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.     

乙型肝炎病毒前核心区及基本核心启动子变异的检测及其对患者疾病谱的影响

目的探讨乙型肝炎病毒(HBV)前核心区(前C区,nt1896)及基本核心启动子(BCP,nt1762/1764)变异在慢性HBV感染者疾病谱的分布及对患者疾病谱的影响。方法416例血清HBsAg阳性、HBVDNA定量大于1.0×104拷贝/毫升的患者,采用微流基因芯片检测HBV前C区及BCP变异。结果416例HBV感染者中302例为HBeAg(-)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%BCP变异,2种同时变异为9.94%。HBeAg(-)的慢性乙型肝炎和肝硬化患者前C区变异分别为64.72%和83.33%(x2=0.89,P>0.05),均大于HBeAg(-)无症状携带者的28.47%(x2=54.20,P<0.01;x2=5.29,P<0.05);而HBeAg(-)无症状携带者BCP变异达77.19%,大于HBeAg(-)慢性乙型肝炎和肝硬化患者(x2=69.73,P<0.01;x2=10.58,P<0.01)。而在114例HBeAg(+)患者中28.95%有前C区或BCP变异。结论前C区或BCP变异在慢性HBV感染者疾病谱的分布不同,在HBeAg(-)/HBVDNA(+)与HBeAg(+)/HBVDNA(+)患者变异率差异显著。HBV前C区可能是该病变反复及加重的一个重要原因,但BCP变异临床意义不明确。     

Cytoplasmic expression of hepatitis B core antigen in chronic hepatitis B virus infection: role of precore stop mutants

Abstract: Aims/Background: The cytoplasmic expression of HBcAg is a possible target of immune hepatocytolysis and it is important for the pathogenesis of hepatic injury in chronic hepatitis B virus (HBV) infection. Cytoplasmic HBcAg expression has been suggested to be related to the precore sequence of HBV, HBV DNA level or cell cycle of hepatocytes and the aim of this study was to understand its mechanism. Material/Methods: We studied the expression pattern of HBcAg and its relationship to serum HBV DNA levels, cell proliferation activity of hepatocytes and precore mutation using 66 patients' sera and biopsied liver specimens of chronic hepatitis B. Results: The expression patterns of HBcAg were cytoplasmic predominant (CP) in 17 cases, nuclear and cytoplasmic (NC) in 10 cases and nuclear predominant (NP) in 9 cases and negative in 30 cases. CP expression cases showed a higher grade of hepatitis activity than NP expression cases. Serum HBV DNA levels showed a wide range and there was no significant difference according to the expression pattern of HBcAg. Cell proliferation activity of hepatocytes, measured by Ki-67 (MIB-1) labelling index was higher in CP expression cases than in NP expression cases and it was also significantly higher in cases of high grade than in low grade hepatitis activity. The precore region was evaluated by primer extension assay in 51 cases and there were 16 cases of 1896 precore mutant, 23 cases of wild type, 12 cases of mixed infection of 1896 precore mutant type and wild type. CP expression of HBcAg was significantly more frequent in 1896 precore mutant cases (86%) than in wild type cases (26%). Conclusion: CP expression of HBcAg is the major pattern of 1896 precore mutant cases and it might be involved in the severe liver injury of precore mutants. One of the mechanisms regulating CP HBcAg expression is suggested to be precore mutation of HBV as well as cell cycle of hepatocyte.     

Mutations in the basic core promotor and the precore region of hepatitis B virus and their selection in children with fulminant and chronic hepatitis B

The involvement of precore stop codon 1896-A and base exchanges in the AT-rich region at positions 1762 and 1764 of the hepatitis B core promotor has been controversely discussed in adults with fulminant hepatitis B. Because no data are currently available on children, we analyzed the basic core promotor (BCP) and precore region in children with chronic and fulminant hepatitis B. The BCP and precore region were sequenced directly and after cloning from mothers and infants. Thirteen children suffered from chronic liver disease, 6 of whom were treated with interferon alfa (IFN-alpha). All 13 patients seroconverted from hepatitis B e antigen (HBeAg) to hepatitis B e antigen antibodies (anti-HBe), and sera were analyzed before and after seroconversion. Nine vertically infected infants developed a fulminant course of hepatitis B. The occurrence of BCP (1762-T/1764-A, 7.7%) and precore (1896-A, 7.7%; 1899-A, 15%) mutations in chronic hepatitis B was rare. A genotype shift from D to A was observed in 3 patients after development of anti-HBe. A high number of base exchanges was detected in those infants with fulminant hepatitis B. Eight of nine showed a G-A exchange at positions 1896/97 (89%), 1899 (56%), and/or mutations at nucleotide (nt) positions 1762 (56%) and 1764 (78%). All virus strains belonged to genotype D, whereas in the only surviving infant, a D-to-A shift was detected. Hepatitis B virus (HBV) DNA clones were examined from 3 babies and 5 mothers. Our results showed a heterogeneous virus population in 4 of 5 mothers. In contrast, a homogeneous virus population emerged in the infants. According to our data, the analysis in children with fulminant and chronic hepatitis B revealed a striking presence of BCP and precore mutants in infants with fulminant hepatitis (FH) when compared with clinically inapparent anti-HBe-positive children (P <.002), which could be one factor in the pathogenesis of fulminant hepatitis B in children.     

