Hepatitis B virus genetic diversity in Argentina: Dissimilar genotype distribution in two different geographical regions; description of hepatitis B surface antigen variants

BACKGROUND: The hepatitis B virus (HBV) molecular epidemiological data of Argentina are still scarce, since most of the previous analyses have been performed in the Metropolitan Region. OBJECTIVES: To deepen the current molecular and epidemiological information about the geographical distribution of HBV genotypes and subgenotypes, and to describe the hepatitis B surface antigen (HBsAg) variants circulating in Argentina. STUDY DESIGN: Eighty-eight Argentine partial HBsAg sequences from both the Northern and the Metropolitan Regions of the country were analyzed along with 67 Argentine HBV sequences existing in GenBank. RESULTS: Phylogenetic and amino acid sequence analysis grouped the 88 samples as genotypes A (14.8%), D (21.6%) and F (63.6%). In the Northern Region, 44 out of the 48 sequences analyzed (91.7%) grouped as genotype F. Differently, in the Metropolitan Region, the 40 samples grouped as genotype F (30.0%), genotype D (42.5%), and genotype A (27.5%). An elevated proportion (14.8%) of the genomes presented mutations in the major hydrophilic region (MHR). CONCLUSIONS: The different genotype distribution in both Argentine regions indicates that the epidemiological landscape of HBV infection appears to be the result of the diverse human migratory movements that have given shape to the present population. Our findings show that the prevalence of HBsAg variants is quite significant among the Argentine population.     

Role of surface promoter mutations in hepatitis B surface antigen production and secretion in occult hepatitis B virus infection

The production, secretion, and localization of surface proteins of hepatitis B virus (HBV) and the ratio of large to small surface protein S was studied in HepG2 cells transfected with the wild-type and mutant pre-S1 and pre-S2/S promoters of HBV molecular clones 313.1 (GenBank accession no. AY161147) and 761.1 (GenBank accession no. AY161159) from two patients with occult HBV infection. Fusion constructs were made by in frame fusion of the wild-type surface gene to the mutant pre-S1 and pre-S2/S promoters and wild-type promoter so that the structural part of the small surface protein remains identical. HepG2 cells transfected transiently were used for analysis. HBV surface proteins production and secretion was determined by enzyme linked immuno assay (ELISA) and localization by immunofluorescence. Immunoprecipitation of the large, middle, and small surface protein was carried out in transient transfected and metabolically labeled cells to determine the ratio of the large to small surface protein. The results indicate that HepG2 cells transfected with mutant HBV promoters had reduced HBV surface proteins secretion compared to wild-type HBV. HepG2 cells transfected with mutant HBV pre-S1 and pre-S2/S promoters showed cytoplasmic aggregation of HBV surface proteins compared to wild-type HBV promoters, which showed diffuse cytoplasmic localization. In all cases, the HBV surface proteins localized to the endoplasmic reticulum. The ratio between the large and small surface protein was 1.89 and 0.56 with mutant HBV 313.1 and 761.1 pre-S1 and pre-S2/S promoters, respectively, compared to 0.17 in wild-type. Thus, the aggregation of surface proteins, altered ratio and secretion of surface proteins were possibly the causes of occult hepatitis B infection.     

隐匿性乙型肝炎患者乙肝病毒preS/S基因突变分析

目的 隐匿性乙肝感染与严重慢性肝损伤的病毒学与免疫学机制尚未完全阐明,拟通过研究隐匿性HBV preS/S区基因变异,初步揭示隐匿性乙肝发生及其致慢性严重肝损伤的病毒学因素。方法 收集瑞金医院门诊及住院HBsAg阴性患者的血清,抽提DNA,利用巢式PCR方法对隐匿性感染进行检测;克隆阳性标本的preS/S区全长基因并测序分析,探讨其突变类型与严重慢性肝损伤的关系。结果 在全部468份HBsAg阴性血清中共检出隐匿性HBV感染69例,HBcAb单独强阳性组、HBeAb单独强阳性组、HBeAg单独阳性组、HBcAb与HBsAb同时强阳性组和5项指标全阴性组的检出率分别为16％、8.7％、36.4％、18.3％和0％。隐匿性感染患者血清HBV-DNA水平明显低于HBsAg阳性感染患者,隐匿性HBV preS/S区缺失突变、preS2基因M1I和Q2K突变,S基因Q129N/R/P、G185R和S210R突变的频率明显高于HBsAg阳性组。伴严重肝损伤的隐匿性感染较无严重肝损伤隐匿性感染患者在性别比例及血清HBV-DNA水平方面均有明显差异。伴严重肝损伤的隐匿性感染的HBV在preS2基因M1I和Q2K,S基因G185R和S210R的突变频率明显高于无严重肝损伤者,但 preS缺失和S基因Q129N/R/P的突变频率低于无严重肝损伤者。以伴严重肝损伤的隐匿性感染与HBsAg阳性严重肝损伤者相比,后者HBV-DNA水平明显高于前者,但preS2基因M1I和Q2K、S基因G185R和S210R突变的频率明显低于前者。结论 隐匿性感染与HBsAg阳性病人之间致慢性严重肝损伤的病毒学因素存在不同;preS2区M1I和Q2K以及S区G185R和S210R等突变对于隐匿性乙肝患者而言,可能是评价其是否进展为严重慢性肝损伤的有用指标。     

