IL-2 regulates T-cell growth, proliferation, differentiation,and the maturation of different subsets of T cells in the thymus.84 The absence of IL-2 can lead to conditions suchas anemia, abnormal lymphoproliferation, and an inflammatory boweldisease akin to ulcerative colitis.85 IL-4may also influence T-cell maturation in the thymus. The gene discussed is IL2; the disease is inflammatory bowel disease.