Podcasts about hla c

This week we hype the seemingly negative impact of KIR2DS1/HLA-C2/C2 genotype on rituximab benefit in aggressive lymphomas. We also cover updates in breast cancer (pembrolizumab in TNBC; AIs in pre-menopausal women) and cervical cancer (cemiplimab). KIR & Rituximab: https://doi.org/10.1016/S2352-3026(21)00369-0 Keynote-522 Update w/ EFS analysis: https://www.nejm.org/doi/full/10.1056/NEJMoa2112651 Premenopausal Breast Cancer AIs vs. Tam Meta-Analysis: https://doi.org/10.1016/S1470-2045(21)00758-0 Cemiplimab in cervical cancer: https://www.nejm.org/doi/full/10.1056/NEJMoa2112187

Today's episode is dedicated to Critical Illness In Children With Hematopoietic Stem Cell Transplants. We are delighted to be joined by Dr. Muna Qayed, Associate Professor of Pediatrics Emory University School of Medicine , Atlanta, GA. She is also the Director of the Blood and Marrow Transplant Program at the Aflac Cancer and Blood Disorders Center at Children's Healthcare of Atlanta. Our Case: A 10 year old female with refractory high-risk ALL s/p mismatched unrelated donor transplantation T+13 days presents as a transfer to the PICU with abdominal distention, worsening jaundice, and escalating nasal cannula requirements. The patient's post-transplant course was complicated by gram-negative bacteremia requiring fluid resuscitation. A CXR upon transfer to the PICU is notable for bilateral airspace disease, a right sided pleural effusion, and hypoexpanded lung fields. The patient is promptly intubated, sedated and started on renal replacement therapy. Echo labs, and further imaging are pending. What are the classic pediatric indications for BMT? Autologous BMT (where donor cells are from the patient/recipient) is used as consolidation in some solid tumors such as High risk neuroblastoma, brain tumors like medulloblastoma, and germ cell tumors, and are a standard treatment approach in relapsed Hodgkin lymphoma Allogeneic BMT-where in the donor cells are derived from another individual are typically used for hematologic malignancies. ALL and AML are most common pediatric indications. Also allogeneic BMT are used for wide spectrum of nonmalignant hematology conditions such as hemoglobinopathies ( Sickle cell disease, Thalassemia), and severe aplastic anemia, and inherited bone marrow failure syndromes, as well as some metabolic disorders and immune-deficiency disorders such as SCID, HLH and other primary immune regulatory disorders. The sources of graft in BMT? Stem cells (which give rise to different types of blood cells - red cells, white cells and platelets are derived from the bone marrow. Thus the overall process is known as Bone Marrow Transplantation. Stem cells can be also derived from peripheral blood - when the donor is treated with granulocyte colony stimulating factor or G-CSF. There are some key advantages here, which include the ability to collect a much higher stem cell dose, with faster hematopoietic recovery. However the downside is a higher T cell content of the graft with subsequent increased risk of graft versus host disease. Umbilical cord blood is also used as a source of stem cells. Mega doses of stem cells are used to overcome histocompatibility barriers of mismatched transplantation. Majority of T cells have to be removed from donor pool to prevent severe GVHD., Increase risk of infection and relapse of patients original disease. Explain the human leucocyte antigen (HLA) and its role in BMT? The Major Histocompatibility complex (MHC) system known as the human leukocyte antigen (HLA) in humans is located on the short arm of chromosome 6 and contains the most polymorphic gene cluster of the entire human genome. The HLA consists of regions designated as "classes". Class I and class II are relevant to stem cell transplant. The main function of HLA class I gene products (HLA-A, -B, and -C) is to present endogenous peptides to responding CD8+ T Cells, HLA class I antigens are expressed on all nucleated cells and platelets. While the class II coded molecules HLA-DR, -DP, and –DQ have restricted expression and process exogenous peptides for presentation to CD4+ helper T Cells, and are expressed on antigen presenting cells. HLA-A, HLA-B, HLA-C and HLA-DR are traditionally the loci critical for matching for stem cell donor. In addition to deciding on the source of the graft, we have to make decisions on who the donor will be. If a matched sibling donor is not available (or in some inherited conditions that may not be an option as a donor), then matched unrelated donors or matched cord blood...

