High level of hepatitis B virus DNA after HBeAg-to-anti-HBe seroconversion is related to coexistence of mutations in its precore and basal core promoter

AIM: G1896A mutation in precore or A1762T/G1764A mutations in basal core promoter are suspected to be responsible for patients with detectable level of HBV DNA in serum after seroconversion from HBeAg to anti-HBe. However, G1896A variant has impaired, while A1762T/ G1764A variant may have intact replication ability. They themselves or their coexistence status may play different roles in such meaningless seroconversion. For these reasons, the significances of these two types of mutations were comparatively investigated in this study. METHODS: One hundred and sixty-five sera with positive anti-HBe and HBV DNA were collected from different patients. Mutations of G1896A and A1762T/G1764A among these serum samples were detected using competitively differentiated PCR. HBV DNA was demonstrated using real-time quantitative PCR. RESULTS: G1896A and/or A1762T/G1764A mutations were detected in 89.1% (147/165) out of patients with detectable HBV DNA in serum after HBeAg-to-anti-HBe seroconversion. The positive rate of G1896A variants was significantly higher than that of A1762T/G1764A mutations (77.6% vs 50.3%, X2= 26.61,P<0.01). The coexistence positive rate of these two types of mutations was 38.8% (64/165). Coexistence mutations were found in 77.1% (64/83) out of sera with A1762T/G1764A mutations, and in 50.0% (64/128) out of sera with G1896A mutation. Compared with variants with G1896A mutation only, the coexistence mutations were predominant in patients with high level of serum HBV DNA, and related to higher total bilirubin, lower serum albumin and progressive liver diseases. CONCLUSION: The coexistence of G1896A mutation and A1762T/G1764A mutations is very common, and responsible for the major cases with high level of HBV DNA in serum and progressive liver diseases after HBeAg-to-anti-HBe seroconversion. This coexistence mutation variant may have higher pathogenicity and replication ability.     

HBV BCP区1762/1764位点变异对肝脏疾病进展及预后的影响

目的:探讨乙型肝炎病毒BCP区A1762T/G1764A变异与肝脏疾病进展的关系。方法:收集78例慢性乙型肝炎患者(CHB)和125例慢性重型乙型肝炎患者(CSHB)的血清及临床资料,并对所有入组患者进行随访,采用聚合酶链反应扩增HBV BCP区基因片段,产物纯化后直接测序,检测BCP区T1762/A1764位点变异。结果:CSHB组患者A1762T、G1764A及A1762T+G1764A的变异频率分别为64.0%(80/125)、60.0%(75/125)、60.0%(75/125),CHB患者3种变异的变异频率分别为30.8%(24/78)、28.2%(22/78)、25.6%(20/78),CSHB组3种变异的变异频率均明显高于CHB组,差异有统计学意义(P0.001)。125例CSHB患者随访48周,死亡组A1762T/G1764A位点变异频率明显高于存活组,差异有统计学意义(x~2=12.42,P0.001);A1762T/G1764A位点变异组的患者累积存活率明显低于未变异组(x~2=9.742,P0.01)。结论:HBV BCP区1762/1764位点变异可能会加重HBV感染后肝脏疾病病情,并且对慢性重型乙型肝炎的发病及预后可能起重要的作用。     

青岛地区乙型肝炎病毒基本核心启动子区基因突变与乙型肝炎病毒所致原发性肝癌的相关性

目的通过分析山东省青岛地区HBV核心启动子基因序列的突变特征,探讨其与乙型肝炎相关原发性肝癌的相关性。方法收取慢性乙型肝炎患者和乙型肝炎相关原发性肝癌患者的血清标本各60例,然后从中提取HBV DNA,采用聚合酶链反应(PCR)扩增、纯化、克隆后测序,根据S基因区的编码序列确定患者的基因型和血清型;分别将HBV核心启动子区的各序列结果与GeneBank中的HBV标准株做对比,用DNAMAN软件对基因序列进行突变分析。采用SPSS17.0软件进行统计学分析。结果 120例标本,HBV株均为B或C基因型,以C基因型为主,其中,HBV组的C基因型所占比率为83.33%,HCC组为90.00%(χ2=0.65,P=0.42);血清型均为adw2或adrq+。HBV基因组核心启动子区常见的点突变为C1653T、T1753V、C1754T及A1762T/G1764A,发生率分别为42.73%、86.36%、71.82%、38.18%。与慢性乙型肝炎患者相比,肝癌患者中发生率比较高的突变位点为C1653T(78.85%,χ2=52.58,P<0.001)及A1762T/G1764A(73.08%,χ2=50.88,P<0.001)。结论山东青岛地区HBV基因组常见为B、C基因型,其中以C型为主;核心启动子区突变发生率高,其中,T1753V与HCC发生无关,C1653T、A1762T和G1764A位点无论单独或是联合突变均与HCC发生密切相关。     

