T cell function in systemic lupus erythematosus: normal production of and responsiveness to interleukin 2

To investigate the role of interleukin 2 (IL-2) in systemic lupus erythematosus (SLE) mononuclear cells (MNC) of 68 SLE patients were tested for their ability to produce and also to respond to IL-2. Cells were collected monthly over an one year period. IL-2 production by MNC was measured under various conditions after optimal and suboptimal stimulation. Although we found a large variation in IL-2 production by individual MNC preparations no statistical significant differences were found between normal and SLE cells. To study IL-2 responsiveness, proliferation of MNC was studied under conditions where endogenous IL-2 production is limiting. Addition of IL-2 resulted in a four- to eight-fold enhancement of proliferative responses. However also in this respect no differences were found between SLE patients and healthy controls. Thus, in this group of SLE patients no abnormalities in IL-2 production or response could be demonstrated.