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''Human herpesvirus 6'' (HHV-6) is the common collective name for Human herpesvirus 6A (HHV-6A) and Human herpesvirus 6B (HHV-6B). These closely related viruses are two of the nine herpesviruses known to have humans as their primary host. HHV-6A and HHV-6B are double stranded DNA viruses within the betaherpesvirinae subfamily and of the genus ''Roseolovirus''. HHV-6A and HHV-6B infect almost all of the human populations that have been tested. HHV-6A has been described as more neurovirulent, and as such is more frequently found in patients with neuroinflammatory diseases such as multiple sclerosis. HHV-6B primary infection is the cause of the common childhood illness exanthema subitum (also known as roseola infantum or sixth disease). Additionally, HHV-6B reactivation is common in transplant recipients, which can cause several clinical manifestations such as encephalitis, bone marrow suppression, and pneumonitis. A variety of tests are used in the detection HHV-6, some of which do not differentiate the two species. ==History== During 1986, Syed Zaki Salahuddin, Dharam Ablashi, and Robert Gallo cultivated peripheral blood mononuclear cells from patients with AIDS and lymphoproliferative illnesses. Short-lived, large, refractile cells that frequently contained intranuclear and/or intracytoplasmic inclusion bodies were documented. Electron microscopy revealed a novel virus that they named Human B-Lymphotrophic Virus (HBLV). Shortly after its discovery, Ablashi et al. described five cell lines that can be infected by the newly discovered HBLV. They published that HSB-2, a particular T-cell line, is highly susceptible to infection. Ablashi's pioneering research concluded by suggesting that the virus name be changed from HBLV to HHV-6, in accord with the published provisional classification of herpes viruses. Years later, HHV-6 was divided into subtypes. Early research (1992) described two very similar, yet unique variants: HHV-6A and HHV-6B. The distinction was warranted due to unique restriction endonuclease cleavages, monoclonal antibody reactions, and growth patterns. HHV-6A includes several adult-derived strains and its disease spectrum is not well defined, although it is thought by some to be more neurovirulent. HHV-6B is commonly detected in children with roseola infantum, as it is the etiologic agent for this condition. Within these two viruses is a sequence homology of 95%. In 2012, HHV-6A and HHV-6B were officially recognized as distinct species.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「human herpesvirus 6」の詳細全文を読む スポンサード リンク
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