Department of Propaedeutic of Internal Diseases and Gastroenterology, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow 127473, Russia.
Central Clinical Hospital with Polyclinic, Presidential Administration of the Russian Federation, Moscow 121359, Russia.
World J Gastroenterol. 2020 Apr 21;26(15):1691-1707. doi: 10.3748/wjg.v26.i15.1691.
The review presents the data accumulated for more than 20 years of research of torque teno virus (TTV). Its molecular genetic structure, immunobiology, epidemiology, diagnostic methods, possible replication sites, and pathogenicity factors are described. TTV is a virus that is frequently detectable in patients with different viral hepatitides, in cases of hepatitis without an obvious viral agent, as well as in a healthy population. There is evidence suggesting that biochemical and histological changes occur in liver tissue and bile duct epithelium in TTV monoinfection. There are sufficient histological signs of liver damage, which confirm that the virus can undergo a replicative cycle in hepatocytes. Along with this, cytological hybridization in TTV-infected cells has shown no substantial cytopathic (cell-damaging) effects that are characteristic of pathogenic hepatotropic viruses. Studying TTV has led to the evolution of views on its role in the development of human pathology. The first ideas about the hepatotropism of the virus were gradually reformed as new data became available on the prevalence of the virus and its co-infection with other viruses, including the viruses of the known types of hepatitides. The high prevalence of TTV in the human population indicates its persistence in the body as a virome and a non-pathogenic virus. It has recently been proposed that the level of TTV DNA in the blood of patients undergoing organ transplantation should be used as an endogenous marker of the body's immune status. The available data show the polytropism of the virus and deny the fact that TTV can be assigned exclusively to hepatitis viruses. Fortunately, the rare detection of the damaging effect of TTV on hepatic and bile duct epithelial cells may be indirect evidence of its conditionally pathogenic properties. The ubiquity of the virus and the variability of its existence in humans cannot put an end to its study.
本文综述了二十多年来对 Torque teno 病毒（TTV）研究的数据。描述了其分子遗传学结构、免疫生物学、流行病学、诊断方法、可能的复制部位和致病因素。TTV 是一种在不同病毒性肝炎患者、无明显病毒病原体的肝炎病例以及健康人群中经常可检测到的病毒。有证据表明，TTV 单一感染会导致肝组织和胆管上皮的生化和组织学变化。有足够的组织学迹象表明肝损伤，这证实了该病毒可以在肝细胞中进行复制周期。与此同时，在 TTV 感染细胞中的细胞杂交显示，没有明显的细胞病变（细胞损伤）效应，这是嗜肝性病毒的特征。对 TTV 的研究导致了人们对其在人类病理学发展中的作用的看法发生了变化。随着新的数据不断出现，表明该病毒的流行及其与其他病毒（包括已知类型肝炎的病毒）的共同感染，病毒的嗜肝性的最初观点逐渐得到修正。TTV 在人类中的高流行率表明其作为病毒组和非致病性病毒在体内持续存在。最近有人提出，移植器官患者血液中的 TTV DNA 水平可作为机体免疫状态的内源性标志物。现有数据表明该病毒的多嗜性，并否认 TTV 可专属于肝炎病毒的事实。幸运的是，TTV 对肝和胆管上皮细胞的损伤作用罕见检测可能间接证明其具有条件致病性。病毒的普遍性和其在人类中的存在的可变性并不能终止对其的研究。
