A minority of patients with rheumatoid arthritis show a dominant rearrangement of T-cell receptor beta chain genes in synovial lymphocytes.

The clonality of T lymphocytes isolated from the synovial fluid and peripheral blood of patients with rheumatoid arthritis was investigated by restriction enzyme fragment mapping of the rearrangements of the beta chain gene of the T-cell antigen receptor. Three patients showed a dominant rearrangement amongst their synovial fluid T cells which was not seen in their peripheral blood T-cell population, suggesting the presence of a predominating T-cell clone. However, most of the patients examined (8 out of 11) demonstrated polyclonal T-cell populations in both their synovial fluid and peripheral blood. Of four synovial fluid T-cell lines investigated, one showed evidence of a dominant T-cell clone.