HBV/HIV共感染与单纯感染HBV 1762T/1764A突变及前S基因缺失的比较研究

目的 比较分析HBV/HIV共感染者与HBV单纯感染者肝癌相关HBV 1762T/1764A突变及前S基因缺失突变率.方法 根据病例对照研究原理,收集未接受HBV及HIV抗病毒治疗的HBV/HIV共感染者和HBV单纯感染者血清标本,用分子生物学技术对血清HBV核心基因启动子(BCP)和前S基因进行分析.结果 病例-对照共61对,平均年龄为(44.9±2.1)岁,共发现3个HBV基因型:基因型B、C和I.共感染者和单纯感染者的主要基因型均为B基因型,分别占63.4%(39/61)和50.8%(31/61).共感染者肝癌相关HBV基因突变总率(52.5%)显著高于HBV单纯感染者(23.0%),差异有统计学意义(χ2=11.307,P<0.05).共感染者BCP的1762T/1764A双突变率(44.3%)显著高于HBV单纯感染者(χ2=7.290,P<0.05).同样,共感染者前S基因缺失率也显著高于HBV单纯感染者(χ2=8.270,P<0.05).随机从两组中各抽20例进行对比分析,结果显示共感染与高病毒载量有关,但是高病毒载量与肝癌相关HBV基因突变无关.肝癌相关HBV基因突变率不随CD+4细胞计数变化而变化.多因素分析结果表明,合并HIV感染与肝癌相关HBV基因突变(包括BCP双突变与前S缺失突变)有关.结论 HBV/HIV共感染可增加肝癌相关HBV基因突变率.     

HBsAg无症状携带者乙型肝炎病毒核心基因启动子突变的研究

目的了解HBsAg无症状携带者乙型肝炎病毒(HBV)核心基因启动子双突变(nt1762 A→T,nt1764 G→A)发生情况及其与基因型、病毒量和HBeAg的关系。方法 HBsAg无症状携带者从隆安研究队列中选择,用套式聚合酶链反应(nested PCR)对研究对象血清HBV核心基因启动子、S基因扩增、序列分析及基因分型,用HBV引物和双标记的TaqMan探针扩增和定量病毒DNA。结果观察开始时核心基因启动子为野毒株的109例观察对象,3年后双突变平均年发生率为2.8%;观察开始时已发生nt1762或nt1764点突变的59例对象,3年后另一个位点也发生突变的平均年发生率为6.8%,两率差异有统计学意义(χ2=5.109 0,P<0.05)。nt1762 A→T突变组HBeAg阳性率(45.5%,10/22)与nt1764 G→A突变组HBeAg阳性率(10.8%,4/37)差异有统计学意义(χ2=9.149,P<0.05)。20例基因型B未发生双突变,重组基因型年双突变率为4.8%(2/14),基因型C年突变率为3.1%(7/75),各基因型间突变率差异无统计学意义(P>0.05)。5例双突变发生后HBeAg仍然阳性者病毒量有下降趋势,而另5例突变发生后HBeAg阴性者其病毒量有升有降。结论 HBV核心基因启动子双突变年发生率较高,这两个位点中的任何一个发生突变是双突变的过渡形式,双突变与基因型无关,nt1764 G→A突变与HBeAg阴性有关。     

