Use of Real-Time PCR to Monitor Human Herpesvirus 6 (HHV-6) Reactivation

Abstract

The diseases caused by infection with human herpesviruses in immunocompromised patients, particularly in transplant recipients, are well recognized and documented [1]. Human herpesvirus 6 (HHV-6) is classified in the same subfamily with Cytomegalovirus, β herpesvirus. HHV-6 causes a life-long persistent infection in over 90% of people before age 2 years, and is a causative agent of febrile illness in children, particularly exanthem subitum. On the basis of molecular and phenotypic characteristics, HHV-6 isolates are categorized into two groups, variant A (HHV-6A) and variant B (HHV-6B) [2]. HHV-6 is normally controlled by the host T cell immune responses, so HHV-6 disease presents when these cell mediated responses are impaired, either through immunosuppressive drugs or organ transplantation, or through human immunodeficiency virus infection. So far, HHV-6 is known to be associated with encephalitis, fatal interstitial pneumonia and stem cell transplant-related complications such as graft-versus-host disease (GVHD) and delayed engraftment [3].