Kwak Min-Sun, Kim Yoon Jun
Min-Sun Kwak, Department of Internal Medicine, Healthcare Research Institute, Gangnam Healthcare Center, Seoul National University Hospital, Seoul 135-984, South Korea.
World J Hepatol. 2014 Dec 27;6(12):860-9. doi: 10.4254/wjh.v6.i12.860.
Occult hepatitis B virus (HBV) infection (OBI) refers to the presence of HBV DNA in the absence of detectable hepatitis B surface antigen. Since OBI was first described in the late 1970s, there has been increasing interest in this topic. The prevalence of OBI varies according to the different endemicity of HBV infection, cohort characteristics, and sensitivity and specificity of the methods used for detection. Although the exact mechanism of OBI has not been proved, intra-hepatic persistence of viral covalently closed circular DNA under the host's strong immune suppression of HBV replication and gene expression seems to be a cause. OBI has important clinical significance in several conditions. First, OBI can be transmitted through transfusion, organ transplantation including orthotopic liver transplantation, or hemodialysis. Donor screening before blood transfusion, prophylaxis for high-risk organ transplantation recipients, and dialysis-specific infection-control programs should be considered to reduce the risk of transmission. Second, OBI may reactivate and cause acute hepatitis in immunocompromised patients or those receiving chemotherapy. Close HBV DNA monitoring and timely antiviral treatment can prevent HBV reactivation and consequent clinical deterioration. Third, OBI may contribute to the progression of hepatic fibrosis in patients with chronic liver disease including hepatitis C. Finally, OBI seems to be a risk factor for hepatocellular carcinoma by its direct proto-oncogenic effect and by indirectly causing persistent hepatic inflammation and fibrosis. However, this needs further investigation. We review published reports in the literature to gain an overview of the status of OBI and emphasize the clinical importance of OBI.
隐匿性乙型肝炎病毒（HBV）感染（OBI）是指在检测不到乙型肝炎表面抗原的情况下存在HBV DNA。自20世纪70年代末首次描述OBI以来，人们对这一话题的兴趣与日俱增。OBI的患病率因HBV感染的不同流行程度、队列特征以及检测方法的敏感性和特异性而异。尽管OBI的确切机制尚未得到证实，但在宿主对HBV复制和基因表达的强烈免疫抑制下，病毒共价闭合环状DNA在肝内持续存在似乎是一个原因。OBI在几种情况下具有重要的临床意义。首先，OBI可通过输血、包括原位肝移植在内的器官移植或血液透析传播。应考虑在输血前进行供体筛查、对高危器官移植受者进行预防以及实施针对透析的感染控制方案，以降低传播风险。其次，OBI可能在免疫功能低下的患者或接受化疗的患者中重新激活并导致急性肝炎。密切监测HBV DNA并及时进行抗病毒治疗可预防HBV重新激活及随之而来的临床恶化。第三，OBI可能促使包括丙型肝炎在内的慢性肝病患者肝纤维化进展。最后，OBI似乎因其直接的原癌作用以及间接导致持续性肝脏炎症和纤维化而成为肝细胞癌的一个危险因素。然而，这需要进一步研究。我们回顾文献中已发表的报告，以了解OBI的现状，并强调OBI的临床重要性。
