Clonal heterogeneity of synovial fluid T lymphocytes in inflammatory synovitis.

Several studies have examined patients with rheumatoid arthritis for the presence of oligoclonal populations of synovial T lymphocytes. The results of these studies have been conflicting. In this study one patient with rheumatoid arthritis and two with other forms of inflammatory synovitis were examined by Southern blot analysis of T cell clones generated from synovial fluid by primary limiting dilution. Evidence of oligoclonality was documented only in a patient with psoriatic arthritis. The distinguishing characteristics of this patient, in addition to the diagnosis, included the fact that only one joint was involved, the synovitis in the affected joint was of recent onset, and the synovial fluid lymphocytes from which the T cells were cloned responded strongly to soluble antigens. Because of the association with the strong response to soluble antigens, synovial fluid T lymphocytes from another patient with rheumatoid arthritis were cloned in response to a crude mycobacterial antigenic mixture. Three of the seven clones examined were identical by Southern blot analysis. These observations suggest that the presence of oligoclonality is limited in patients with inflammatory arthritis. The relationship of a specific antigen-driven response within the joint to the detection of oligoclonal T cells within that joint remains to be determined.