Hemophagocytic lymphohistiocytosis induced by radio-chemo-immunotherapy: a case report

Abstract

Background Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome characterized by supramaximal immune activation. Although rare, HLH has been increasingly recognized as an immune-related adverse event in patients undergoing immune checkpoint inhibitor (ICI) therapy. Case presentation We report the case of a female patient treated with concomitant radio-chemo-immunotherapy for cer vical cancer (according to the KEYNOTE-A18 trial). She developed HLH following a single dose of pembrolizumab, presenting initially with immune-mediated pneumonitis and subsequently with fever, prolonged pancytopenia, and elevated inflammatory markers. After intensive diagnostics, broad-spectrum anti-infective treatment and granulocyte colony-stim ulating factor (G-CSF) stimulation was started, without improvement. The diagnosis was finally made by HLH-2004 criteria, strongly indicated by an H-score of 251 (>99% probability of HLH). The HLH was successfully treated with corticosteroids alone. Conclusion This case highlights the importance of early recognition and aggressive management of HLH secondary to immunotherapy, particularly in patients presenting with unexplained fever, G-CSF-refractory cytopenia, and hyperferritine mia.