海南汉族乙型肝炎病毒基因型与BCP区和前C区基因突变的关系

目的探讨海南汉族乙型肝炎病毒（HBV）基因型与前C区G1896A和BCP区A1762T／G1764A基因突变的关系。方法采用RT-PCR方法检测乙型肝炎患者的HBV基因型,PCR方法扩增包含C启动子和前C区基因核苷酸（nt1643-nt2112）,对PCR产物进行DNA测序。结果基因型C的BCP区A1762T／G1764A突变率（58．82％）显著地高于基因型B（10．53％）（P〈0．05）。基因型CG1896A突变率为29．41％,基因型BG1896A突变率为47．37％,两者比较差异无统计学意义（P〉0．05）。结论不同基因型HBV致病能力可能与病毒基因组BCP区A1762T／G1764A突变率的不同有关,而与前C区G1896A突变无关。     

慢性乙型肝炎病毒基因型与BCP区变异的临床研究

为了研究乙型肝炎病毒 (HBV)基因型与C基因启动子 (BCP)基因变异的关系 ,对 6 9例慢性乙型肝炎患者分别用聚合酶链反应 (PCR)—限制性片段长度多态性 (RFLP)技术和PCR微板核酸分子杂交技术 ,进行基因分型及HBVBCP基因变异检测。在 6 9例慢性乙型肝炎患者中 ,各基因型发生的BCP区A176 2T/G176 4A双突变分别为C型 18例 (4 3 9% )B型 3例 (16 7% )D型 2例 (2 0 % )。C型的BCP双突变率明显高于B型 ,两者相比有显著性差异(P <0 0 5 )。故可以认为乙型肝炎病毒基因型与BCP区双突变存在有一定的相关性。推测A176 2T/G176 4A双突变可能是造成C型患者比B型存在更严重肝损害的原因之一     

乙型肝炎病毒前C区和BCP基因突变对肝脏疾病进程的影响

乙型肝炎病毒（HBV）是人类肝脏疾病的主要病原体之一,感染呈世界性流行,目前全球大约有4亿HBV慢性感染者,每年约有50万人死于HBV相关性肝硬化和肝细胞癌;我国属于HBV高流行区。研究发现,HBV比其他DNA病毒更易出现变异,在HBV感染者体内常形成以一个优势株为主的相关突变株病毒群。HBV基因突变给乙型肝炎的诊断、治疗及预后判断带来许多临床问题。现将HBV前C区和BCP突变对肝脏疾病进程度的影响综述如下。     

乙型肝炎病毒前C/BCP区变异的研究现状

HBV的前C区及基本核心启动子（BCP）变异可降低HBeAg的合成与分泌,也可增加病毒复制能力,导致HBeAg阴性慢性乙型肝炎（CHB）,对临床产生重要的影响。本文就HBV前C/BCP区变异的分子机理、生物学意义、实验室检测以及对临床和抗病毒治疗的影响等方面的研究进展作一综述。     

乙型肝炎病毒基本核心启动子及前C区突变对疾病进展的影响

目的　研究乙型肝炎病毒 (HBV)基本核心启动子 (BCP)T176 2 /A176 4双突变及前C区A1896突变与肝脏损伤程度的相关性。方法　 2 0 0 0～ 2 0 0 2年哈尔滨医科大学附属第二医院及广东省廉江市医院随机选取 113例慢性HBV感染者 ,采用INNO -LiPA法测定HBVBCPT176 2 /A176 4双突变及前C区A1896突变 ,同时测定HBVS基因序列明确基因型。结果　CHB组、LC组、HCC组BCPT176 2 /A176 4双突变率明显高于AsC组 (分别为 2 4 . 1%比 2. 8% ,χ2 =5 .93,P <0 . 0 5 ;71. 4 %比 2 .8% ,χ2 =2 3 .83,P <0 .0 1和 5 5 . 6 %比 2 .8% ,χ2 =13. 0 9,P <0 . 0 1) ,LC组BCPT176 2 /A176 4双突变率显著高于CHB组 (71 .4 %比 2 4 . 1% ,χ2 =9 .12 ,P <0 .0 1) ;单一C基因型感染者CHB、LC和HCC组BCPT176 2 /A176 4双突变率明显高于AsC组 (分别为 33 .3%比 5 . 3% ,χ2 =3 .89,P <0 .0 5 ;6 9 .2 %比5 . 3% ,P <0 . 0 1和 5 0 .0 %比 5. 3% ,P <0 . 0 5 )。各组前C区A1896突变率均较低 ,在CHB组和LC组无一例发生 ;HCC组前C区A1896突变率与AsC组比较差异无显著性 (11 .1%比 8. 3% ,χ2 =0 . 0 0 ,P >0 . 0 5 )。结论　在慢性HBV感染者中 ,BCPT176 2 /A176 4双突变与慢性肝病进展有关。     