Dr. Diana Alecsandru of IVI Madrid reviews how far we've come in understanding the relationship between immunology and infertility. She also discusses her recent study published in Fertility and Sterility, showing how HLA-C allotypes can be used to predict live birth rates during in vitro fertilization (IVF) cycles, especially in patients with recurrent implantation failure or recurrent miscarriages. Podcast website: https://www.ivi-rmainnovation.com/?utm_source=podcast&utm_medium=episode&utm_campaign=ep23  

O décimo episódio do Podcast Sonho BemVindo é sobre KIR HLA-C, que é um exame específico para avaliar a complexa relação imunológica entre embrião e o útero. Apesar do tema parecer muito específico, os casais que têm abortamentos de repetição e falhas de implantação após várias transferências de embrião, podem encontrar neste exame um desfecho. No bate-papo falamos sobre a história das células NK, a diferença entre as uterinas e as periféricas, o conceito do que é o KIR, como é feito esse exame, sua logística e fluxograma clínico ao pedi-lo, quando solicitar, quanto tempo demora e como os resultados impactam nas condutas diferenciadas para cada casal.A convidada deste episódio e especialista no assunto é a Dra. Natália Gonçalves, bióloga com Doutorado em genética pela Universidade da Carolina do Norte e Pós-doutorado em genética pela USP, é membro da Sociedade Brasileira de Genética e diretora do Departamento de Genética e Biologia Molecular do RDO, em São Paulo, consultora genética para Reprodução Humana.Discutimos:[06:00] O que é o KIR HLA-C e sua história? Como podem estar relacionados com as falhas de implantação e abortos de repetição?[09:25] O que é célula NK (Natural Killer Cell) e seu processo com o embrião?[16:00] Qual é o conceito do KIR? O que ele vai causar na reprodução?[20:30] O que é o HLA do embrião e de onde veio esse material genético?[24:50] Quais são as implicações que causam a falha de implantação?[27:38] Como acontece o exame KIR e HLA?[36:57] Onde o desfecho é ovodoação, testamos a doadora de óvulo ou mãe receptora?[39:30] Com histórico de abortamento de repetição e falha de implantação, devemos fazer o teste?[47:00] Cenários onde o exame é indicado.Toda semana um novo episódio na sua vida! Um conteúdo ARTE Academy e Clínica VidaBemVinda.#DarVidaASonhos

Jane Ferguson:                Hello everyone, and happy new year. Welcome to episode 24 of Getting Personal: Omics of the Heart. It's January 2019, I am Jane Ferguson, an assistant professor at Vanderbilt University Medical Center and an associate editor at Circulation Genomic and Precision Medicine. We have a great line-up of papers this month in the journal, so let's jump right into the articles.                                            First up, a paper from Christopher Nelson, Nilesh Samani, and colleagues from the University of Lester entitled, "Genetic Assessment of Potential Long-Term On-Target Side Effects of PCSK9 Inhibitors."                                            I think most listeners are well aware of the efficacy of PCSK9 inhibition in reducing cardiovascular risk. However, as a relatively new treatment option, we do not yet have data on potential long-term side effects of PCSK9 inhibition. In this study, they utilized genetics as a proxy to understand potential long-term consequences of lower PCSK9 activity. They examined a PCSK9 variant that associates with lower LDL, as well as examining two LDL-lowering variants in HMGCR, the target of statins, which served as a positive control of sorts. They used data from over 479,000 individuals in the UK Biobank and looked for associations between the three LDL-lowering variants and 80 different phenotypes.                                            For the PCSK9 variant, the allele which is associated with lower LDL was significantly associated with the higher risk of type 2 diabetes, higher BMI, higher waist circumference, higher waist-hip ratio, higher diastolic blood pressure, as well as increased risk of type 2 diabetes and insulin use. The HMGCR variants were similarly associated with type 2 diabetes as expected.                                            Mediation analysis suggested that the effect of the PCSK9 variant on type 2 diabetes is independent of its effect on obesity. There were nominal associations between the PCSK9 variant and other diseases, including depression, asthma, chronic kidney disease, venous thromboembolism, and peptic ulcer.                                            