CD4+ CD25+ Foxp3+ regulatory T cells (Tregs), are produced in the thymus or generates from conventional CD4+ T cells in peripheral sites, suppress the activation and proliferation of autoreactive cells to control the immune response to antigens and play a fundamental role in the maintenance of immune homeostasis, which have been found numerically and functionally deficient in development and progression of some autoimmune diseases (7). The gene discussed is CD4; the disease is autoimmune disease.