新疆维吾尔族慢性乙型肝炎病毒感染者病毒基因型及亚型分布特点

目的 了解新疆维吾尔自治区(简称新疆)维吾尔族慢性HBV感染者基因型、基因亚型分布情况及其与预后的关系.方法 采用聚合酶链反应限制性片段长度多态性分析方法,分析109例新疆维吾尔族慢性HBV感染者感染病毒的基因型及基因亚型.多标本均数比较采用单向方差分析.结果 109例新疆维吾尔族慢性HBV感染者,其中慢性乙型肝炎88例,乙型肝炎肝硬化17例,肝癌4例.13基因型HBV感染者9例,占8.3%,C基因型感染者50例,占45.9%,C/D基因型重组体32例,占29.4%,D基因型感染者18例,占16.5%,C基因型、C/D基因型重组体为主要基因型.经过聚合酶链反应限制性片段长度多态性分析及测序检测,鉴定9份B基因型HBV,均为Ba亚型.50例C基因型HBV感染者病毒基因亚型分布情况:Cl亚型27例,占54%,C2亚型23例,Cl亚型比C2亚型感染者多.在慢性乙型肝炎、乙型肝炎肝硬化、肝癌患者中,HBV Ba基因亚型感染者分别为8例(9.1%)、1例(5.8%)和0例;C2基因亚型感染者分别为17例(19.3%)、8例(47.5%)和2例(50%);C/D基因型感染者分别为29例(33.0%)、2例(11.9%)和1例(25%),随着病情加重,Ba基因亚型和C/D基因型感染者所占比例呈下降趋势,C2基因亚型感染者所占比例增加.结论 新疆地区维吾尔族慢性HBV感染者以Cl基因亚型为主,新疆维吾尔族慢性HBV感染者存在C/D基因型重组体.C2基因亚型HBV感染预示病情严重,预后差.     

乙型肝炎病毒基因型研究进展

1988年Okamoto等[1]通过对18株不同血清型乙型肝炎病毒(HBV)DNA进行全序列分析,将HBV分为A、B、C、D四种基因型。目前,根据HBV全基因组核苷酸序列差异≥8%或S基因序列差异≥4%,将HBV分为8个基因型,分别命名为A~H。每种基因型又可分为不同亚型,如A基因型可进一步分为A1(Aa)、A2(Ae)、A3(Ac)亚型;B基因型分为B1(Bj)、B2(Ba)、B3、B4和B5亚型;C基因型分为C1(Cs)、C2(Ce)、C3、C4和C5亚型;D基因型分为D1、D2、D3和D4亚型;F基因型分为F1和F2亚型等[2-6]。一、HBV基因型的地域和种族分布HBV基因型的分布具有明显的种族和…     

一株新疆维吾尔族D型乙型肝炎病毒的全基因克隆分析

目的 进行一株新疆维吾尔族D型HBV的全基因克隆.方法应用PCR扩增HBV全基因,进行全基因克隆,挑取阳性克隆进行序列测定,使用BioEdit和美国国立生物技术信息中心(NCBI)-BLAST工具进行生物信息学分析.结果获得1例新疆维吾尔族慢性HBV感染者D型HBV病毒株的全基因序列,其基因组全长为3174 bp,与目前D基因型参照序列比较,同源性为92%～98%,与1株来自中国的DC重组基因型(AY862865)比较,同源性为91%.进一步分析发现,该新疆病毒株与目前D基因型基因库参照序列比较,有9个碱基缺失,位于核苷酸第1760～1768位(ATTAAAGGT),即可能发生了缺失突变.氨基酸分析发现,其血清型为ayw2型.重组位点分析发现,该新疆病毒株未与其他基因型重组.该新疆株与2株来自土耳其的HBV株(AY796032和AY721605)遗传距离最近.结论成功克隆了一例维吾尔族慢性HBV感染者D型HBV病毒株的全基因序列,新疆维吾尔族D基因型HBV病毒株有其自身特点.     