While genetics cannot fully recapitulate the information that would be gained from long-term clinical follow up, these data suggest that like statins, PCSK9 inhibition may increase the risk of diabetes and potentially other disease. Overall, the cardiovascular efficacy of PCSK9 inhibition may outweigh these other risks, however, future studies should carefully examine these potential side effects.                                            Next up, we have a paper from Xiao Cui, Fang Qin, Xinping Tian, Jun Cai, and colleagues from Peking Uni and Medical College, on "Novel Biomarkers for the Precise Diagnoses and Activity Classification of Takayasu's Arteritis."                                            They were interested in identifying protein biomarkers of Takayasu arteritis, to improve diagnosis and understanding of disease activity in this chronic vascular disease. They ran a proteomic panel including 440 cytokines on 90 individuals, including individuals with active disease, inactive disease, and healthy controls. They found a number of candidates and validated one protein, TIMP-1, as a specific diagnostic biomarker for Takayasu arteritis. For assessing disease activity, there was no single biomarker that could be used for classification, however, the combination of eight different cytokines identified through random forest-based recursive feature elimination and [inaudible] regression, including CA 125, FLRG, IGFBP-2, CA15-3, GROa, LYVE-1, ULBP-2, and CD 99, were able to accurately discriminate disease activity versus inactivity.                                            Overall, this study was able to identify novel biomarkers that could be used for improved diagnosis and assessment of Takayasu arteritis, and may give some clues as to the mechanisms of pathogenesis.                                            Our next paper is entitled, "Familial Sinus Node Disease Caused By Gain of GIRK Channel Function," and comes from Johanna Kuß, Birgit Stallmeyer, Marie-Cécile Kienitz, and Eric Schulze-Bahr, from University Hospital Münster. They were interested in understanding novel genetic underpinnings of inherited sinus node dysfunction.                                            A recent study identified a gain of function mutation in GNB2 associated with sinus node disease. This mutation led to enhanced activation of the G-protein activated inwardly rectifying potassium channel, or GIRK, prompting the researchers to focus their interest on the genes encoding the GIRK subunits, KCNJ3 and KCNJ5. They sequenced both genes in 52 patients with idiopathic sinus node disease, and then carried out whole exome sequencing in family members of patients with potential disease variants in either gene. They identified a non-synonymous variant in KCNJ5, which was not present in the EVS or ExAC databases, and which segregated with disease in the affected family. This variant was associated with increased GIRK currents in a cell system, and in silico models, predicted the variant altered or spermine binding site within the GIRK channel. Thus, this study demonstrated that a gain of function mutation in a GIRK channel subunit associates with sinus node disease, and suggests that modulation of GIRK channels may be a viable therapeutic target for cardiac pacemaking.                                            Our next paper, "Key Value of RNA Analysis of MYBPC3 Splice-Site Variants in Hypertrophic Cardiomyopathy," comes from Emma Singer, Richard Bagnall, and colleagues from the Centenary Institute and the University of Sydney.                                            They wanted to understand the impact of variants in MYBCP3, a known hypertrophic cardiomyopathy gene, on splicing. They recruited individuals with a clinical diagnosis of hypertrophic cardiomyopathy and genetic testing of cardiomyopathy-related genes. They further examined individuals with a variant in MYBCP3 which had an in silico prediction to affect splicing. They sequenced RNA from blood or from fixed myocardial tissue and assessed the relationship between each DNA variant and gene splicing variation.                                            Of 557 subjects, 10% carried rare splice site variants. Of 29 potential variants identified, they examined 9 which were predicted to affect splicing, and found that 7 of these were indeed associated with splicing errors.                                            Going back to the families, they were able to reclassify four variants in four families from uncertain clinical significance to likely pathogenic, demonstrating the utility of using RNA analysis to understand pathogenicity in genetic testing.                                            