HBV前-C区和BCP区变异与肝细胞癌的相关性分析

目的探讨HBV前-C区G1896A和BCP区A1762T/G1764A变异与肝细胞癌(HCC)的关系及其可能的机制。方法选择于青岛市传染病医院住院的HBV DNA104拷贝/ml的慢性HBV感染者82例,其中慢性乙型肝炎(CHB)29例,乙型肝炎肝硬化(LC)27例,HBV相关肝细胞癌(HCC)26例,采用实时荧光PCR法检测其HBV前-C区1896位变异和BCP区1762/1764位变异,并采用ELISA法检测血清肿瘤坏死因子α(TNF-α)水平。结果 HCC组和LC组前-C区G1896A和BCP区A1762T/G1764A变异率、血清TNF-α水平均显著高于CHB组,但HCC组和LC组间无显著差异。前-C区G1896A和BCP区A1762T/G1764A变异者血清TNF-α水平均显著高于非变异组。结论 HBV前-C区G1896A和BCP区A1762T/G1764A变异与HCC形成有关,机制是否与HBV变异和TNF-α水平间的因果关系相关,有待进一步研究。     

黎族HBV感染者其病毒基因型及C基因启动子/前C区基因突变与肝硬化和肝癌的关系

HBV感染是一个严重的公共卫生问题.在中国,慢性乙型肝炎是导致肝硬化和原发性肝癌的主要危险因素之一[1].目前,根据HBV核苷酸变异＞8％,将HBV分为A～H8种基因型[2].有研究结果显示,HBV基因型、HBV基因组前C区(PreC)第1896位核苷酸G→A(G1896A)以及其启动子(BCP) 1762位核苷酸A→T和1764位核苷酸G→A的突变(BCP A1762T/G1764A)与病毒的复制、转录、抗原表达水平以及疾病的临床过程密切相关[3-4].黎族是海南岛的原住居民,目前关于海南岛黎族肝硬化及肝癌患者HBV基因型、PreC G1896A基因突变和BCP A1762T/G1764A基因突变流行病学分布的研究鲜见报道.本研究旨在了解HBV基因型、PreC G1896A基因突变和BCP A1762T/G1764A基因突变与海南岛黎族肝硬化及肝癌患者发病机制的关系.     

慢性HBV感染者抗病毒治疗前HBV基本核心启动子及前C区突变的检测及意义

目的研究慢性乙型肝炎病毒（HBV）感染者抗病毒治疗前HBV基本核心启动子（BCP）突变和前C区（PreC）突变与HBeAg、HBV DNA水平和慢性肝病进展的关系。方法收集283例慢性HBV感染者抗病毒治疗前的血清标本,其中慢性乙型肝炎（CHB）185例,肝硬化（LC）98例。采用PCR后直接测序法检测HBV BCP和PreC区突变,同时确定基因型。结果在HBeAg阴性和HBeAg阳性CHB患者中,前C区A1896变异率分别为44.6%（37/83）和21.6%（22/102）（χ2=11.154,P=0.001）,LC患者分别为43.4%（23/53）和17.0%（8/47）（χ2=8.101,P=0.004）。在HBeAg阳性患者中,BCP T1762/A1764双突变率LC组和CHB组分别为89.4%（42/47）和70.6%（72/102）（χ2=6.310,P=0.012）。在单变量分析中,只有年龄（≥45岁）（χ2=27.861,P〈0.001）、BCP T1762/A1764双突变（χ2=8.675,P=0.003）和HBV DNA（≥105拷贝/ml）（χ2=20.499,P〈0.001）与LC进展有关。多因素Logistic回归分析（匹配年龄和性别）发现,BCP T1762/A1764双突变（OR=3.260,95%CI：1.401～7.586;wald=7.517,P=0.006）和HBV DNA（≥105拷贝/ml）（OR=4.640,95%CI：2.331～9.237;wald=19.089,P〈0.001）是LC进展的危险因素。结论前C区A1896突变与HBeAg的消失有关;年龄（≥45岁）、BCP T1762/A1764双突变和HBV DNA高载量（≥105拷贝/ml）与肝硬化进展有关。     

