Hepatitis B virus genotypes and subgenotypes in China

Eight Hepatitis B virus (HBV) genotypes (A to H) have been identified based on an intergenotype divergence of 8% or more in the entire nucleotide sequence. Subgenotypes have also been identified in different HBV genotypes. As a highly endemic area for HBV infection, the prevalence of chronic HBV infection in China is between 8 and 20% of the general population. Genotypes B and C were identified as the most common HBV strains and account for approximately 95% of Chinese patients. Further study confirmed all genotype B strains belong to subgenotype Ba. Two of genotype C subgenotypes, C1 (Cs) and C2 (Ce), were found in China and they showed different geographic distributions. Genotype A was very rarely found, while genotypes E, F, G and H have not beenreported until now. Two types of HBV C/Drecombinant viruses have been identified in west China and distinct geographic and ethnic distributions were observed. Significant differences were observed ( P  < 0.001) in the prevalence of A1896 and T1762/A1764 mutations among HBV Ba, C1 and C2 subgenotypes in Chinese patients. Accumulating evidence showed the response rate to antiviral therapy in Chinese patients is higher in genotype B than genotype C patients on interferon treatment, but no difference was observed on nucleoside/nucleotide analog treatment.     

Hepatitis B virus genotypes in Europe

There are eight genotypes of hepatitis B virus (HBV). Most genotypes can be further divided into subgenotypes. HBV genotypes influence the course of disease and treatment, and show geographic preferences. In Europe, A and D are the main genotypes found. Genotype A is more prevalent in northern Europe, where genotype D is mainly found in countries surrounding the Mediterranean Sea and in Eastern Europe. Subgenotype A2 is the dominant subgenotype in Europe, but the geographic prevalence of the four subgenotypes found in genotype D is not yet clear. On treatment with interferon HBV, genotype A, compared to genotype D, showsbetter virological response and in a large proportion of patients, even development of anti-HBs. However, in the first year of treatment with lamivudine, higher rates of emergence of YMDD variants are observed in genotype A. This work summarizes the current knowledge on HBV genotypes in countries with low and intermediate HBV carriership from Europe.     

HBV基因分型的研究进展

乙型肝炎病毒(HBV)感染是一个影响全球的健康问题.HBV有8种基因型,呈地域性分布.研究表明HBV基因型对慢性HBV感染的自然病程、临床结局、抗病毒治疗等具有影响.A基因型与C基因型与严重的肝损害相关;A基因型与B基因型对干扰素的应答率分别较D基因型与C基因型均更高;有研究发现HBV的基因型可能影响HBV的传播途径.然而,目前大多数临床资料来自亚洲及对B、C基因型的相关研究,基于基因型的地域性分布,对HBV基因型的全面认识,还有待进一步的国际化合作.     

乙型肝炎病毒基因型与抗病毒药物疗效关系的研究进展

乙型肝炎在全球发病率高,严重危害人类健康.随着HBV基因型研究的深入,大量研究显示HBV基因型与临床疾病谱密切相关.目前抗病毒治疗是慢性乙型肝炎治疗的最主要措施,越来越多的学者对HBV基因型与抗病毒药物疗效的关系进行了研究,本文就目前国内外关于HBV基因型与抗病毒疗效关系的研究进展作一综述.     

肝癌患者血清中乙型肝炎病毒基因分型及临床意义

目的:探讨血清中乙型肝炎病毒(HBV)基因型及HBV DNA水平与肝细胞癌的关系。方法:应用巢式聚合酶链反应扩增乙型肝炎病毒与基因,用末端标记方法对PCR产物标记并直接测序,测序结果和GenBank中登录的标准基因型序列相比较,应用荧光定量PCR法检测HBV DNA水平。对61例肝癌、65例慢性乙型肝炎、10例乙型肝炎病毒携带者进行了检测。结果:136例中B基因型59例(43.4%)、C基因型77例(56.6%),随着病情加重,C基因型比例逐渐增高;不同基因型HBV感染的肝癌患者间HBV DNA水平差异有显著意义,P<0.05;在慢性乙型肝炎患者中,HBV DNA水平差异无显著性意义。结论:本地区乙型肝炎病毒以B、C基因型为主,乙型肝炎病毒C基因型及高水平的HBV DNA感染与肝癌的发生相关。     

Identification of a natural intergenotypic recombinant hepatitis delta virus genotype 1 and 2 in Vietnamese HBsAg‐positive patients