广西HBsAg无症状携带者HBV前S基因缺失突变的分子流行病学研究

目的 了解广西HBsAg 无症状携带者乙肝病毒(HBV)前S 基因(PreS)缺失突变株的流行情况.方法 按现况研究的原理,用三阶抽样法,在广西东、西、南、北、中各选定1 个县,然后在每个县选择人口约1 000 人的自然村,调查该村全人群HBV 感染情况,用套式聚合酶链反应(nested PCR)对HBsAg 阳性血清HBV 前S 基因扩增和序列分析.结果 共调查4 513 人,HBsAg 总阳性率为8.7%(395/4 513),Pre-S 基因缺失突变率为4.9%(17/350),男、女突变率(5.1%、4.5%)无显著性差异(X2=0.07,P >0.05),25 岁以下没有出现缺失突变,突变率在50 岁年龄组最高,但各组间无显著性差异(P >0.05).汉族人群突变率较高(6%);钦州突变率最高(7.5%),苍梧最低(1.5%),各民族之间、各县之间突变率均无显著性差异(P >0.05).所有Pre-S 缺失突变都是框内突变,82.4%(14/17)的突变发生在或涉及Pre-S2 的5'端.Pre-S2 起始密码发生突变率为6.9%(24/350).基因型B、C、I 和D 前S 基因缺失突变率分别为6.1%(7/114)、4.1%(9/221)、7.1%(1/14)和0(0/1),各组间无显著性差异(P >0.05).结论 广西HBV 无症状携带者前S 基因缺失突变率较低,PreS1 的3'端和PreS2的5'端是缺失突变的好发部位,低年龄组罕见,突变与性别、民族、地理位置和基因型无关.     

西宁地区乙型肝炎病毒基因前C区及启动子突变的研究

[目的]分析西宁地区乙型肝炎病毒(HBV)C基因前区(preC/C)与C基因启动子(BCP)的变异株在HBV感染者中的状态及与HBeAg在血清学中的关系. [方法]使用一条PCR错配引物和引入BCL1酶切位点,扩增一条nt1765-nt1895核苷酸片断,以序列分析扩增产物. [结果]在nt130核苷酸片断中,A83突变率为9.3%,BCP突变率为43.6%,25例野毒株的突变率达17.0%;HBeAg阴性病例中A83突变率为9.3%,BCP突变率为78.1%;HBsAg阴性、抗-HB8阳性的双阳病例中A83和BCP双突变为99.7%;HBV感染的不同临床病例主要显示于慢性肝炎重度和肝硬化组,BCP突变率分别为75%及71%. [结论]HBV双突变与肝炎的严重性有密切联系,BCP双突变对e系统表达有一定影响.PCR技术和基因测序分析有重要指导价值和临床意义.     

广西壮族自治区肝癌高发区HBV基因型、BCP/前C区突变与肝癌相关性的研究

目的 研究广西壮族自治区(广西)扶绥县肝癌高发区HBV基因型、基本核心启动子(BCP)/前C区突变与肝癌的关系。方法 采用病例对照方法收集53例肝癌患者和70例HBV健康携带者的血清,提取HBV DNA,用巢式PCR扩增 HBV S区、BCP/前C区,扩增产物纯化后测序,分析基因型、基因突变与肝癌发生的关系。结果 BCP区A1762T/G1764A及前C区T1858C在病例组中的突变率高于对照组,分别为94.3% vs. 75.7%(P=0.006)和50.9% vs. 31.4%(P=0.029);A1775G在对照组中的突变率高于病例组28.6% vs.13.2%(P=0.041)。多因素logistic回归分析显示,HBV A1762T/G1764A和T1858C突变是肝癌发生的危险因素,OR值分别为5.459(95%CI:1.397~21.332,P=0.015)和3.881(95%CI:1.462~10.305,P=0.006);A1775G突变是肝癌发生的保护因素,OR=0.192(95%CI:0.059~0.622,P=0.006)。结论 HBV C基因型是广西肝癌高发区的主要流行株,HBV BCP区A1762T/G1764A、A1775G、前C区T1858C 突变与HBV相关肝癌的发生有密切关系。     

宫内传播中乙型肝炎病毒前S/S基因序列分析

目的　研究宫内传播中乙型肝炎病毒 (HBV)的前S/S基因结构 ,探讨HBV基因变异与宫内传播的关系。方法　根据新生儿发生HBV宫内感染与否 ,将其HBsAg阳性母亲分为宫内感染组和非宫内感染组 ,经PCR扩增HBV前S/S基因 2 848- 835位核苷酸序列 ,克隆、测序 ,比较 2组基因结构的差异。结果　全部HBV株序列都属于C基因亚型、adr亚型 ,宫内感染组中母婴序列的相似性达 99.2 %～ 1 0 0 .0 %。 2组患者在前S1区、前S2区和S区均有各自的突变位点 ,S区“a”决定簇表位几乎没有突变发生。非宫内感染组中nt2 90 9、nt399、nt2 93和nt483突变出现较多 ,而在宫内感染组尤其是新生儿的序列中出现较少。而且非宫内感染组前S2区 (P <0 .0 5)、S区 (P <0 .0 1 )和前S/S区 (P <0 .0 5)突变率也高于宫内感染组。结论　引起新生儿宫内感染的HBV前S/S基因异质性较低 ,提示前S/S区突变率低的HBV株可能容易引起新生儿的宫内感染     