乙型肝炎病毒前C/BCP区基因变异对特异性细胞毒性T淋巴细胞免疫应答的影响

目的 研究HBV前C/BCP区基因变异对慢性乙型肝炎(CHB)患者特异性细胞毒性T淋巴细胞(CTL)免疫应答的影响.方法 采用HBV核心抗原表位肽core18-27,流式细胞术胞内细胞因子(CFC)分析法检测CHB患者外周血单个核细胞(PBMC)中的特异性CTL,对扩增产物进行测序分析.结果 54例CHB患者中G1896A突变毒株21例,占38.9%;1762/1764位核苷酸联合突变26例,占48.1%;3位点同时突变毒株13例,占24.1%.3种变异株体外HBV核心抗原表位肽core18-27刺激后,特异性CTL水平[(0.41±0.09)%、(0.36±0.08)%、(0.48±0.08)%]显著高于野毒株[(0.11±0.06)%,P＜0.05].结论 G1896A变异及1762/1764位核苷酸联合突变能显著增强特异性CTL水平,在CHB患者病情活动过程中起重要作用.     

清热利湿法对慢性乙型肝炎HBV基因突变株复制的影响

目的:研究清热利湿法对慢性乙型肝炎(CHB)患者HBV前C区基因突变株复制的影响。方法:采用基因芯片技术定量检测CHB肝胆湿热/湿热中阻证患者治疗(清热利湿法)前后的HBV前C基因变异。结果:治疗前的HBV前C区1762、1764、1896位点变异率明显高于1899位点变异率,差异有显著性意义(P<0.01);治疗后各位点变异率下降,其中治疗组1764、1896位点变异率显著下降(P<0.05)。治疗前不同位点变异株信号强度1896>1764>1762>1899,差异具有显著性意义(P<0.05);治疗后1762、1764、1896位点变异株信号强度下降,其中1896位点信号强度显著下降(P<0.05)。结论:清热利湿法在改善CHB肝胆湿热/湿热中阻证患者临床证候的同时,可在一定程度上抑制HBV前C区突变株的复制。     

HBV突变与HBV相关慢加急性肝衰竭相关性研究

目的探讨HBV突变与慢加急性肝衰竭(acute-on-chronic liver failure,ACLF)之间的相关性。方法以87例HBV相关ACLF患者为研究对象,另选取52例慢性乙型肝炎(chronic hepatitis B,CHB)患者和51例HBV肝硬化(liver cirrhosis,LC)患者为对照,应用聚合酶链反应及基因测序对患者血清标本进行HBV基本核心启动子区、前C区和C区13个位点的突变检测,分析HBV突变与ACLF发生的相关性。结果 CHB、LC、ACLF组人均核苷酸变异检出位点分别为2.31、3.55和3.86个。nt1762、nt1846、nt1899和nt1913 4个突变位点的核苷酸突变率比较,ACLF组高于CHB组;nt1764位点突变率组间比较LC组高于ACLF组,而nt1846和nt1913位点突变率比较LC组低于ACLF组;nt1753、nt1762、nt1764和nt1899 4个突变位点的核苷酸突变率比较,LC组高于CHB组。多因素分析提示A1846T和C1913(A/G)核苷酸突变是预测ACLF的有效指标。结论 CHB或LC患者HBV基因序列的A1846T和C1913(A/G)核苷酸突变可能与其发生ACLF密切相关。     

乙型肝炎病毒X区基因变异与原发性肝癌的关系研究

目的初步研究乙型肝炎病毒(HBV)X区基因变异与原发性肝癌的关系。方法收集39例HBV感染患者的肝(癌)石蜡组织标本,其中慢性乙型肝炎(CHB)14例、肝细胞癌(HCC)25例。采用聚合酶链式反应(PCR)方法扩增组织中HBV X区基因,并对PCR产物进行DNA测序,分析常见变异位点的变异情况。结果 1.HCC组与CHB组相比,在X区发生插入/缺失变异,联合变异的位点及例数增多,并且A1762T与G1764A常发生双突变。2.HBV X区变异频率较高位点依次是C1655T/G、A1605C/G、A1762T、G1764A、A1772B、A1645C、C1687A、G1776T。结论 HBV X区存在点突变、插入/缺失变异及联合变异,可能在HCC的发生和发展过程中起重要作用。     

