Hepatitis B virus genotype distribution among chronic hepatitis B virus carriers in Shanghai, China

Role of viral factors in the natural course and therapy of chronic hepatitis B

Hepatitis B virus (HBV) infection is a global health problem that causes a wide spectrum of liver disease, including acute or fulminant hepatitis, inactive carrier state, chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). The pathogenesis of hepatocyte damage associated with HBV is mainly through immune-mediated mechanisms. On the basis of the virus and host interactions, the natural history of HBV carriers who are infected in early life can be divided into four dynamic phases. The frequency, extent, and severity of hepatitis flares or acute exacerbation in the second immune clearance and/or fourth reactivation phase predict liver disease progression in HBV carriers. In the past decade, hepatitis B viral factors including serum HBV DNA level, genotype, and naturally occurring mutants predictive of clinical outcomes have been identified. The higher the serum HBV DNA level after the immune clearance phase, the higher the incidence of adverse outcomes over time. In addition, high viral load, genotype C, basal core promoter mutation, and pre-S deletion correlate with increased risk of cirrhosis and HCC development. As to the treatment of chronic hepatitis B, patients with high HBV DNA level and genotype C or D infection are shown to have a worse response to interferon therapy. In conclusion, serum HBV DNA level, genotype, and naturally occurring mutants are identified to influence liver disease progression and therapy of chronic hepatitis B. More investigations are needed to clarify the molecular mechanisms of the viral factors involved in the pathogenesis of each stage of liver disease and the response to antiviral treatments.

Different natural courses of chronic hepatitis B with genotypes B and C after the fourth decade of life

AIM: To investigate the different impact of genotypes B and C on the development of liver cirrhosis (LC) among different age groups of patients with chronic hepatitis B (CH-B).

METHODS: We examined the outcome of 121 patients with CH-B, divided by age and genotype. Univariate analyses were used to compare different groups. The Cox proportional hazard model was employed to evaluate factors affecting the development of LC.

RESULTS: In patients < 30 years old, there were no significant predictors for development of LC. However, in patients ≥ 30 years old, genotype C was the only significant predictor. In the genotype C group, 8 of 12 patients who progressed to LC were 30-49 years old at initial diagnosis of chronic hepatitis (7 patients were positive for HBeAg). In the genotype B group, 4 of 8 patients who developed LC were ≥ 50 years old at initial diagnosis and were HBeAg-negative.

CONCLUSION: The rate of development of LC was comparable in patients infected with genotypes B and C when CH-B occurred at < 30 years old. However, CH-B patients infected with genotype C showed poor prognosis if they were 30-49 years old and were positive for HBeAg. Age-specific natural course of CH-B should be considered when patients with CH-B are treated with antiviral drugs.

Mutations in preS genes of genotype C hepatitis B virus in patients with chronic hepatitis B and hepatocellular carcinoma

BACKGROUND

Hepatitis B virus (HBV) preS mutations are frequently isolated from patients with severe forms of liver disease. Meanwhile, genotype C has been shown to cause more serious liver disease than genotype B. This study assesses the frequency of preS mutation in Chinese patients with genotype C chronic HBV infection and its relation to liver damage.

METHODS

Seventy-nine persistently infected patients (25 asymptomatic carriers, 28 with chronic hepatitis, and 26 with hepatocellular carcinoma) with genotype C HBV were analyzed. Levels of HBV DNA, hepatitis B e antigen (HBeAg), alanine aminotransferase, and aspartate transaminase and mutations in the preS region were determined.

RESULTS

The correlations of preS deletion with disease progression were distinct: preS deletion mutations were more commonly found in the hepatocellular carcinoma (HCC) group than in the chronic hepatitis B (CHB) or asymptomatic carrier (ASC) groups, with the frequencies of 38.46% (10/26) in the HCC, 7.14% (2/28) in the CHB, and 4.00% (1/25) in the ASC (P = 0.001) groups. The HBeAg-positive rate and HBV DNA levels were comparable between patients with the preS mutation and those without.

CONCLUSIONS

PreS deletion mutations of genotype C HBV might play a role in HBV-related hepatocarcinogenesis.

