir konnten nach schwerer Verbrennungsverletzung eine verstärkte Expression des vorherrschenden T-Zellrezeptors (TCR) a/b und der akzessorischen T Zellmoleküle CD2, CD7, CD28, CD29 und CD80 nachweisen. Die Zunahme von CD28-Molekülen auf der Oberfläche von CD4+ und CD8+ T-Zellen ist besonders bemerkenswert, da mit zunehmender Signalstärke des über CD28 vermittelten Signals die Differenzierung einer T-Zelle auf die TH2-Entwicklung ausgerichtet wird. Die Aktivierung von T-Lymphozyten ist außerdem mit markanten Veränderungen im Expressionsmuster einzelner CD45 Isoformen verknüpft. Die Induktion der CD45RO Isoform und der Verlust von CD45RA waren beim Schwerstverbrannten besonders auffällig. Die durchflusszytometrische Bestimmung des Aktivierungsstatus des Immunsystems hat unseres Erachtens das Potenzial einer Standardmethode zur Ermittlung von Hochrisikopatienten mit deren Hilfe immunsupprimierte Patienten und solche mit SIRS und Sepsis unterschieden werden können. Die zentrale Vorbedingung für eine effektivere Sepsistherapie stellt eine verbesserte Diagnostik im Sinne kontinuierlicher zellbiologischer Informationen („Online-Monitoring“) am Krankenbett dar, um die meist sehr schnell wechselnden immuninflammatorischen Zustandsbilder direkt zu erkennen und einer zeitgerechten, individuell adaptierten Behandlungsintervention zuzuführen.