慢性重型乙型肝炎患者HBVDNA前C／BCP区突变基因分析

目的分析慢性重型乙型肝炎（慢重乙肝）患者HBVDNA前C区和基本核心启动子（前C／BCP）区突变特点与意义。方法收集87例慢重乙肝和196例慢性乙型肝炎（慢乙肝）患者血清，提取HBVDNA，用巢式PCR扩增HBVDNA前C／BCP区基因，PCR产物进行DNA测序，用NBI软件比对结果，重点分析G1896、G1862、G1899、A1762、G1764、T17536个位点突变。结果慢重乙肝组和慢乙肝组6个位点突变全阴率分别为3．4％和28．1％（P〈0．01）；慢重乙肝组在其中5个位点上的突变检出率显著高于慢乙肝组。此外，慢重乙肝组和慢乙肝组≥三联突变检出率分别为56．3％和35．2％（P〈0．01），≥四联突变检出率分别为25.3％和8．7％（P〈0．01），插入／缺失突变检出率分别为10．3％和1．0％（P〈0．01）。结论HBVDNA前c／BcP区基因突变发生频率的增加与慢乙肝发生重症化相关，结合临床资料分析突变的意义将有助于认识慢乙肝重症化的发生机制。     

重型乙型肝炎患者血清乙型肝炎病毒全基因克隆及测序

目的建立重型乙型肝炎患者血清乙型肝炎病毒（HBV）DNA克隆并测序，从全基因水平分析HBV基因变异与重型乙型肝炎发病的关系。方法10例重型乙型肝炎患者血清提取HBV DNA，聚合酶链反应（PCR）扩增HBV全基因。PCR产物构建到PUCm-T载体上，转化至大肠杆菌感受态DH-5α细胞，经酶切鉴定，获得含3．2Kb HBVDNA的重组克隆菌，全基因测序，分析各读码框核苷酸和氨基酸变化。结果4例成功构建HBV DNA克隆，并完成全基因测序。其中3例在前C区发生G1896A变异，产生一个终止密码子，导致HBeAg缺失；1例在C启动子区1762、1764双位点出现突变；有多处点突变及缺失变异分布于PreS2区及C区已知细胞毒T淋巴细胞、B淋巴细胞和T淋巴细胞的细胞表位。结论该法可用于临床研究HBV病毒基因结构与重型乙型肝炎发病的关系，并为进一步研究其HBV基因功能奠定基础。     

Association of core promoter/precore mutations and viral load in e antigen-negative chronic hepatitis B patients

Apart from core promoter A1762T/G1764A and precore G1896A mutations, other hepatitis B virus (HBV) mutants are detected in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB). The aim of this study was to determine the effects of those mutants on clinical manifestation and viral loads of genotypes B and C HBV. Seventy-nine HBeAg-negative CHB patients with hepatitis flare were enrolled in this study and their HBV precore/core region were sequenced. Serial biochemical profiles and viral loads were assessed and compared. Fifty-three patients (67%) were infected by genotype B HBV and 26 (33%) were infected by genotype C HBV. The clinical manifestation and HBV viral loads were comparable between the two groups. However, genotype B was significantly associated with precore G1896A mutation (92.5%), and more mutations within nucleotide 1809-1817 were detected in patients infected by genotype B as compared with those infected by genotype C (18.9%vs 3.8%). Most of the cases had mutations at the -2, -3 or -5 position from the precore AUG initiation codon. Triple core promoter mutations T1753C/A1762T/G1764A [corrected] appeared to be linked to genotype C rather than genotype B HBV (19.2%vs 1.9%; P = 0.013). In multivariate analysis, the presence of either triple core promoter 1753/1762/1764 mutation or nucleotide 1809-1817 mutation was the only factor associated with lower HBV viral load (<70 Meq/mL) (odds ratio = 9.01; 95% CI 1.11-71.43; P = 0.04). In conclusion, minor HBV variants with mutations in the core promoter and precore region were detectable in genotypes B and C. Such HBV variants are genotype specific and related to viraemia levels.     