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。     

乙型肝炎病毒基因型对乙型肝炎病毒变异的影响

目的探讨乙型肝炎病毒(HBV)基因型对病毒前核心区(前C区,nt1896)及基本核心启动子(BCP,nt1762/1764)变异的影响.方法416例血清HBsAg阳性、HBV DNA定量大于1.0×104拷贝/ml的患者,采用微流基因芯片检测HBV基因型、前C区及BCP变异.结果416例HBV感染者中406例有基因分型结果:B型20.9%、C型65.9%、BC混合型10.8%,10例患者未分出基因型.302例为HBeAg(-)且HBV DNA( )患者,其中248例(82.12%)有前C区或BCP变异,41.06%为前C区变异,31.12?P变异,2种同时变异为9.94%.B型患者前C区变异率为22.9%(20/87),与C型患者前C区变异率39.4%(108/274)及B、C混合型变异率40.0%相比均有显著差异(P＜0.01).在BCP变异及双变异,C型患者变异率均大于B型患者,但差异无统计学意义(P＞0.05).B、C混合型患者前C区及BCP变异率与C型相似.结论HBV基因型可影响病毒前C区及BCP变异,以C型为著.     

乙型肝炎病毒C基因启动子和前C基因变异与HBeAg含量和肝炎病情的临床研究

研究乙型肝炎病毒(HBV)C基因启动子(CP)和前C基因变异对HBeAg表达和病情的影响。通过DNA扩增、基因序列分析检测48例慢性乙肝和12例慢性重型乙肝患者血清的HBV CP和前C基因序列,及通过微粒子发光法定量检测血清中HBeAg的含量。(1)前C终止变异(nt1896G→A)在重型乙型肝炎病例中的发生率显著升高(66.7％);CP双变异(nt1762A→T和1764G→A)则在慢性乙型肝炎中度和重度的病例中的发生率显著升高(分别为52.6％和54.5％)。(2)双变异组和终止变异组的HBeAg含量均显著下降,P<0.01。但终止变异组HBeAg含量的下降较双变异组更为明显,P<0.05,且eAb阳性率也显著升高,P相似文献   

乙型肝炎病毒前C区和/或核心启动子区突变的临床意义

目的探讨乙型肝炎病毒前C区和／或核心启动子区突变的临床意义。方法应用全自动DNA基因测序仪检测91例慢性乙型肝炎及肝硬化患者乙型肝炎病毒前C区和／或核心启动子区位点变异情况，并观察发生突变组与未发生突变组在HBVDNA载量和肝脏病理改变等方面有无差异。结果HBeAg阳性慢性乙型肝炎患者的变异率为10．7％，HBeAg阴性慢性乙型肝炎患者的变异率为65．2％（P〈0．05）；肝硬化代偿期组变异率为46．2％，失代偿期组变异率为35．7％（P〉0．05）；35例基因变异患者HBVDNA载量（取1g值）为4．98±1．38，与56例未变异患者的6．36±1．31无显著差异（P〉0．05）；基因变异的慢性乙型肝炎患者肝组织病理损害较未变异患者为重。结论乙型肝炎病毒前C区和／或核心启动子区突变多见于HBeAg阴性慢性乙型肝炎患者中，但似乎与肝硬化的发生无明显的关系。     

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。     

Comparative study of genotype B and C hepatitis B virus-induced chronic hepatitis in relation to the basic core promoter and precore mutations

