HHV-6 infection in patients with HIV-1 infection and disease

Human herpesvirus 6 (HHV-6) is among the most widespread of the human herpesviruses. In immunocompetent children, it causes exanthem subitum, febrile episodes without skin rash, and non-Epstein-Barr and non-cytomegalovirus infectious mononucleosis. HHV-6 has also been associated with clinical disease in bone marrow and solid organ transplant recipients. Its potential role in HIV-1-associated clinical syndromes is now being recognized and evaluated. In this review, we describe the virus, the pathogenesis of HHV-6-associated disease, and the diagnostic tests used to differentiate active from latent infection. We then discuss possible clinical manifestations of HHV-6 in HIV-1-infected patients, how to evaluate the need for treatment, and which pharmacologic agents are potentially useful. There is no consensus on these issues in the medical community, and HHV-6 is not now included among indicator infections for the diagnosis of AIDS.