The next paper this issue comes from Catriona Syme, Jean Shin, Zdenka Pausova, and colleagues from the University of Toronto, and is entitled, "Epigenetic Loci of Blood Pressure: Underlying Hemodynamics in Adolescents and Adults."                                            A recent large meta epigenome-wide association study identified methylation loci that associate with blood pressure. In this study, they wanted to understand more about how these loci related to blood pressure and hemodynamics. They recruited adolescents and middle-aged adults and assessed 13 CPG loci for associations with hemodynamic markers, including systolic and diastolic blood pressure, heart rate, stroke volume, and total peripheral resistance, measured over almost an hour during normal activities. Several of the loci replicated associations with blood pressure, and two of these also showed age-specific associations with hemodynamic variables. One site in PHGDH was particularly associated with blood pressure and stroke volume in adolescents, as well as with body weight and BMI, where lower methylation resulting in higher gene expression associated with higher blood pressure. A second site in SLC7A11 associated with blood pressure in adults but not adolescents, with lower methylation and consequent higher gene expression associated with increased blood pressure.                                            Overall, this study indicates that methylation mediated changes in gene expression may modulate blood pressure and hemodynamic responses in an age-dependent manner.                                            Next up is a research letter from Ben Brumpton, Cristen Willer, George Davey Smith, Bjørn Olav Åsvold, and colleagues from the Norwegian University of Science and Technology, entitled, "Variation in Serum PCSK9, Cardiovascular Disease Risk, and an Investigation of Potential Unanticipated Effects of PCSK9 Inhibition: A GWAS and Mendelian Randomization Study in the Nord-Trøndelag Health Study, Norway."                                            As we heard about from the first study this issue, the long-term side effects of PCSK9 inhibition remain unknown. In this study, they also applied a genetic approach to understand potential unanticipated consequences of PCSK9 inhibition. They analyzed phenotypes from over 69,000 participants in the Nord-Trøndelag Health Study and measured serum PCSK9 in a subset.                                            In PCSK9 GWAS of over 3,600 people, with replication in over 5,000 individuals from the twin gene study. They defined a genetic risk score for serum PCSK9 and assessed the relationship between genetically predicted PCSK9 and outcomes. They saw the expected associations between lower PCSK9 and lower LDL and coronary heart disease risk. However, there was minimal evidence for associations with other outcomes.                                            While our first study in this issue, from Nelson, et al, found that lower PCSK9 from a single genetic variant was associated with higher diabetes risk, this risk was not found here using the genetic risk score. Differences in the genetic definitions and in the populations used can perhaps explain these differences between the two studies, but overall, the studies are consistent in suggesting that long-term PCSK9 inhibition is unlikely to be associated with major adverse outcomes.                                            Our second research letter comes from Young-Chang Kwon, Bo Kyung Sim, Jong-Keuk Lee, and colleagues from Asan Medical Center in Seoul, on behalf of the Korean Kawasaki Disease Genetics Consortium. The title is, "HLA-B54:01 is Associated with Susceptibility to Kawasaki Disease," and reports on novel Kawasaki disease variants.                                            HLA genes have been previously associated with disease, and in this report, the authors sequenced selected axons in HLA-DRB1, HLA-DQB1, HLA-A, HLA-B, HLA-C, and HLA-DBP1 in 160 Kawasaki disease patients and 278 controls. They find a significant association with HLA-B, and replicated this in a sample of 618 Kawasaki disease patients, compared with over 14,000 in-house controls. They identified specific amino acid residues conferring disease susceptibility, highlighting HLA-B as a potential modulator of Kawasaki disease.                                            Our third and final research letter concerns "Serum Magnesium and Calcium Levels and Risk of Atrial Fibrillation: a Mendelian Randomization Study," and comes to us from Susanna Larsson, Nikola Drca, and Karl Michaëlsson, from the Karolinska Institute.                                            