High incidence of human herpesvirus 6 infection with a high viral load in cord blood stem cell transplant recipients

Abstract

Human herpesvirus 6 (HHV-6) infection in recipients of cord blood stem cell transplants (CBSCTs) was estimated by semiquantitative and real-time quantitative polymerase chain reaction (PCR) and reverse-transcription PCR. Of the CBSCT recipients, 7 (70%) of 10 had active HHV-6 infection after transplantation, and all 7 were inferred from their age to have already had a primary infection. Because HHV-6 DNA is seldom detected in cord blood, these cases were considered likely to represent reactivation. In contrast, the 3 patients without HHV-6 infection were all believed to be naive regarding HHV-6 primary infection because of their age and the results of PCR assays given before the transplantation procedure. The incidence of HHV-6 infection after transplantation was significantly higher (P < .05) than after bone marrow (BM) transplantation and peripheral blood stem cell (PBSC) transplantation, when recipients without primary HHV-6 infection prior to transplantation were excluded (CBSCT, 100%; BMT/PBSCT, 56.3%). Real-time PCR revealed a higher level of viral DNA in the peripheral blood mononuclear cells from CBSCT recipients than from BMT/PBSCT recipients or patients with exanthem subitum (P < .05). HHV-6 mRNA of the U79/80gene was also detected by reverse-transcription PCR in all analyzed patients with HHV-6 infection. Its detection was correlated with the emergence of viral DNA in the plasma and symptoms such as fever and rash. Thus, HHV-6 infection was more frequent and the viral load was higher in CBSCT recipients with prior primary infection.

Risk factors of human herpesvirus 6 encephalitis/myelitis after allogeneic hematopoietic stem cell transplantation

“…We also demonstrated that CBT was a significant risk of HHV‐6 encephalitis/myelitis in this study. This may be associated with the absence of primed HHV‐6‐specific memory T cells and the immunologic immaturity of CBT . Yoshihara et al .…”

Pre‐engraftment syndrome after unrelated donor umbilical cord blood transplantation in patients with hematologic malignancies

“…These factors include immunosuppressive agents, chemotherapeutic or antibiotic agents, systematic use of G‐CSF, and reaction or allergy to blood products. In addition, viral infections, especially human herpesvirus 6 (HHV‐6) reactivation may be associated with fever and rash after CBT (13). Although Patel et al.…”

HHV‐6 DNA throughout the tissues of two stem cell transplant patients with chromosomally integrated HHV‐6 and fatal CMV pneumonitis

“…In the immunocompetent patient HHV‐6B is the cause of sixth disease (exanthem subitum). HHV‐6 (mainly variant B) infection has also been associated with morbidity post‐haematopoietic stem cell transplant (HSCT), especially delayed platelet and monocyte engraftment (Ljungman et al , 2000), encephalitis (Zerr, 2006) and fever and rash (Sashihara et al , 2002).…”