Performance of HBsAg quantification assays for detection of Hepatitis B virus genotypes and diagnostic escape-variants in clinical samples

BackgroundThe impact of hepatitis B virus (HBV) genomic variability on the measurement of HBsAg level has been poorly evaluated.ObjectiveThis study was designed to compare the performance of all the available assays measuring HBsAg level in this setting.Study designA large selection of wild type HBV genotypes (n = 184) and HBsAg strains harboring mutations in the S gene (n = 81) from clinical samples was studied with three HBsAg quantification assays: Architect HBsAg (Abbott), LiaisonXL Murex HBsAg Quant (DiaSorin) and the Elecsys HBsAgII (Roche).ResultsThe overall percentage of positive results was 99.2% for Abbott, 98.9% for DiaSorin and 98.1% for Roche. Abbott and Roche assays provided an excellent concordance in HBsAg quantification (global mean bias of −0.006 logIU/mL). By contrast, DiaSorin underestimated HBsAg level with values 0.112 logIU/ml and 0.103 logIU/ml lower than Abbott and Roche, respectively. By contrast, DiaSorin slightly over quantified gtC (2.5% over the expected value) while Abbott provided values 6.2% lower than expected and 16.2% lower than what observed for the other genotypes. HBsAg quantitative assays were influenced by HBs protein substitutions irrespective to the genotype but no specific protein pattern that would particularly impair the quantification by one technique has been identified. However, Roche seemed to be particularly impacted by substitutions at 145 residue: 75% of under quantified samples carried a substituted 145 residue.ConclusionThis head-to-head comparison indicates a good correlation between all current systems used to quantify HBsAg but clearly shows an influence of both the genotype and the presence of “a” determinant variants in the absolute quantification of HBsAg. While these discrepancies may not translate into major clinical consequence, they may explain an absence of detection of weak concentration of HBsAg on some systems.     

肾组织preS1/S2-Ag检测在乙型肝炎病毒相关性肾炎诊断中的作用

 目的：观察前S1/S2抗原（preS1/S2-Ag）及其它乙型肝炎病毒(HBV)抗原在HBV相关性肾小球肾炎（HBV-GN）患者肾组织中的表达,探讨它们在HBV-GN诊断中的应用价值。方法：回顾性收集2003年1月~2013年1月于中山大学附属第三医院肾内科住院的患者,并符合以下入组标准：血清学HBsAg阳性;有血尿、蛋白尿等临床表现;经肾组织活检病理诊断为肾小球肾炎病变;排除合并有系统性红斑狼疮、过敏性紫癜、糖尿病、丙肝等疾病。入组共49例。用免疫组织化学的方法对其肾组织石蜡切片进行preS1/S2-Ag、HBeAg、HBsAg和HBcAg检测。随机选取 5例HBsAg阴性的肾小球轻微病变患者,5例HBsAg阳性的非肾小球肾炎患者作对照。结果： 49例HBV感染合并肾小球肾炎患者中preS1/S2-Ag、HBeAg、HBsAg和HBcAg检出阳性率分别为32.7%（16例）、 388%（19例）、14.3%（7例）和46.9%（23例）,总阳性率为70.2%（36例）;preS1/S2-Ag主要表达在肾小管上皮细胞、肾小球系膜细胞和内皮细胞胞质内;其表达与肾组织HBcAg的表达呈正相关（r=0459, P<001）。5例HBsAg阴性的肾小球轻微病变患者,4种抗原均未检测到;5例HBsAg阳性的非肾小球肾炎患者有2例表达HBeAg,1例表达HBcAg,无1例表达preS1/S2-Ag及HBsAg。结论：HBV-GN患者肾组织中检测到preS1/S2-Ag; preS1/S2-Ag、HBeAg、HBsAg和HBcAg联合检测可提高HBV-GN的临床诊断率。     

