Infections and the immunopathogenesis of seronegative spondyloarthropathies

Evidence is accumulating for invasion of joints by bacterial antigens in the seronegative spondyloarthropathies. In spite of the inability to isolate bacteria directly from joint material, indirect evidence, provided by antibody and cellular immune studies, points to a local response to local antigen within the joint. Using monoclonal or polyclonal antibodies, several groups have reported detection of bacterial antigens in synovial fluid cells and synovium itself both in reactive arthritis and in undifferentiated forms of seronegative arthritis. There appear to be direct parallels with animal models insofar as bacterial persistence and arthritogenicity are concerned. To date, however, attempts to detect bacterial DNA in joint material, with the possibility of viability that such findings might imply, have been negative.