Genetic characteristics of hepatitis B virus genotypes as a factor for interferon-induced HBeAg clearance

The factors determining the responsiveness of different hepatitis B virus (HBV) genotypes to interferon treatment are not fully understood. We investigated the relationship between HBV genetic characteristics and the outcome of short (16 weeks) or prolonged (32 weeks) treatment with standard interferon-alpha in a prospectively followed cohort of 103 patients across Europe with HBeAg positive chronic hepatitis B. INNO-LiPA assays and HBV DNA sequencing were used to determine HBV genotypes, mutations in the core promoter and precore/core regions. After 16-weeks interferon-alpha treatment, the rate of HBeAg clearance was higher in genotype A versus all other genotypes (P = 0.014), or genotype D alone (P = 0.05). The HBV genome analysis revealed that: (i) after 16-weeks treatment, an HBV subpopulation with core promoter mutations emerged or increased (P < 0.001) only in genotype A; (ii) the core gene of genotype A has the lowest number of amino acid variations in comparison with genotypes B, C, or D. Logistic regression analysis identified genotype A as a positive predictor of short (16 weeks) treatment response (P = 0.001; odds ratio 6.19, 95 confidence interval 1.94-19.8), having a greater impact than baseline HBV DNA or alanine aminotransferase (ALT) levels. In contrast, the response to prolonged interferon-alpha treatment was not different between HBV genotypes. These results suggest that HBV genotype A responds earlier to interferon treatment than other genotypes, which is associated with its molecular characteristics. The optimal duration of interferon-based therapies in chronic hepatitis B may vary between different HBV genotypes.

Differences of HBV genotypes and hepatocellular carcinoma in Asian countries

Hepatitis B virus (HBV) genotype B (HBV B) and genotype C (HBV C) are prevalent in Asia. Recently HBV B has been classified into two subtypes, HBV Ba, which is ubiquitous in Asia, and HBV Bj specific to Japan. However, little is known about etiological, virological and clinical differences among patients who have various genotypes and who developed hepatocellular carcinoma (HCC). We investigated the relation of HBV subgenotype with etiological and clinical differences of HCC patients between Taiwan and Okinawa in Japan. HBV Bj may be associated with lower incidence of HCC and older development of HCC while HBV Ba or HBV C may be associated withhigher incidence of HCC and younger development of HCC. In addition, we demonstrated the relationship of the specific mutation of HBV, T1653 mutation in the core promoter region, with development of HCC in Japanese patients with HBV C. These data suggest that great differences exist among patients with HCC who are infected with different HBV genotypes or genotype-specific mutations.

Hepatitis B virus genotypes and subgenotypes in China

Eight Hepatitis B virus (HBV) genotypes (A to H) have been identified based on an intergenotype divergence of 8% or more in the entire nucleotide sequence. Subgenotypes have also been identified in different HBV genotypes. As a highly endemic area for HBV infection, the prevalence of chronic HBV infection in China is between 8 and 20% of the general population. Genotypes B and C were identified as the most common HBV strains and account for approximately 95% of Chinese patients. Further study confirmed all genotype B strains belong to subgenotype Ba. Two of genotype C subgenotypes, C1 (Cs) and C2 (Ce), were found in China and they showed different geographic distributions. Genotype A was very rarely found, while genotypes E, F, G and H have not beenreported until now. Two types of HBV C/Drecombinant viruses have been identified in west China and distinct geographic and ethnic distributions were observed. Significant differences were observed (P < 0.001) in the prevalence of A1896 and T1762/A1764 mutations among HBV Ba, C1 and C2 subgenotypes in Chinese patients. Accumulating evidence showed the response rate to antiviral therapy in Chinese patients is higher in genotype B than genotype C patients on interferon treatment, but no difference was observed on nucleoside/nucleotide analog treatment.

Distribution of hepatitis B virus genotypes and its clinical significance in Hubei province, China

