Impaired antigen-specific suppressor cell activity in patients with systemic lupus erythematosus.

Antigen-specific suppressor cell activity of peripheral blood mononuclear cells was investigated in twenty-nine patients with systemic lupus erythematosus (SLE) and sixteen normal, age- and sex-matched healthy controls. Suppressor cell activity was generated by priming peripheral blood mononuclear cells with high dose antigen (ovalbumin) and adding the washed primed or control (unprimed) cells to autologous optimally stimulated target plaque-forming cell (PFC) cultures. The ability of the primed cells to interfere with an optimal ovalbumin-specific PFC response in the target cultures was used as a measure of antigen-specific suppressor cell activity. The results demonstrated reduced suppressor cell activity in the SLE patients relative to controls--46.8 +/- 3.6% vs 63 +/- 2.4% suppression respectively (P less than 0.01). Consistent with reduced suppressor cell activity was an increase in the plaque-forming cell response to ovalbumin in patients relative to controls (880 +/- 73 vs 763 +/- 102 PFC/10(6) cells respectively [P = 0.10]). No correlation was demonstrated between suppressor cell activity in SLE patients and disease activity or therapy.