Discordant interleukin 2 production in monozygotic twins concordant for systemic lupus erythematosus.

We present data from monozygotic twins concordant for SLE. IL-2 production by peripheral blood mononuclear cells from the patients, when they were discordant for SLE activity, were measured employing cellular mixing experiments. Macrophages from active SLE had a suppressive effect on IL-2 production. Furthermore, SLE T cells appeared to have a defect in IL-2 production irrespective of disease activity. These defects might play an important role in the disordered immunoregulation in SLE.