Cytoplasmic expression of hepatitis B core antigen in chronic hepatitis B virus infection: role of precore stop mutants.

AIMS/BACKGROUND: The cytoplasmic expression of HBcAg is a possible target of immune hepatocytolysis and it is important for the pathogenesis of hepatic injury in chronic hepatitis B virus (HBV) infection. Cytoplasmic HBcAg expression has been suggested to be related to the precore sequence of HBV, HBV DNA level or cell cycle of hepatocytes and the aim of this study was to understand its mechanism. MATERIAL/METHODS: We studied the expression pattern of HBcAg and its relationship to serum HBV DNA levels, cell proliferation activity of hepatocytes and precore mutation using 66 patients' sera and biopsied liver specimens of chronic hepatitis B. RESULTS: The expression patterns of HBcAg were cytoplasmic predominant (CP) in 17 cases, nuclear and cytoplasmic (NC) in 10 cases and nuclear predominant (NP) in 9 cases and negative in 30 cases. CP expression cases showed a higher grade of hepatitis activity than NP expression cases. Serum HBV DNA levels showed a wide range and there was no significant difference according to the expression pattern of HBcAg. Cell proliferation activity of hepatocytes, measured by Ki-67 (MIB-1) labelling index was higher in CP expression cases than in NP expression cases and it was also significantly higher in cases of high grade than in low grade hepatitis activity. The precore region was evaluated by primer extension assay in 51 cases and there were 16 cases of 1896 precore mutant, 23 cases of wild type, 12 cases of mixed infection of 1896 precore mutant type and wild type. CP expression of HBcAg was significantly more frequent in 1896 precore mutant cases (86%) than in wild type cases (26%). CONCLUSION: CP expression of HBcAg is the major pattern of 1896 precore mutant cases and it might be involved in the severe liver injury of precore mutants. One of the mechanisms regulating CP HBcAg expression is suggested to be precore mutation of HBV as well as cell cycle of hepatocyte.     

Frequent integration of precore/core mutants of hepatitis B virus in human hepatocellular carcinoma tissues

The development of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) frequently follows persistent HBV infection and may arise in individuals who are hepatitis B e antigen (HBeAg) negative, indicating the possible presence of precore/core mutants. It is unclear whether precore/core mutants are associated with tumour development or are selected for after chromosomal integration of the wild-type viral DNA. We studied the status and sequence variation of the precore/core region of HBV in 56 patients with HBV-associated HCC and in various corresponding non-tumour tissues by Southern blot analysis, polymerase chain reaction and direct sequencing. Southern blot showed that integrated HBV DNA existed in 43 of 56 HCC tissues. Sequence analysis revealed mutations in 65% of the HCC (26/40) and 45% (14/31) of the corresponding non-tumour tissues. The mutation at nucleotide (nt) 1896, known to prevent HBeAg synthesis, was detected in 40% (16/40) of the tumours and in 35.4% (11/31) of the non-tumour tissues. Other mutations were found at nt 1899 (eight of 40 in HCC; three of 31 in non-tumour tissues), nt 1898 (seven of 40 in HCC; two of 31 in non-tumour tissues), nt 1912 (seven of 40 in HCC; none of 31 in non-tumour tissues) and nt 1886 (three of 40 in HCC; none of 31 in non-tumour tissues). To determine whether this finding merely reflected the prevalence of such mutants in this geographical region, HBV DNA from the sera of patients (also in this region) with acute and chronic hepatitis were sequenced. The nt 1896 mutant was found in 5.6% (one of 18) of patients with acute hepatitis B and in 22.8% (nine of 35) of patients with chronic hepatitis B. However, the nt 1898 mutation was not found in any of these sera. The precore/core mutant was observed with increasing frequency from acute hepatitis to chronic hepatitis, non-tumour and HCC, and this difference in frequency was significant between HCC and acute hepatitis B groups (P < 0.01), suggesting that the precore/core mutant or hepatocytes harbouring this mutant may be under immune selection and that such mutations may facilitate integration and subsequent tumour development.     

