Autoimmune Pancreatitis Secondary to Immune Checkpoint Inhibitor Therapy (Type 3 AIP): Insights Into a New Disease From Serial Pancreatic Imaging

Immune checkpoints are normal regulatory proteins that modulate T-cell–mediated immune responses to avoid autoimmunity. These proteins include cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed cell death receptor 1 (PD-1), and programmed cell death ligand 1 (PD-L1). Cancers sometimes hijack these checkpoint pathways to avoid immune surveillance. Immune checkpoint inhibitor therapies (ICI-Rxs) are monoclonal antibodies that block CTLA-4 and PD-1/PD-L1. They target cancers by facilitating T-cell activation and proliferation, abrogating T regulatory cell functions, and possibly boosting humoral autoimmunity.