Phagocyte function and cell-mediated immunity in systemic lupus erythematosus.

Lymphocyte, granulocyte, and macrophage function were studied simultaneously in 26 untreated patients with systemic lupus erythematosus (SLE) and 26 matched controls. The overall cellular response, as assessed in vivo by skin tests and sensitization to dinitrochlorobenzene, was diminished in the SLE group. Although T cells were reduced in number in patients with SLE, their function appeared unimpaired, as shown by normal lymphocyte transformation to phytohemagglutinin and bacterial and fungal antigens. The depressed cutaneous reactivity observed in vivo was explained by the finding of major deficits in the efferent limb of cellular immunity. Initial rate of phagocytosis of both polymorphonuclear neutrophils and macrophages was significantly reduced in patients with SLE as compared with normal persons. Because of cell interaction, the presence of an intrinsic macrophage defect in SLE may contribute to the alleged T- and B-cell dysfunction in that disease.