Naturally Occurring Precore/Core Region Mutations of Hepatitis B Virus Genotype C Related to Hepatocellular Carcinoma

Previous studies have proved the presence of several distinct types of mutations in hepatitis B virus (HBV) infections, which are related to the progression of liver disease. However, few reports have detailed the mutation frequencies and mutation patterns in the precore/core (preC/C) region, which are based on the clinical status and HBeAg serostatus. Our aim in this study is to investigate the relationships between the preC/C mutations and clinical severity or HBeAg serostatus from patients chronically infected with HBV genotype C. A total of 70 Korean chronic patients, including 35 with hepatocellular carcinoma (HCC), participated in this study. HBV genotyping and precore/core mutations were analyzed by direct sequencing. All patients were confirmed to have genotype C infections. Mutations in the C region were distributed in a non-random manner. In particular, mutations in the MHC class II restricted region were found to be significantly related to HCC. Six (preC-W28*, C-P5H/L/T, C-E83D, C-I97F/L, C-L100I and C-Q182K/*) and seven types (preC-W28*, preC-G29D, C-D32N/H, C-E43K, C-P50A/H/Y, C-A131G/N/P and C-S181H/P) of mutations in the preC/C region were found to be related to HCC and to affect the HBeAg serostatus, respectively. In conclusion, our data indicated that HBV variants in the C region, particularly in the MHC class II restricted region, may contribute to the progress of HCC in chronic patients infected with genotype C. In addition, we found several distinct preC/C mutations in the Korean chronic cohort, which affect the clinical status of HCC and HBeAg serostatus of patients infected with genotype C.     

乙肝病毒前C区变异与其真核表达的研究进展

乙型肝炎病毒(HBV)变异与乙型肝炎病情的发展、对该疾病病情的监测等关系密切。其中,HBV前C区基因变异可使HBeAg产生异常的表达,并对HBV基因组的复制也有一定的影响。现就对HBV前C区基因常见变异及其生物学意义,及其真核表达模型构建相关因素等方面进行综述。     

乙肝病毒前C区变异与其真核表达的研究进展

乙型肝炎病毒（HBV）变异与乙型肝炎病情的发展、对该疾病病情的监测等关系密切。其中,HBV前C区基因变异可使HBeAg产生异常的表达,并对HBV基因组的复制也有一定的影响。现就对HBV前C区基因常见变异及其生物学意义,及其真核表达模型构建相关因素等方面进行综述。     

2010年舟山某医院拉米夫定无良好应答乙肝患者耐药监测分析

目的观察2010年舟山某医院拉米夫定单药治疗无良好应答的乙肝患者其基因型和P区耐药位点突变的关系。方法随机选取舟山某医院就诊的124例拉米夫定单药治疗无良好应答的本地乙肝患者,男64例,女60例,平均年龄(46.92±15.16)岁,用实时荧光定量PCR检测其基因型和HBV-DNA,并用毛细管电泳测序技术对P区进行突变位点检测。结果 124例患者35例(28.23%)B型和89例(71.77%)C基因型。C型HBV-DNA为(5.83±0.91)log10 copies/mL,高于B型的(5.07±1.13)log10 copies/mL,差异具有统计学意义(t=3.55,P<0.01)。拉米夫定在B基因型中的耐药率为45.71%(16/35),低于C基因型的65.17%(58/89),差异具有统计学意义(2χ=3.951,P<0.05)。拉米夫定耐药株在B基因型中rtM204 I/V/S位点突变率为68.75%(11/16),高于C基因型的37.93%(22/58),差异具有统计学意义(2χ=4.821,P<0.05)。结论对于本地区拉米夫定治疗无良好应答的C基因乙肝患者,应加强拉米夫定的耐药位点筛查,而拉米夫定治疗无良好应答的B基因乙肝患者应加强rtM204 I/V/S位点检测。     

乙型肝炎病毒preC／C基因在杆状病毒载体系统中的表达

通过ＰＣＲ获得长度为６４０ｂｐ的ＨＢＶ ｐｒｅＣ／Ｃ基因片段,将其克隆入转移载体质粒ｐＳＸＩＶＶＩ＾＋Ｘ３／４,构建出重组质粒ｐＳＸＩＶＶＩ＾＝Ｘ３／４－ｐＣ＝Ｃ。利用共转染的方法,构建出既能形成多角体又能表达ｐｒｅＣ／Ｃ基因的重组毒株ＴｎＮＰＶ－Ｃ／Ｃ－ＯＣＣ＾＋。该重组毒株中ｐｒｅＣ／Ｃ基因受到串联的双启动子－合成启动子和含ＨｉｎｄⅢ接头的ＸＩＶ启动子的双重调控。     