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C/D重组体毒株的三种鉴定方法

目的针对HBV C/D重组体在我国西部地区尤其是藏族人群中广泛流行,基因分型时易被错分为D基因型等问题,建立相对准确的鉴定C/D重组体的方法。方法以来自西部地区的25例HBV感染者为例,分别通过PCR片段长度法、S和前C/C基因序列进化树分析法、全基因序列精细分析法对C/D重组体进行鉴定比较。结果 D基因型存在33 bp缺失,在S基因区酶切或测序的基础上,通过跨缺失区段的PCR产物长度可区分D与C/D重组体,该法简单易操作,适于大样本初筛;S和前C/C基因序列进化树分析法可明确鉴定C/D重组体,准确度高;全基因序列精细分析法可对重组类型和重组位点进行精确分析,结果最为可靠。结论根据研究目的不同,应综合考虑运用几种C/D重组体鉴定方法,提高研究的效率和结果的可靠性。     

泉州地区慢性重型肝炎患者乙型肝炎病毒基因型及亚型分布特点

目前已知,HBV被分为A～H 8种基因型,由于在同一基因型病毒株之间还存在着一定的差异,故依据全基因序列异质性>4%且<8%的原则,进一步将基因型分为不同亚型,如B型分为B1(Bj)、B2(Ba)、B3(Ba)、B4(Ba)等亚型,C型分为C1(Cs)、C2(Ce)、C3、C4、C5等亚型,在基因型亚型之间也存在着地域分布及临床差异[1-3].泉州地区HBV感染引起慢性重型肝炎的基因型以B型为主,其次为C型,亦存在一定比例的B/C基因型混合感染[4].为进一步明确泉州地区重型肝炎HBV基因型、基因亚型的分布特点,我们对慢性重型肝炎患者进行HBV S基因测序,通过HBV S基因进化树图验证了HBV基因型、区分HBV基因亚型.     

武汉重症手足口病EV-A71分离株全基因组特征分析北大核心CSCD

目的分析武汉重症肠道病毒A71型(Enterovirus A71,EV-A71)病毒株全基因组特征。方法自湖北武汉2例手足口病Ⅱ期患儿咽拭子中分离EV-A71,利用overlap-PCR扩增EV-A71全基因组的6个首尾重叠的基因片段,利用生物信息学软件DNAStar5.0、MEGA-Ⅹ和SimPlot3.5.1分析基因组特征。结果获得2株EV-A71分离株wh064和wh170的全基因组序列,二者核苷酸和氨基酸序列同源性分别为99.95%和99.86%。2株EV-A71病毒株属于C4a2亚型。系统进化分析和遗传距离计算发现,在P1区域,2株病毒株与C基因型EV-A71位于同一进化分支,遗传距离最小;在P2区域,2株病毒株与B基因型EV-A71和CVA16位于同一分支,与B基因型EV-A71之间遗传距离最小(C4亚型除外);在P3区域,2株病毒株与B3亚型EV-A71和CVA16位于同一分支,与B3亚型EV-A71和CVA16之间遗传距离较小。基因重组分析发现,2株分离株P1区域与C基因型EV-A71相似度最高,P2区域与B基因型EV-A71、CVA4、CVA5、CVA14和CVA16原型株的相似度高于C基因型EV-A71,P3区域与B3亚型EV-A71、CVA4、CVA14和CVA16原型株相似度高于其他病毒株,重组断点位于2A-2B连接处和3C处。此外,2株病毒株基因组中突变位点5’UTR-61T、VP1-27S(L)、VP1-98K和3D-396S亦存在于武汉其他重症和死亡病例EV-A71分离株。结论武汉2株EV-A71是重组病毒株,可能由C基因型和B3亚型EV-A71病毒株重组而来,亦或由C基因型EV-A71和CVA4、CVA14、CVA16重组而来。某些位点突变可能影响EV-A71毒力。     

