2 dimensional flow cytometric analysis of activation antigens expressed on the synovial fluid T cells in rheumatoid arthritis.

Synovial fluid T cells expressed a higher percentage of all 3 activation antigens examined (anti-Ia antigen [HLA-DR]; antiinterleukin 2 receptor antigen [Tac], and antitransferrin receptor [TF-R] antigen) than the paired peripheral blood T cells obtained simultaneously from 19 patients with rheumatoid arthritis (RA) (p less than 0.001-0.05). A highly significant correlation was observed between disease activity and the percentage of Tac+ T cells in the synovial fluid from patients with RA (p less than 0.001).