Hepatitis D virus (HDV) infection is acquired as a co‐ /superinfection of Hepatitis B virus (HBV) and can modulate the pathophysiology of chronic hepatitis B and related liver diseases including hepatocellular carcinoma. Among the eight distinct HDV genotypes reported, relatively few studies have attempted to investigate the prevalence of HDV mixed genotypes and RNA recombination of HDV. With a recorded prevalence of 10–20% HBV infection in Vietnam, this study investigated the HDV variability, HDV genotypes and HDV recombination among twenty‐one HDV isolates in Vietnamese HBsAg‐positive patients. HDV subgenomic and full‐length genome sequences were obtained using newly established HDV‐specific RT‐PCR techniques. The nucleotide homology was observed from 74.6% to 99.4% among the investigated full‐length genome of the HDV isolates. We observed HDV genotype 1 and HDV genotype 2 in the investigated Vietnamese patients. Although no HDV genotype mixtures were observed, we report here a newly identified recombinant of HDV genotypes (HDV 1 and HDV 2). The identified recombinant HDV isolate C03 revealed sequence homology to both HDV genotype 1 (nt1 to nt907) and HDV genotype 2 (nt908 to nt1675; HDAg coding region) with a breakpoint at nt908. Our findings demonstrate the prevalence of intergenotypic recombination between HDV genotypes 1 and 2 in a Vietnamese HBsAg‐positive patient. Extended investigation on the distribution and prevalence of HDV, HDV mixed genotypes and recombinant HDV genotypes in a larger Vietnamese population offers vital insights into understanding of the micro‐epidemiology of HDV and subsequent pathophysiology in chronic HBV‐ /HDV‐related liver diseases.     

B和C基因型乙型肝炎病毒对阿德福韦酯治疗的病毒学应答比较

目的 阐明不同基因型HBV对阿德福韦酯治疗反应是否存在差异.方法 首先利用型特异引物PCR法结合型特异核苷酸分析法检测HBV基因型,然后根据基因型对阿德福韦酯Ⅲ期临床资料进行分析及统计学处理(计量资料用t检验,计数资料用卡方检验).结果 177例临床标本检出B基因型HBV感染者102例,C基因型感染者65例,B+C混合型感染者6例,B+D混合型感染者4例.治疗第12、24周时,B基因型组和C基因型组血清HBV DNA下降均值分别为2.2log10>拷贝/ml、2.1log10拷贝/ml和2.7log10拷贝/ml、2.4log10拷贝/ml,两组差异均无统计学意义(P>0.05),第48周时两组HBV DNA分别下降3.6log10拷贝/ml和3.1log10拷贝/ml,差异有统计学意义(P<0.05).治疗结束时(48周)B基因型组和c基因型组分别有43例(42.2%)和22例(33.8%)出现血清HBV DNA转阴,差异有统计学意义(P<0.05);两组患者HBeAg阴转率抗-Hbe血清转换率分别为30.4%、29.2%和21.6%、20.0%,差异无统计学意义(P>0.05).两组患者血清ALT复常率在治疗第12、24、36周和48周时分别为35.3%、33.9%,51.0%、53.9%,63.4%、61.5%和83.3%、81.5%,各时间段两组ALT复常率差异均无统计学意义(P>0.05).结论 阿德福韦酯治疗慢性乙型肝炎48周时,部分病毒学指标(如血清HBV DNA下降均值和HBV DNA阴转率)B基因型优于C基因型HBV感染者.但由于阿德福韦酯起效较慢,抑制病毒作用相对较弱,有必要延长治疗时间进一步证实这一现象.     