乙型肝炎病毒基因亚型研究进展

近年来,各国学者对乙型肝炎病毒（HBV）基因型及其亚型的研究十分关注。HBV基因型不仅能反映核酸变异程度和病毒种系发生关系,而且与感染者的临床表现、预后及疗效有关。目前,根据HBV全基因组序列差异≥8％,或S基因序列≥4％,将HBV分为A、B、C、D、E、F、G、H等8个基因型,但基因型H是否是独立于F的一个新基因型,还有待进一步证实。各基因型之间还存在混合感染,如B与C、C与D混合感染等∞。有人认为,混合感染可能与重叠感染或基因型之间的同源重组或部分转换有关。值得注意的是：近年来,除研究HBV基因型外,对HBV基因亚型也进行了深入研究,发现A基因型可进一步分为Aa和Ae亚型0;B型可分为B1（Bi）、B2（Ba）、B3和B4亚型N;C型可分为c1、c2、c3和c4亚型;D型可分为D1、D2、D3和D4亚型,F型可分为F1和F2亚型等（见表1）。     

山东地区HBeAg阳性慢性乙型肝炎患者病毒基因型和亚型分布与临床

根据HBV全基因组序列差异≥8%或S基因序列差异≥4%,可将HBV分为A、B、C、D、E、F、G、H 8个基因型。目前已有报道,不同基因型可进一步分为不同的基因亚型。本研究对128例山东地区HBeAg阳性CHB患者HBV基因型、亚型及其临床意义进行了初步探讨。     

乙型肝炎病毒基因型及其临床意义的研究进展

乙型肝炎病毒(HBV)基因型的研究是目前乙型肝炎国内外研究的热点.HBV基因分型比血清亚型更能准确地反映原型病毒株之间的自然异质性,HBV基因分型方法有多种,以全基因测序为HBV基因分型的金标准,基于全基因核苷酸序列比较,HBV可分为A,B,C,D,E,F,G,H 8个基因型.HBV基因型呈地理区域性分布,且不同基因型致病性不同,HBV基因型与乙型肝炎病情的进展、临床表现、治疗、预后有密切的关系.本文就近几年HBV基因型及其临床意义的研究进展作一综述.     

Japanese case of hepatitis B virus genotypes C/D hybrid

Hepatitis B virus (HBV) is classified into eight genotypes based on complete genome sequence. Each genotype is related to geographic distribution and race. In Japan, most of the genotypes are B and C. In the present study, we report the first Japanese strain of HBV having a recombination between genotypes C and D. A 30-year-old woman was admitted to Kobe Medical Center because of liver dysfunction. She was diagnosed with spontaneous reactivation of chronic hepatitis B. She had no history of blood transfusion and her parents were negative for HBV. The phylogenetic analysis based on the complete genome sequences revealed that this strain was classified into genotype C, whereas the analysis based on Sgene sequence showed that this strain was genotype D. By using a SimPlot program, this strain was confirmed as a recombinant strain between genotypes C and D. Compared with previous recombinant strains in China, the breakpoint was the same and the difference was only 0.8% of the complete genome sequence. It was unclear whether or not this strain was transmitted from China, but the recombinant strains and intergenotypes of HBV have already existed in Japan.     

Diversity of Hepatitis B virus infecting Malaysian candidate blood donors is driven by viral and host factors

Summary. Malaysia is a medium endemic country for hepatitis B virus (HBV) infection but little is known about HBV strains circulating in Malaysian blood donors. Viral load, HBsAg concentrations and nested PCR products from 84 HBV surface antigen (HBsAg) positive samples were analysed in detail. Median viral load was 3050 IU/mL and median HBsAg 1150 IU/mL. Fifty‐six full genome, 20 pre‐S/S, 1 S gene and six basic core promoter/precore‐only sequences were obtained. Genotypes B and C were present at a ratio of 2:1, and two genotype D samples were obtained, both from donors of Indian background. Phylogenetically, genotype B was more diverse with subgenotypes B2‐5, B7 and B8 present, while most genotype C strains were from subgenotype C1. Genotypes B and C were equally frequent in ethnic Malays, but 80% of strains from Chinese were genotype B. HBsAg concentrations were higher in genotype C than in genotype B, in Chinese than Malays and in donors under the age of 30. HBV vaccine escape substitutions (P120S/T, I126N and G145G) were present in six strains. In the large surface protein, immuno‐inactive regions were more mutated than CD8 epitopes and the major hydrophilic region. Strains of genotype B or from ethnic Malays had higher genetic diversity than strains of genotype C or from Chinese donors. Hence HBV strains circulating in Malaysia are phylogenetically diverse reflecting the ethnic mix of its population. Ethnic Malays carry lower HBsAg levels and higher genetic diversity of the surface antigen, possibly resulting in more effective immune control of the infection.     

