Incidence and risk factors of EBV reactivation after unrelated cord blood transplantation: a Eurocord and Société Française de Greffe de Moelle-Therapie Cellulaire collaborative study.

EBV viremia and post-transplantation lymphoproliferative disorders (PTLDs) have been associated with high mortality rates after allogeneic hematopoietic SCT (allo-HSCT). Few retrospective studies, without EBV load monitoring postulated that umbilical cord blood transplantation (UCBT) might be associated with high incidence of EBV events. We retrospectively studied 175 UCBT recipients for whom RQ-PCR was used to monitor EBV blood load at least once a week during the first 3 months after UCBT. Median age was 23 years, 74% had leukemia. Conditioning was myeloablative in 54% and reduced intensity conditioning (RIC) was used in 46%. A total of 24 patients presented an EBV reactivation. For 15 patients, the reactivation occurred during the first 100 days (cumulative incidence: 8%) and included 4 EBV-PTLD. Rituximab as preemptive treatment was used in 12 of these 15 patients. In univariate analysis, the increased risk of early EBV reactivation was associated with RIC in combination with antithymocyte globulin (P=0.03) and previous history of auto-HSCT (P=0.01). Multivariate analysis did not find any independent risk factor. EBV reactivation as time-dependent covariate was not statistically associated with survival. Therefore, EBV events were not major complications after UCBT when EBV load is weekly monitored and preemptive treatment started.