Emerging drugs for the treatment of hepatitis B

Introduction: Nucleos(t)ide analogs and interferon-based compounds are currently approved for the treatment of chronic hepatitis B (CHB). Although these treatments are effective in suppressing viral replication, it is unable to completely eradicate the virus from the host. Therefore, CHB patients are at a life-long risk of developing complications, including hepatocellular carcinoma.

Areas covered: Drugs targeting novel sites of the hepatitis B virus (HBV) replication cycle and the host immune response in development are discussed. As current available drugs only target a small segment of the HBV life cycle, the development of new agents targeting different sites is an important step in eradicating HBV. The host immunological response is also vital in viral clearance. Newer agents in development include immunomodulatory agents and therapeutic vaccines.

Expert opinion: For any chance of eradication, a combination of drugs targeting both the host factors and different sites of the viral life cycle will be required. Two key components to achieving this goal include the removal of covalently closed circular DNA (cccDNA) together with restoration of the immune control against HBV.     

乙型肝炎病毒核心抗原相关抗原(HBcrAg)的研究进展

HBcrAg包括HBcAg、HBeAg、p22cr蛋白,在HBV感染中具有重要的临床意义.本文旨在对近年来HBcrAg的概念、检测方法及其在乙型肝炎诊治中的检测意义等方面的进展作一综述.     

乙型肝炎病毒感染肾炎患者肾组织病毒抗原和复制中间体的检测及其意义

目的：观察乙型肝炎病毒(HBV)感染者肾组织中三种病毒抗原成分的分布特点及其与HBV感染状态和临床病理之间的联系，探讨在肾组织局部是否存在HBV的复制。方法：免疫组化法检测合并HBV感染的30例膜性肾病和12例膜增生性肾炎病例的肾活检组织切片中的HBsAg、HBcAg和HBeAg，同时检测肾小球和循环中的HBV基因组DNA及其复制中间体——闭合环状双链DNA(cccDNA)。结果：膜性肾病肾组织中病毒抗原的检出率(83．3％)显著高于膜增生性肾炎(33％)；膜性肾病肾组织检出的抗原以HBc舷和HBeAg多见，其中，血清HBeAg阳性病例肾组织HBeAg的检出率显著高于HBeAg阴性的病例。膜增生性肾炎肾组织检出的抗原主要是HBeAg。肾组织HBeAg的检出与循环中HBeAg的存在明显相关。伴血清转氨酶升高者肾组织HBV抗原的检出率较转氨酶正常者有升高的趋势。肾小球HBVDNA和cccDNA的检出均与循环中的检测结果高度一致，并以伴活动性HBV感染者检出率为高。结论：在合并HBV感染的肾炎患者中，肾组织HBV抗原的检出率在膜性肾病患者明显高于膜增生性肾炎。肾小球中检出的HBV抗原成分以HBeAg和HBcAg最多见，肾小球HBe他的检出与血清中是否存在HBeAg明显相关。合并肝功能损害者肾组织HBV抗原的检出率较肝功能正常者有增高趋势。在乙肝相关性肾炎患者的肾小球中确实能检测到HBV复制中间体的存在，它的出现与循环中HBV复制中间体检出的高度一致性，不能排除循环中HBV感染细胞在肾组织潴留对结果的影响，其意义还有待进一步阐明。     

Persistence of cccDNA during the natural history of chronic hepatitis B and decline during adefovir dipivoxil therapy

BACKGROUND & AIMS: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is a unique episomal replicative intermediate responsible for persistent infection of hepatocytes. Technical constraints have hampered the direct study of cccDNA maintenance and clearance mechanisms in patients. The aim of this study was to develop a sensitive and specific assay for quantifying cccDNA in biopsy samples from chronic hepatitis B patients during different natural history phases and in patients undergoing antiviral therapy. METHODS: Intrahepatic cccDNA levels were quantified by a specific real-time PCR assay. Ninety-eight liver biopsy samples from patients in the major phases of the natural history of chronic hepatitis B and 32 pairs of samples from patients receiving adefovir dipivoxil (ADV) therapy were assessed. RESULTS: cccDNA was detected, at levels ranging over 3 orders of magnitude, in patients in different phases of the natural history of chronic hepatitis B. cccDNA levels were strongly correlated with levels of total intracellular HBV DNA and serum HBV DNA. Forty-eight weeks of ADV therapy resulted in a significant 0.8 log decrease in cccDNA copies/cell. Changes in cccDNA were correlated with a similar reduction in serum HBsAg titer but not with a decrease in the number of HBV antigen-positive cells during ADV treatment.CONCLUSIONS: cccDNA persists throughout the natural history of chronic hepatitis B, even in patients with serologic evidence of viral clearance. Long-term ADV therapy significantly decreased cccDNA levels by a primarily noncytolytic mechanism.     

