[Autoimmune reactions to immune checkpoint inhibitors]

Immune checkpoint inhibitors (ICI) have dramatically changed the face of cancer treatment and are gaining in importance. The ICIs have now been approved for the treatment of advanced cancers, including melanoma, non-small-cell and small cell lung cancers, renal cell carcinoma, Hodgkin's lymphoma, head and neck cancers and urothelial carcinoma and further indications are to be expected. The organs most affected by an autoimmune reaction are the intestines, the musculoskeletal system, skin, endocrine organs, the liver and the lungs. As the indications for immune checkpoint blockade expand and ICIs are used in combination, it becomes increasingly more important for rheumatologists to recognize immune-related adverse events (irAEs), their connection to cancer immunotherapy and how to treat these events appropriately. The role of rheumatologists will take on growing importance as immunotherapies become more common as standard treatment of cancer and when used earlier in the course of the disease. Previously controlled autoimmune diseases can deteriorate when using ICIs, so this is a consideration when evaluating patients. Increased awareness of inflammatory arthritis, as well as other rheumatic manifestations as an adverse association with cancer immunotherapies, is imperative for making the diagnosis. Treatment algorithms are based on the severity of symptoms but in the case of rheumatic disease, treatment often needs to be tailored to the individual. The general strategy for evaluation and management of irAEs includes a thorough evaluation for infections. Mild irAE may be self-limiting, while more severe reactions are generally steroid responsive, albeit with potentially high dosage requirements.