Abstract
BACKGROUND AND OBJECTIVE: Epstein-Barr virus-associated hemophagocytic lympho-histiocytosis (EBV-HLH) is common among HLH in paediatric patients, severe cases are often complicated by multiple organ dysfunction syndrome (MODS), leading to poor prognosis and high mortality rate. Emapalumab, an interferon (IFN)-γ inhibitor, can effectively improve patient prognosis without MODS, but it remains unclear whether patients with MODS can achieve clinical benefits. In this study, we aim to evaluate the efficacy and safety of emapalumab in treating EBV-HLH with MODS. METHODS: The paediatric cases admitted to the paediatric intensive care unit were prospectively included, with worsening labs and IFN-γ > 500 pg/mL after standard care, and were given intravenous infusions of emapalumab at a dose of 1-2 mg/kg. Outcomes measured included body temperature, lab results, in-hospital mortality, and stem cell transplant rates. RESULTS: Three paediatric cases were included, and treatment was uninterrupted. Among these, Case 2 exhibited refractory EBV-HLH. After conventional therapy, the laboratory parameters, hyperthermia and pSOFA score remained unimproved withthe blood IFN-γ > 500 pg/mL. Emapalumab infusion was administered, with significant improvement within one week. Case 2 later developed a cytomegalovirus infection, leading to treatment discontinuation despite stable IFN-γ level. Cases 1 and 3 remained stable without additional treatments during a one-year follow-up. CONCLUSION: The use of emapalumab to treat paediatric patients with EBV-HLH complicated by MODS can significantly improve body temperature and HLH-related laboratory parameters, but the overall clinical benefit for refractory cases remains unclear. During treatment, it is essential to keep vigilance against concurrent infections, and monitoring for potential latent pathogens is also warranted.