HIV-1/HBV共感染患者HBV病毒基因组前S区、BCP区和前C区的变异

目的探讨乙型肝炎病毒(HBV)合并人类免疫缺陷病毒1型(HIV-1)感染者和HBV单独感染者HBV基因组三个重点区域的变异。方法收集湖南省HIV-1/HBV合并感染患者(试验组)和HBV单独感染患者(对照组)血清各40份,进行HBV全基因组扩增及测序,并对突变位点进行分析。结果有59份血清HBV成功分型和测序,其中试验组21份,对照组38份,试验组与对照组HBV载量值和不同基因型比较,差异均有统计学意义(均P0. 05)。试验组4例患者血清标本HBV在前S区22个氨基酸发生变异,12例在前C区和BCP区45个核苷酸发生突变,试验组和对照组前S区氨基酸总体缺失突变率分别为0. 60%、0. 64%,差异无统计学意义(χ~2=0. 042,P 0. 05)。试验组与对照组前C区和BCP区各个主要突变位点变异发生率比较,差异无统计学意义(均P 0.05),试验组和对照组前C区和BCP区总体变异发生率分别为1. 36%、1. 73%,差异无统计学意义(χ~2=1. 920,P 0. 05)。结论共感染患者的HBV变异水平与单感染患者基本一致,短时间内HIV-1暂未对HBV的进化突变造成显著影响。     

HBV核心区基因突变的研究

目的 研究乙型肝炎病毒(HBV)核心区的突变模式.方法 在核酸序列比对的基因上,设计靶向HBV各基因型核心区的通用引物.PCR扩增血清病毒DNA,经DNA测序和随后的序列分析,检测和分析核心区的突变模式.结果 在34例可检测样本中,共有23例患者存在HBV核心区突变;其中,基本核心启动子区(BCP)的A1762T(50.0%)和G1764A(52.9%)是最常见的突变位点,并且,通常表现为双碱基突变;其次是核心(C)基因区的L60V氨基酸突变(17.6%);就各基因区的突变频率而言,BCP区、前核心(Pre-C)区和C基因区突变患者分别有18、6、10例,其中,BCP区通常表现为A1762T和G1764A双突变(94.7%),pre-C区以G1896A最为常见(83.3%),C基因区则主要是L60V的氨基酸单突变(50.0%).结论 HBV核心区最常见的突变形式是BCP区A1762T和G1764A的碱基双突变;由于HBV核心区基因具有复杂的突变模式,因此,研究HBV核心区基因突变模式对HBV感染的病情预测和预后判断具有重要的临床应用价值.     

HBsAg与anti-HBs共阳性慢性乙肝患者病毒S蛋白序列分析

目的分析慢性乙型肝炎(chronic hepatitis B,CHB)患者乙型肝炎病毒S蛋白序列突变与HBs Ag、anti-HBs共阳性的相关性。方法随机选择33例HBs Ag、anti-HBs共阳性的CHB患者作为试验组,随机选择33例HBs Ag阳性而anti-HBs阴性的CHB患者作为对照组,对乙型肝炎病毒S区基因进行扩增测序并进行序列分析。结果两组感染的乙型肝炎病毒均为B或C基因型,未见其它基因型;两组在年龄、性别、HBV基因型、血清HBV DNA水平上差异无统计学意义(均P>0. 05);试验组S蛋白在N-端(2. 61%vs. 1. 21%)、主要亲水结构区域(1. 69%vs. 0. 48%)(major hydrophilic region,MHR)、特别是"α"决定簇(3. 23%vs. 0. 63%)的氨基酸突变率均显著高于对照组(均P<0. 01),但在C-端(1. 75%vs. 1. 22%)氨基酸突变率差异无统计学意义(P>0. 05);试验组突变率最高的点是S蛋白的第126位氨基酸;两组氨基酸插入和缺失突变差异无统计学意义(P>0. 05)。结论 CHB患者中S蛋白序列氨基酸的突变特别是"α"决定簇的突变可能与HBs Ag、anti-HBs共阳性相关。     