Because magnesium and calcium are known to influence atrial fibrillation, this group was interested in whether genetic predictors of serum methyls associated with disease. They constructed genetic predictors from GWAS of calcium in over 61,000 individuals, and GWAS of magnesium in over 23,000 individuals. They applied these predictors to an AF GWAS including over 65,000 cases and over 522,000 controls. Genetically predicted magnesium was inversely associated with atrial fibrillation, while there was no association with genetically predicted calcium.                                            While this study does not definitively prove causality, future studies aimed at assessing whether dietary or other strategies to raise serum magnesium are protective against AF may yield novel strategies for disease prevention.                                            And that's it from us for this month. Thank you for listening, and come back next month for more from Circulation Genomic and Precision Medicine.                                            This podcast was brought to you by Circulation Genomic and Precision Medicine and the American Heart Association Council on Genomic and Precision Medicine. This program is copyright American Heart Association, 2019.  

Distinguir lo propio de lo ajeno, y lo normal de lo aberrante, no es tarea fácil. De hecho, una parte importantísima de nuestra energía se consume en las operaciones del sistema inmune, el encargado de esta tarea. Para el efecto, es vital el complejo mayor de histocompatibilidad, o CMH (MHC en inglés) y su expresión en la superficie de nuestras células, a saber, las moléculas del sistema de antígenos leucocitarios o HLA, por sus siglas en inglés. Conocer a profundidad este tema nos permitirá comprender su implicación en enfermedades alérgicas, autoinmunes, cáncer y muchas más. Existen, básicamente, dos grupos de moléculas del HLA: las HLA-A, HLA-B y HLA-C, pertenecientes a la clase I; y las HLA-DP, HLA-DQ y HLA-DR, de la clase II. Las primeras, presentes en la gran mayoría de células, presentan antígenos provenientes de péptidos de síntesis endógena, que han sido fraccionados por el proteasoma, y las segundas, más característicamente halladas en células presentadoras de antígeno profesionales, albergan péptidos que vinieron de proteínas captadas del exterior de la célula, digeridas en el complejo de vesículas de los endosomas y lisosomas. Las moléculas del CMH clase I presentan sus péptidos a los linfocitos T CD8+, citotóxicos, y son el blanco de estas últimas en caso de presentar algo "indebido", por ser reconocido como ajeno o aberrante. Por otra parte, las moléculas del CMH clase II son responsables de presentar los antígenos a linfocitos T colaboradores, es decir, CD4+. Revisaremos su estructura, su síntesis, ensamblaje y transporte, y las excepciones a la regla que hemos relatado en párrafos anteriores. Revisaremos la sorprendente (y descubriremos por qué no es tan soprendente) forma en que con poquísimos aminoácidos, este complejo de moléculas de superficie puede ayudar a distinguir las proteínas propias y normales de las que no lo son, y revisaremos el fantástico rol que cumplen en esta ecuación los linfocitos NK o natural killers, las células del sistema inmunitario "asesinas por naturaleza". ¿Quieres enterarte semana a semana de las nuevas publicaciones, y acceder a contenido exclusivo? Únete a la lista de correo de Leucocitos isotópicos. Para suscribirte al Podcast de Medicina, estas son las opciones más recomendadas: Apple Podcasts Google Podcasts Si prefieres explorar más alternativas, haz clic aquí. ¿Te gustó el episodio? Seguro disfrutarás este también: El sistema inmunitario y su dualidad (027) Además, puedes acceder a la lista curada y actualizada de los episodios con mayor aceptación. Este show es para ti. Puedes apoyarlo entrando a iTunes y dejando allí una calificación positiva. Encuentra las notas de este episodio y dirige a tus amigos a isotopicos.com/020 El objetivo de Leucocitos isotópicos es entretenerte mientras complementas lo que recibes en tu Escuela o Facultad de Medicina. Soy Médico Internista, y comprendo lo demandante que puede ser nuestra Carrera. Por eso decidí crear el Podcast como un curso de Medicina ameno y sin una estructura rígida, que despierte tu interés y curiosidad por esta maravillosa Ciencia. Nunca reemplazará a la Universidad, ni a los libros, pero cumplirá con la misión que lo fundamenta: Ser el lugar donde descansamos de leer, sin dejar de aprender. No olvides que la mejor manera de ayudar a que el proyecto crezca, es contarle a todos de él. ¡Gracias por compartir este episodio con alguien!

