Loss of suppressor T-lymphocyte function in patients with systemic lupus erythematosus (SLE)

Immunological reactivity in patients with SLE was studied in vitro trinitrobenzene sulphonate (TNP) specific antibody formation by peripheral blood lymphocytes. Lymphocytes from patients with SLE could produce an increased number of TNP-specific plaque-forming cells (PFC), while no such response could be seen in normal controls. Co-culture of lymphocytes from active SLE patients and normal controls was performed with TNP-Horse red blood cells (TNP-HRBC). The number of PFC by B lymphocytes from active SLE patients was suppressed by T lymphocytes from normal controls. On the other hand, the number of PFC by B lymphocytes from normal controls was increased by T lymphocytes from active SLE patients. Co-culture of lymphocytes from identical twins discordant for SLE was also performed, and the same results were obtained. We further examined the effects of Con A on antibody formation. Con A-treated T lymphocytes from a normal control markedly suppressed TNP-specific PFC by peripheral lymphocytes from active SLE patients. However, Con A-treated T lymphocytes from an active SLE patient did not suppress TNP-specific PFC by lymphocytes from another active SLE patient. These results suggest that active SLE patients showed a loss of suppressor T-lymphocyte function.