孤独症儿童亚甲基四氢叶酸还原酶基因C677T多态性分析

【目的】 探讨孤独症儿童亚甲基四氢叶酸还原酶(methylenetetra-hydrofolate reductase,MTHFR)基因C677T多态性,为孤独症病因的寻找提供实验依据。 【方法】 采用限制性片段长度多态性聚合酶链反应(polymerase chain reaction-restriction fragment length polymorphism,PCR-RFLP)和基因测序的方法,对98例孤独症儿童与性别年龄匹配的70例对照组儿童的MTHFR基因C677T多态性进行分析。 【结果】 病例组(TT和CT为突变基因型)突变率为46.9%,对照组(TT和CT)突变率为14.3%,差异有统计学意义(χ²=19.59,P<0.005)。病例组与对照组的C、T等位基因频率相比差异有统计学意义(χ²=24.38,P<0.0005)。对病例组与对照组的基因型突变率差异进行多重比较,TT基因型和CT基因型的突变率与CC基因型相比差异均有统计学意义(χ²=10.12和19.76,P均<0.0125),而TT基因型突变率与CT基因型突变率在病例组和对照组中的分布无统计学意义(P>0.0125)。 【结论】 MTHFR基因C677T突变可能是儿童孤独症发病的遗传危险因素。     

Subgenotype D5, BCP and MHR mutations in hepatic complications among hepatitis B virus infected patients from Orissa,India

The study was undertaken to investigate the clinical implications of hepatitis B virus (HBV) genotypes, basal core promoter (BCP), precore (PC) and surface gene mutations in HBV infected patients from Orissa, southeastern India. HBV infections were identified by serology testing and HBV DNA amplification by polymerase chain reaction among the 152 patients. After sequencing, surface gene mutation were studied by sequence analysis as well as by using BLOSUM scores and BCP mutations were studied only by sequence analysis. A high proportion of HBV/D5 (66.0%) was found among the study samples having significant relation with liver cirrhosis (LC) and hepatocellular carcinoma (HCC) patients (p < 0.05). The BCP mutation, TA (81.4%) and C1753/TA (75.0%) was found in significant proportion (p < 0.05) among HCC cases and in fact a gradual increase in these mutations were noted between inactive carriers (IC) to HCC group and also showed higher viral load. An increasing trend of major hydrophilic region (MHR) mutations in S gene was also observed from IC (56.0%) to chronic liver disease (CLD) (60.4%) to LC (72.4%) to HCC (95.0%) patients. In conclusion, our study suggests that the predominant HBV subgenotype HBV/D5 with high viral load and BCP mutations (double and triple) and high mutations in MHR region was significantly associated with advanced liver disease (LC and HCC) and might act as predictor of severe hepatic complications.     

The incidence rate over 10 years of naturally occurring,cancer related mutations in the basal core promoter of hepatitis B virus

Cross-sectional analyses showed that the prevalence of basal core promoter (BCP) double mutations (nt 1762T, 1764A) of hepatitis B virus (HBV) gradually increases with age. We aimed to determine the incidence rate of the mutations over 10 years. Study subjects were selected from the Long An cohort established in 2004, including 59 with HBV with single mutations at nt 1762 or 1764 in the BCP and 342 with wild type BCP sequences at baseline. Their serum samples for analysis were obtained at the 3rd and 10th annual visits, respectively. The results showed that the annual incidence rate of BCP double mutations is 3.8% (95% confidence interval [CI]: 1.4–6.2) and tends to decrease with age. The peak incidence is in the 30–34 years age-group. The incidence rate in HBeAg positive individuals (5.5%) is significantly higher than in those without HBeAg (3.4%) (P < 0.05). The incidence rate is significantly higher in genotype C (4.8%) than in genotype B (2.8%) or I (3.1%). The incidence rate of the mutations (6.8%) developing from a single mutation at nt 1762 or 1764 is significantly higher than that (3.8%) from the wild type sequence (P < 0.005). The difference in incidence of single mutations between nt 1762 (0.7%) and 1764 (0.03%) is significant (P < 0.05). In conclusion, the incidence rate of BCP double mutations tends to decrease with age after the age of 35 years. Viruses with a single mutation at nt 1762 or 1764 are more prone to develop double mutations. Nt 1762 is the more common site of the first mutation.     

