乙型肝炎病毒基因型

乙型肝炎病毒(hepatitis B virus,HBV)是嗜肝DNA病毒家族的重要成员,所引起的慢性乙型病毒性肝炎及肝衰竭、肝硬化、肝癌等是严重危害人民健康的疾病.据统计,目前我国有慢性乙型肝炎患者2000万人,是我国现阶段最为突出的公共卫生问题之一.HBV遗传变异率很高,有8个基因型,由于独特的流行病学特性,多数又可以分为不同的基因亚型.另外DNA基因型的高度异质性使重组基因型也增加了.有研究证实HBV基因型与疾病进展关系密切.不同基因型HBV的流行病学特征不同,同时其临床感染特点和致病性也有差异.本文综述了本领域研究进展,包括HBV生物学特性、基因型与基因亚型、重组基因型、HBV基因型的流行病学特点以及HBV基因型与临床等方面.     

Hepatitis B virus taxonomy and hepatitis B virus genotypes

Hepatitis B virus (HBV) is a member of the hepadnavirus family. Hepadnaviruses can be found in both mammals (orthohepadnaviruses) and birds (avihepadnaviruses).The genetic variability of HBV is very high. There are eight genotypes of HBV and three clades of HBV isolates from apes that appear to be additional genotypes of HBV. Most genotypes are now divided into subgenotypes with distinct virological and epidemiological properties. In addition, recombination among HBV genotypes increases the variability of HBV. This review summarises current knowledge of the epidemiology of genetic variability in hepadnaviruses and, due to rapid progress in the field,updates several recent reviews on HBV genotypes and subgenotypes.     

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.     

Hepatitis B virus genotypes in chronic liver disease patients from New Delhi, India

INTRODUCTION Approximately, two billion people in the world have been infected by Hepatitis B virus (HBV), 350 million of whom are chronic carriers of the virus[1,2]. Worldwide HBV isolates have been classified into eight genotypes: A, B, C, D, E, F, G an…     

山西省HBV基因型及亚型分布调查

目的了解山西省乙型肝炎病毒(HBV)的基因型及亚型分布情况。方法对136例乙型肝炎表面抗原(HBsAg)阳性者血清采用PCR-PFLP结合基因型特异性引物-PCR法进行HBV基因型及亚型检测。结果 136例HBV感染者的血清标本经PCR-PFLP分析,B基因型18例,均为Ba亚型,占13.2%;C基因型113例,占83.1%,除4例未分型外均为Ce亚型;D基因型5例,占3.7%。经型特异性引物-PCR分析,18例HBV B基因型中有4例为B/C基因型混合感染;5例经PCR-PFLP确定的D基因型病毒经型特异性引物法分析有2例扩增出E基因型条带。C、B基因型病毒感染者的平均年龄分别为(39.5±13.1)岁和(30.5±14.1)岁,差异有统计学意义(P<0.05);与B基因型相比,C基因型病毒感染者的HBeAg阴转率减慢。结论山西省HBV基因型主要为C(Ce),有少量的B(Ba)和D基因型,且存在B/C混合基因型,且可能存在D和E基因型病毒的重组体;与B基因型比较,感染C基因型病毒更难被机体清除,疾病更易慢性化。     

乙型肝炎病毒基因型与聚合酶基因异质性

目的 对202株乙型肝炎病毒(HBV)聚合酶基因(P基因)序列进行系统分析，研究HBV基因型间P基因差异，为进一步研究HBV基因型、P基因变异与病毒复制及核苷类似物耐药的关系提供参考。方法 采用计算机软件对GenBank中己发表的202株HBV全序列及P基因进行分析比较。结果 HBVP基因在各基因型具有自身特点：在反转录酶(rt)区，A基因型氨基酸的型内差异较小，C、D基因型氨基酸的型内差异较大，在rt区A—F6个高度保守区域，发现在基因型间及型内存在氨基酸水平的差异。结论 (1)P基因及其氨基酸存在基因型间和型内异质性，因而分析某些氨基酸差异是与耐药有关还是准株被选择的结果，应综合考虑在该位点是否存在基因型间或型内的氨基酸差异，(2)对核苷类似物抗病毒治疗应答以及治疗中耐药现象的发生在HBV不同基因型可能不同。     