我国常见乙型肝炎病毒基因型与基本核心启动子及前C区突变关系的初步研究

收集81份HBV DNA阳性血清标本,经PCR扩增和序列测定确定其中有50份属于基因型C,31份属于基因型B;C基因型的基本核心启动子BCP T1762/A1764的突变率(38%)明显高于B基因型(12.9%,P<0.05);前C区A1896的突变在B、C两基因型间无显著性差异,B基因型为9.7%,C基因型为12%,P>0.05;HBeAg的表达与否与BCP双突变或前C区A1896突变均无明显相关性。经定量PCR检测证明,HBeAg阳性组中的HBV DNA含量明显高于抗-HBe阳性组,P<0.05。组内BCP双突变株和野生株及前C1896突变株和野生株的HBV DNA含量无显著性差异。     

Genetic Diversity of the Hepatitis B Virus Strains in Cuba: Absence of West-African Genotypes despite the Transatlantic Slave Trade

Cuba is an HBsAg low-prevalence country with a high coverage of anti-hepatitis B vaccine. Its population is essentially the result of the population mix of Spanish descendants and former African slaves. Information about genetic characteristics of hepatitis B virus (HBV) strains circulating in the country is scarce. The HBV genotypes/subgenotypes, serotypes, mixed infections, and S gene mutations of 172 Cuban HBsAg and HBV-DNA positive patients were determined by direct sequencing and phylogenetic analysis. Phylogenetic analysis of HBV S gene sequences showed a predominance of genotype A (92.4%), subgenotype A2 (84.9%) and A1 (7.6%). Genotype D (7.0%) and subgenotype C1 (0.6%) were also detected but typical (sub)genotypes of contemporary West-Africa (E, A3) were conspicuously absent. All genotype A, D, and C strains exhibited sequence characteristics of the adw2, ayw2, and adrq serotypes, respectively. Thirty-three (19.1%) patients showed single, double, or multiple point mutations inside the Major Hydrophilic domain associated with vaccine escape; eighteen (10.5%) patients had mutations in the T-cell epitope (amino acids 28-51), and there were another 111 point mutations downstream of the S gene. One patient had an HBV A1/A2 mixed infection. This first genetic study of Cuban HBV viruses revealed only strains that were interspersed with strains from particularly Europe, America, and Asia. The absence of genotype E supports previous hypotheses about an only recent introduction of this genotype into the general population in Africa. The presence of well-known vaccine escape (3.5%) and viral resistance mutants (2.9%) warrants strain surveillance to guide vaccination and treatment strategies.     

荧光分子信标探针检测拉米夫定耐药基因的研究

建立荧光分子信标探针方法,探讨乙肝病毒对拉米夫定耐药的发生及病程进展。观察77例乙肝病人口服拉米夫定治疗前及治疗后12个月及24个月肝功能(ALT)及免疫学指标及检测HBVDNA含量,并采用PCR荧光分子信标技术检测YMDD耐药突变株(包括YIDDYVDD突变株)。结果表明,口服拉米夫定12个月或24个月,近半数病人血清HBVDNA转阴(小于01pgml),35%(2777)的病人出现e抗原血清转换或单纯e抗原转阴,而e抗原血清转换绝大多数发生于HBVDNA低于100pgml血清的病人。30%(2376)的病人出现YMDD耐药(YIDDYVDD),在HBVDNA小于10pgml(106拷贝ml)的病人中YMDD耐药株与野生株共存。加大口服拉米夫定剂量,绝大多数YMDD耐药株仍不能转变为YMDD野生株。提示中国乙肝患者YMDD耐药后不适合加大剂量继续使用拉米夫定治疗 。     

乙型肝炎病毒全基因序列的测定

测定７ 例慢性 Ｈ Ｂ Ｖ 携带者 Ｈ Ｂ Ｖ 基因组全序列,经同源性比较,确定基因型。２ 例基因型为 Ｂ 型,余均为 Ｃ 型;血清型ａｄｒ ４ 例,ａｄｗ ３ 例。各序列间 Ｘ 基因差异最大。未见 Ａ１８９６ 、 Ｔ１７６２ Ａ１７６４等重要位点的变异。结合已有的２ 株 Ｈ Ｂ Ｖ 中国流行株全基因序列,初步建立以中国流行株序列为基础的 Ｈ Ｂ Ｖ 标准序列,该标准序列与国外标准序列仅有２２ 个位点的差异     

