Epstein-Barr virus-related post-transplant lymphoproliferative disease (EBV-PTLD) in the setting of allogeneic stem cell transplantation: a comprehensive review from pathogenesis to forthcoming treatment modalities

Epstein-Barr virus (EBV) is a ubiquitous herpes virus that infects the majority of the population worldwide. The virus can establish a lifelong latent infection in host B-lymphocytes. In the setting of immunocompromise as is the case post transplantation, the virus can reactivate and cause one of the deadliest complications post hematopoietic stem cell transplantation (HSCT), post-lymphoproliferative disease (PTLD), the incidence of which has been increasing. Multiple risk factors have been associated with the onset of PTLD such as age, reduced intensity conditioning, EBV serology mismatch and cytomegalovirus (CMV) reactivation. The rarity of clinical trials involving PTLD and the lack of approved treatment modalities renders the management of PTLD challenging. While the first-line treatment involves weekly administration of rituximab, there is no consensus when treating rituximab-refractory PTLD. There is a handful of clinical trials that investigate the role of EBV-specific cytotoxic T-lymphocytes (CTLs) and novel agents, such as bortezomib, lenalidomide, everolimus, panobinostat, and brentuximab. This article aims to explore the entity of EBV-PTLD in HSCT recipients, expanding on clinical presentation, risk factors, modes of monitoring and treatment, and so highlighting the gaps in knowledge that are needed in order to build a treatment paradigm suitable for all patients at risk.