CD274 and inflammatory bowel disease: A recent study suggested that the maladjustment of the Th1 response in the inflammatory colonic mucosa of IBD patients was caused by a change in PD-L1 expression in the mucosal mesenchymal stromal cell compartment, because increased PD-L1 expression inhibits Th1 cell activity in UC, whereas the loss of PD-L1 expression observed in CD leads to the persist existence of a Th1 inflammatory milieu [95].