BACKGROUND: The clinicopathological profiles and outcome of chronic hepatitis B can differ by hepatitis B virus (HBV) genotypes. In Japan, genotype B and C are two major HBV genotypes. The basic core promoter and precore mutations are other known viral factors for disease activity, although the relationship between HBV genotypes and these mutations is not fully understood. METHODS: The HBV genotypes in 90 patients with chronic hepatitis B were determined using an ELISA. Obtained data were correlated with clinicopathological parameters, basic core promoter, precore and the nucleotide 1858 mutations of the HBV genome. RESULTS: Among 90 cases, 20 (22.2%) had genotype B and 70 (77.8%) had genotype C HBV. Genotype B patients were older than genotype C patients (44.0 +/- 13.9 vs 34.7 +/- 11.0 P = 0.0022). The HBeAg was more prevalent in genotype C than B patients (P = 0.0008) while anti-HBe was more common in genotype B than C patients (P = 0.0002). Serum aspartate aspartate aminotransferase/alanine aminotransferase levels (B: 220.7 +/- 612.8/257.0 +/- 498.0 IU/L vs C: 111.3 +/- 122.8/201.6 +/- 229.4 IU/L, P = 0.16/0.48) and HBV viral loads in blood (B: 6.1 +/- 3.1 log genome equivalent [LGE]/mL vs C: 6.7 +/- 2.3 LGE/mL, P = 0.42) were equivalent. The seroconversion from HBeAg to anti-HBe occurred significantly earlier in genotype B than C patients (62 +/- 53 months vs 136 +/- 54 months, P = 0.0028) during the mean observation period of 149 +/- 82 months even under various therapeutic modalities. The categories III and IV of the histological activity index in genotype C were higher (III: P < 0.005, IV: P < 0.05, n = 68) than that in B patients whereas category II was higher in genotype B than C patients (P < 0.05). The double mutation (1762T/1764A) in the basic core promoter was more frequently found in genotype C than in B HBV (P = 0.0068), whereas the precore mutation (1896A) was more common in genotype B than C HBV (P = 0.0233). The incidence of 1858C that was complementary to the precore mutation site in the stem-loop structure in, was equally rare in both genotype B and C HBV. CONCLUSIONS: Genotype B patients were older, had earlier HBeAg seroconversion and exhibited more severe lobular necroinflammation, less portal inflammation and fibrosis than genotype C patients. This genotypic difference is related to the basic core promoter and precore mutations irrespective of 1858C. (c) 2004 Blackwell Publishing Asia Pty Ltd.     

Hepatitis B virus genotypes, subgenotypes, precore, and basal core promoter mutations in the two largest provinces of Pakistan

Background and Aim:  Hepatitis B virus (HBV) genotyping has been done in most countries, but unfortunately, in Pakistan, HBV genotypic distribution is still unclear. The aim of the present study was to determine the prevalent genotype and subgenotype in the two most populated provinces in Pakistan: Punjab and Sind.
Methods:  In total, 236 HBV DNA-positive samples were selected for genotyping by polymerase chain reaction–restriction fragment length polymorphism (RFLP). The RFLP results were further confirmed with whole genome and partial genome sequencing.
Results:  Genotype D was detected as the most prevalent (93.22%) genotype in all eight cities of both provinces; genotype C was present in 5.93% and genotype A was present in 0.85% of the samples. The D1 subtype was present in 84%, and D2 was present in 8% of 25 whole genome-sequenced samples. The C2 subtype was detected in 58.33% of S gene-sequenced samples, while D1 was detected in the remaining 41.67% of 24 samples sequenced for the S gene. Subtype D1 is the most dominant in D, while C2 is dominant in genotype C. Eight- and 15-bp deletion mutations were also detected in genotype D samples. Other precore and basal core promoter (BCP) mutations included T1915 (100%), A1679 (86.96%), T1762 (39.13%), and A1764 (30.43%), which were also detected in the genotype D samples.
Conclusion:  Genotype D subtype D1 is the most prevalent HBV strain in Pakistan with 8-bp deletion mutants the most common in HBV carriers.     