The distribution of hepatitis B virus genotype in Hubei province and its clinical significance were investigated. HBV genotypes of 276 patients were detected by PCR-microplate sandwich hybridization-ELISA technique. The level of HBV DNA was detected by using PCR-fluorescence quantification test. Among 276 patients, there were 78 cases of HBV asymptomatic carriers, 110 cases of chronic hepatitis B (CHB), 62 cases of severe hepatitis (SH) or liver cirrhosis (LC) and 26 cases of hepatocellular carcinoma (HCC). The genotypes of HBV included C, B, mixtures (B+C, B+D, C+D) and D, accounting for 55.8%, 25.4%, 16.7% and 2.1% respectively. The average level of HBV DNA in genotypes C, B, mixtures and D was 1.20x10(6), 7.81x10(4), 3.26x10(5) and 5.01x10(4) copies/mL respectively. The ratio of SH, LC and HCC in genotype B, C and mixtures was 20%, 30% and 48% respectively. Statistical analysis revealed the percentage of genotype mixtures infection was significantly higher than that of genotype B infection. There was no significant difference in the percentage between genotype B and genotype C or between genotype C and mixtures. The distribution of genotype B, C and mixtures in SH, LC and HCC was significantly different. The frequency of HCC was zero in patients with co-infection. Genotype D was only related with SH and LC. The increased ALT could be converted to categorical grades of severity. From mild, moderate to severity, the prevalence of genotype C showed an opposite trend, although no statistically significant difference was observed. The HBeAg positive rate was higher in patients with genotype C infection than in those with genotype B, especially in the patients whose ages were from 31 to 40 years old. Compared with genotype B, genotype C showed a higher HBeAg positive rate in patients with SH and LC. The percentage of SH, LC and HCC was higher in patients with genotype C and mixtures infection. On the contrary, the percentage of genotype B was lower. The HBeAg positive rate in patients with genotype C infection was higher than those with genotype B infection. Genotype C and mixtures may be associated with development of severe liver disease.

No significant differences in histology and response to interferon treatment in hepatitis B carriers of genotypes C and recombinant B

Hepatitis B virus (HBV) genotypes B and C are most prevalent in China and genotype B is found exclusively in recombination with the pre-C/C gene of genotype C. We investigated whether there is a difference in clinical relevance between the two genotypes sharing the same pre-C/C gene. Thus, we determined the genotype of HBV among consecutive HBeAg-positive patients with tailored interferon-alpha (IFN-alpha) therapy, and the demographic, baseline clinical characteristics and treatment results were compared between them. The median values of alanine transaminase (ALT) were 4.5 and 5.0 times the upper limit of normal (P = 0.419), HBV-DNA levels were 1.4 x 10(7) and 1.5 x 10(7)copies/mL (P = 0.829), mean scores of necroinflammatory histological activity 9.8 and 10.44 (P = 0.105) and fibrotic activity 2.64 and 2.86 (P = 0.227) in genotype B and C patients, respectively. The end-of-treatment response was 42.7% and 39.0% (P = 0.531) with mean tailored treatment months of 8.28 and 9.34 (P = 0.160), and the sustained response 43.4% and 37.5% (P = 0.31) at the end of a 12-month follow-up period in genotype B and C patients, respectively. These results remained similar when follow-up was extended to nearly 3 years. In conclusion, no significant differences in clinical characteristics and response to IFN-alpha between genotypes B and C were found, probably, because both types shared a common pre-C/C encoding region.

Detection of hepatitis B virus genotypes using oligonucleotide chip among hepatitis B virus carriers in Eastern China

AIM: To determine the genotype distribution of hepatitis B virus (HBV) with a newly oligonucleotide chip assay among the HBV carriers in Eastern China.

METHODS: An assay using oligonucleotide chip was developed for detection of HBV genotypes in serum samples from HBV DNA-positive patients in Eastern China. This method is based on the principle of reverse hybridization with Cy5-labeled amplicons hybridizing to type-specific oligonucleotide probes that are immobilized on slides. The results of 80 randomly chosen sera were confirmed by direct sequencing.

RESULTS: HBV genotype B, C and mixed genotype were detected in 400 serum samples, accounting for 8.3% (n = 33), 83.2% (n = 333), and 8.5% (n = 34), respectively. The evaluation of the oligonucleotide assay showed 100% concordance with the amplicon phylogenetic analysis except 9 mixed genotype infections undetected by sequencing.

CONCLUSION: The study indicates that HBV genotype C and B prevail in the Eastern China. It is suggested that the oligonucleotide chip is a reliable and convenient tool for the detection of HBV genotyping.

Hepatitis B virus genetic variability and evolution

Hepatitis B virus has been evolving gradually over a long period of time, resulting in a large amount of genetic diversity, despite the constraints imposed by the complex genetic organization of the viral genome. This diversity is partly due to virus/host interactions and partly due to parallel evolution in geographically distinct areas. Recombination also appears to be an important element in HBV evolution. Also, human intervention in the form of mass vaccination and antiviral treatment will reduce the burden of HBV-related liver disease but may also be accelerating evolution of the virus.

