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HLA Antigens (hla + antigen)
Selected AbstractsHLA haplotypes in recurrent aphthous stomatitis: a mode of inheritance?INTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 6 2008E. Albanidou-Farmaki Summary The aim of this study was to investigate the genetic association between recurrent aphthous stomatitis (RAS) and human leucocyte antigen (HLA) class I and II alleles and HLA haplotypes. Families selected had at least one child suffering from recurrent aphthous stomatitis in addition to one or both of the parents. HLA-A, -B and -DR alleles were typed in 29 families, 27 nuclear and two extended (121 subjects). HLA haplotypes of all family members with RAS were compared with those who were RAS negative. Although major histocompatibility complex class I and II gene analysis failed to demonstrate any significant association between RAS and HLA antigens, the study of HLA haplotypes revealed a significant association between HLA haplotypes and susceptibility to RAS. The results indicate that susceptibility to RAS segregates in families in association with HLA haplotypes. [source] Blood group antigens and immune responses,detailed knowledge is necessary to prevent immunization and to follow up immunized individualsISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue n1 2010A. Husebekk Background The immune system is educated to detect and react with foreign antigens and to tolerate self-antigen. Transfusion of blood cells and plasma and pregnancies challenge the immune system by the introduction of foreign antigens. The antigens may cause an immune response, but in many instances this is not the case and the individual is not immunised after exposure of blood group antigens. Aims The aim of the presentation is to dissect some immune responses to blood group antigens in order to understand the mechanism of immunisation. Methods The results of immune responses to blood group antigens can be detected by the presence of antibodies to the antigens. If the antibodies are of IgG class, the activated B cells have received help from antigen specific T cells. Both antibodies, B cells and T cells can be isolated from immunised individuals and studied in the laboratory. Also B-cell receptors and T-cell receptors as well as MHC molecules on antigen presenting cells can be studied and models of the immune synapses can be created in vitro. Results The most classic immune responses in transfusion medicine and in incompatible pregnancies are immune responses to the RhD antigen on red cells, HLA class I molecules on white cells and platelets and human platelet antigens. The nature of these antigens are different; RhD antigens are part of a large complex, present on red cells from RhD positive individuals and completely lacking on red cells from RhD negative individuals. It is likely that many peptides derived from this antigen complex may stimulate T cells and B cells. HLA antigens are highly polymorphic and the antigens are known to induce strong alloimmune responses. The HPA antigens are created by one amino acid difference in allotypes based on a single nucleotide polymorphism at the genetic level. HPA 1a induce immune responses in 10% of HPA 1b homozygote pregnant women. The result of these immune responses is destruction of blood cells with clinical consequences connected to the effect of transfusions or the outcome of pregnancies. Summary/Conclusions Even though there is emerging knowledge about the immune responses to some of the blood group antigens, more information must be gained in order to understand the complete picture. The action of the innate immune response initiating the adaptive immune response to blood group antigens is not well understood. A detailed understanding of both the innate ad the adaptive part of the immune response is necessary to identify individuals at risk for immunisation and to prevent immunisation to blood group antigens. [source] Psoriasis vulgaris and human leukocyte antigensJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 3 2007FF Cassia Abstract Background, Psoriasis vulgaris is a skin disease with a complex immunological and genetic background, triggered by environmental factors. The association of human leukocyte antigens (HLA) and psoriasis has long been reported on population and familial studies. Objectives, To review and discuss studies on psoriasis vulgaris and HLA, in Caucasian and non-Caucasian populations. Methods, The major population studies on psoriasis vulgaris and the associated HLA antigens and alleles are described and discussed based on a review of the current literature. Results, Population studies demonstrate the presence of different HLA specificities as well as extended haplotypes in patients with psoriasis, when compared to controls. Some alleles occur in a lower frequency in patients with psoriasis, indicating they could be protection alleles. In all studies which HLA class I was typed, Cw6 or Cw*0602 was present in a significant frequency in patients with psoriasis, mainly when early onset and positive family history were