Con A-induced suppressor cell activity and T-lymphocyte subpopulations in peripheral blood lymphocytes of patients with rheumatoid arthritis and juvenile rheumatoid arthritis.

Suppressor cell activity was investigated in peripheral blood lymphocytes from twenty patients with rheumatoid arthritis (RA) and twenty patients with juvenile rheumatoid arthritis (JRA) using a concanavalin A/mixed lymphocyte culture assay. The mean suppression in the RA patients was slightly reduced compared with the suppressor cell activity in adult controls (25 +/- 5% suppression compared with 37 +/- 5%; P less than 0.05, Student's t test), whereas the JRA patients had normal suppressor cell activity (mean 46 +/- 5% versus 43 +/- 5% in healthy children matched for age and sex). The RA patients had normal proportions of T-cell subpopulations, 13.3% T gamma cells and 49.8% T mu cells, compared with 13.8% and 58.0% in controls. The JRA patients, however, had a significantly reduced mean percentage of T gamma cells, 6.6%, compared with 13.8% in healthy children (P less than 0.05, Mann-Whitney U-test). The mean percentage of T mu cells was 53.7%, versus 56.2% in the controls. The relation between suppressor cell activity and suppressor cells enumerated by membrane markers is discussed.