Aggrawal evaluated the role of TNF-induced apoptosis in T cell deficiency in lymphocytes from aged humans, expression of TNF receptors (TNFRI and TNFRII), and the adapter molecules, including TNFR-associated death domain protein (TRADD), TNFR-associated factor 2 (TRAF-2), and receptor-interacting protein (RIP). This evidence concerns the gene TNFRSF1B and congenital T-cell immunodeficiency.