Reactive arthritis : The human antibody responce elicited by Yersinia enterocolitica and Clamydia trachomatis

Sammanfattning: A central issue in the pathogenesis of reactive arthritis (ReA) is whether or not individuals developing arthritis have an aberrant immune response to individual antigens of potential triggering microorganisms. Although evidence exists that Yersinia and Chlamydia are two agents that precipitate ReA it has not been shown that these pathogens share common antigens. To address this hypothesis, the antibody responses in individuals with ReA associated with Yersinia or Chlamydia have been analysed.Results reveal that 60% of patients with ReA following urogenital infectionhave antibodies to C. trachomatis, compared to 33% of patients withankylosing spondylitis and 19% of healthy blood donors.All patients infected with Y. enterocolitica developed IgG and IgA immuneresponses against a limited number of antigens, which can be detected within weeks of the onset of symptoms. The immune response to most of these antigens persisted throughout the follow-up period (the longest being 993 days). The IgG response was partly directed against different antigens not involved in the IgA response. There were substantial differencies between patient sera as regards anti genic specificity patterns. Individual variations were more pronounced than any putative similarities among patients with ReA or uncomplicated enterocolitis (UEC).Sera from patients with Y. enterocolitica-triggered ReA with or withoutantibodies to Chlamydia and sera from patients with UEC caused by Y. enterocolitica were analysed for cross-reactions with Salmonella typhimurium and C. trachomatis, representing two arthritis-associated bacteria. It was found that three antigens were restricted to arthritis associated organisms. Affinity purification suggested that one antigen of 74 kDa was recognized in Yersinia-, Salmonella-, and Chlamydia antigen preparations.A standardized method for quantitative Western blot analysis, using ascanning and image-processing system, was developed. Using this system it was found that the degree of antibody response could vary significantly between different runs. The amount of antigen transferred was found to be the key factor affecting the interpretation of the antibody response.