Genotype and phylogenetic characterization of hepatitis B virus among multi-ethnic cohort in Hawaii

AIM: Hepatitis B virus (HBV) genomes in carriers from Hawaii have not been evaluated previously. The aim of the present study was to evaluate the distribution of HBV genotypes and their clinical relevance in Hawaii. METHODS: Genotyping of HBV among 61 multi-ethnic carriers in Hawaii was performed by genetic methods. Three complete genomes and 61 core promoter/precore regions of HBV were sequenced directly. RESULTS: HBV genotype distribution among the 61 carriers was 23.0% for genotype A, 14.7% for genotype B and 62.3% for genotype C. Genotypes A, B and C were obtained from the carriers whose ethnicities were Filipino and Caucasian, Southeast Asian, and various Asian and Micronesian, respectively. All cases of genotype B were composed of recombinant strains with genotype C in the precore plus core region named genotype Ba. HBeAg was detected more frequently in genotype C than in genotype B (68.4% vs 33.3%, P<0.05) and basal core promoter (BCP) mutation (T1762/A1764) was more frequently found in genotype C than in genotype B. Twelve of the 38 genotype C strains possessed C at nucleotide (nt) position 1858 (C-1858). However there was no significant difference in clinical characteristics between C-1858 and T-1858 variants. Based on complete genome sequences, phylogenetic analysis revealed one patient of Micronesian ethnicity as having C-1858 clustered with two isolates from Polynesia with T-1858. In addition, two strains from Asian ethnicities were clustered with known isolates in carriers from Southeast Asia. CONCLUSION: Genotypes A, B and C are predominant types among multi-ethnic HBV carriers in Hawaii, and distribution of HBV genotypes is dependent on the ethnic background of the carriers in Hawaii.     

Geographic distribution, virologic and clinical characteristics of hepatitis B virus genotypes in China

The significance of hepatitis B virus (HBV) genotypes for the heterogeneity of chronic HBV infection and severity of liver disease is not well understood. The aim of this study was to determine the distribution and virologic characteristics of HBV genotypes in China and possible association with the diversity of liver disease. The study includes 1096 chronic HBV carriers from nine provinces in China. We collected clinical and laboratory data and analysed the HBV strains in sera by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and nucleotide sequencing techniques. The most common HBV genotypes were B (41%) and C (53%), while genotypes A and D were also found. A North-South divide was identified in genotype B and C distribution - genotype C was predominant in northern China, while genotype B was more prevalent in southern provinces. Patients with genotype B were younger than those with genotype C, and had a lower prevalence of HBeAg - 65%vs 72%, respectively (P = 0.03). However, the severity of liver disease did not differ significantly between patients infected with genotype B or C - neither when comparing liver function tests (1024 patients), nor hepatic inflammation and fibrosis (264 patients). Amongst 47 patients with genotype D (by PCR-RFLP), 37 (79%) were infected with a new subtype (designated Dc), having a recombination fragment from genotype C precore/core region. This is the first large-scale HBV genotype study from China and convincing documentation of the North-to-South gradient of genotypes C vs B in this country. HBV DNA recombination over the surface and precore/core genes increases the diversity of HBV strains and may have diagnostic and clinical implications.     

