title: Non-antigen presenting effects of HLA-B27.
abstract: Spondyloarthropathies (SpA) are a group of chronic rheumatic diseases, which show a strong asoociation with human leukocyte antigen (HLA)-B27. Although the association between HLA-B27 and the susceptibility to SpA was discovered thirty years ago, the exact mechanism by which HLA-B27 predisposes to disease development remains unclear. The classical role of MHC class I molecules is to present peptides for CD8+ T cells. Therefore, it has been proposed that the antigen presenting function of HLA-B27 is somehow altered in the patients developing SpA. However, despite extensive research, the attempts to create a comprehensive theory that would explain the role of HLA-B27 as an antigen presenting molecule in the development of SpA have been unsuccessful. Reactive arthritis (ReA) belongs to the group of SpA. It is a joint inflammation developing after certain bacterial infections e.g. Salmonella, Yersinia, and Chlamydia. Several unrelated observations indicate that HLA-B27 modulates the interaction between ReA-triggering bacteria and host cell. These findings suggest that HLA-B27 may possess functions, which are unrelated to antigen presentation. In this paper, we summarize these findings and discuss their potential impact in the development of SpA.
authors.affiliation: National Public Health Institute, Department of Human Microbial Ecology and Inflammation, Turku, Finland. markus.penttinen@utu.fi
authors.forename: Markus A
authors.initials: MA
authors.lastname: Penttinen
authors.forename: Päivi
authors.initials: P
authors.lastname: Ekman
authors.forename: Kaisa
authors.initials: K
authors.lastname: Granfors
mesh_terms: D017951:Antigen Presentation / Q000276:immunology; D004198:Disease Susceptibility / Q000276:immunology / Q000382:microbiology; D004781:Environmental Exposure / Q000009:adverse effects; D016905:Gram-Negative Bacterial Infections / Q000150:complications / Q000276:immunology* / Q000378:metabolism; D015796:HLA-B27 Antigen / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology / Q000378:metabolism; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D018716:Molecular Mimicry / Q000276:immunology; D000091402:Prohibitins; D012216:Rheumatic Diseases / Q000209:etiology / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D001613:beta 2-Microglobulin / Q000276:immunology / Q000378:metabolism
chemical_list: D015796:HLA-B27 Antigen; D015395:Histocompatibility Antigens Class I; D008070:Lipopolysaccharides; C000717331:PHB2 protein, human; D000091402:Prohibitins; D001613:beta 2-Microglobulin