武汉市新分离2株乙型脑炎病毒E基因分型及序列分析

目的 对2009年武汉市新分离的2株乙型脑炎（简称乙脑）病毒进行基因分型和序列分析,了解本地乙脑病毒株的分子生物学特性。方法 将2009年从三带喙库蚊中分离的两株乙型脑炎病毒用RT-PCR法扩增E基因,将其进行测序,并用DNAstar and MegAlign软件与其他基因型代表株进行比对。结果 16组样品检出两株阳性（WHJX9-09、WHJX10-09）,这两株阳性均属于GI型。两株新分离JEV之间的核苷酸和氨基酸同源性分别为98.9％和100％。同目前在武汉市使用的疫苗株SA-14-14-2相比,核苷酸同源性分别为87.4％、87.9％,氨基酸同源性为96.9％。共有15个氨基酸发生变异分布在3个不同结构域,中和位点没有变异但是神经毒力位点仍然存在。结论 武汉市本地新分离乙脑病毒基因型为GI型,不同于1988年在武汉检出的GⅢ型的基因型,和疫苗株SA-14-14-2相比,其神经毒力并没有减弱,但疫苗产生的抗体对新出现的GI型乙脑病毒仍有中和作用。因此提高乙脑疫苗的接种率并配合防蚊灭蚊措施对控制乙脑疫情依然至关重要。同时有必要对本市蚊虫及乙脑患者进行长期的病原学监测工作,为乙脑预测预警体系的建立提供科学依据。     

戊型肝炎病毒第Ⅳ基因型毒株中和抗原表位的鉴定

目的确定在我国新发现的戊型肝炎病毒（HEV）第Ⅳ基因型毒株的中和抗原表位特征及其与世界各地其他基因型HEV毒株中和抗原表位的异同。方法制备HEV第Ⅳ基因型ORF2重组衣壳蛋白p166Chn及其单克隆抗体（McAb），采用体外中和试验鉴定McAb的中和活性；通过间接ELISA和免疫印迹法测定中和性McAb与不同基因型HEVORF2编码蛋白p166的免疫反应性，并结合相加ELISA确定p166Chn中和抗原表位的分布和性质。结果获得6株稳定分泌抗-p166Chn McAb的杂交瘤细胞株。所得McAb能在体外中和HEV中国毒株（第Ⅳ基因型）对PLC/PRF／5细胞的感染性，并与来源于HEV4种不同基因型代表株的7种p166重组蛋白（p166Chn、p166Bur、p166Mor、p166Pak、p166Mex、p166Us和p166Nz）均能发生阳性反应。抗体间的相加ELISA结果为阴性。表明6株McAb识别p166上的同一个中和抗原表位。结论在我国新发现的HEV第Ⅳ基因型毒株与分布在世界各地的其他基因型毒株具有共同的中和抗原表位。     

Hepatitis B virus gene mutations in the sera of three patients with coexisting hepatitis B surface antigen and anti-surface antibody

We analyzed gene mutations in the Hepatitis B virus of three virus carriers with coexisting Hepatitis B surface(HBs) antigen and anti-HBs antibody. Viral DNAs were extracted from sera and the pre-S, S and X(including core promoter and pre-core region) regions were amplified by PCR, and sequenced. Case 1 and Case 2 were positive for HBe antigen, while Case 3 was negative. All three cases were positive for HBe antibody and HBV DNA. In the S gene region, various point mutations were detected in all three cases. Mutations were clustered in the first hydrophilic loop region(codon 47-46) essential for the secretion of surface antigen. A few mutations were detected in 'a' loop(codon 124-147) of the S gene. None of the cases had an amino acid substitution of codon 145 of the S gene that is reported to be responsible for weak recognition by the HBs antibody. These data suggest the existence of hyper-variable sequence in S region, or otherwise result of low-fidelity of Taq DNA polymerase-reaction. Case 1 possessed a point mutation, T to C at nucleotide position 1753, in the region overlapping the coding region of the X gene and the CCAAT/enhancer binding protein(C/EBP) binding region within the core promoter region. Case 2 possessed both a large deletion(129 bp) in the pre-S1 and in-frame deletions of 15 and 27 bp in the pre-S2 region. Case 3 had an in-frame deletion of 30 bp in the pre-S2 region, and a point mutation in precore region. The point mutation, G to A at a nucleotide position 1986, converts Trp(TGG) to a stop codon TAG, and may contribute the fulminant hepatitis. These results suggest that the mutations in the pre-S, the core promoter, or the X gene may imply coexistence of the HBs antigen and antibody after seroconversion, while the point mutations in the S region are not likely to be responsible for the HBV escape mutant.     

