Human herpesvirus 6 reactivation on the 30th day after allogeneic hematopoietic stem cell transplantation can predict grade 2-4 acute graft-versus-host disease

Background Viral infections and their occult reactivation occasionally cause not only organ damage, but also exacerbation of acute graft‐versus‐host disease (aGVHD), which may increase transplantation‐related mortality synergistically. To determine correlations between viral reactivation and transplantation‐related complications, we performed various viral screening tests on the 30th day after allogeneic hematopoietic stem cell transplantation (HSCT), and assessed the clinical implications. Patients and methods Between August 2007 and January 2013, 49 patients (37 men, 12 women) underwent HSCT in our hospital. The stem cell sources were bone marrow (n = 21), peripheral blood (n = 13), and cord blood (n = 15). The presence of cytomegalovirus (CMV), Epstein–Barr virus (EBV), herpesvirus (HHV) 6, and HHV7 in plasma samples prospectively collected from HSCT recipients on day 30 after HSCT was assayed by quantitative polymerase chain reaction, and the correlations with transplantation‐related complications were evaluated. Results The positivities of CMV, EBV, HHV6, and HHV7 were 44.9%, 22.4%, 53.1%, and 18.3%, respectively. We analyzed transplantation‐related complications, and a significant correlation was found only between HHV6 and grade 2–4 aGVHD from day 30 to day 100 (P