Natural killer funciton in systemic lupus erythematosus.

Peripheral blood lymphocytes from patients with systemic lupus erythematosus (SLE) demonstrated significantly less cytotoxicity against two different lymphoblastoid cell lines and one myeloid cell line than peripheral blood lymphocytes from normal individuals. Short-term culture and other attempts to remove interfering immune complexes failed to restore low natural killer (NK) function. Six day culture in fetal calf serum resulted in increased cytotoxicity by mononuclear cells from normal individuals and some SLE patients, but this effect was shown to be dependent on Fc-, not Fc+, effector cells. Suppressor cells were not demostrable as a cause for decreased NK activity.