World J Gastroenterol. 2011 Mar 28;17(12):1529-30. doi: 10.3748/wjg.v17.i12.1529.
Occult hepatitis B virus (HBV) infection is a world-wide entity, following the geographical distribution of detectable hepatitis B. This entity is defined as the persistence of viral genomes in the liver tissue and in some instances also in the serum, associated to negative HBV surface antigen serology. The molecular basis of the occult infection is related to the life cycle of HBV, which produces a covalently closed circular DNA that persists in the cell nuclei as an episome, and serves as a template for gene transcription. The mechanism responsible for the HBsAg negative status in occult HBV carriers is a strong suppression of viral replication, probably due to the host's immune response, co-infection with other infectious agents and epigenetic factors. There is emerging evidence of the potential clinical relevance of occult HBV infection, since this could be involved in occult HBV transmission through orthotopic liver transplant and blood transfusion, reactivation of HBV infection during immunosuppression, impairing chronic liver disease outcome and acting as a risk factor for hepatocellular carcinoma. Therefore it is important to bear in mind this entity in cryptogenetic liver diseases, hepatitis C virus/HIV infected patients and immunosupressed individuals. It is also necessary to increase our knowledge in this fascinating field to define better strategies to diagnose and treat this infection.
隐匿性乙型肝炎病毒（HBV）感染是一种全球性的现象，其分布与可检测到的乙型肝炎一致。该病症被定义为病毒基因组在肝组织中持续存在，在某些情况下也在血清中存在，同时伴有 HBV 表面抗原阴性的血清学表现。隐匿性感染的分子基础与 HBV 的生命周期有关，HBV 产生共价闭合环状 DNA，作为附加体存在于细胞核中，作为基因转录的模板。隐匿性 HBV 携带者 HBsAg 阴性的原因是病毒复制受到强烈抑制，这可能是由于宿主的免疫反应、与其他感染因子的共同感染以及表观遗传因素所致。越来越多的证据表明隐匿性 HBV 感染具有潜在的临床相关性，因为它可能通过原位肝移植和输血进行隐匿性 HBV 传播、免疫抑制期间 HBV 感染的再激活、影响慢性肝病的结局以及作为肝细胞癌的危险因素。因此，在隐匿性肝脏疾病、HCV/HIV 感染患者和免疫抑制个体中，有必要牢记这一病症。我们还需要进一步了解这一迷人的领域，以确定更好的诊断和治疗该感染的策略。
