Recent studies in the ileitis-prone SAMP mice have convincingly shown that Th9 cell induction can be promoted by the death receptor 3 (DR3), a member of the TNFR superfamily 25, which is preferentially expressed on activated T cells and acts as the functional receptor for TNF-like cytokine 1A (191). Here, TNFRSF25 is linked to Crohn ileitis.