Human Herpesvirus 6A, 6B, 7, and 8 in Hematopoietic Stem Cell Transplant: A Clinical Review

Immunosuppression related to allogeneic hematopoietic stem cell transplant increases the risk of reactivation of latent herpesviral infections. This can include the roseolaviruses, human herpesvirus-6A, human herpesvirus-6B, human herpesvirus-7, and human herpesvirus-8 or Kaposi sarcoma herpesvirus. Reactivation is typically asymptomatic, and many cases have unclear clinical significance. Defined syndromes and diseases may be associated with some, such as human herpesvirus-6B. Epidemiology, clinical syndromes, and associated transplant outcomes are reviewed for each of these viruses. Available evidence and guidelines are discussed with a narrow focus on the most pertinent clinical information, but substantial further evaluation and studies are required to characterize the significance of these viruses in stem cell transplant patients.