Histological spectrum of chronic hepatitis in precore mutants and wild-type hepatitis B virus infection

This study compares the histology of liver biopsies in precore mutant (PCM) and wild-type hepatitis B virus (HBV) infection. Thirty cases of PCM and 60 cases of wild-type HBV infection were included. Patients were diagnosed on the basis of serological profile and HBV DNA assessment. Liver biopsies in each case were assessed for histological activity and stage of fibrosis using a modification of Knodell's scoring system. There was no statistically significant (P=0.14) difference in histological activity in the two groups. The difference in stage of fibrosis in the two groups was statistically significant (P=0.001). Quantitative estimation of viral load did not show any correlation with liver histology. PCM HBV showed greater stage of fibrosis compared with wild-type infection, and this may be related to disease progression and lack of response to therapy.     

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     

Variations of hepatitis B virus precore/core gene sequence in acute and fulminant hepatitis B

Variations of the hepatitis B virus (HBV) precore/core sequence has been shown to play a role in the development of active liver disease in chronic hepatitis B. Whether this is also an important viral factor in the pathogenesis of acute and fulminant hepatitis B is unknown. To determine the precore/core gene sequence in patients with acute and fulminant hepatitis B, 11 patients with fulminant hepatitis B and seven patients with acute hepatitis B were studied. The sequences of precore/core gene were determined by direct sequencing of the polymerase chain reaction amplicons generated from the HBV isolated from patients' serum. For the 11 patients with fulminant hepatitis B, the precore/core regions were successfully amplified in 10 patients. Eight patients exhibited precore stop codon mutations. In addition, nine of the 10 fulminant hepatitis B patients had frequent nucleotide substitutions with corresponding changes in the predicted amino acid sequences in the mid-core and the 5 terminus region of the core gene. In contrast, precore stop codon mutants were not detected, and variations of the HBV core gene were minimal in patients with acute hepatitis B. The association of HBV precore mutants and HBV core gene variations with fulminant hepatitis B and not acute hepatitis B suggested that these variations may be important in modulating the clinical course of HBV infection.     

重型乙型肝炎病毒C基因启动子变异

目的了解我国重型肝炎Ｃ基因调节序列变异特点。方法克隆及聚合酶链反应（ＰＣＲ）产物直接测序方法对,检测７例重型乙型肝炎患者乙型肝炎病毒（ＨＢＶ）Ｃ基因调节序列变异。结果４例存在Ｔ１７６２Ａ１７６４变异;但在Ｔ１７６２Ａ１７６４以外位点也存有诸多变异,其中１例在ｎｔ１７７６－１７７７之间有１１ｂｐ的插入变异。结论重型肝炎ＨＢＶＣ基因启动子区存在较多的变异位点,推测这些变异对Ｃ启动子的调节活性影响可能是综合性的。     

Detection of hepatitis B virus precore stop codon mutants by selective amplification method: Frequent detection of precore mutants in hepatitis B e antigen positive healthy carriers

The precore region of hepatitis B virus (HBV) is indispensable for secretion of e antigen protein. Therefore, the precore stop codon mutants may play an important role in the process of e antigen seroconversion. However, the presence of the mutants in hepatitis B e antigen positive carriers has not been fully studied because of difficulties in detecting the mutants in the presence of large amounts of wild-type viruses. To overcome this, a sensitive method has been developed to detect the presence of G to A stop codon mutants at codon 28 of precore region. Primers for polymerase chain reaction (PCR) were devised to introduce restriction enzyme site Sty I for wild-type viruses and Dde I for the mutants. The amplification products with these primers were digested with Sty I to exclude the products from wild-type viruses. The remaining amplicon from precore mutants were re-amplified, and the presence of precore mutant was confirmed with Dde I digestion. The presence of precore mutants was examined in 61 HBV carriers by the method combining PCR and restriction enzyme digestion. Approximately 0.1% of precore mutant DNA among 10⁶ copies of wild-type virus DNA was detectable by this method. The presence of the precore mutants was detected in seven of 10 (70%) e antigen positive asymptomatic carriers, and in 29 of 36 (81%) e antigen positive patients with chronic liver diseases, and in all 15 (100%) anti-e antibody positive patients with chronic liver diseases. This study revealed that a small amount of the precore mutants was present in the majority of HBV carriers.     

Absence of hepatitis B virus precore mutants in patients with chronic hepatitis B responding to interferon-alpha.