considered. HLA-DRB1*0701 was also present in a higher frequency in patients in different populations. Conclusions, Different antigens and alleles from both HLA classes I and II were seen in a significantly higher frequency in patients with psoriasis vulgaris. HLA Cw*0602 and DRB1*0701 were represented in different reports, and the former was related mainly to psoriasis type I. [source] Calculated PRA (CPRA): The New Measure of Sensitization for Transplant CandidatesAMERICAN JOURNAL OF TRANSPLANTATION, Issue 1 2010J. M. Cecka The ways we measure whether a patient is sensitized to HLA antigens and to what extent sensitization affects access to transplantation have changed remarkably during the past decade. What we mean by sensitized and broadly sensitized today is heavily dependent upon the sensitivity of the test that is used to measure antibodies. Because we provide additional allocation points for broadly sensitized patients in the United States kidney allocation system in an effort to compensate for their biological disadvantage, some consistency and accountability are required. The calculated panel-reactive antibody, which provides an estimate of the percentage of deceased organ donors that will be crossmatch incompatible for a candidate provides both consistency and accountability. [source] HLA,B27 heavy chains distinguished by a micropolymorphism exhibit differential flexibilityARTHRITIS & RHEUMATISM, Issue 4 2010Heinz Fabian Objective Although the products of the HLA subtypes B*2705 and B*2709 differ only in residue 116 (Asp versus His) within their peptide-binding grooves, they are differentially associated with inflammatory rheumatic diseases such as ankylosing spondylitis (AS): B*2705 occurs in AS patients, whereas B*2709 is only rarely encountered. The reasons for this distinct association are still unclear but could include subtype-specific conformational and dynamic properties of these antigens. The present study was undertaken to investigate structural and dynamic differences between B*2705 and B*2709 and their possible relationship to subtype-specific disease association. Methods The membrane-distal segments of the B*2705 and B*2709 heavy chains were expressed in vitro and reconstituted together with ,2 -microglobulin and a peptide. HLA,B27 complexes loaded with 2 self peptides (TIS [RRLPIFSRL] and pVIPR [RRKWRRWHL]) and a sequence-related viral peptide (pLMP2 [RRRWRRLTV]) were studied by isotope-edited infrared spectroscopy to detect differences in their structure and flexibility at physiologic temperature. Results Our analyses revealed the existence of subtype-specific conformational differences between the 2 HLA,B27 heavy chains at physiologic temperature, which are undetectable using x-ray crystallography. Irrespective of the bound peptide, the heavy chain of the B*2705 complex exhibited higher conformational flexibility than the B*2709 heavy chain. Conclusion The present study demonstrates the existence of previously undetected systematic conformational and dynamic differences between the heavy chains of the 2 HLA,B27 subtypes. Since effector cell recognition of cells expressing HLA antigens is dependent on the dynamic properties of the interacting cell surface molecules, this HLA,B27 subtype,specific heavy chain flexibility could have a role in the distinct association of HLA,B27 subtypes with spondylarthritides. [source] 3364: Cytokines in enucleated eyesACTA OPHTHALMOLOGICA, Issue 2010MJ JAGER Purpose One of the prognostically bad parameters in uveal melanoma is the presence of an inflammatory phenotype, characterized by an increased expression of HLA antigens and an immunologic infiltrate. We wondered whether the presence of specific chemokines and cytokines in the aqueous humor (AqH) from uveal melanoma-containing eyes is associated with this inflammatory phenotype, with the presence of macrophages, and/or with survival. Methods Directly following enucleation, AqH was obtained from 37 eyes containing uveal melanoma. Samples were stored at -80 °C till use. Using a multiplex bead array, 15 different cytokines were measured. Determination of intratumoral macrophages was performed by immunohistochemistry and immunofluorescence. The presence of specific cytokines was compared to histopathological, genetic and clinical tumor characteristics, as well as patient survival. Results Several cytokines showed a significantly higher expression in the AqH from uveal melanoma-containing eyes compared to the AqH from eyes undergoing cataract surgery. Only MCP-3 was associated with the presence of macrophages and the tumor promoting M2-type macrophage in uveal melanoma patients. Hardly any correlations were found between cytokine levels and known prognostic factors for uveal melanoma. Also, cytokine levels were not of predictive value for survival. Conclusion Although increased levels of inflammation-related cytokines are present in the AqH of uveal melanoma-containing eyes, hardly any associations with the presence of macrophages and their subtypes, with clinical and histopathological parameters, and prognosis were found. [source] | ||||||||||