Objective: To investigate the antigenic specificity of synovial T cells in juvenile chronic arthritis (JCA).
Methods: Synovial fluid and peripheral blood mononuclear cells from 24 patients with JCA were tested for their proliferative responses to recall antigens, enteric organisms associated with reactive arthritis, influenza A and a recombinant preparation of a mycobacterial heat shock protein, HSP65. To investigate further recognition of this last antigen, synovial T cells from one B27+ patient with pauciarticular disease were cloned using HSP65. The specificity of the resultant clones was then examined.
Results: Marked synovial T cell responses to enteric organisms and to HSP65 were noted, particularly in HLA-B27+, pauciarticular patients; these were similar to those seen in a B27+ patient with reactive arthritis. Responses to enteric organisms and to HSP65 were significantly correlated, suggesting recognition of an epitope common to these antigen preparations. However, all of the T cell clones obtained using HSP65 proved to recognize E. coli derived antigens contaminating the recombinant HSP65 rather than the mycobacterial antigen; these contaminants included the 60 kDa E. coli HSP, GroEL. The GroEL specific T cells did not respond to heat shocked human cells; this suggests (but does not prove) that they do not crossreact with human HSP60.
Conclusion: Synovial T cell recognition of antigens from enteric organisms associated with reactive arthritis is a common feature in pauciarticular JCA. Among the target antigens is the GroEL HSP, but T cells recognizing this antigen do not necessarily crossreact with the homologous human HSP60.