Recent studies indicate that several TNFSF members, notably TNF (TNFSF2, also known as TNF-α) [34], FasL (TNFSF6, also known as CD95L) [35] and TRAIL (TNF-related apoptosis inducing ligand, TNFSF10) [36], contribute to the pathogenesis of certain autoimmune diseases, such as IBD and CD, by enhancing the proinflammatory functions of T cells. Here, TNF is linked to Cowden disease.