Successful Treatment of Relapsed Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis After Allo-HSCT with PD-1 Blockade: A Case Report

Background: Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) is a rare and aggressive disease with high mortality and poor prognosis. To date, allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only way to cure EBV-HLH. However, relapse of EBV-HLH after allo-HSCT is common and remains a major challenge.Case Presentation: A 22-year-old woman with persistent fever for a month presented to our center with EBV-HLH. After induction of remission using two cycles of the L-DEP (PEG-aspargase, liposomal doxorubicin, etoposide, and high-dose methylprednisolone) regimen, the patient underwent an human leukocyte antigen (HLA)-identical sibling allo-HSCT. However, she experienced disease relapse soon after the procedure, and none of the possible treatment options achieved a sustained response. Finally, she received a sintilimab injection and achieved complete resolution of EBV-HLH.Conclusion: We summarize a case of relapsed EBV-HLH after allo-HSCT that was successfully treated with a programmed cell death protein-1 (PD-1) antibody. Further studies are needed to determine whether PD-1 blockade has therapeutic potential for relapsed EBV-HLH after allo-HSCT.