Contributor: Don Stader, MD Educational Pearls: Checkpoint inhibition normally helps our body detect abnormal cells and terminate it but cancerous cells often are able to avoid this countermeasure Monoclonal antibodies that bind to checkpoint inhibitors can stop cancerous cells from turning off immunologic T cells and allows the immune system to continue to attack cancers. These therapies carry risks of exacerbating autoimmune problems due to the ramped up immune response Most often this autoimmune attack leads to skin and GI symptoms but can affect many other organ systems. In the emergency room this can present many different ways, but the mainstay of treatment is steroids to stop these exacerbations. Chimeric Antigen Receptor (CAR) T-cell Therapy is another immunotherapy where antigens to a cancerous cell are re-introduced to spur a directed immune response Cytokine release syndrome can occur in these patients and mimic other presentations such as septic shock, a result of tumor break down This is treated with steroids and monoclonal antibodies that help thwart the cytokine release References Hay, KA. Cytokine release syndrome and neurotoxicity after CD19 chimeric antigen receptor-modified (CAR-) T cell therapy. Br J Haematol. 2018 Nov;183(3):364-374. doi: 10.1111/bjh.15644. Epub 2018 Nov 8. Hryniewicki AT, Wang C, Shatsky RA, Coyne CJ. Management of Immune Checkpoint Inhibitor Toxicities: A Review and Clinical Guideline for Emergency Physicians. J Emerg Med. 2018;55(4):489-502. doi:10.1016/j.jemermed.2018.07.005 Summarized by Jackson Roos, MS4  | Edited by Erik Verzemnieks, MD