恩替卡韦治疗慢性乙型肝炎患者血清HBV cccDNA和HBV pgRNA水平变化*

目的 探讨血清 HBV 共价闭合环状 DNA(HBV cccDNA)和HBV前基因组 RNA(HBV pgRNA)水平预测血清HBeAg阳性慢性乙型肝炎(CHB)患者接受恩替卡韦治疗后疗效的临床价值。方法 2018年1月～2020年1月我院收治的HBeAg阳性CHB患者89例,均口服恩替卡韦分散片治疗48 w。使用COOBAS TAQMAN和COBAS Amliprep系统和采用荧光定量PCR法检测血清HBV cccDNA和HBV pgRNA水平,采用化学发光法定量检测血清HBsAg和HBeAg水平。应用受试者工作特征曲线(ROC)分析血清各指标预测恩替卡韦治疗的CHB患者疗效的价值。结果 89例HBeAg阳性CHB患者经恩替卡韦治疗48 w后,获得病毒学应答85例(95.5%),生化学应答80例(89.9%),血清学应答9例(10.1%);获得完全应答75例(84.3%);完全应答组血清ALT、HBsAg、HBeAg、HBV DNA, HBV cccDNA和HBV pgRNA水平分别为(228.3±34.9)U/L、(2.5±0.4)lg IU/mL、(18.6±1.9)S/CO、(6.1±0.6)lg IU/mL、(2.2±0.2)cps/mL和(4.5±0.6)cps/mL,与非完全应答组【分别为(69.5±17.1)U/L、(3.7±0.7)lg IU/mL、(163.2±16.3)S/CO、(6.8±0.7)lg IU/mL、(3.9±0.4)cps/mL和(7.0±0.7)cps/mL】比,差异显著(P＜0.05);应用血清HBV cccDNA与HBV pgRNA水平联合预测CHB患者接受恩替卡韦治疗疗效的ROC曲线下面积为0.892,其敏感性为81.6%,特异性为89.5%。结论 在抗病毒治疗前,检测HBeAg阳性慢性乙型肝炎患者血清HBV cccDNA和HBV pgRNA水平预测疗效有一定的应用价值,值得进一步研究。     

Hepatitis B virus infection in lymphatic tissues in inactive hepatitis B carriers

BACKGROUND/AIMS: Hepatitis B virus (HBV) infection in extrahepatic tissues is controversial. To clarify whether episomal HBV can infect nonhepatic tissues, we investigated the molecular forms of HBV in the lymphatic cells of inactive HBV carriers who lacked viremia, thus avoiding contamination with HBV genomes originating from the viral particles present in the serum. METHODS: We assessed HBV genome, replicative forms, and viral integrants in the liver, serum, peripheral blood mononuclear cells (PBMC), and lymph nodes of 21 inactive HBV carriers who tested positive for antibodies against the HBV core antigen (anti-HBc). RESULTS: Of the 21 anti-HBc positive individuals, HBV-DNA was detected in liver samples of 15 (71.4%), in the lymph nodes of 11 (52.4%), and in PBMC of three (14.3%). However, none of the detected HBV genomes from lymphatic tissues included the replicative forms of HBV. In one case, integrated HBV was present in the lymphatic tissues and the host-viral junction was present in the intronic sequences of chromosome 17. CONCLUSIONS: These data suggest that human lymphatic tissues cannot support viral replication in anti-HBc positive inactive HBV carriers, while retaining the viral genome as an integrated form.     

乙型肝炎病毒cccDNA的临床检测研究进展

我国有约3000万慢性乙型肝炎患者，每年需要近1000亿元的治疗费用。虽然近年来乙型肝炎抗病毒治疗取得了一定进展，但治疗的疗程、停药后的复发等一系列问题，一直是困扰临床的难题。目前已经证明，乙型肝炎病毒（HBV）共价闭合环状DNA（covalently closed circular DNA，cccDNA）是HBV前基因组RNA复制的原始模板，虽然其含量远低于HBV存在的一般形式松驰环状DNA（relaxed circular DNA，rcDNA），但对HBV的复制以及感染状态的建立具有十分重要的意义，是HBV持续感染和抗病毒药物停用后病情反复的关键因素，只有清除或有效降低了cccDNA，才能消除乙肝患者病毒携带状态或使病情稳定。本文将HBV cccDNA检测的研究进展做一综述。