Hepatitis B viral genotypes: clinical relevance and molecular characteristics

Hepatitis B virus (HBV) infection is a global health problem and the clinical outcome of chronic HBV infection depends on the frequency and severity of hepatitis flares in the immune clearance phase. Currently, four subtypes and seven genotypes of HBV are identified and most have specific geographic distributions. The impact of HBV genotypes on the clinical outcome of chronic HBV infection has been partially clarified. In Taiwan, genotype C is associated with more severe liver disease and genotype B is associated with the development of hepatocellular carcinoma (HCC) in young non-cirrhotic patients. In contrast, genotype B has a relatively good prognosis in Japan and China and is rarely associated with the development of HCC. Similarly, genotype D is associated with more severe liver disease than genotype A in India and may predict occurrence of HCC in young patients. Although superinfection of HBV on top of hepatitis B carriers occurs in Taiwan, it is rarely associated with acute exacerbations. As to the response to antiviral treatment, genotypes C and D are associated with a lower response rate to interferon therapy compared with genotypes B and A. In addition, the subtype adw is reported to be associated with a higher risk of lamivudine resistance than ayw. In HBV subtype adw-infected HCC patients, genotype B responds better to embolization therapy and has a lower rate of HCC recurrence than genotype C. In summary, pathogenic and therapeutic differences do exist among HBV genotypes and determining the genotype in patients with chronic HBV infection would help gain further information for etiologic, clinical, virologic and anthropologic investigations. Further studies to clarify the molecular virological factors that contribute to these differences are awaited.     

Hepatitis B virus infection in immigrant populations

Hepatitis B virus (HBV) is the most common cause of hepatitis worldwide, with nearly 350 million people chronically infected and 600000 deaths per year due to acute liver failure occurring during acute hepatitis or, more frequently, in HBV-related liver cirrhosis or hepatocellular carcinoma. Ongoing immigration from countries with a high HBV endemicity to those with a low HBV endemicity warrants particular attention to prevent the spread of HBV infection to the native population. This review article analyzes the epidemiology and virological and clinical characteristics of HBV infection in immigrant populations and in their host countries, and suggests prophylactic measures to prevent the spread of this infection. Among the immigrants from different geographical areas, those from South East Asia and sub-Saharan Africa show the highest prevalences of hepatitis B surface antigen (HBsAg) carriers, in accordance with the high endemicity of the countries of origin. The molecular characteristics of HBV infection in immigrants reflect those of the geographical areas of origin: HBV genotype A and D predominate in immigrants from Eastern Europe, B and C in those from Asia and genotype E in those from Africa. The literature data on the clinical course and treatment of HBsAg-positive immigrants are scanty. The management of HBV infection in immigrant populations is difficult and requires expert personnel and dedicated structures for their assistance. The social services, voluntary operators and cultural mediators are essential to achieve optimized psychological and clinical intervention.     

慢性乙型肝炎拉米夫定耐药患者HBV基因型及ALT变化的观察

观察慢性乙型肝炎患者用拉米夫定治疗后HBVP基因变异与不同HBV基因型感染及HBV DNA复升水平和转氨酶变化.收集51例慢性乙型肝炎患者用拉米夫定治疗52-78周后发生YMDD变异的血清标本,对照组128例未用拉米夫定治疗的慢性乙型肝炎患者血清标本,应用聚合酶链反应方法,测定HBV DNA基因型;用限制性片段长度多态性分析方法(PCR RELP)测定HBV DNA YMDD变异;同时进行HBV DNA定量分析.结果显示51例拉米夫定治疗后HBV DNA基因变异患者以B型和C型为主,分别为10例(19.6%)和39例(76.47%),B C混和型2例(3.92%),未见其它基因型.拉米夫定治疗引起HBVDNAYMDD变异可以发生在不同HBV基因型感染的慢性乙型肝炎患者中,与对照组比较二者没有显著性差异.     

HBV宫内传播的研究进展

HBV宫内感染是乙肝免疫失败的主要原因, HBV宫内传播的途径主要有胎盘途径、PBMCS途径及经生殖细胞的传播. 其中胎盘的渗漏或胎盘细胞的感染是主要的途径. 母亲血清HBV DNA含量、HBV基因型、遗传因素是影响宫内感染的主要因素. 近年来的临床研究显示孕期使用乙肝高效价免疫球蛋白或拉米夫定可以阻断大部分宫内感染, 但目前尚缺乏大样本的随机对照研究, 探索宫内感染的机制和可行的阻断措施是我国控制乙型肝炎流行的关键所在.     

乙型肝炎病毒基因型检测及其临床应用

目的:探讨HBV基因型的检测及其在临床上的应用.方法:用微板核酸分子杂交-ELISA方法检测468例HBV DNA阳性的慢性乙型肝炎患者血清HBV基因型.分析HBV基因型与病毒复制、基本C基因启动子(BCP)变异、肝病病情轻重、干扰素疗效的关系.结果:深圳地区HBV基因型以B和C基因型为主,分别占25.0%和64.9%;C基因型的HBeAg阳性率(68.8%)高于B基因型的HBeAg阳性率(35.0%)(P＜0.01);C基因型的血清HBV DNA水平也明显高于B基因型(1g 6.74 copies/ml vs. 1g 5.44 copies/ml, P＜0.01);轻中度慢性肝炎以B基因型为主,而重度慢性肝炎以C基因型为主;B基因型对干扰素的有效应答率为47.2%,C基因型的有效应答率为28.9%,两组比较差异有显著性意义(P＜0.05).结论:HBV基因分型有助于临床判断病情、估计预后及抗病毒治疗疗效预测.     

