Fulminant cytokine release syndrome in a paediatric patient with refractory Epstein–Barr virus-associated haemophagocytic lymphohistiocytosis receiving nivolumab treatment

Immune checkpoint blockade using programmed cell death 1 (PD-1) antibody is an effective approach to enhance T-cell activity against cancers, and it is an emerging cause of haemophagocytic lymphohistiocytosis (HLH) [1]. Recent studies report that the PD-1 antibody nivolumab can cure Epstein–Barr virus-associated HLH (EBV-HLH) by restoring the defective anti-EBV response without severe adverse events [2,3]. Herein, we report on a paediatric patient with relapsed/refractory EBV-HLH who developed fulminant cytokine release syndrome after receiving nivolumab treatment.