贵州省乙型肝炎病毒前C区及基本核心启动子变异分布

目的调查贵州省乙型肝炎病毒(HBV)前C区A1896、基本核心启动子区(BCP) T1762/A1764变异分布。方法收集贵阳、遵义、凯里、都匀4地区不同民族无症状携带者(ASC)、慢性肝炎(CH)、肝炎肝硬化(LC)、肝细胞肝癌(HCC)患者血清482份,用测序及限制性片段长度多态性检测A1896、T1762/A1764变异,用S基因PCR-RFLP确定基因型。结果A1896、T1762/A1764变异检出率分别为23.03%和29.67%。汉族感染者A1896、T1762/A1764变异检出率为27.64%和36.04%,高于侗、苗、布依族感染者合并后的7.96%、8.85%(P<0.01)。A1896变异在B、C基因型中的分布为20.34%和27.13%(P>0.05),T1762/A1764变异为18.97%和46.28%(P<0.01)。A1896、T1762/A1764变异在HBeAg阴、阳性组间的分布差异有统计学意义(P值均<0.01)。从ASC到HCC组,A1896、T1762/A1764变异分布逐渐增高,LC、HCC组的检出率明显高于CH和ASC组(P值均<0.01)。A1896、T1762/A1764变异的分布:贵阳(分别为31.79%和41.06%)高于遵义(10.94%和14.06%)、都匀(8.64%和11.1I%)及凯里(2.86%和2.86%),但多因素logistic回归分析在控制了HBeAg、HBV基因型及临床类型影响后,在地区间分布差异无统计学意义。结论A1896、T1762/A1764变异在贵州省不同民族间分布有一定差异。C型感染者易发生T1762/A1764变异,两种变异均与疾病进展有关。     

TaqMan MGB探针检测HBV DNA C区双突变方法的建立

目的建立简便、灵敏的HBV DNA C区序列中核心启动子（BCP）双突变的检测方法。方法采用Taq-Man MGB探针技术进行双突变的检测,首先根据双突变的序列设计FAM荧光标记的TaqMan MGB探针和配套的引物,对标准阳性对照和标准阴性对照进行扩增检测,确定灵敏度和特异性,然后对临床HBV DNA阳性血清进行扩增检测,并通过PCR产物直接测序验证所建立方法检测结果的准确性。结果该方法检测出HBVDNA BCP双突变序列的灵敏度为3&#215;10^0拷贝/ml的模板,并且可以稳定地从1&#215;10^3拷贝/ml标准阴性对照中检测出1&#215;10^1拷贝/ml的标准阳性对照。结论该技术适用于临床检测血清中HBV DNA C区BCP双突变。     

C型乙型肝炎病毒的全基因组序列分析

目的 探索乙型肝炎病毒(HBV)全基因组的结构特点。方法 应用直接PCR基因分型法确定HBV基因型。然后随机选择1例单纯HBVC基因型感染的患血清，分3个相互重叠片段扩增HBV基因并分别克隆测序。利用Vector NTI Suite7．0软件包、GeneDoc2．6和TreeView1．5，将该3个基因片段拼接为全基因组序列，命名为BDHBl，并进行基因进化树分析和同源性比较。结果 HBVC基因型序列全长为3215bp，其中A占22．2％，G占22．4％。C占26．8％。T占28．6％；有S、C、P和X区4个开放读码框架(ORFs)；HBsAg亚型为adr；HBVRT区549～552aa为YMDD，未发生变异；未发现前C区：ntl896G变异：BCP区ntl762、1764发生双突变。对HBV分段序列及全基因组序列进行基因进化树分析显示，BDHBl与HBVVC基因型的同源性最高。结论 BDHBl基因组符合HBVC基因型结构特点，在BCP区存在双突变。分片段扩增再拼接可作为全基因组序列分析方法之一。     

