TNFSF15 is differentially expressed in Crohn’s disease and ulcerative colitis and its protein product TL1A is part of the tumor necrosis factor superfamily and a ligand for two receptors: DR3 encoded by TNFRSF25, which activates pro-inflammatory signaling, and soluble TR6 encoded by TNFRSF6B, which acts as a non-functional decoy-receptor59,60. Here, TNFRSF6B is linked to Crohn disease.