乙型肝炎病毒全基因序列的测定

Seven cases of chronic hepatitis B virus carriers were included for sequencing of whole gene sequences of hepatitis B virus (HBV). The serotype of 4 strains of HBV were adr, and 3 strains were adw. Two strains were classified to genotype B, and the other 5 strains to genotype C. No significant mutations, such as A¹⁸⁹⁶, T¹⁷⁶²A¹⁷⁶⁴ were present. With other reported 2 complete sequences of HBV strains prevailing in mainland China, 7 strains of HBV whole sequences of genotype C from mainland China were analyzed to produce the consensus sequence of HBV of China. Comparing of the consensus sequence with that from Genbank, there were only 22 sites with different nucleotides.     

Subgenotypes and Mutations in the S and Polymerase Genes of Hepatitis B Virus Carriers in the West Bank,Palestine

The mutation rate and genetic variability of hepatitis B virus (HBV) are crucial factors for efficient treatment and successful vaccination against HBV. Until today, genetic properties of this virus among the Palestinian population remain unknown. Therefore, we performed genetic analysis of the overlapping S and polymerase genes of HBV, isolated from 40 Palestinian patients'' sera. All patients were HBsAg positive and presented with a viral load above 10⁵ HBV genome copies/ml. The genotyping results of the S gene demonstrated that HBV D1 was detected in 90% of the samples representing the most prominent subgenotype among Palestinians carrying HBV. Various mutations existed within the S gene; in five patients four known escape mutations including the common G145R and D144E were found. Furthermore, a ratio of 4.25 of non-synonymous to synonymous mutations in the S gene indicated a strong selection pressure on the HBs antigen loops of HBV strains circulating in those Palestinian patients. Although all patients were treatment-naïve, with the exception of one, several mutations were found in the HBV polymerase gene, but none pointed to drug resistance. The study presented here is the first report to address subgenotypes and mutation analyses of HBV S and polymerase genes in Palestine.     

HLA-DP Polymorphisms Affect the Outcomes of Chronic Hepatitis B Virus Infections,Possibly through Interacting with Viral Mutations

Genetic polymorphisms of HLA-DP have been associated with hepatitis B virus (HBV) persistence. We aimed to determine the effect of HLA-DP polymorphisms on the generation of HBV mutations and their interactions on the outcomes of HBV infection. rs3077, rs3135021, rs9277535, and rs2281388 were genotyped in 1,342 healthy controls, 327 HBV clearance subjects, and 2,736 HBV-positive subjects, including 1,108 hepatocellular carcinoma (HCC) patients, using quantitative PCR. HBV mutations were determined by sequencing. Multiplicative interactions of HLA-DP polymorphisms and viral mutations were assessed by multivariate logistic regression. rs3077 (from subjects with genotype CT combined with those from subjects with genotype TT [CT+TT] versus CC), rs3135021 (GA+AA versus GG), rs9277535 (GA+AA versus GG), and rs2281388 (CC versus CT+TT) significantly decreased HBV persistence. This effect was found only in genotype B HBV-infected subjects compared to HBV clearance subjects. HLA-DP polymorphisms promoting HBV clearance were associated with a lower prevalence of mutations increasing HCC risk (C1653T, T1674C/G, A1846T, G1896A and pre-S2 mutations and pre-S deletion in genotype C) and a higher prevalence of mutations decreasing HCC risk (G1652A, T1673C, T1674C, G1719T, G1730C, and G1799C in genotype B and A1727T in genotype C). Significant effects of viral mutations on cirrhosis and HCC were selectively evident in those with HLA-DP polymorphisms promoting HBV persistence. The interactions of C1653T, T1674C/G, and G1896A mutations with HLA-DP polymorphisms promoting HBV clearance significantly decreased cirrhosis risk. The interaction of rs9277535 AA with the T1674C/G or G1719T mutation in genotype C significantly decreased HCC risk. In conclusion, HLA-DP polymorphisms affect genotype B HBV clearance, regulate immune selection of viral mutations, and influence cirrhosis and HCC risks contributed by HBV mutations.     

