Successful rituximab treatment of a patient with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis accompanied by X-linked lymphoproliferative syndrome type 1

Abstract

X-linked lymphoproliferative syndrome (XLP) is a rare primary immunodeficiency disease (PID) characterized by vulnerability to the Epstein-Barr virus (EBV). XLP is divided into XLP1 caused by SH2D1A mutation and XLP2 caused by XIAP mutation. Approximately 60% of patients with XLP1 present with EBV-associated hemophagocytic lymphohistiocytosis (HLH), which may be fatal despite treatment with etoposide and cyclosporine A. EBV mainly infects CD8⁺ T cells in sporadic EBV-HLH, whereas it mainly infects B cells in PIDs including XLP1. Treatment with an anti-CD20 monoclonal antibody (rituximab) may be effective in patients with EBV-HLH accompanied by XLP1. Here, we describe a 3-year-old boy with XLP1, who presented with severe EBV-HLH and was successfully treated with rituximab.