Molecular analysis of the hepatitis B virus presurface and surface gene in patients from eastern China with occult hepatitis B

This study was designed to detect and analyze mutations that occur within the presurface and surface (pre‐S/S) gene of HBV in patients with occult hepatitis B, and determine their relationship to that disorder. Among 254 HBsAg negative samples of blood collected in eastern China, 183 were positive for anti‐HBc alone, 61 were positive for anti‐HBe alone, and 10 samples were positive for HBeAg. Within this group, 15 samples were found to be HBV DNA positive by real‐time PCR and were designated Group I. A control group of 28 HBsAg positive samples were chosen at random from patients with chronic hepatitis B and designated Group II. The HBV pre‐S/S gene was amplified by PCR and subjected to sequencing analysis. Occult hepatitis B was found in 1.6% of the patients with anti‐HBc alone and in 3.3% of those with anti‐HBe alone. Occult hepatitis B also was found in all HBsAg negative but HBeAg positive samples. Sequencing analysis showed a significant correlation between point mutations within the “a” determinant and occult hepatitis B (P < 0.0001), and a close relationship between pre‐S deletion mutations and occult hepatitis B (P = 0.06). There were unique amino acid mutations at the G145 position other than G145R. The HBV DNA levels in patients with occult hepatitis B were significantly lower than those found in the control group. The “a” determinant mutations and pre‐S deletions may play important roles in occult hepatitis B by affecting the expression, synthesis and secretion of the S protein and by impeding viral release and replication. J. Med. Virol. 85: 979–986, 2013. © 2013 Wiley Periodicals, Inc.     

Hepatitis B virus BCP,precore/core,X gene mutations/genotypes and the risk of hepatocellular carcinoma in India

The study aims to characterize mutations of the HBV genome involving BCP, Precore/core and X regions and also defines HBV genotypes in patients of hepatocellular carcinoma (HCC). The study involved 150 HBV‐related HCC cases and 136 HBV‐related chronic liver disease patients without HCC as controls. HBV DNA was subjected to mutational analysis using SSCP technique, genotyping by RFLP, and direct nucleotide sequencing. HBV DNA was found in 58.7% (88/150) of the HCC cases and 74.3% (101/136) of controls. HBV mutants were observed in 44.3% of HCC cases and 43.2% of controls. HBV/D was prevalent amongst the patients and controls, followed by HBV/A. The prevalence of the TT1504 mutation in the X gene, the V1753 and T1762/A1764 mutations in the BCP region, and G1914 mutation in the core gene were significantly higher in the HCC group than in the non‐HCC group. Multivariate analyses showed that the TT1504, V1753, A1762T/G1764A, and the G1914 mutations and the patient's age, sex, and HBeAg status increased the risk of HCC development significantly. Also, patients with HCC had lower levels of serum albumin, viral load, and platelet counts but higher values of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, bilirubin, and Alpha feto‐protein than those of controls (P < 0.001 for all comparisons). HBV/D was the predominant genotype associated with HCC cases seen in India. The presence of different types of HBV mutations, age, sex, HBeAg status, and viral load was found to increase significantly the risk of HCC development in India. J. Med. Virol. 82: 1115–1125, 2010. © 2010 Wiley‐Liss, Inc.     

载体和基因片段的选择对戊型肝炎病毒基因免疫抗原表达的影响

目的比较不同载体和不同大小的目的基因片段对戊型肝炎病毒(HEV)基因免疫抗原表达的影响,为基于HEV中和抗原表位的HEV基因免疫提供一定的依据。方法将含Ⅳ型HEV中国株中和抗原表位的p166和p179片段编码基因分别克隆入pTR421和pCDNA3.1两种真核表达载体,用脂质体介导基因转染HepG2人肝癌细胞系,经间接免疫荧光和Western blot分析以及将质粒注射小鼠局部肌肉组织后经免疫组织化学染色检测,分析目的基因在体内外的表达水平。结果成功构建了pTR421-166、pTR421-179、pCDNA3.1-166和pCDNA3.1-179四种重组质粒,经限制性内切酶双酶切和核苷酸测序鉴定,编码基因正确无误;pTR421-179转染的细胞以及注射小鼠的局部肌肉组织可以检测到p179的表达,而pCDNA3.1-179、pCDNA3.1-166以及pTR421-166均检测不到目的基因在体内、外的抗原表达。结论载体和目的基因片段的选择显著影响HEV抗原在体内、外的表达,直接关系到基因免疫的成功与否。     

