Yersinia enterocolitica: a cause of chronic polyarthritis.

To investigate the role of Yersinia persistence in chronic undifferentiated arthritis, two patients who had chronic undifferentiated polyarthritis and circulating IgA and IgG antibodies to Yersinia outer proteins were studied. Immunofluorescence using antibodies directed against Yersinia adhesin A was performed on colonic and synovial tissue. Synovial tissue T cells were cloned aspecifically and screened for their proliferative responses to Yersinia enterocolitica. Furthermore, a Yersinia-specific polymerase chain reaction (PCR) was performed on synovial tissue. Both patients were found to have Yersinia antigens in colonic and synovial tissue. Y. enterocolitica-positive T-cell clones were grown from the synovial tissue: 4 CD4+ clones of 37 clones from patient 1 and 6 CD4+ clones of 53 clones from patient 2. Yersinia-specific PCR products were not detected in the synovial tissue specimens. The results support the hypothesis that an immune-mediated response to Yersinia antigens may play an important role in the pathogenesis of chronic undifferentiated arthritis.