Hepatitis B virus genotypes and lamivudine resistance mutations in Jordan

AIM：To investigate and identify prevalent hepatitis B virus（HBV） genotypes and to explore lamivudine-resistant mutations among treated and untreated patients in Jordan.METHODS：A total of 107 cases with chronic hepatitis B were recruited from different medical centers in Jordan.Serological tests were preformed for all cases using a microparticle enzyme immunoassay.HBV Genotyping was performed for 70 cases using Line probe genotyping assay.The YMDD mutations were explored for 20 cases（4 were lamivudine naive） using the INNO-LiPA HBV DR assay.RESULTS：Genotype D was the only detected genotype.A total of 6 YMDD mutations were detected in 5 treated patients（31%） while one mutation was detected in the naive patients.Seventeen percent of cases were positive for HBeAg and had statistically significant higher levels of serum aminotransferases.CONCLUSION：HBV genotype D appears to be the only circulating type in Jordanian patients.The YMDD mutations were detected in 31% of lamivudine-treated cases with similar patterns to those found in the literature.We also found a relatively low prevalence of HBeAg expression among examined cases（17%）.Awareness of these serologic,genotypic and resistance patterns might help in the formulation of management plans and for predicting clinical outcomes.Further larger scale studies are needed to confirm our results and to examine possible associations among clinical,serologic,and genetic patterns of HBV infections in Jordan.     

乙型和丙型肝炎病毒感染与肝细胞癌

为探讨乙型和丙型肝炎病毒（ＨＢＶ和ＨＣＶ）感染与肝细胞癌（肝癌）发生的关系，采用ＥＬＩＳＡ和聚合酶链反应（ＰＣＲ）对沈阳地区１１７例肝癌、１０７例肝硬化和４５例血液透析患者血清进行了ＨＢＶ和ＨＣＶ血清标志及ＨＢＶＤＮＡ和ＨＣＶＲＮＡ检测，并采用限制性片段长度多态性对其中７３例ＨＣＶＲＮＡ阳性血清进行了ＨＣＶ基因分型。结果，肝癌组ＨＢＶ感染率（６０７％）显著高于ＨＣＶ感染率（３３３％，Ｐ＜００１），肝硬化组ＨＢＶ感染率（４３９％）明显高于ＨＣＶ感染率（２９０％，Ｐ＜００５）；血液透析组ＨＢＶ和ＨＣＶ重叠感染率（２６７％）明显高于肝硬化组（１０３％，Ｐ＜００５）；各组均以ＨＣＶⅡ型为主（６５２％～８００％），ＨＣＶⅢ型次之（２００％～３１４％）。结果提示：沈阳地区肝癌的诱发因素仍以ＨＢＶ为主，血液透析患者ＨＢＶ和ＨＣＶ重叠感染的机会更大，ＨＣＶⅡ型感染在本地区ＨＣＶ相关性肝癌和肝硬化的发生中可能起主要作用。     

Hepatitis B virus genotypes and genome characteristics in China

AIM: To analyze the hepatitis B virus (HBV) characters in China, as well as the correlation between several HBV mutation and hepatitis symptoms.METHODS: A total of 1148 HBV genome sequences from patients throughout China were collected via the National Center For Biotechnology Information database (information including: genotype, territory and clinical status). HBV genotypes were classified by a direct reference from the Genbank sequence annotation, phylogenetic tree and online software analysis (http://www.ncbi.nlm.nih.gov/projects/genotyping/formpage.cgi). The phylogenetic tree was constructed based on the neighbor-joining method by MEGA5.0 software. HBV sequences were grouped based on phylogenetic tree and the distance between the groups was calculated by using the computer between group mean distance methods. Seven hundred and twelve HBV sequences with clear annotation of clinical symptoms were selected to analyses the correlation of mutation and clinical symptoms. Characteristics of sequences were analyzed by using DNAStar and BioEdit software packages. The codon usage bias and RNA secondary structures analysis were performed by RNAdraw software. Recombination analysis was performed by using Simplot software.RESULTS: In China, HBV genotype C was the predominant in Northeastern, genotype B was predominant in Central Southern areas, genotype B and C were both dominant in Southwestern areas, and the recombinant genotype C/D was predominant in Northwestern areas. C2 and B2 were identified as the two major sub-genotypes, {"type":"entrez-nucleotide","attrs":{"text":"FJ386674","term_id":"213495273","term_text":"FJ386674"}}FJ386674 might be a putative sub-genotype as B10. The basal core promoter double mutation and pre-C mutation showed various significant differences between hepatitis symptoms. In addition to ATG, many other HBV initiation codons also exist. HBV has codon usage bias; the termination codon of X, C and P open reading frames (ORF) were TAA, TAG, and TGA, respectively. The major stop codons of S-ORF were TAA (96.45%) and TGA (83.60%) in B2 and C2 subtype, respectively.CONCLUSION: This study recapitulated the epidemiology of HBV in China, and the information might be meaningful critical for the future prevention and therapy of HBV infections.     

