Surface characteristics of synovial fluid and peripheral blood lymphocytes in inflammatory arthritis

In order to characterize the T‐ and B‐cell populations of inflammatory arthritides, synovial fluid and peripheral blood lymphocytes from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), juvenile rheumatoid arthritis (JRA), and rheumatoid variant diseases (RV) were studied. Normal peripheral blood lymphocytes were examined as controls. T cells were identified by spontaneous sheep red blood cell (E) rosette formation. B cells were determined by complement receptor lymphocyte (EAC) rosette formation and by the presence of surface immunoglobulins (SIg) utilizing fluoresceinated polyvalent antiglobulin. Synovial fluids were analyzed in terms of duration, mucin quality, white cell count, and differential. Synovial fluid and peripheral blood lymphocytes from patients with RA and RV were distributed in T‐ and B‐cell percentages similar to those found in normal peripheral blood. In contrast, significant T‐cell depression was observed in the percentage of synovial fluid and peripheral blood lymphocytes of SLE and JRA patients. This depression was apparent in comparison with normal peripheral blood and with the synovial fluid and peripheral blood from RA patients. B‐cell percentages were similar in all patient groups and in comparison to normal peripheral blood lymphocytes. No differences were noted in B‐cell percentages when the EAC and SIg techniques of identification were compared. The percentage of cells bearing neither T‐ nor B‐cell markers (null cells) was enumerated for each patient group and found to be significantly elevated in the synovial fluid and peripheral blood of SLE and JRA patients. Though the mean synovial fluid and peripheral blood null cell percentages in RA patients were similar to those in controls, a definite bimodal distribution was found in the synovial fluids. These data suggest that evaluation of T‐, B‐, and null‐cell populations may be clinically useful in differentiating patients with SLE and JRA from those with rheumatoid arthritis and variant diseases.