Predominance of cells with T-markers in the lymphocytic infiltrates of synovial tissue in psoriatic arthritis.

Synovial tissue from 8 patients with psoriatic arthritis (PSA) were investigated by direct immunofluorescence technique with FITC-conjugated anti-F(ab')2 antiserum, and with a specific rabbit anti-human T-lymphocyte antiserum by indirect immunofluorescence method with FITC-conjugated goat-anti-rabbit Ig antiserum as the second layer. The majority of the lymphocytes in the tissue displayed membrane fluorescence with the anti-T antiserum. Staining with the conjugated anti-F(ab')2 antiserum revealed both intra- and extracellular immunoglobulins. These results indicate that the majority of the lymphocytes in the synovial tissue of PSA are T-lymphocytes, and that a minor number of the cells belong to the B-cell line.