Song Sang Hee, Hwang Seong Gyu
Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea.
Korean J Gastroenterol. 2013 Sep;62(3):148-53. doi: 10.4166/kjg.2013.62.3.148.
Occult HBV infection (OBI) is defined as presence of HBV DNA in the liver tissue in patients with serologically undetectable HBsAg. There are differences in virologic and serological profiles of OBI. Majority of OBI are positive for anti-HBs and/or anti-HBc and minor portion are negative for all HBV markers. However, there are no HBV mutations in the surface and its regulatory regions. HBV infection persists by the presence of covalently closed circular DNA (cccDNA) within the infected hepatocytes, which serves as a reservoir for future infection. OBI increases the risk of HBV transmission through transfusion, hemodialysis, and organ transplantation. Therefore effective measures should be employed to screen OBI. Antiviral therapy is needed in HBsAg-negative transplant patients who are anti-HBc positive to prevent the recurrence of HBV infection. Since HBV replication is strongly suppressed by immune surveillance system in OBI patients, immunosuppression results in massive HBV replication. This leads to acute hepatitis and sometimes mortality when immune surveillance is recovered after stopping immunosuppressive drugs/anticancer chemotherapy. Therefore, narrow surveillance is required to recognize the viral reactivation and start antiviral agents during immunosuppressive therapy/anticancer chemotherapy in patients with OBI.
隐匿性乙型肝炎病毒感染（OBI）定义为血清学检测不到HBsAg的患者肝脏组织中存在HBV DNA。OBI的病毒学和血清学特征存在差异。大多数OBI患者抗-HBs和/或抗-HBc呈阳性，少数患者所有HBV标志物均为阴性。然而，表面及其调控区域不存在HBV突变。受感染的肝细胞内存在共价闭合环状DNA（cccDNA），HBV感染借此持续存在，cccDNA是未来感染的储存库。OBI增加了通过输血、血液透析和器官移植传播HBV的风险。因此，应采取有效措施筛查OBI。抗-HBc阳性的HBsAg阴性移植患者需要抗病毒治疗，以预防HBV感染复发。由于OBI患者的免疫监视系统强烈抑制HBV复制，免疫抑制会导致大量HBV复制。在停用免疫抑制药物/抗癌化疗后免疫监视恢复时，这会导致急性肝炎，有时甚至会导致死亡。因此，需要进行严密监测，以识别病毒再激活情况，并在OBI患者接受免疫抑制治疗/抗癌化疗期间启动抗病毒药物治疗。