Precore defective HBV mutants may gradually prevail because of immune selection and explain spontaneous seroconversion from HBeAg to anti-HBe in HBV carriers. We have analyzed whether the presence of precore HBV mutants is a determinant of responsiveness to interferon-alpha therapy. Fifteen carriers (nine responders and six nonresponders) who were treated with interferon-alpha were examined. Serum samples were collected before and after therapy. After extraction of DNA, the precore region was amplified by the polymerase chain reaction, and the product was identified by gel electrophoresis and ethidium bromide staining and then Southern blotting and molecular hybridization. The amplified products in all patients were asymmetrically amplified by a modified polymerase chain reaction, and the precore region was directly sequenced. All patients were HBV DNA positive initially. Circulating HBeAg-negative mutants were not identified before treatment in either responders or nonresponders. All nine responders were negative for HBV DNA in serum by dot blot during or after treatment, but seven remained positive by polymerase chain amplification and Southern-blot hybridization. All of the nonresponders remained positive for HBV DNA by dot blot. A silent mutation involving the substitution of an A for G at position 1888 was found in seven carriers; however, no HBeAg-negative mutants were detected in the follow-up of either responders or nonresponders to interferon-alpha.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reversion from precore/core promoter mutants to wild-type hepatitis B virus during the course of lamivudine therapy

The effect of lamivudine administration on the evolution of precore/core promoter mutation is unknown. The aim of this study was to determine the changes of precore/core promoter sequences in chronic type B hepatitis patients treated with lamivudine. Serial sera were obtained from 11 patients before, at the beginning of, and during therapy. Serum samples were polymerase chain reaction-amplified, and nucleotide sequences of hepatitis B virus (HBV) were analyzed. At baseline, precore and core promoter mutations were found in 6 and 4 of 11 patients, respectively. A precore stop codon mutant was replaced by a wild-type virus in all 6 patients infected with precore mutant at a median treatment of 12 months (vs. before therapy; P =.011). Mutations in the core promoter appeared in only 1 of 10 patients (vs. before therapy; P =.021). However, precore and core promoter mutations appeared in 5 and 7 of 10 patients at a median treatment of 21 months, respectively. Acute exacerbation occurred after lamivudine withdrawal in 2 patients who had hepatitis B e antigen (HBeAg) loss or seroconversion. The serum remained HBeAg-negative throughout the study period, and each of 2 patients had precore wild-type virus during acute exacerbation. HBV mutants with core gene deletions are not eliminated completely during prolonged therapy in 2 patients in whom the HBV genomes had core gene deletions at baseline. In conclusion, lamivudine therapy resulted in reversion from precore/core promoter mutants to wild-type. However, mutations in the precore and core promoter region reappeared during prolonged therapy. HBeAg-negative wild-type precore hepatitis B virus could be selected after lamivudine withdrawal in patients who had HBeAg loss or seroconversion.     

Fulminant hepatitis B: induction by hepatitis B virus mutants defective in the precore region and incapable of encoding e antigen

Clones of hepatitis B virus were propagated from 10 cases of fulminant hepatitis B after amplification by polymerase chain reaction and their nucleotide sequences of the precore region were determined. All 113 clones from 9 cases had a point mutation from guanine to adenine at nucleotide 83 in the precore region, which converted codon 28 for tryptophan (TGG) to a stop codon (TAG) and prohibited the synthesis and secretion of hepatitis B e antigen. Precore-region defects were not detected in any of 23 clones from the remaining 1 case. By contrast, precore-region defects were not found in any of 180 clones from 8 cases of acute hepatitis B without hepatic failure serving as controls. The source of infection was traceable in 3 cases. The same precore-region defect, along with the sequence identity of 435 nucleotides, was observed in clones from the case of a baby and his grandmother, who carried the virus and was implicated in the transmission, and also in clones from two pediatricians and the carrier patients they attended. These findings support the hypothesis that precore-defective mutants have stronger activity to induce fulminant hepatitis than nondefective viruses.     

Prevalence of hepatitis B virus precore stop codon mutations in chronically infected children

AIM: To find out whether there is a significant difference in the prevalence of the precore stop codon mutation between HBeAg positive and anti-HBe positive children. METHODS: We investigated a large pediatric population of 155 European children (mean age 10.9 years) with chronic hepatitis B by PCR and direct sequencing. Ninety were HBeAg positive and 65 had seroconversion to anti-HBe. Additionally genotyping was performed. RESULTS: Seventy-four (48%) of the sequenced HBV strains were attributed to genotype D and 81 (52%) to genotype A. In the group of 90 HBeAg positive patients, 2 (2.2%) 1896-G-to-A transitions leading to precore stop codon mutation were found, and in the group of 65 anti-HBe positive children, 5 (7.7%) were identified harbouring HBeAg-minus mutants. The difference was not statistically significant (P=0.13). CONCLUSIONS: HBeAg minus variants as predominant viral HB strains play a minor role in the course of chronic hepatitis B in European children.     

