title: HLA-B27M1M2 and high immune responsiveness to Shigella flexneri in post-dysenteric arthritis.
abstract: The heterogeneous HLA-B27 antigen is closely associated with post-infectious or reactive arthritis (ReA) and is comprised of two serologically defined variants: B27M1+M2+ and B27M1+M2-. An outbreak of dysentery (n = 120) caused by a Shigella flexneri 2a strain, which possessed cell envelope antigens with epitopes resembling B27M2, resulted in five B27M1+M2+ patients with ReA. The remaining seven B27M1+M2+, one B27M1+M2- and all but three B27-negative patients remained free of joint symptoms; the latter three displayed arthralgia. IgM, IgG and IgA serum titers were statistically raised in all patient groups, but were exceptionally and persistently high in the B27M1+M2+ patients with ReA, especially IgA, as determined in acute-phase sera and sera sampled 1 year after dysentery. B27M1+M2+ thus appears to be a marker for a subset of disease, characterized by a high immune response. It is concluded that the B27M2 epitope is not unequivocally disease-related to Shigella ReA, that B27M1+M2+ is not likely to be the only immune-response-regulating gene involved in this form of ReA and that cross-reactivity between bacterial antigenic epitopes and B27 can only be part of a multifactorial process leading to ReA and in itself not sufficient to produce ReA. The intensity of the immune response appears to be another important factor.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000917:Antibody Formation; D000954:Antigens, Surface / Q000276:immunology; D001170:Arthritis, Infectious / Q000097:blood / Q000276:immunology*; D002648:Child; D004405:Dysentery, Bacillary / Q000097:blood / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D006680:HLA Antigens / Q000276:immunology*; D015796:HLA-B27 Antigen; D006801:Humans; D008875:Middle Aged; D000091402:Prohibitins; D012763:Shigella flexneri / Q000276:immunology*
chemical_list: D000954:Antigens, Surface; D000939:Epitopes; D006680:HLA Antigens; D015796:HLA-B27 Antigen; C000717331:PHB2 protein, human; D000091402:Prohibitins