Correlation of hepatitis B virus (HBV) genotypes and mutations in basal core promoter/precore with clinical features of chronic HBV infection

BACKGROUND/AIMS

To investigate the correlation of hepatitis B virus (HBV) genotypes and basal core promoter (BCP) and precore (PC) mutations in patients with chronic hepatitis B.

METHODS

HBV genotyping, nucleotide mutation, serum HBV DNA level and serological markers were analyzed in 121 patients with chronic HBV infection using INNO-LiPA HBV genotyping, polymerase chain reaction (PCR) product-based sequencing, fluorescence quantitative PCR and enzyme-linked immunosorbent assays respectively.

RESULTS

Forty (33.0%), 77 (63.6%), two (1.7%) and two (1.7%) patients had genotypes B, C, B/C and D infections respectively. Significant differences were found in serum HBV DNA levels (log10 copies/ml: 6.18 vs. 5.61, P=0.042) and mutations at nucleotide (nt) 1762/1764 (71.4% vs. 42.5%, P=0.002) between genotypes C- and B-infected patients. There were significant differences in the mean age, serum biochemical parameter levels and mutation rates in BCP/PC among hepatitis e antigen (HBeAg)-positive and -negative chronic hepatitis B (CHB) and liver cirrhosis (LC) groups.

CONCLUSION

Genotypes C and B are predominant in China, and the frequent nt 1762/1764 mutation, which occurs commonly in HBeAg-negative CHB, especially in genotype C patients, may be associated with the progress of chronic HBV infection.

Factors influencing liver disease progression in chronic hepatitis B

Abstract: Chronic hepatitis B virus (HBV) infection is a serious health issue in the Asia‐Pacific region, where most infections are acquired perinatally or during early childhood and may lead to the development of chronic sequelae such as liver cirrhosis and hepatocellular carcinoma (HCC). Studies have identified several host factors (age, gender, immune status) and viral factors (HBV viral load, genotype, basal core promoter and other naturally occurring HBV mutations) associated with disease progression. Other factors, including lifestyle (habitual alcohol consumption, cigarette smoking), exposure to aflatoxin, and viral superinfection may also influence liver disease progression in patients with chronic HBV. This review highlights pertinent data on the factors associated with progressive HBV‐related liver disease in patients with chronic hepatitis B. An enhanced understanding of factors associated with HBV disease progression may lead to improvements in the selection of candidates for intervention and overall disease management. Interventions such as lifestyle changes and antiviral therapy may thus prevent or reduce disease progression.

Nucleotide change of codon 38 in the X gene of hepatitis B virus genotype C is associated with an increased risk of hepatocellular carcinoma

BACKGROUND/AIMS

The hepatitis B virus (HBV) genotype C is associated with the development of hepatocellular carcinoma (HCC). In addition, the HBV X gene, which encodes the pleiotropic transactivator HBx, has also been associated with the development of HCC. In this study, we investigated whether nucleotide changes in the X gene of genotype C are associated with the development of HCC.

METHODS/RESULTS

We sequenced the X gene in age- and sex-matched 39 HBV-infected patients with HCC and 36 HBV-infected patients without HCC. A novel nucleotide change that resulted in a proline to serine substitution at codon 38 in HBx (codon-38 change) was preferentially found in patients with HCC. Then, sera were collected from a new group of age- and sex-matched 52 patients with HCC and 51 patients without HCC. In this cohort also, the codon-38 change was associated with HCC. Multiple logistic regression analysis showed the prevalence of the codon-38 change was significantly associated with HCC in all patients (P=0.001, odds ratio: 4.89).

CONCLUSION

The codon-38 change in genotype C is an independent risk factor for the development of HCC and may serve as a useful molecular marker for predicting the clinical outcomes in patients infected with HBV.

Hepatitis B genotypes: relation to clinical outcome in patients with chronic hepatitis B in Saudi Arabia

AIM

To identify the most common hepatitis B virus (HBV) genotype in Saudi Arabia, and correlate the prevailing genotypes with the clinical outcome of patients.

METHODS

Patients were consecutively recruited from the hepatology clinics of two tertiary care referral centers. Patients were categorized into 4 different groups: group 1, patients with hepatitis B and normal liver enzymes; group 2, patients with hepatitis B and abnormal liver enzymes but without cirrhosis; group 3, patients with hepatitis B and liver cirrhosis; group 4, patients with hepatitis B and hepatocellular carcinoma. All patients had a positive hepatitis B surface antigen (HBsAg). Genotyping of HBV was performed by nested PCR-mediated amplification of the target sequence and hybridization with sequence-specific oligonucleotides.

