New strategies in the diagnosis and treatment of immune-checkpoint inhibitor-mediated colitis

Figure 1 Proposed immune-mediated pathways of immune checkpoint inhibitor-mediated colitis. In normal mucosa, T regulatory cells are fully capable of inducing tolerance while balancing pro-inflammatory cells and molecules (i.e. Th17 cells) and anti-inflammatory molecules (i.e. IL-10, TGFb, etc). By blocking cytotoxic T-lymphocyte antigen-4 (CTLA-4) or programmed cell death ligand-1, immune checkpoint inhibitors promote pro-inflammatory cytokines, chemokine production, Treg differentiation inhibition, and suppression of IL-10 and TGFb secretion. Parts of the figure were drawn by using pictures from Servier Medical Art. Servier Medical Art by Servier (https://smart.servier.com/) is licensed under a Creative Commons Attribution 4.0 Unported License (Supplementary material). CTLA-4: Cytotoxic T-lymphocyte antigen-4; PD-L1: Programmed cell death ligand-1.