拉米夫定对湖北地区乙型肝炎病毒基因型的影响

目的研究拉米夫定对湖北地区乙型肝炎病毒基因型的影响及其临床意义。方法采用多对型特异性引物-聚合酶链反应检测160例慢性乙型肝炎患者血清HBV基因型;采用基因芯片技术对86例拉米夫定治疗18个月的慢性乙型肝炎患者进行酪氨酸—蛋氨酸—天冬氨酸—天冬氨酸(YMDD)基序、G1896A、A1814C、A1792T和G1764A单碱基变异检测。结果160例慢性乙型肝炎患者,B基因型127例(79%),C基因型24例(15%),BC混合型9例(6%),未发现A、D和E基因型。拉米夫定治疗的86例患者中,17例(19.7%)发生YMDD变异,B型14例,C型2例,BC混合基因型1例,其中6例发生多重变异,包括B型4例,C型2例;HBeAg/HBeAb血清转换率B型41例(68.3%)高于C型8例(40%)(P<0.05)。另外17例患者,经拉米夫定治疗后,HBVDNA仍阳性,亦未发现YMDD变异株。结论湖北地区HBV存在B、C和BC混合基因型,B型为本地区优势基因型,B型在拉米夫定治疗中更易发生YMDD变异;未变异者,血清HBeAg/HBeAb转换率高。     

山西省HBV基因型分布特点和临床意义

目的:了解山西省常见的乙型肝炎病毒(HBV)基因型,探讨HBV各基因型与血清HBV-DNA水平以及疾病进展的临床意义.方法:随机收集山西省HBV DNA阳性病例680例进行基因分型,并结合临床资料进行统计学分析.结果:680例HBV感染者中,有65例(9.6％)未测出基因型.在可检出基因型的615例患者中,基因型B、C、B/C分别占8.9％、82.6％、8.5％.C型、B/C型的HBV DNA载量明显高于B型(P＜0.05);各基因型与肝病的严重程度间差异有显著性意义(P＜0.05).结论:山西省HBV基因型中以C型为优势,其次为B/C和B型.基因C型和B/C型在慢性重型肝炎中较为常见,基因C型更易发生肝硬化和肝癌.     

天津地区家族聚集性慢性乙型肝炎病毒感染者病毒载量及组织病变与基因型的关系

目的探讨天津地区家族聚集性HBV感染患者基因型特征与病毒载量及肝组织病理的关系。方法随机采集临床确诊家族聚集性的慢性HBV表面抗原携带者(ASC)35例和轻型CHB患者65例。分别进行HBV基因分型、HBV DNA载量、肝组织病理学检测。结果HBV基因型显示:B型7例,HBV DNA主要为低载量(57.14%),病理损害程度较轻。BC混合型11例,HBV DNA以低、中载量为主(45.45%、36.36%),病理损害多为轻至中度≤G2 10例(90.91%),≤S2 9例(81.82%)。C型82例,其中ASC 29例,HBV DNA以高载量为主(72.41%),均有不同程度的病理损伤(100%);CHB 53例,HBV DNA主要为中、高载量(39.62%,49.06%),病理损害≥G2者38例(71.70%),≥S2者25例(47.17%)。结论天津地区家族聚集性ASC和CHB以基因C型为主、病毒载量高、肝组织病理损伤较严重,为乙型肝炎预后不良的主要因素;家族聚集性ASC不仅存在HBV病毒高载量,而且均有不同程度的肝脏病理损伤,临床可视肝组织病理结果酌情抗病毒治疗;肝组织病理学检查作为ASC和CHB患者治疗前的常规检测手段,为规范CHB的抗病毒治疗提供可靠依据。     

Hepatitis B virus genotype G infection in a Turkish patient undergoing hemodialysis therapy

Background

Genotype G is the least common of all the hepatitis B virus (HBV) genotypes. The existence of the genotype G strain of HBV was first noted in 2000 and little information is available on its global geographical distribution. Previous studies have demonstrated the dominance of genotype D in patients with HBV infections in Turkey.