RESULTS

Seventy patients were enrolled in this study. They were predominantly male (72.9%) in their mid-forty's (mean age 47 years). Forty-nine (70%) patients were hepatitis B envelope antigen (HBeAg) negative. The majority of patients (64%) acquired HBV through unknown risk factors. Hepatitis B genotyping revealed that 57 patients (81.4%) were genotype D, 1 patient (1.4%) had genotype A, 1 patient (1.4%) had genotype C, and 4 patients (5.7%) had genotype E, while 7 patients (10%) had mixed genotype (4 patients ADG, 1 patient DE, 1 patient DF, and 1 patient ADFG). Based on univariate analysis of genotype D patients, significant predictors of advanced liver disease were age, gender, aspartate transaminase, alanine transaminase, albumin, bilirubin, and alkaline phosphatase (all P < 0.001). In multivariate analysis decreased hemoglobin (r = -0.05; 95% CI: -0.08 to -0.03; P = 0.001) and albumin levels (r = -0.004; 95% CI: -0.007 to -0.001; P = 0.002) were highly significant predictors of advanced liver disease. In patients with HBV genotype D, HBeAg negativity was found to increase across advancing stages of liver disease (P = 0.024).

CONCLUSION

This study highlights that the vast majority of Saudi patients with chronic hepatitis B have genotype D. No correlation could be observed between the different genotypes and epidemiological or clinical factors. The relationship between genotype D and HBeAg status in terms of disease severity needs to be further elucidated in larger longitudinal studies.

Precore/basal core promoter mutants and hepatitis B viral DNA levels as predictors for liver deaths and hepatocellular carcinoma

AIM: To conduct a retrospective study in 400 chronic hepatitis B patients in order to identify hepatitis B viral factors associated with complications of liver disease or development of hepatocellular carcinoma.

METHODS: The mean follow-up time was 83.6 ± 39.6 mo. Alpha-fetoprotein test and abdominal ultrasound were used for cancer surveillance. Hepatitis B basal core promoter mutants, precore mutants, genotypes, hepatitis B viral DNA (HBV DNA) level and hepatitis B e antigen (HBeAg) were measured. Univariate analysis and logistic regression were used to assess odds ratios for viral factors related to liver deaths and hepatocellular carcinoma development.

RESULTS: During follow-up, 38 patients had liver deaths not related to hepatocellular carcinoma. On multivariate analysis, older age [odds ratio: 95.74 (12.13-891.31); P < 0.0001], male sex [odds ratio: 7.61 (2.20-47.95); P = 0.006], and higher log₁₀ HBV DNA [odds ratio: 4.69 (1.16-20.43); P < 0.0001] were independently predictive for these liver related deaths. Also, 31 patients developed hepatocellular carcinoma. Multivariate analysis showed that older age [odds ratio: 26.51 (2.36-381.47); P = 0.007], presence of precore mutants [odds ratio: 4.23 (1.53-19.58); P = 0.02] and presence of basal core promoter mutants [odds ratio: 2.93 (1.24-7.57); P = 0.02] were independent predictors for progression to hepatocellular carcinoma.

CONCLUSION: Our results show that high levels of baseline serum HBV DNA are associated with non-hepatocellular carcinoma-related deaths of liver failure, while genetic mutations in the basal core promoter and precore regions are predictive for development of hepatocellular carcinoma.

Simultaneous quantification and genotyping of hepatitis B virus for genotypes A to G by real-time PCR and two-step melting curve analysis

Both the viral titer and the genotype significantly determine clinical outcomes and responses to antiviral treatment in chronic hepatitis B virus (HBV) infection. A method was developed for large-scale A-to-G genotyping with simultaneous viral quantification. The assay was run on a LightCycler instrument using hybridization probes. The genotype was determined from the melting points of the probes in a two-step manner. Set 1 amplicons differentiated genotypes B, E, and F from A, C, D, and G and simultaneously quantified viremia by real-time PCR. Melting curve analysis using the set 2-1 amplicon or the set 2-2 amplicon reaction mixture was then used to differentiate these genotype groups into single genotypes. HBV DNA quantification was consistent with that of the Amplicor assay and linear in a range from 10(2) to 10(13) copies/ml. By comparison with the restriction fragment length polymorphism method, 92.3% of 441 samples were accurately genotyped by the current assay. The method should be useful for genotyping and quantification of HBV DNA in areas where all genotypes exist.

