Human herpesviruses-6, -7 and -8 in organ transplant recipients.

The newer herpesviruses are being increasingly recognized as significant opportunistic pathogens in organ transplant recipients. Published data support the role of human herpesvirus-6 as a potential cause of encephalitis and bone marrow suppression in transplant setting. An association of human herpesvirus-6 with fungal infections and cytomegalovirus infection has also been documented. Human herpesvirus-7 also appears to be an immunomodulatory agent and may facilitate the pathogenicity of cytomegalovirus. Unlike human herpesviruses -6 and -7, human herpesvirus -8 is not ubiquitous; its seroprevalence exhibits wide geographic variation. Human herpesvirus-8 has been causally associated with post-transplant Kaposi's sarcoma. The complete spectrum of pathogenicity and ultimately the effective prophylaxis and management of these viruses has yet to be fully elucidated.