Hepatitis B genotypes and precore/basal core promoter mutants in HBeAg-negative chronic hepatitis B

Background. Mutations in the precore stop codon (G1896A) and the basal core promoter (A1762T and G1764A) are frequently found in hepatitis B envelope antigen (HBeAg)-negative chronic hepatitis B. However, the clinical significance of these mutations remains controversial. We therefore investigated the influence of hepatitis B virus (HBV) genotypes, as well as precore/basal core promoter mutants, on the clinical and virological features of patients with HBeAg-negative chronic hepatitis B. Methods. Serum samples from 37 patients with HBeAg-negative chronic hepatitis B were collected for serological and molecular assays. The precore and basal core promoter regions were amplified by polymerase chain reaction and the amplicons were directly sequenced and analyzed. HBV geno-type was determined by polymerase chain reaction-restriction fragment length polymorphism. Results. Most of the patients had detectable serum HBV DNA, and genotypes B and C were the predominant strains. The overall prevalence of the precore stop codon mutant and basal core promoter mutant was 67% and 60%, respectively. The baseline clinical and virological features of patients with genotype B and genotype C infection were comparable. However, in the patients with precore/basal core promoter dual mutations there was a significantly lower proportion of individuals with a high detectable serum HBV DNA level (>100 pg/ml) than in the patients with either the precore stop codon mutation alone or the basal core promoter mutation alone (P = 0.04 by the logistic regression test for the trend). Conclusions. Our data suggest a high prevalence of precore stop codon and basal core promoter mutation in Taiwanese patients with HBeAg-negative chronic hepatitis B, and the influence of the basal core promoter mutation on HBV replication is modulated by the emergence of the precore stop codon mutation. Received: May 14, 2001 / Accepted: September 14, 2001     

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.     

Effects of hepatitis B virus precore and basal core promoter mutations on the expression of viral antigens: genotype B vs C

Hepatitis B virus (HBV) genotypes/mutants are known to affect natural outcomes. The virologic differences among HBV genotype, precore and basal core promoter (BCP) mutations were investigated. HBV strains were isolated from 18 hepatitis B e antigen (HBeAg)-positive patients (nine genotype B and nine genotype C). All had precore and BCP wild-type sequences. After cloning of full-length HBV genome, the effects of viral genotype, precore and BCP mutations singly or additively on the expression of viral DNA and antigens were investigated by mutagenesis and transfection assays in Huh7 cells. Significant findings included the following: (i) expression of intracellular core protein increased when precore or BCP mutation was introduced in genotype C strains; (ii) expression of intracellular surface protein was lower in genotype C precore wild-type strain compared with genotype B; (iii) precore mutation was associated with a lower extracellular expression level of HBV DNA; (iv) secretion of hepatitis B surface antigen in genotype C was lower than that in genotype B; and (v) secretion of HBeAg in genotype B was lower than that in genotype C. No additive effect was observed by combining precore and BCP mutations. Hence, HBV genotype and precore/BCP mutations correlate with intrahepatic expression of viral antigens in vitro.     

Clinical significance and evolution of core promoter and precore mutations in HBeAg-positive patients with HBV genotype B and C: a longitudinal study.

BACKGROUND/AIMS: The aims of this longitudinal study were to investigate whether the clinical outcome and evolution of core promoter and precore mutations were different during hepatitis B e antigen (HBeAg) seroconversion between hepatitis B virus (HBV) genotypes B and C in HBeAg-positive patients with chronic hepatitis B. PATIENTS AND METHODS: The core promoter and precore sequences were determined from serial sera of 156 HBeAg-positive patients with chronic HBV infection. RESULTS: In HBV genotype C, the T1762/A1764 mutant was detected earlier than the A1896 mutant, and the frequency was significantly higher than in HBV genotype Ba over the entire follow-up period. In HBV genotype Ba, A1896 was found earlier than the T1762/A1764 mutant, and the frequency was significantly higher than in genotype C only before HBeAg seroconversion, and the A1896 mutant played an important role in HBeAg seroconversion in HBV genotype Ba. In addition, the T1846 variant was an independent factor associated with HBeAg seroconversion. Furthermore, HBV genotype C was associated with the development of G or C1753 and T1766/A1768 mutations, and the reactivation of hepatitis after HBeAg seroconversion. Based on Cox's regression analysis, the significant risk factors of liver cirrhosis were older age at entry [hazard ratio (HR)=1.085, 95% confidence interval (CI)=1.036-1.136, P=0.001], alanine transaminase (ALT) >80 U/l (HR=3.48, 95% CI=1.37-8.86, P=0.009), and the T1762/A1764 mutant (HR=5.54, 95% CI=2.18-14.08, P<0.001). CONCLUSIONS: Our study showed that different HBV genotypes were associated with various mutations in the core promoter and precore regions during HBeAg seroconversion. T1762/A1764 mutation could be useful in predicting clinical outcomes in HBeAg-positive patients with HBV infection.     