Relationship between viral load and genotypes of hepatitis B virus in children with chronic hepatitis B

OBJECTIVE

We evaluated the prevalence and clinical significance of hepatitis B virus (HBV) genotypes in children with chronic hepatitis B.

METHODS

Hepatitis B virus genomes of 249 hepatitis Be antigen-positive chronic hepatitis B surface antigen carriers were genotyped based on restriction fragment length polymorphism. Genotypes were correlated with corresponding values for alanine aminotransferase levels, quantitative HBV DNA and histological findings.

RESULTS

One hundred and sixty-two boys and 87 girls (mean age, 7.2 years) were studied. Ninety-six percent were attributed to HBV genotypes A (32.5%) or D (63.5%). The remaining were classified as genotypes B, C, E and F. There was no significant difference in both alanine aminotransferase levels and histological findings among different genotypes. However, there was a clear association between very high HBV DNA levels and individuals with genotype D (P = 0.006). Mean time follow-up of 3.6 years showed later anti-HBe seroconversion in patients with genotype D than in those with genotype A (58% vs 37%).

CONCLUSIONS

Compared with children with genotype A, children with genotype D showed a significantly higher viral load. Inasmuch as a relationship exists between viral load and response to treatment in children infected through vertical transmission, children with genotype D have to be carefully monitored. Long-term studies are needed to determine whether these patients are at risk of a poorer outcome.

A unique amino acid substitution, T126I, in human genotype C of hepatitis B virus S gene and its possible influence on antigenic structural change

Amino acid substitutions in the S gene of hepatitis B virus (HBV), especially in the 'a' determinant region, have been suggested to affect the antigenicity of the virus and the clinical outcome of the infected patient. However, no convincing evidence has been presented for this hypothesis, partly because the 3D structure of the S protein has not been determined. Comparative analysis of viral genes offers an approach to testing this hypothesis, as it may reveal signals of natural selection and provide insights into the functional significance of the observed amino acid substitutions. In this study, we analyze HBV S gene sequences obtained from 24 patients infected with HBV genotypes B or C, together with 16 representative viral strains of HBV genotypes A-F retrieved from GenBank. We use phylogenetic methods to infer evolutionary changes among HBV genotypes and to identify amino acid residues potentially under positive selective pressure. Furthermore, we employ the fragment assembly method to predict structural changes in the S protein. The results showed that an amino acid substitution within the 'a' determinant, T126I, was unique to genotype C, may affect the antigenicity of the HBsAg, and may result in poorer clinical outcomes of patients infected with genotype C viral strains. We suggest that an integrated approach of evolutionary comparison and structural prediction is useful in generating hypotheses for further laboratory validation.

Genotyping Hepatitis B virus from whole- and sub-genomic fragments using position-specific scoring matrices in HBV STAR

Hepatitis B virus (HBV) genomes have been classified into eight genotypes based on phylogenetic analysis of sequence variation. Identifying and tracking the movement of HBV genotypes is important in terms of both monitoring infection rates and predicting disease and treatment. An HBV genotyping tool has been developed that compares query sequences with position-specific scoring matrices representing the eight HBV genotypes. This tool (hbv star) is rapid, robust and accurate and assigns genotype based on a statistically defined scoring model. hbv star confidently assigned 90% of 590 full-length HBV genomes to an HBV genotype (Z score >2.0). Thirty-two of the residual 48 sequences were identified as non-human primate viruses and 16 sequences were identified as recombinant or putative recombinants. Receiver-Operated Characteristic (ROC) analysis was used to compare the accuracy of genotype prediction using basal core promoter sequences and surface and core genes with the accuracy achieved by using full-length sequences. A web interface to hbv star is available at http://www.vgb.ucl.ac.uk/starn.shtml.