Hepatitis B virus infection in Latin America: A genomic medicine approach

Hepatitis B virus (HBV) infection is the leading cause of severe chronic liver disease. This article provides a critical view of the importance of genomic medicine for the study of HBV infection and its clinical outcomes in Latin America. Three levels of evolutionary adaptation may correlate with the clinical outcomes of HBV infection. Infections in Latin America are predominantly of genotype H in Mexico and genotype F in Central and South America; these strains have historically circulated among the indigenous population. Both genotypes appear to be linked to a benign course of disease among the native and mestizo Mexicans and native South Americans. In contrast, genotypes F, A and D are common in acute and chronic infections among mestizos with Caucasian ancestry. Hepatocellular carcinoma is rare in Mexicans, but it has been associated with genotype F1b among Argentineans. This observation illustrates the significance of ascertaining the genetic and environmental factors involved in the development of HBV-related liver disease in Latin America, which contrast with those reported in other regions of the world.     

The influence of hepatitis B virus genotype and subgenotype on the natural history of chronic hepatitis B

Background  Chronic infection with hepatitis B virus (HBV) is associated with a high lifetime risk of developing hepatocellular carcinoma (HCC) and cirrhosis of the liver. Purpose  To review the studies published to date regarding the association of HBV genotypes and subgenotypes in the development of adverse sequelae from HBV. Methods  Review of the literature for articles describing studies of HBV genotype/subgenotypes and development of HCC, cirrhosis, and liver-related death. Results  Eight genotypes of HBV (A through H), which differ from each other in viral genome sequence by more than 8%, and multiple subgenotypes, which differ from each other by 4–8% have been identified. Recently, studies investigating the association between the risks of developing HCC and cirrhosis by specific HBV genotypes and subgenotypes have reported marked differences in outcome. Certain HBV genotypes and subgenotypes, including genotype C, B2-5, and F1, appear to be associated with a higher risk of developing HCC, and others, including genotypes B1, B6, and A2, appear to be associated with a lower risk of complications of HBV. Our understanding of the role of HBV genotypes and subgenotypes on the outcome of HBV infection is limited, as few population-based prospective studies have been performed and most studies compare only the outcome in areas where two genotypes predominate whereas others have not examined subgenotypes. Conclusions  Studies to date suggest that HBV genotypes/subgenotypes have important influences on the outcome of chronic HBV infection, but more population-based prospective studies examining multiple genotypes are needed.     

Hepatitis B virus infection and the risk of hepatocellular carcinoma

Epidemiological studies have provided overwhelming evidence for a causal role of chronic hepatitis B virus(HBV) infection in the development of hepatocellular carcinoma(HCC).However,the pathogenesis of HBV infection and carcinogenesis of HBV-associated HCC are still elusive.This review will summarize the current knowledge on the mechanisms involved in HBV-related liver carcinogenesis.The role of HBV in tumor formation appears to be complex,and may involve both direct and indirect mechanisms.Integration of H...     

重型肝炎患者乙型肝炎病毒基因型及其进化树分析

乙型肝炎病毒（HBV）变异发生率高，已明确HBV为A～H8个基因型。HBV基因型是反映HBV自然史发生变异的特点，是病毒变异进化的结果。HBV变异是引起重型肝炎的重要原因，累积变异可引起基因型的改变。国内有关重型肝炎与HBV基因型及进化树的研究报道较少。我们应用聚合酶链反应（PCR）-限制性片段长度多态性分析技术（RFLP）对65例HBV感染的重型肝炎患者进行了HBV基因分型，对部分B型和C型重型肝炎HBVS基因进行测序及其进化树分析，旨在探讨重型肝炎基因型分布及进化特点。     

Hepatitis B virus: origin and evolution

Summary. The pathogenesis of hepatitis B virus (HBV) is complex and it appears that molecular variants play a role in this process. HBV undergoes numerous rounds of error prone production within an infected host. The resulting quasispecies are heterogeneous and in the absence of archaeological records of past infection, the evolution of HBV can only be inferred indirectly from its epidemiology and by genetic analysis. This review gathered the controversies about the HBV origin and factors influencing its quasispecies. Also, it provided some evidence on how HBV genotypes correlated with human history and patterns of migration. It is our belief that this topic deserves further attention and thus it is likely that more critical research work will be performed to elucidate the unknown mechanisms and processes in this area.