Background: Epstein-Barr virus (EBV) reactivation after hematopoietic stem-cell transplantation can lead to posttransplant lymphoproliferative disease (PTLD), which carries a high mortality rate. Among therapeutic and prophylactic options being developed, B-cell depletion with monoclonal antibodies is encouraging. Because viral load after transplantation is correlated with PTLD occurrence, we developed a preemptive attitude based on polymerase chain reaction (PCR)-guided rituximab administration.
Methods: We monitored 115 transplant patients with a quantitative PCR for EBV DNA performed on whole-blood samples. Criteria for treatment initiation were a single PCR above 40,000 DNA genome copies per milliliter (gCop/mL) or two rising values above 10,000 gCop/mL. Weekly rituximab infusion at the dose of 375 mg/m was administered until negative PCR results were available. We evaluated the incidence of EBV reactivation and PTLD development.
Results: Nineteen patients (16.5%) met the criteria for treatment. Incidence of reactivation was the same in high-risk and standard-risk patients (12 vs. 7, P=0.38). One patient developed PTLD after discontinuation of therapy due to a serious adverse event. No other serious adverse events were noticed. Viral load disappeared after a median of three cycles of therapy, and weekly monitoring allowed prompt intervention. No PTLD-related death was observed, all-cause mortality in the treated population was 68%.
Conclusions: Our PCR-guided and rituximab-based preemptive approach to avoid PTLD after allogeneic hematopoietic stem-cell transplantation is feasible but probably overtreated patients. Prospective trials are strongly needed, they should use uniform PCR techniques and consider higher threshold values for treatment initiation.