Control of human cytomegalovirus (HCMV) depends on CD8+ T cell responses that are shaped by an individual's repertoire of MHC molecules. MHC class I presentation is modulated by a set of HCMV-encoded proteins. Here we show that HCMV immunoevasins differentially impair T cell recognition of epitopes from the same viral antigen, immediate-early 1 (IE-1), that are presented by different MHC class I allotypes. In the presence of immunoevasins, HLA-A- and HLA-B-restricted T cell clones were ineffective, but HLA-C*0702-restricted T cell clones recognized and killed infected cells. Resistance of HLA-C*0702 to viral immunoevasins US2 and US11 was mediated by the alpha3 domain and C-terminal region of the HLA heavy chain. In healthy donors, HLA-C*0702-restricted T cells dominated the T cell response to IE-1. The same HLA-C allotype specifically protected infected cells from attack by NK cells that expressed a corresponding HLA-C-specific KIR. Thus, allotype-specific viral immunoevasion allows HCMV to escape control by NK cells and HLA-A- and HLA-B-restricted T cells, while the virus becomes selectively vulnerable to an immunodominant population of HLA-C-restricted T cells. Our work identifies a T cell population that may be of particular efficiency in HCMV-specific immunotherapy.

Die bullöse Dermatose Pemphigoid gestationis ist eine äußerst seltene schwangerschaftsassoziierte Autoimmunerkrankung, bei der Antikörper gegen Strukturen der Plazenta produziert werden, die mit dem BP180 der mütterlichen Haut kreuzreagieren und schließlich zur Blasenbildung führen. Ziel der vorliegenden Arbeit war die Assoziation der Erkrankung mit sämtlichen klassischen Humanen Leukozyten-Antigenen (HLA) zu überprüfen. Dafür wurden HLA-Kompletttypisierungen (HLA-A, -B, -C, -DRB1, -DQB1, -DPB1) bei 18 betroffenen Patientinnen und falls vorhanden von Partnern und Kindern der Betroffenen vorgenommen. Von Kindern und Partnern standen insgesamt 27 DNA-Proben zur Verfügung. Diverse Studien wiesen eine Assoziation der Erkrankung mit den HLA-Klasse II-Allelen HLA-DRB1*03 und *04 nach. Eine pathogenetische Rolle paternaler HLA-Moleküle bei der Erkrankung wird aufgrund der Häufung des HLA-DRB1*02-Phänotyps im Kollektiv der Partner vermutet. Die statistischen Berechnungen der Typisierungsergebnisse dieser Arbeit zeigten im Kollektiv der PG-Patientinnen eine signifikante Häufung der HLA-Allele B*08 (p=0,0019), B*18 (p=0,0455), DRB1*03 (p=0,001), DQB1*02 (p=0,0283) und DPB1*0101 (p=0,0011). In Übereinstimmung mit Daten aus der Literatur trat im PG-Patientinnen-Kollektiv der DRB1*03/*04-Phänotyp und im Kollektiv der Partner der HLA-DR02-Phänotyp signifikant gehäuft auf. Untersuchungen auf Aminosäureebene zeigten Gemeinsamkeiten der HLA-DRB1-Allele, die in dem Kollektiv der Mütter vertreten waren auf. Bei der Betrachtung der Genkonstellationen kompletter Stammbäume war ersichtlich, dass im Fall von 3 der 6 aufgeführten Stammbäume die Vererbung des väterlichen DRB1*02-Alleles mit der Krankheitsentwicklung in der entsprechenden Schwangerschaft zusammenfiel. Es wurden keine Hinweise gefunden, dass die Interaktion von HLA-C bzw. HLA-B mit KIR (killer cell immunglobulin-like receptors) für das Auftreten der Krankheit