Clark Duncan A, Ward Katherine N
Department of Virology, Barts and The London NHS Trust, London, UK.
Herpes. 2008 Nov;15(2):28-32.
Human herpesvirus-6 (HHV-6) exists as two closely related variants: A and B. Whereas no disease has been firmly associated with HHV-6A, variant B causes febrile illness in young children and is pathogenic in immunosuppressed transplant recipients. Chromosomally integrated HHV-6 (with either variant A or B) occurs in a minority of people. This phenomenon has the potential to confound the diagnosis of active HHV-6 infection, since chromosomally integrated HHV-6 DNA sequences are inherited through the germline. Therefore, viral DNA is in every nucleated cell in the body and can be found in a range of body fluids including whole blood, serum, plasma and cerebrospinal fluid. There are characteristically very high viral loads in whole blood (> 6 log10 HHV-6 genomes/ml) and serum (5 log10 HHV-6 genomes/ml); these can be used to differentiate individuals with viral chromosomal integration from those with active HHV-6 infection, where viral loads are significantly lower. Increasingly, the polymerase chain reaction (to detect viral nucleic acid) is used for diagnosis; therefore, it is important to exclude HHV-6 chromosomal integration before concluding that there is evidence of active HHV-6 infection.
人类疱疹病毒6型（HHV - 6）以两种密切相关的变体形式存在：A和B。虽然尚未有疾病被确凿地认定与HHV - 6A相关，但B变体可导致幼儿发热性疾病，并且在免疫抑制的移植受者中具有致病性。少数人存在染色体整合的HHV - 6（A或B变体均可）。这种现象有可能混淆活动性HHV - 6感染的诊断，因为染色体整合的HHV - 6 DNA序列是通过种系遗传的。因此，病毒DNA存在于体内的每个有核细胞中，并且可以在包括全血、血清、血浆和脑脊液在内的一系列体液中检测到。全血（> 6 log10 HHV - 6基因组/ml）和血清（5 log10 HHV - 6基因组/ml）中的病毒载量通常非常高；这些可用于区分病毒染色体整合个体与活动性HHV - 6感染个体，后者的病毒载量显著更低。越来越多地，聚合酶链反应（用于检测病毒核酸）被用于诊断；因此，在得出存在活动性HHV - 6感染证据的结论之前，排除HHV - 6染色体整合很重要。