乙型肝炎病毒RT 区变异及其与基因型分布的关系

目的:探讨大样本乙型肝炎病毒(HBV)感染患者RT区耐药位点变异的流行情况,及各耐药位点变异与HBV基因型的关系。方法:采用P区测序法对1117例慢性乙型肝炎患者的血清病毒进行P区测序、进化树分型。结果:RT区耐药位点变异发生率与基因型关系密切,在基因型C患者中的变异发生率远远高于基因型B患者(P=0.000)。Rt180、rtM204V、rtM204I、rt181、rt213位点变异均与基因型C有关(P<0.05)。主要的三种变异类型rt180+rtM204V、rtM204I、rt180+rtM204I间基因型分布存在显著差异(P=0.003)。不同HBeAg状态下,耐药变异的发生有显著差异(P=0.020),特别是rt181和rt236位点变异。结论:HBV基因型影响RT区耐药变异发生率及变异类型,且耐药变异发生率也与HBeAg状态有关。     

Association of Hepatitis B Virus Pre-S Deletions with the Development of Hepatocellular Carcinoma in Qidong,China

Background/Aim

To investigate the roles of mutations in pre-S and S regions of hepatitis B virus (HBV) on the progression of hepatocellular carcinoma (HCC) in Qidong, China.

Methods

We conducted an age matched case-control study within a cohort of 2387 male HBV carriers who were recruited from August, 1996. The HBV DNA sequence in pre-S/S regions was successfully determined in 96 HCC cases and 97 control subjects. In addition, a consecutive series of samples from 11 HCC cases were employed to evaluate the pre-S deletion patterns before and after the occurrence of HCC.

Results

After adjustment for age, history of cigarette smoking and alcohol consumption, HBeAg positivity, pre-S deletions, pre-S2 start codon mutations, and T53C mutation were significantly associated with HCC, showing adjusted odds ratios (ORs) from 1.914 to 3.199. HCC patients also had a lower frequency of T31C mutation in pre-S2 gene, compared with control subjects (0.524; 95% CI 0.280-0.982). HBV pre-S deletions were clustered mainly in the 5′ end of pre-S2 region. Multivariate analysis showed that pre-S deletions and pre-S2 start codon mutations were independent risk factors for HCC. The OR (95% CI) were 2.434 (1.063–5.573) and 3.065 (1.099–8.547), respectively. The longitudinal observation indicated that the pre-S deletion mutations were not acquired at the beginning of HBV infection, but that the mutations occurred during the long course of liver disease.

Conclusion

Pre-S deletions and pre-S2 start codon mutations were independently associated with the development of HCC. The results also provided direct evidence that pre-S deletion mutations were not acquired from the beginning of infection but arose de novo during the progression of liver disease.     

Variability in the precore and core promoter regions of HBV strains in morocco: characterization and impact on liver disease progression

Background

Hepatitis B virus (HBV) is one of the most common human pathogens that cause aggressive hepatitis and advanced liver disease (AdLD), including liver cirrhosis and Hepatocellular Carcinoma. The persistence of active HBV replication and liver damage after the loss of hepatitis B e antigen (HBeAg) has been frequently associated with mutations in the pre-core (pre-C) and core promoter (CP) regions of HBV genome that abolish or reduce HBeAg expression. The purpose of this study was to assess the prevalence of pre-C and CP mutations and their impact on the subsequent course of liver disease in Morocco.

Methods/Principal Findings

A cohort of 186 patients with HBeAg-negative chronic HBV infection was studied (81 inactive carriers, 69 with active chronic hepatitis, 36 with AdLD). Pre-C and CP mutations were analyzed by PCR-direct sequencing method. The pre-C stop codon G1896A mutation was the most frequent (83.9%) and was associated with a lower risk of AdLD development (OR, 0.4; 95% CI, 0.15–1.04; p = 0.04). HBV-DNA levels in patients with G1896A were not significantly different from the other patients carrying wild-type strains (p = 0.84). CP mutations C1653T, T1753V, A1762T/G1764A, and C1766T/T1768A were associated with higher HBV-DNA level and increased liver disease severity. Multiple logistic regression analysis showed that older age (≥40 years), male sex, high viral load (>4.3 log₁₀ IU/mL) and CP mutations C1653T, T1753V, A1762T/G1764A, and C1766T/T1768A were independent risk factors for AdLD development. Combination of these mutations was significantly associated with AdLD (OR, 7.52; 95% CI, 4.8–8; p<0.0001).

Conclusions

This study shows for the first time the association of HBV viral load and CP mutations with the severity of liver disease in Moroccan HBV chronic carriers. The examination of CP mutations alone or in combination could be helpful for prediction of the clinical outcome.