Distribution of genotype/subtype and mutational spectra of the surface gene of hepatitis B virus circulating in Hanoi, Vietnam

In order to ascertain the molecular epidemiological features and mutational spectra of hepatitis B virus (HBV) in Hanoi, Vietnam, direct sequencing of the 219-nucleotide fragment of the surface (S) gene of HBV from the sera of 40 patients mostly with chronic hepatitis were carried out. The samples were classified into genotypes by phylogenetic and genotype-specific analysis, and subtypes by the deduced amino acid sequences. The results showed that genotype B with ayw1 was predominant genotype/subtype (63%), followed by genotype C with adr (18%). The quasi-species nature of the HBV in the sera was observed in 24 of 40 samples examined. One sample (HN109) showed mixture of genotypes B and C. Among 26 amino acid substitutions, 16 were the variants and the remainders were mutations. In the "a" determinant region, three mutations with methionine to leucine (L) changes at the 133 amino acid residue were in the first loop and no mutations were in the second loop. A new mutation, threonine to methionine at 126 amino acid residue, was observed in one sample. In conclusion, the analysis of the S gene region of HBV showed that in Hanoi, genotype B with ayw1 was prevalent and the quasi-species nature of HBV was also common.     

乙型肝炎病毒PreS1基因的原核表达及免疫学性质鉴定

目的 构建含乙型肝炎病毒(HBV)PreS1基因的原核表达载体,获得高纯度、有生物活性的PreS1重组蛋白.方法 采用PCR法扩增PreS1及其N末端和C末端部分基因序列,克隆入原核表达载体pGST-MOLUC.重组质粒经IPTG诱导表达后进行SDS-PAGE电泳分析和Western blot检测.用谷胱甘肽-Sepharose 4B凝胶亲和层析纯化的重组融合蛋白免疫新西兰家兔,制备GST-PreS1融合蛋白的抗血清.进一步用ELISA分析融合蛋白特异抑制HBV病毒与抗体结合的能力.结果 重组质粒转化宿主菌后成功诱导出Mr39 000、31 000和32 000的GST-PreS1、GST-PreS1N及GST-PreS1C融合蛋白,均与预期相对分子质量相符.Western blot检测获得特异的杂交条带.采用谷胱甘肽-Sepharose 4B凝胶纯化的融合蛋白纯度约为90%左右.融合蛋白免疫家兔后抗体滴度达到10-7.病毒捕获ELISA实验表明,融合蛋白能特异抑制病毒与家兔免疫血清结合.结论 GST-PreS1融合蛋白能够在大肠杆菌中高效表达,其纯化产物是研究PreS1基因在HBV感染过程中作用的有用工具.     

HBsAg阴性preS1Ag阳性的HBV携带者HBVS基因多态性分析

目的探讨HBsAg（-）／HBeAg（＋）／HBcAb（＋）／preS1Ag（＋）少见血清学模式形成的原因。方法采用聚合酶链反应（PCR）、单链构象多态性分析（SSCP）、异源双链分析（HA）和基因测序的方法，对该少见模式乙肝病毒携带者HBVS基因进行分析，并与其母亲及参考序列HBVS基因进行比较，分析其变异情况。结果该少见模式乙肝病毒携带者与其母亲HBVS基因PCR扩增结果均为阳性，经SSCP、HA和核苷酸序列比对分析，两者HBVS基因多态性不明显，同源性为99．82％。与其母亲或参考序列（AF411409）比对，该少见模式乙肝病毒携带者HBVS基因在第353位由野生型的C变为A，从而使HBsAg118位氨基酸由苏氨酸变为赖氨酸（aa118T→K）。结论该少见模式乙肝病毒携带者所感染的HBV在HBsAg第118位氨基酸上错义突变（T→K），改变了HBsAg的空间结构和抗原性，影响了HBsAg与抗-HBs的结合能力。     

Performance of a new rapid test for the detection of hepatitis B surface antigen in various patient populations

