OBJECTIVETo monitor blood cells EBV-DNA copies by quantitative Epstein-Barr virus (EBV) polymerase chain reaction after hematopoietic stem cell transplantation (HSCT) and to evaluate its implication.

METHODSEBV-DNA copies of peripheral blood mononucleated cells (PBMNCs) were detected by fluorescence quantitative PCR once a week since conditioning regimen from fifty one patients received HSCT. Correlation between development of lymphoproliferative disorders (LPD) and EBV-DNA copies and influence factors of EBV reactivation were analyzed.

RESULTSThe cumulative incidence of EBV viremia was 58.8%. EBV reactivation occurred (39.6 +/- 23.5) days after HSCT, later than that of cytomegalovirus (CMV) reactivation (25.0 +/- 15.1) days (P < 0.01). HLA mismatch (P < 0.01), use of antithymocyte globulin (ATG) (P < 0.01), age less than twenty (P < 0.001) were factors for EBV reactivation, (93.3% vs 48.1%, 92.3% vs 18.7%, and 100% vs 53.1%, respectively). EBV related post-transplant lymphoproliferative disorders (EBV-PTLD) occurred only in 4 out of 30 (13.3%) EBV reactivation patients, whose EBV DNA load maintained over 10(6) copies/ml for at least two weeks (4 out of 13 cases). The median survival time of EBV-PTLD patients was 19.5 (11 - 75) days.

CONCLUSIONSEBV reactivation occurs frequently after HSCT, especially in those received HLA mismatch grafts, used antithymocyte globulin or aged under twenty. Patients with EBV loads over 10(6) copies/ml, especially lasting over two weeks, appear to have an increased risk for PTLD, and pre-emptive therapy may be of clinical useful.