Immune checkpoint inhibitor-induced hemophagocytic lymphohistiocytosis in lung cancer: a case series

Immune checkpoint inhibitors (ICIs) are established treatments for various malignancies, including lung, kidney, and colorectal cancers. However, their broad use has led to an increase in immune-related adverse events (irAEs), with thyroiditis, colitis, and pneumonitis being the most common. Hemophagocytic lymphohistiocytosis (HLH) is a rare but severe irAE characterized by excessive immune activation, leading to systemic inflammation and multi-organ dysfunction. We present three cases of ICI-induced HLH in patients with lung cancer who were treated with ICIs. All patients showed elevated inflammatory markers and responded to high-dose corticosteroids without the addition of etoposide. These cases underscore the importance of early recognition and treatment of HLH in patients receiving ICIs to mitigate morbidity and mortality. Large-scale studies are needed to establish standardized guidelines for diagnosing and managing ICI-induced HLH.