British Journal of Rheumatology 1983:22(suppl 2):46-49 YERSINIA ARTHRITIS IN THE MIDLANDS: CLINICAL AND IMMUNOLOGICAL FEATURES IN TEN CASES DURING 1980-1983

and Iy83. Diagnostic difficulty arose in four cases owing to unusual form of presentation or course Two of the cases studied during the acute phase showed a marked degree of lymphocyte transformation in the presence of Y enierocolmcaOJ in a dosc-rclatcd form This does not lend support to the concept of molecular mimicry between the bacterial antigen and the B27 gene product since this would be more likely to result in a diminished response. KEY WORDS: Yersinia arthritis. HLA-B27. YERSINIA arthritis is unusual in Britain. Most reports have been from Scandinavia though cases seen in the United Kingdom have occasionally been reported (1-4). The arthritis is reactive in type and has been shown to occur predominantly in HLA-B27 individuals (5). The mechanisms involved in B27 associated arthritides are open to conjecture but at least in reactive arthritis as compared with ankylosing spondylitis the role of a given bacterium is not in dispute. This report notes the clinical features, standard serology and cell-mediated responses to several bacterial antigens. Materials and methods Ten cases of serologically-proven Yersinia arthritis were diagnosed in the Leicester, Nottingham, Walsall and Northampton areas between 1980 and early 1983. Clinical and laboratory data were collated. There were seven males. The overall ages ranged from 10 to 42 (mean 24.5) years. Laborator