A novel hepatitis B virus subgenotype D10 circulating in Ethiopia

Hepatitis B virus (HBV) is genetically highly divergent and classified in ten genotypes and forty subgenotypes in distinct ethno‐geographic populations worldwide. Ethiopia is a country with high HBV prevalence; however, little is known about the genetic variability of HBV strains that circulate. Here, we characterize the complete genome of 29 HBV strains originating from five Ethiopian regions, by 454 deep sequencing and Sanger sequencing. Phylogenetically, ten strains were classified as genotype A1 and nineteen as genotype D. Fifteen genotype D strains, provisionally named subgenotype D10, showed a novel distinct cluster supported by high bootstrap value and >4% nucleotide divergence from other known subgenotypes. In addition, the novel D10 strains harboured nine unique amino acid signatures in the surface, polymerase and X genes. Seventy‐two per cent of the genotype D strains had the precore premature stop codon G1896A. In addition, 63% genotype A and 33% genotype D strains had the basal core promoter mutations, A1762T/G1764A. Furthermore, four pre‐S deletion variants and two recombinants were identified in this study. In conclusion, we identified a novel HBV subgenotype D10 circulating in Ethiopia, underlining the high genetic variability of HBV strains in Africa.     

New HBV subgenotype D9, a novel D/C recombinant,identified in patients with chronic HBeAg‐negative infection in Eastern India

Genome diversity is a hallmark of hepatitis B virus (HBV), which allowed its classification into 10 genotypes (A–J) and numerous subgenotypes. Among them, Genotype D is currently segregated into eight subgenotypes (D1–D8). Here, we report the identification and characterization of a novel subgenotype within genotype D of HBV from chronic hepatitis B e antigen (HBeAg)‐negative patients of Eastern India. Phylogenetic tree analysis based on complete genome sequences revealed that six of 39 HBV/D isolates formed a distinct cluster supported by high bootstrap value and had nucleotide divergence >4% relative to the known D subgenotypes (D1–D8), justifying their assignment into a new subgenotype (D9). By comparing the amino acid sequences of the four ORFs of HBV/D9 with D1–D8, 36 specific residues, including a unique one (E₁₁₂ in the core region), were identified that could be considered as a signature of D9. Further analysis by Simplot, BootScan and jpHMM demonstrated that D9 resulted from a discrete recombination with genotype C over the precore–core region. This type of recombination has not been described previously as all C/D recombinants reported so far possessed genotype C backbones with mosaic fragments derived from HBV/D. Interestingly, compared to other subgenotypes of HBV/D, D9 isolates had a higher frequency of mutations (A1762T and G1764A) in the basal core promoter region that had been implicated in the development of hepatocellular carcinoma. Further investigations are needed to determine the overall prevalence and clinical significance of these newly characterized D9 strains and to assess the impact of inter‐genotypic recombination on viral properties.     

Distinct geographical and demographic distribution of hepatitis B virus genotypes in the Canadian Arctic as revealed through an extensive molecular epidemiological survey

Summary. Very little is known of hepatitis B virus (HBV) in Canadian Arctic indigenous populations, where HBV was considered endemic prior to the introduction of HBV vaccine. This study expands upon an HBV seroepidemiological survey conducted between 1983 and 1985 throughout the Canadian Arctic, to characterize HBV in this population. Archived hepatitis B surface antigen (HBsAg)‐positive sera (n = 401) were processed for HBV DNA, followed by sequencing and phylogenetic analysis of the HBsAg‐ and HBcAg‐coding regions. Sixty‐nine per cent of samples (277/401) were DNA positive, with most having low viral load (median 3.4 log 10 IU/mL). The predominant HBV genotype observed was genotype B (HBV/B, 75%), followed by HBV/D (24%) and HBV/A (1%). All HBV/B strains clustered within subgenotype B6, a newly recognized HBV genotype among western circumpolar Inuit and Alaska Native people. HBV/D strains included both D3 (88%) and D4 (12%) subgenotypes, while all HBV/A strains were subgenotype A2. An association of HBV genotype B with Inuit living in the eastern Arctic and an association of genotype D with First Nation (Dene) living in the western Arctic was observed. This study establishes the high prevalence of HBV/B6 and HBV/D genotypes in Arctic populations and reveals their marked distribution within the Canadian Arctic based on geographical and demographic attributes.