BackgroundHemophagocytic Lymphohistiocytosis (HLH), a rare but potentially fatal syndrome of immune hyperactivation, may be an under-recognized immune-related adverse event (irAE). Unlike other irAEs, HLH triggered by immune checkpoint blockade is not well described; no particular diagnostic guidelines and treatment regimens exist. The HLH-2004 criteria remain as the common diagnostic guide. For the treatment of HLH, various combinations of chemotherapeutic, immunosuppressive and glucocorticoid agents are used.Case presentationWe report a case of HLH in a 58-year-old metastatic melanoma patient who was undergoing immune checkpoint blockade with pembrolizumab, a programmed cell death-1 (PD-1) receptor inhibitor. The patient presented with fever, upper normal sized spleen, anemia, thrombocytopenia, hypertriglyceridemia, hyperferritinemia, reduced NK cell activity and elevated sCD163 levels, fulfilling the Histiocyte Society HLH-2004 diagnostic criteria. Our patient was successfully treated with oral prednisone (1 mg/kilogram/day), suggesting that HLH from immune checkpoint inhibitors may respond to steroids alone.ConclusionEarly diagnosis and treatment of HLH are critical to avoid progressive tissue damage, organ failure and possibly death. HLH should be suspected in clinical presentations with fever, cytopenias and hyperinflammatory markers. HLH in the setting of immune checkpoint blockade may be treated with steroids only but further evidence is required.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.