Supplementary Material for: A Case Report of Immune Checkpoint related Hemophagocytic Lymphohistiocytosis and Review of the Literature

Introduction: Hemophagocytic lymphohistiocytosis (HLH) secondary to immune checkpoint inhibitors (irHLH) is rare, and consequently optimal management strategies remain to be defined. There are sparse reports of the successful treatment of irHLH with steroids and tocilizumab. This case adds to the body of literature supporting this management strategy.
Case description: We present a case of a patient with thoracic malignancy who received dual checkpoint inhibitors and developed weakness, fever, confusion and cytopenias. Further testing revealed an extremely elevated ferritin level. Cytokine levels as well as HLH-2004 criteria and HScore results were consistent with irHLH. Clinical parameters and symptoms promptly improved after the administration of corticosteroids and tocilizumab.
Conclusion: This case highlights an important treatment strategy for an immune checkpoint inhibitor toxicity associated with a high mortality rate.