广西慢性乙型肝炎患者HBV核心基因启动子突变的研究

目的 了解HBV核心基因启动子突变与肝损害程度或HBeAg状态的关系。方法 用套式PCR扩增59例慢性乙型肝炎患者血清HBV核心基因启动子,阳性者用直接测序法检测。结果35例HBV DNA阳性,阳性率为59.3％。无正常序列标本,最常见的突变类型是nt1762、1764发生双突(A→T、G→A),占57.1％;其次为nt1799位点突变,由C→G,占54.4%,为无义突变;nt1752位点突变,由A→G,使该密码由异亮氨酸变为缬氨酸,占37.1％;nt1753T→C,占20.0%。T_(1762)A_(1764)突变株在HBeAg阳性、阴性患者组中的分布分别为31.3％、79.0％,两者差异有显著性,x~2 8.068 8,P<0.05。结论 HBV核心基因启动子突变在广两慢性乙型肝炎患者较常见,T_(1762)A_(1764)突变株与HBeAg阴性及慢性肝炎有关。     

慢性乙型肝炎病毒感染者病毒前C区和基本核心启动子区变异检测及意义

目的 探讨乙型肝炎病毒（HBV）前C区和基本核心启动子（BCP）区变异与基因型及疾病进展间的关系。方法 收集HBV携带者（ASC）、慢性乙型肝炎（CHB）、肝炎肝硬化（LC）、肝细胞肝癌（HCC）患者血清148份，用半巢式聚合酶链反应扩增HBV前C／C基因部分片段，产物纯化后直接测序，检测前C区A1896及BCP区T1762／A1764变异。用S基因聚合酶链反应-限制性片段长度多态性分析（PCR-RFLP）方法确定HBV基因型。结果 有128份血清能够成功分型和测序，其中B基因型60份，C基因型68份。在B基因型感染者中前C区A1896变异检出率（48．33％）明显高于C基因型感染者（29．41％，X^2=4．83，P〈0．05）；而BCP区T1762／A1764变异检出率却明显低于C基因型感染者，差异亦有统计学意义（30．00％：73．54%，X^2=24．25。P〈0．05）。前C区A1896变异在CHB、LC、HCC中的阳性检出率分别为46．88％（15/32）、39．39％（13／33）、51．52％（17／33）。与ASC的13．33％（4／30）相比，P分别〈0．05，差异有统计学意义。BCP区T1762／A1764变异检出率在HCC、LC组分别为87．88％（29／33）和72．73％（24／33）．明显高于CHB组的37．50％（12／32）及ASC组10.00％（3／30）（P〈0．05）。结论 前C区A1896变异常见于B基因型感染者，而BCP区T1762/A1764变异C基因型感染者多见。除ASC外．前C区A1896变异与疾病进展关系不大．而BCP区T1762/A1764变异与乙型肝炎进展及顶后相关。     

Hepatitis B virus genotype and basal core promoter/precore mutations are associated with hepatitis B‐related acute‐on‐chronic liver failure without pre‐existing liver cirrhosis

Summary. The study was undertaken to investigate the features and clinical implications of hepatitis B virus (HBV) genotypes, basal core promoter (BCP) and precore (PC) mutations in hepatitis B‐related acute‐on‐chronic liver failure (HB‐ACLF). Samples from 75 patients with HB‐ACLF and without pre‐existing liver cirrhosis and 328 age‐matched patients with chronic hepatitis B (CHB) were analyzed. HBV genotype and BCP/PC mutations were determined by direct sequencing. Mutations at 8 sites of the BCP/PC region were compared between the two groups of patients. A significantly higher ratio of genotype B to C was found in patients with HB‐ACLF than in patients with CHB (30.7–69.3%vs16.5–82.6%, P < 0.01). Single mutations including T1753V (C/A/G), A1762T, G1764A, G1896A and G1899A and triple mutations T1753V/A1762T/G1764A and A1762T/G1764A/C1766T (or T1768A) were more frequently detected in patients with HB‐ACLF than in patients with CHB. Correspondingly, BCP/PC wild‐type sequences were absent in patients with HB‐ACLF in contrast to 27.1% in patients with CHB. The BCP/PC mutations were found to be associated with increased HBeAg negativity, higher alanine aminotransferase level and lower viral load. Patients with HB‐ACLF infected with the PC mutant virus had a higher mortality. The findings suggest that patients with CHB infected with genotype B with BCP/PC mutations were more likely to develop HB‐ACLF than those with genotype C with wild‐type BCP/PC regions, and patients with HB‐ACLF with the PC mutation had increased risk of a fatal outcome.     

