Evolution of synovial fluid mononuclear cell responses in a HLA B27-positive patient with Yersinia-associated juvenile arthritis.

A 15-year-old boy who developed acute arthritis following an episode of urethritis, was found to have agglutinating antibodies (titre 1:320) against Yersinia enterocolitica 0:3. Synovial fluid mononuclear cell (SFMC) proliferative responses to this agent and other antigens were examined on four occasions over the subsequent 40 months. Responses to Yersinia were predominant during the first year, but after 29 months responses to purified protein derivative of Mycobacterium tuberculosis and Salmonella were greater than to Yersinia. Moderate responses to a mycobacterial heat shock protein (HSP65) were present throughout the illness. These results suggest that maximal mononuclear cell proliferative responses may change over time, and raise the possibility that responses which are initially specific for the inciting arthritogenic agent may eventually become more generalized.