Low frequency of mutations in the X gene, core promoter and precore region of hepatitis B virus infected Vietnamese

Numerous mutations in the hepatitis B virus (HBV) genome have been described, but in most cases their role in the pathogenesis of HBV infection is still unclear. Therefore, we analysed specific mutations in HBV-infected Vietnamese patients and assessed their potential relationship with their clinical outcome. A total of 153 HBV-infected Vietnamese patients with well-characterised clinical profiles were enrolled. None of the study participants had a history of alcohol or drug use and none received any antiviral or immunosuppressive therapy before or during the course of this study. The HBx- and core promoter regions were analysed by sequencing. The majority of isolates corresponded to genotype A. The presence of hepatitis B e antigen (HBeAg) was associated with significantly higher viral loads in the chronic HBV-infection group (P = 0.026). Double mutations in the core promoter (1762/1764) were more frequent in those with cancer than in noncancer patients (P < 0.01). Mutations at nucleotide (nt) 1766/1773 were found at low prevalence but with no obvious association to clinical presentation. Cytosine at nt 1858 was predominant but the stop codon mutation in the precore region was not detected. In the study, 4/48 hepatocellular carcinoma (HCC) patients revealed truncated HBx, whilst the serine to alanine mutation (codon 31) of HBx was more prevalent in cancer patients than in asymptomatic HBV carriers (P < 0.01). Thus, the low frequency of mutations indicates the relation of the absence of antiviral pressure in this population. The exclusively found prevalence of certain mutations detected in those with HBV-related carcinoma nevertheless indicates a degree of association with disease progression.     

Clinical features of hepatitis B patients at immune‐tolerance phase with basal core promoter and/or precore mutations

Little data exist on basal core promoter/precore (BCP/PC) mutations in chronic hepatitis B (CHB) patients at the immune‐tolerance (IT) phase. We studied consecutive treatment‐naïve, CHBe‐antigen (HBeAg)‐positive patients who had undergone liver biopsy and genotyping. Those in the IT phase or immune‐clearance (IC) phase were enrolled for comparison of the frequency of BCP/PC mutations and their clinical presentations. Subgroup analyses for the IT group were also performed between patients with and without mutations, and IC patients between fibrosis stages ≤2 vs fibrosis >2. Among 301 patients enrolled, 88/301 (29.24%) and 213/301 (70.76%) were at the IT and IC phase, respectively. The frequency of BCP/PC mutations in IT phase was significantly lower than those in IC phase (15.91% vs 64.79%, P < .001). The BCP mutation only was significantly more frequent than the PC mutation in both groups and also in all IC subgroups. IT patients with BCP/PC mutations had significantly higher quantitative anti‐HBc levels compared with those of patients with wild‐type virus (P < .05). They also had significantly lower mean levels of alanine transaminase, aspartate transaminase, total bilirubin and qAnti‐HBc compared with those of IC patients (all P < .05). Additionally, they were significantly younger in mean age, had higher platelet count, higher levels of HBV DNA and surface antigen, as well as higher frequency of genotype B than those of IC patients with fibrosis >2 (all P < .05). BCP/PC mutations were found in IT patients with CHB. They had distinct clinical characteristics when compared with patients with wild‐type or at IC phase. Further studies are needed to understand their natural history and treatment outcomes.