乙型肝炎病毒X区核苷酸序列变异的检测

目的：了解乙型肝炎患者血清中乙型肝炎病毒（HBV）DNA X区核苷酸序列的变异情况。方法：采用聚合酶链反应（PCR）扩增24例乙型肝炎患者血清HBV DNA X区产物，并直接测序进行分析。结果：24例患者血清中HBV DNA X区都有程度不等的点突变（2－15），11例同时具有nt1762(A→T),nt1764(G→A）发生变异，8例患者同时在nt1636-nt1741几处位点发生变异。结论：HBV DNA X区核苷酸位于nt1762,nt1764双位变异与HBeAg阴性表型有关。     

Hepatitis B Virus Genomes of Chronic Hepatitis Patients Do Not Contain Specific Mutations Related to Acute Exacerbation

To determine the specific viral variants associated with acute exacerbation of chronic hepatitis from hepatitis B virus (HBV) infection, we analyzed the complete nucleotide sequences of the HBV genome in serial serum samples from two chronic active hepatitis patients who seroconverted from HBeAg to anti-HBe. HBV DNA was amplified by polymerase chain reaction (PCR) and sequenced. A 1896 precore stop codon mutant (G to A at nt 1896) coexisting with the wild sequence was found in both patients prior to seroconversion from HBeAg to anti-HBe. Core promoter mutations at nucleotide positions 1762 (A to T) and 1764 (G to A) were found in both patients throughout the observation period. Mutations were observed in the HBV genome of the two patients at different time points, and there was no correlation between the mutations and liver disease or DNA polymerase levels. The nucleotide divergence rate and the composition of quasispecies in the HBV sequence at the time of acute exacerbation were almost the same as were found at other time points. These results suggest that acute exacerbation does not appear to be caused by a characteristic HBV species. The multiple factors that cause generalized HBV replication activation may contribute to acute exacerbation.     

乙型肝炎病毒基本核心启动子突变与基因型的关系

目的研究乙型肝炎病毒（HBV）基本核心启动子（BCP）突变与HBV基因型的关系。方法随机选取我院68例慢性乙型肝炎患者外周血，采用荧光定量PCR结合TaqmanMGB探针技术检测HBV基因型，并用基因扩增和DNA测序方法检测BCPT1762／A1764双突变。结果68例患者HBV分型中，B基因型20例，C基因型46例，B、C混合型1例，未分型（非B非C型）1例。66例B、C两基因型中，B基因型组T1762／A1764双突变5例，突变率25．0％（5／20），C基因型组T1762／A1764双突变24例，突变率52．2％（24／46），C基因型T1762／A1764双突变率明显高于B基因型（P〈0．05）。结论苏州地区慢性乙型肝炎患者基因型以C型和B型为主，C基因型比B基因型更易发生T1762／A1764双突变。     

HBeAg阴性慢性乙型肝炎患者出现前C和基本核启动子联合突变的意义

目的 探讨HBeAg阴性慢性乙型肝炎患者出现前C区G1896A突变和基本核启动子(BCP)区A1762T／G1764A双突变，以及两者的联合突变对患者血清病毒含量的影响。方法 收集240份HBeAg阴性、60份HBeAg阳性慢性乙型肝炎患者血清及40份阴性对照血清，采用竞争分化聚合酶链反应(CD-PCR)检测G1896A突变及A1762T/G1764A双突变，采用实时荧光定量聚合酶链反应(PCR)检测血清中病毒含量。结果 G1896A突变在HBeAg阴性和HBeAg阳性患者中的检出率分别为57．6％和6．7％；A1762T／G1764A双突变的检出率分别为37．9％和31．7％；其中两者联合突变在HBeAg阴性患者中的检出率为13．5％。在HBeAg阴性患者中，G1896A突变主要出现在血清病毒含量低的患者，而A1762T／G1764A双突变与血清病毒含量无关。联合变异株主要见于重度慢性乙型肝炎患者，与血清病毒含量无关。结论 G1896A变异株复制能力较低，而A1762T／G1764A变异株对病毒复制能力影响可能较为复杂，对HBeAg合成的影响较G1896A变异株小。联合变异株的致病力相对较强，其复制能力较单纯G1896A强，值得警惕。