Characteristics of Epstein–Barr virus reactivation after allogeneic haematopoietic stem cell transplantation in patients with chronic active Epstein–Barr virus disease: favorable responses to rituximab

Epstein–Barr virus (EBV) belongs to the herpesvirus family. The infection rate exceeds 90% worldwide. Primary EBV infection is occult and lacks typical symptoms. The virus quickly enters the latent infection phase and is characterized by a lifelong presence in B cells [1]. In some cases, patients develop persistent fever, lymphadenopathy, hepatosplenomegaly, and significantly elevated EBV-DNA load and/or abnormal EBV antibodies in blood or EBV-encoded RNA and viral proteins in affected tissues [2, 3]. When these situations persist for more than 3 months, it is determined as chronic active Epstein–Barr virus infection (CAEBV). In Chinese patients, the most infected lymphocyte cell types during CAEBV infection are T and NK cells.