BackgroundRapid diagnostic tests (RDT) have been developed for the detection of hepatitis B surface antigen (HBsAg). They represent a promising alternative to enzyme immunoassays and a powerful tool for large-scale screening and diagnosis of HBV infection, especially in regions without easy access to serological and molecular testing.ObjectivesThe aims of the present study were to evaluate the characteristics and clinical performance of a new CE-marked HBsAg RDT, DRW-HBsAg v2.0 assay (Diagnostics for the Real World™, Ltd., USA), in various patient populations, including those chronically infected with HBV, patients with severe acute hepatitis of unknown origin and pregnant women with unknown HBV serological status at delivery.ResultsThe lower limit of detection of the assay, evaluated in 21 clinical samples, ranged from 0.30 ± 0.07 to 0.97 ± 0.26 international units/mL (using Abbott Architect as a reference), depending on the HBV genotype. The assay tested positive in 100% of patients with chronic hepatitis B, 96.3% of HBsAg-positive acute hepatitis patients, and 95.2% of HBsAg-positive pregnant women. Its specificity was 98.8% in HBsAg-negative patients, 98.7% in HBsAg-negative patients with acute hepatitis of unknown origin and 97.8% in HBsAg-negative pregnant women. Amino acid substitutions in the HBsAg major hydrophilic region did not affect HBsAg detection by DRW-HBsAg v2.0.ConclusionsThe new DRW-HBsAg v2.0 assay is a simple, rapid, easy-to-run and highly sensitive assay that can be used in both high- and low-risk populations for the diagnosis of HBsAg carriage. It appears to be a promising new tool for large-scale screening and diagnosis of HBV infection.     

母婴传播感染HBV儿童及其母亲体内HBV preS/S基因准种序列以及变异特点研究

目的：对经母婴传播获得乙型肝炎病毒（HBV）感染子女及其母亲无症状携带者（AsC)体内HBV preS/S基因进行研究，了解来源相同的HBV毒株在不同程度病毒血症情况下preS/S有无准种存在及其特点。方法：应用T－A克隆技术构建重组质粒pGEM-preS/S、双酶切进行鉴定，每个病人选6个酶切鉴定正确的克隆测序并进行分析。结果：3对AsC母子呈不同程度病毒血症，HBV均为基因型B／血清型adw2。36个克隆序列建立的进化树显示3对母子的preS/S为同一分支HBV preS/S进化而来，每例病人6个序列呈准种分布。低病毒血症HBV preS/S的核苷酸变异率明显高于高病毒血症，2个低病毒血症病人的变异位点绝大多数相同，其中错义变异多位于T－细胞表位和B－细胞表位内或／和附近。变异率和变异位点均与年龄无关。结论：经母婴传播而获得HBV感染儿童及其母亲无症状携带者，无论病毒血症高低，体内HBV preS/S序列均呈准种分布。来源相同的HBV preS/S在不同程度病毒血症病人体内差异较大，而与年龄无关。高病毒血症病人变异率低，而在低病毒血症变异率较高，但变异是有规律的，可能与免疫逃逸有关。     

Comprehensive analysis of the prevalence of hepatitis B virus escape mutations in the major hydrophilic region of surface antigen

Escape mutations in the major hydrophilic region (MHR) of hepatitis B surface antigen (HBsAg) are reported widely worldwide; these mutations lead to diagnostic problems, emergence of vaccine-escape mutants, and hepatitis B immunoglobulin (HBIG) therapy failure. However, the prevalence of these mutations in different genotypes remains to be studied systematically. In the current study, 11,221 non-redundant hepatitis B virus (HBV) sequences of 8 genotypes (from A to H), obtained from the National Center for Biotechnology Information (NCBI), were analyzed to determine the prevalence of HBsAg escape mutations that were previously described. Eight important mutations associated with diagnostic failure, P120T, T126S, Q129H, G130N, S143L, D144A, and G145A/R, were prevalent in one or more genotypes, with the frequency of no less than 1%. With regard to escape variants that evade vaccine or immunoglobulin therapy, mutations were located mainly at positions 120, 126, 129, 130, 133, 134, 137, 140, 143, 144, and 145. The majority of such mutations showed genotypic heterogeneity, indicating the different distribution of the escape mutations. Most of the escape mutations clustered in the "a" determinant, indicating that this region was more likely to be affected by immune selection or antiviral therapy than other regions. Understanding the prevalence and heterogeneity of escape mutations could provide useful guidance for the improvement of diagnostic assays, design of new vaccines, and prevention of failure of HBIG therapy.