Previous studies demonstrated that TRAIL inhibited T-cell activation in an apoptosis-independent manner in autoimmune arthritis and encephalitis.10,11 In support of this, in the present study, TRAIL-treated T cells significantly suppressed the development of colitis and gut inflammation, indicating that TRAIL inhibited effector T-cell functions in the pathogenesis of autoimmune colitis. Here, TNFSF10 is linked to colitis.