Objectives

To report for the first time in Turkey, the case of a 61 year old male patient who developed the HBV genotype G infection.

Case report

According to HBV genotyping using phylogenetic analysis and an INNO-LiPA assay, the patient was infected with genotype G and G+A, respectively.

Conclusions

The present clinical study suggests that the transmission of an HBV genotype other than genotype D, namely HBV genotype G, is possible in Turkey. Epidemiological and clinical information on genotype G infection is currently limited, and this is most likely due to its low prevalence throughout the world. Therefore, it may be important to determine the epidemiologic and molecular characteristics of the HBV genotype G as it relates to chronic hepatitis, to enable better understanding of its circulation and progression around the world.     

Genetic diversity of hepatitis viruses in West-African countries from 1996 to 2018

The severity of hepatic pathology and the response to treatment depend on the hepatitis virus genotype in the infected host. The objective of this review was to determine the distribution of hepatitis virus genotypes in West African countries. A systematic review of the literature in PubMed, Google Scholar and Science Direct was performed to identify 52 relevant articles reporting hepatitis A, B, C, D, E and G viruses genotypes. Hepatitis B virus (HBV) genotype E with a prevalence of 90.6% (95%CI: 0.891-0.920) found in this review, is characterized by low genetic diversity. Hepatitis C virus (HCV) genotypes 1 and 2 represented 96.4% of HCV infections in West African countries, while hepatitis delta virus, hepatitis A virus, hepatitis G virus genotypes 1 and HEV genotype 3 were reported in some studies in Ghana and Nigeria. HBV genotype E is characterized by high prevalence, low genetic diversity and wide geographical distribution. Further studies on the clinical implications of HBV genotype E and HCV genotypes 1 and 2 are needed for the development of an effective treatment against this viral hepatitis in West African countries. Surveillance of the distribution of different genotypes is also needed to reduce recombination rates and prevent the emergence of more virulent viral strains.     

HBV基因型与阿德福韦酯抗病毒疗效的关系

目的 探讨HBV不同基因型对阿德福韦酯抗病毒疗效的影响.方法 选取42例应用阿德福韦酯治疗的慢性乙肝患者作为研究对象,观察治疗24周及48周时抗病毒疗效.采用型特异性引物进行巢式PCR,对患者血清中的HBV进行基因分型,采用荧光定量PCR检测患者血清HBV DNA复制水平,HBV血清病毒标志物采用双抗体夹心ELISA法检测.结果 42例慢性乙肝患者的HBV基因型分布为:B型23例,C型10例,B C混合型9例,未发现A、D、E、F基因型.不同基因型患者治疗前HBVDNA水平无统计学差异(P＞0.05).HBV基因型B型、C型和B C混合型患者治疗24周及48周时HBV DNA载量的变化、丙氨酸氨基转移酶(ALT)复常及HBeAg血清转换均无统计学差异(P＞0.05).结论 HBV基因型B型或C型对阿德福韦酯治疗的病毒学应答和生化应答相当,提示HBV基因型可能对阿德福韦酯的疗效无影响.     

Incidence of HBV variants with a mutation at nt551 among hepatitis B patients in Nanjing and its neighbourhood

AIM: To investigate the epidemiology of hepatitis B virus (HBV) strains with a mutation at nt551 in surface gene among hepatitis B patients in Nanjing and its neighbourhood. METHODS: By using mutation-specific polymerase chain reaction (msPCR) established by our laboratory for amplifying HBV DNAs with a mutation at nt551, 117 serum samples taken from hepatitis B patients were detected. RESULTS: The results showed that 112 samples were positive for nt551A, 4 samples were positive for nt551G. One sample was positive for nt551T. No nt551C of HBV DNA was found. The incidence of HBsAg mutants with G, C, T, A at nt551 among 117 samples was 3.42%, 0%, 0.85%, 95.73%, respectively. CONCLUSION: In Nanjing and its neighbourhood, hepatitis B patients are mainly infected with wild genotype HBV. The incidence of mutants with a mutation at nt551 in HBV genome is significantly lower than that in wild genotype HBV DNA (P<0.01). The necessity of adding components of HBsAg mutants to HBV vaccine needs further investigation.