Increased hepatitis B virus quasispecies diversity is correlated with liver fibrosis progression

Host immune response and viral factors are involved in disease progression in patients with chronic hepatitis B virus (HBV) infection. However, the relationship between HBV quasispecies and liver fibrosis progression remains unclear. In this study, 447 patients with chronic HBV infection, including 239 with chronic hepatitis B (CHB), 104 with liver cirrhosis (LC) and 104 with hepatocellular carcinoma (HCC) were enrolled. The 239 CHB patients were divided into groups F1, F2, and F3 according to liver fibrosis score. Four fragments of the HBV genome were determined and analyzed using next-generation sequencing. Specific mutations, such as A1762T, G1764A and G1896A, in the BCP/PC region were more common in patients with advanced liver disease and formed the majority of the viral quasispecies pool in patients with LC and HCC. The viral complexity and diversity increased as the fibrosis progressed, especially in patients with CHB who were comparable in age but at different stages of fibrosis. Patients with early-stage fibrosis experienced higher purifying selection pressure in the four sequenced regions, whereas different protein-coding region experienced different negative selection with disease progression. HBV quasispecies diversity may increase fibrosis progression in CHB patients with aging under immune selection.     

Genetic analysis of precore/core and partial pol genes in an unprecedented outbreak of fulminant hepatitis B in India

SUMMARY We investigated an unprecedented outbreak of fulminant hepatitis B virus (HBV) that occurred in Modasa, Gujarat (India) in 2009. Genomic analysis of all fulminant hepatic failure cases confirmed exclusive predominance of subgenotype D1. A1762T, G1764A basal core promoter (BCP) mutations, insertion of isoleucine after nt 1843, stop codon mutation G1896A, G1862T transversion plus seven other mutations in the core gene caused inhibition of HBeAg expression implicating them as circulating precore/BCP mutant virus. Two rare mutations at amino acids 89 (Ile→Ala) and 119 (Leu→Ser) in addition to other mutations in the polymerase (pol) gene may have caused some alteration in either of four pol gene domains to affect encapsidation of pregenomic RNA to enhance pathogenicity. Sequence similarity among patients' sequences suggested an involvement of a single hepatitis B mutant strain/source to corroborate the finding of gross and continued usage of HBV mutant-contaminated syringes/needles by a physician which resulted in this unprecedented outbreak of fulminant hepatitis B. The fulminant exacerbation of the disease might be attributed to mutations in the BCP/precore/core and pol genes that may have occurred due to selection pressure during rapid spread/mutation of the virus.     

乙型肝炎病毒基因型和前C及基本核心启动子突变与乙型肝炎疫苗阻断母婴传播的关系

目的探讨乙型肝炎（乙肝）病毒（HBV）基因型和前C及基本核心启动子（BCP）突变与乙肝疫苗阻断母婴传播的关系。方法采集江苏省16对乙肝疫苗阻断失败的母婴血清样本32份,以及88对阻断成功的母婴血清样本176份。以型特异性引物PCR法检测16对乙肝疫苗阻断失败的母婴和88例阻断成功的母亲血清样本中HBV基因型,用PCR产物直接测序法检测HBV前C/ BCP突变,采用Clustal W 1．8软件进行序列分析。结果在16例阻断失败的母亲中,15例（93．8%）为HBeAg阳性,且均为C型（15/15,100%）;88例阻断成功的母亲中,51例（58．0%）为HBeAg阳性,其中C基因型占45．1%（23／51）。在HBeAg阳性母亲中,阻断失败组的C基因型检出率明显高于阻断成功组（X~2=14．3,P=0．003）。但在C基因型HBeAg阳性母亲中,阻断成功组与失败组的T1762/ A1764突变率差异无统计学意义（分别为13．3%和33．3%,P=0．4）,且均无A1896突变。结论感染HBV基因C型的母亲可能更易导致乙肝疫苗阻断失败,而前C/BCP基因突变与阻断母婴传播无关。