They are highly expressed in small intestinal intraepithelial TRM and cooperatively repress genes associated with tissue egress, including Klf2, S1pr1, Ccr7, and Tcf7. In T cell–specific Hobit and Blimp1 double-knockout mice, CD8+TRM failed to form in the gut despite normal effector expansion, thereby ameliorating disease severity in multiple experimental colitis models (42). This evidence concerns the gene S1PR1 and colitis.