CD274 and inflammatory bowel disease: Intestinal antigen-presenting cells in IBD patients exhibit a defective expression of programmed death (PD) ligand 1 (PDL1) (52), which is known to engage PD1 on T cells thereby promoting the function of T-regulatory cells (Tregs), a class of T cells expressing CD25 and the transcription factor Foxp3 and known to maintain immune tolerance (53).