eine Rolle spielen. Die Ergebnisse legen einerseits nahe, dass aufgrund der Häufung von Allelen verschiedener HLA-Loci mehrere Gene eine ätiopathogenetische Rolle spielen, andererseits die Häufung mehrerer Gene verschiedener Loci auf einer Kopplung beruhen könnte. Desweiteren liefern die Untersuchungen der Aminosäurensequenzen Hinweise darauf, dass sich bestimmte Aminosäurensubstitutionen in der Bindungsgrube der HLA-Klasse II-Moleküle als protektiv 72 oder als erhöhtes Risiko auswirken könnten. Die Rolle des väterlichen HLA-DR bleibt weiterhin ungeklärt. Die Konstellation der HLA-DR-Vererbung innerhalb kompletter Familien suggeriert, dass die Vererbung des HLA-DRB1*02 an das Kind als zusätzlicher Risikofaktor zu bewerten ist, aber nicht als ursächlich für die Erkrankung betrachtet werden kann. Zur weiteren Klärung der paternalen Rolle wäre die Überprüfung der HLA-Klasse II-Expression in PG-Plazenten mit modernen molekularbiologischen Methoden von großem Interesse.

An expressed beta-tubulin gene (TUBB) has previously been localized to chromosome region 6pter-p21 in man. By using a panel of deletion mutant cell lines and radiation-reduced hybrids containing fragments of chromosome 6, the TUBB locus could be mapped to the HLA class I region at 6p21.3. A long range restriction map including TUBB and several HLA class I genes was then generated by rotating field gel electrophoresis. The results show that TUBB maps to a segment 170-370 kb telomeric of HLA-C. This location suggests that a mutation at the TUBB locus could be the cause for certain forms of HLAlinked microtubule dysfunction, including immotile cilia syndrome.

Several new HLA-B (B8, B51, Bw62)- and HLA-C (Cw6, Cw7)-specific genes were isolated either as genomic cosmid or cDNA clones to study the diversity of HLA antigens. The allele specificities were identified by sequence analysis in comparison with published HLAB and -C sequences, by transfection experiments, and Southern and northern blot analysis using oligonucleotide probes. Comparison of the classical HLA-A, -B, and -C sequences reveals that allele-specific substitutions seem to be rare events. HLA-B51 codes only for one allelespecific residue: arginine at position 81 located on the cd helix, pointing toward the antigen binding site. HLA-B8 contains an acidic substitution in amino acid position 9 on the first central/3 sheet which might affect antigen binding capacity, perhaps in combination with the rare replacement at position 67 (F) on the Alpha-l helix. HLA-B8 shows greatest homology to HLA-Bw42, -Bw41, -B7, and -Bw60 antigens, all of which lack the conserved restriction sites Pst I at position 180 and Sac I at position 131. Both sites associated with amino acid replacements seem to be genetic markers of an evolutionary split of the HLA-B alleles, which is also observed in the leader sequences. HLA-Cw7 shows 98% sequence identity to the JY328 gene. In general, the HLA-C alleles display lower levels of variability in the highly polymorphic regions of the Alpha 1 and Alpha 2 domains, and have more distinct patterns of locusspecific residues in the transmembrane and cytoplasmic domains. Thus we propose a more recent origin for the HLA-C locus.