Case Report: Hyperinflammatory toxicities after Epstein-Barr virus-associated post-transplant lymphoproliferative disorder and hemophagocytic lymphohistiocytosis in a pediatric kidney transplant recipient.

Background: Epstein-Barr virus (EBV) is a common trigger of secondary hemophagocytic lymphohistiocytosis (HLH), particularly in transplant recipients. Adoptive cellular therapy with EBV-specific T cells is an emerging option for refractory EBV-driven disease but may precipitate cytokine toxicities. Case: We report a boy with a history of congenital nephrotic syndrome who in infancy underwent maternal kidney transplantation. At the age of 6 years, he developed monomorphic EBV-positive post-transplant lymphoproliferative disorder, followed by EBV-driven HLH. Despite etoposide- and steroid-based HLH therapy, IVIG, anakinra, and a maternal virus-specific T-cell infusion, he showed recurrent hyperinflammation. After a single dose of the allogeneic EBV-specific T-cell product tabelecleucel (Ebvallo) and exacerbation of HLH, he experienced cytokine release syndrome and neurotoxicity with acute liver failure, coagulopathy, and renal failure. He died from refractory lactic acidosis and multiorgan failure. Conclusion: This case highlights the therapeutic complexity of EBV-HLH in a solid-organ transplant recipient and underscores both the rationale for and risks of cellular immunotherapy amid severe hyperinflammation and organ dysfunction.