Identification of a novel hepatitis B virus precore/core deletion mutant in HIV/hepatitis B virus co-infected individuals

OBJECTIVES: Although HAART has resulted in improved health outcomes for most HIV-infected individuals, liver failure has emerged as a major cause of morbidity and mortality in people co-infected with hepatitis B virus (HBV). In HBV mono-infected individuals, core deletion mutants are associated with more aggressive liver disease. As HIV accelerates HBV liver disease progression, we hypothesized that HIV-HBV co-infected individuals have increased frequency of core mutations including deletions. To test this hypothesis, we have analysed genome-length sequences of HBV DNA from patients both prior to and during antiviral therapy. SETTING: Prospective HIV/HBV co-infected cohort study. METHODS: Genomic length HBV DNA was amplified by PCR from the serum samples of ten HIV/HBV co-infected individuals and five HBV mono-infected individuals prior to the commencement of lamivudine therapy and again after nine to 74 months of treatment. The complete genomes were sequenced and in order to further analyse some mutations, their frequency was determined in additional HIV/HBV co-infected and HBV mono-infected individuals. RESULTS: A novel -1G mutation was identified in the HBV precore and overlapping core genes that truncated the deduced precore/core proteins. The mutant genome was the dominant species in some HIV/HBV co-infected individuals and was more prevalent in HIV/HBV co-infected individuals than HBV mono-infected individuals. The mutation was also associated with high HBV DNA concentrations in HIV/HBV co-infected individuals. Additional mutations were identified in the core/precore and polymerase genes and regulatory regions. CONCLUSION: Mutations in the HBV core and precore genes may be contributing to disease pathogenesis in HIV/HBV co-infected individuals.     

234例慢性乙型肝炎患者HBV前C/BCP区突变分析

目的调查慢性乙型肝炎患者血清HBV前C/基本核心启动子（BCP）区的突变情况,分析各种突变对HBeAg表达的影响。方法抽提患者血清DNA,采用改进的巢式PCR技术,扩增HBV前C/BCP区基因,对PCR产物进行DNA测序。用NTI软件比对结果,根据文献报道,选取1753、1762、1764、1862、1896和1899共6个位点进行突变分析,并重点分析不同突变对患者血清HBeAg阳性率和病情的影响。结果在234例中6个位点均无突变者为74例（31.6%）,其血清HBeAg阳性率为74.3%（55/74）。在234例中6个位点检出至少1种突变的病例为160例（68.4%）,突变形式包括4种单一位点突变和21种组合形式的突变;检出G1896A突变73例（31.2%）,其中36例检出有共存未突变序列,37例仅检出突变序列,后者血清HBeAg的阳性率为18.9%（7/37）。检出G1896A以外其他形式突变的有87例,HBeAg阳性率为63.2%（55/87）;其中以A1762T＋G1764A最为常见,HBeAg阳性率为69.4%（34/49）。在1753、1862位点上检出4种特殊碱基突变,前C区有基因片段插入或缺失的有2例。结论多数慢性乙型肝炎患者在HBV前C/BCP区可检出突变,突变形式多样,其中G1896A突变样本血清HBeAg阳性率显著下降,而其他突变对其影响较小。应用DNA序列测定法分析HBV前C/BCP区基因突变,获得的信息全面,对临床评估病情进展和实施抗病毒治疗有参考价值。     

乙型肝炎病毒前C区基因及核心启动子双变异临床研究

目的探讨乙型肝炎病毒（HBV）前C区基因及基本核心启动子（BCP）变异在慢性肝病中出现的规律。揭示HBV前C基因变异及BCP双变异与慢性肝病的病情进展及预后的相关性。方法通过DNA扩增、基因序列分析检测21例慢性乙型肝炎（CHB）、18例肝硬化（LC）和15例肝癌（HCC）血清的HBV前C区和BCP的基因序列。结果前C区终止变异（nt1896G→A）在慢性乙肝重度、中度组中的发生率显著高于慢性乙肝轻度组、肝硬化和肝癌组（75％、42．86％和10％、22．22％、20％）（P〈0．01）；BCP双变异（nt162A→T和nt1764G→A）则在肝硬化和肝癌组中的发生率显著高于慢性乙肝组（55．56％、60％和10％、28．57％、25％）（P〈0．05）。结论前C区终止变异与慢性肝病病情进展密切相关，BCP双变异促进肝硬化和肝癌的产生。