Monitoring of human herpesviruses after allogeneic peripheral blood stem cell transplantation and bone marrow transplantation

Herpesviruses frequently cause serious complications after allogeneic bone marrow transplantation (allo‐BMT). Recent studies have shown more rapid immune reconstitution after allogeneic peripheral blood stem cell transplantation (allo‐PBSCT) compared with allo‐BMT. However, it has not been clarified whether the improved immune reconstitution after allo‐PBSCT is associated with a lower incidence of herpesvirus infections. We monitored the emergence of Epstein‐Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus 6 (HHV‐6) and HHV‐7 DNA by a nested‐double polymerase chain reaction in peripheral blood leucocytes from 22 allo‐BMT and 16 allo‐PBSCT patients. Each virus had an unique temporal profile of detection. HHV‐6 DNA was detected most frequently at 3 weeks after transplantation, whereas CMV and EBV DNA were detected later (2–3 months). Detection rates of HHV‐6 DNA at 3 and 4 weeks after allo‐BMT were significantly higher than those after allo‐PBSCT (9/16 v 2/13 at 3 weeks, P