Impact of the hepatitis B virus genotype and genotype mixtures on the course of liver disease in Vietnam

Eight genotypes (A-H) of hepatitis B virus (HBV) have been identified. However, the impact of different genotypes on the clinical course of hepatitis B infection remains controversial. We investigated the frequency and clinical outcome of HBV genotypes and genotype mixtures in HBV-infected patients from Vietnam, Europe, and Africa. In addition, we analyzed the effects of genotype mixtures on alterations in in vitro viral replication. In Asian patients, seven genotypes (A-G) were detected, with A, C, and D predominating. In European and African patients, only genotypes A, C, D, and G were identified. Genotype mixtures were more frequently encountered in African than in Asian (P = .01) and European patients (P = .06). In Asian patients, the predominant genotype mixtures included A/C and C/D, compared to C/D in European and A/D in African patients. Genotype A was more frequent in asymptomatic compared with symptomatic patients (P < .0001). Genotype C was more frequent in patients with hepatocellular carcinoma (HCC; P = .02). Genotype mixtures were more frequently encountered in patients with chronic hepatitis in comparison to patients with acute hepatitis B (P = .015), liver cirrhosis (P = .013), and HCC (P = .002). Viral loads in patients infected with genotype mixtures were significantly higher in comparison to patients with a single genotype (P = .019). Genotype mixtures were also associated with increased in vitro HBV replication. In conclusion, infection with mixtures of HBV genotypes is frequent in Asia, Africa, and Europe. Differences in the replication-phenotype of single genotypes compared to genotype-mixtures suggest that co-infection with different HBV-genotypes is associated with altered pathogenesis and clinical outcome.

Clinical Significance of the Genotype and Core Promoter/Pre-Core Mutations in Hepatitis B Virus Carriers

It has been shown that clinical and virological characteristics vary among hepatitis B virus (HBV) genotypes. In this study, we measured the virus level, disease severity, and presence or absence of core promoter (CP)/pre-core (PC) mutations in 241 HBV carriers, and investigated the clinical significance of measuring the HBV genotype. In genotype C HBV carriers, the proportion of hepatitis B e antigen (HBeAg)-positive patients was significantly higher than that in genotype B HBV carriers (0 vs. 34.4%, p < 0.05), and the virus level was higher (4.9 vs. 4.05 LGE/ml). In the genotype B HBV carriers, the incidence of PC mutation was significantly higher (69 vs. 34%, p < 0.05). In the genotype C HBV carriers, the incidence of CP mutation was significantly higher (13 vs. 78%, p < 0.05). We compared patients with the wild (W)/mutant (M) pattern in the CP/PC regions to those with the M/W pattern in the CP/PC regions among the genotype C HBV carriers. Both the proportion of HBeAg-positive patients (65.8 vs. 15.4%, p < 0.05) and the alanine aminotransferase (ALT) level (48 vs. 21.5 IU, p < 0.05) were higher in the patients with the M/W pattern in the CP/PC regions, and the disease severity was deteriorated. In conclusion, genotype B HBV may more frequently induce HBe seroconversion via PC mutation compared to genotype C HBV. Among the genotype C HBV carriers, hepatitis activity and the deterioration of the disease severity were significantly inhibited in the group in which PC mutation initially occurred, in comparison to the group in which CP mutation initially occurred.

Multicentre study of hepatitis B virus genotypes in France: correlation with liver fibrosis and hepatitis B e antigen status

The clinical significance of hepatitis B virus (HBV) genotypes is still under debate. The aims of this study were to assess the distribution of HBV genotypes in France and to identify the associations between HBV genotypes and patient demographics, severity of liver disease and HBeAg status in patients referred to tertiary care centres. This was a French, multicentre, retrospective study on 262 patients with chronic HBV infection. HBV genotypes were determined using INNO-LiPA. Liver fibrosis damage was evaluated by histological analysis of biopsy samples. Patients were mainly male (74%), of Caucasian (65%), Asian (17%) or African (18%) ethnicity and 36% were HBeAg positive. All A-G genotypes were found, the most frequent being genotypes D (27%) and A (24%), followed by E (13%) and C (12%), and B (7%). Mixed genotypes were detected in 16% of the cases. Genotype A was associated with sexual contact (P < 0.001) and genotype D with transfusion (P < 0.001) and HBe antibody positivity (P = 0.03).The distribution of HBV genotypes differed with regard to the ethnicity, and may reflect migration patterns. Genotypes A and D were the most frequent in France. Genotype A was associated with HBeAg positivity and genotype D with HBe antibody positivity. In our European patients, we find no clear association between a given HBV genotype and liver disease severity.

