The real-time polymerase chain reaction-guided modulation of immunosuppression enables the pre-emptive management of Epstein-Barr virus reactivation after allogeneic haematopoietic stem cell transplantation

To assess a real-time polymerase chain reaction-based modulation of immunosuppression in patients with an increasing Epstein-Barr virus (EBV) viral load, we studied 79 paediatric allogeneic stem cell transplantations (allo-SCT) performed between January 1998 and December 2003. EBV reactivation was observed in 42 of 79 patients (53%) after a median time of 45 d from allo-SCT: 37 (88%) and five (12%) patients had received the graft from an unrelated and a related donor respectively (P = 0(.)001). Twenty-eight patients (67%) had a viral load greater than or equal to300 genomic copies x 10(5) peripheral blood mononuclear cells (PBMC) and antithymocyte globulin was the only factor significantly associated with EBV reactivation (P = 0(.)001, RR 7(.)1). Among these 28 patients, immunosuppression was suspended and reduced in 17 and 11 patients respectively. Overall, posttransplant lymphoproliferative disease was diagnosed in one of 79 patients (1%). The pre-emptive modulation of immunosuppression in patients with EBV reactivation and a viral load 300 genomic copies x 10(5) PBMC did not negatively influence transplant-related mortality, overall survival or eventfree survival. In conclusion, EBV reactivation is frequent even in 'low risk' patients and the pre-emptive modulation of immunosuppression enables it to be managed safely, with no significant flare in graft- versus-host disease status.