IL-2 production is decreased in systemic lupus erythematosus (SLE) patients and affects T cell function and other aspects of host immunity. Transcription factors regulating IL-2 production behave aberrantly in SLE T cells. In addition to IL-2 dysregulation, other IL-2 family members (IL-15 and IL-21) are abnormally expressed in SLE. Decreased IL-2 production in SLE patients leads to many immune defects such as decreased T(reg) production, decreased activation-induced cell death (AICD), and decreased cytotoxicity. IL-2 deficiency results in systemic dysregulation of host immune responses in patients suffering from SLE disease.