For instance, the Bcl-2 and Bcl-XL genes, which inhibit the intrinsic apoptotic pathway, are essential for both T-cell development and peripheral maintenance.4, 5 However, lack of cell death, as in the case of inactivation of Bim, a pro-apoptotic protein of the Bcl-2 family, results in lymphoproliferative and autoimmune diseases.6 The extrinsic pathway of apoptosis is triggered through cell receptors, including Fas/Apo-1 and tumor necrosis factor receptor 1 (TNFR1). This evidence concerns the gene FAS and autoimmune disease.