Hepatitis B virus genotypes, core promoter variants, and precore stop codon variants in patients infected chronically in North-Eastern Italy

The hepatitis B virus (HBV) genotypes distribution and the core promoter (CP)/precore (PC) variability were evaluated by a line probe assay in 272 patients infected chronically enrolled consecutively in an area of the North-Eastern Italy. Seven out of the eight genotypes were detected. Italian subjects (83% of the sample) were infected mainly by genotype D (73%) and A (26%); genotype F, and genotype H, were detected only in one subject. In foreigners, the genotype distribution reflected the distribution described for the areas of origin, that is, in Asia genotypes B, C, and D; in Africa genotypes A and E. CP and PC variants prevalence rates were 51% and 60%, respectively, and were significantly higher in Italian patients, probably in relation to their older age. In the analysis restricted to genotypes A and D, PC wild type was linked strongly to genotype A (OR = 4.08, 95% CI = 3.07-5.43, P < 0.0001). In genotype A-infected patients, only e seroconversion was associated significantly with CP variants. In genotype D-infected subjects, CP variants were linked significantly to older age and to a higher e seroconversion rate, while PC variants also showed a strong relationship with an ALT lower activity and a lower viral load. In multivariate analysis, HBeAg positivity was associated strongly and independently with younger age, genotype A and CP wild type. Independent determinants of higher viral loads were recognized by increasing age, in male gender and concomitant presence of HBeAg and the CP wild type virus.

Association of hepatitis B virus genotypes with clinical phenotypes of hepatitis B virus infection in Beijing

AIM: To investigate the relationship between the genotypes of hepatitis B virus (HBV) and the clinical outcomes of HBV infection in Beijing area.

METHODS: A total of 1 321 patients, including those with self limited HBV infection (n = 245), chronic hepatitis B (n = 668), liver cirrhosis (n = 108) and asymptomatic carriers (n = 300), were concluded in this study. Serum samples were collected for the detection of HBV markers by enzyme linked immunosorbent assay (ELISA). A simple and precise genotyping system based on polymerase chain reaction (PCR) using type-specific primers was developed for the determination of the genotypes of HBV.

RESULTS: Of the 1 321 serum samples, 804 (60.1%) were HBV DNA positive. HBV with the genotype of B, C, and B+C covered a larger percent. The percentage of HBV with genotype A, B, C, and B+C were 0.25% (2/804), 20.77% (167/804), 69.53% (559/804) and 9.45% (78/804), while none of HBV with genotype D, E, and F was found. Of all the patients with self limited HBV infection, 14 were HBV DNA positive, and the rates of genotype B, C, and B+C were 28.6% (4/14), 64.3% (9/14) and 7.1% (1/14), respectively. Of the samples from asymptomatic carriers, 128 were HBV DNA positive, and the rates of genotype B, C, and B+C were 28.1% (36/128), 68.8% (88/128), and 3.1% (4/128), respectively. Of the patients with in chronic hepatitis B, 608 cases were positive for HBV DNA, and the percentage of genotype B, C, B+C, and A were 19.9% (121/608), 68.6% (417/608), 10.4% (68/608), and 0.3% (2/608), respectively. Of the patients with liver cirrhosis, 54 were HBV DNA positive, and the percentage of genotype B, C, and B+C were 11.1% (6/54), 88.3% (45/54), and 5.6% (3/54), respectively. The rate of genotype C in liver cirrhosis patients was markedly higher than that in the patients with chronic hepatitis B, self limited HBV infection, and asymptomatic carriers (all P <0.05). In addition, genotype distribution showed no significant differences between the age and sex of patients.

CONCLUSION: Genotype B and C are major genotypes in Beijing. HBV with genotype C is predominant in patients with HBV infection, and it may be associated with the development of liver cirrhosis.

Therapeutic implications of hepatitis B virus genotypes

BACKGROUND/AIMS

Hepatitis B virus (HBV) is a global health problem. In addition to the implementation of universal hepatitis B vaccination, effective and individualized treatment of chronic hepatitis B to prevent progression into end-stage liver diseases and hepatocellular carcinoma is still needed. HBV has been designated eight genotypes (A-H) based on genome sequence divergence. The epidemiology of HBV genotypes and their implications on the responses to antiviral therapy have become increasingly recognized in both Asian and Western countries.

METHODS

Published data are thus reviewed.

RESULTS

Each genotype has its distinct geographical and ethnic distribution. Genotypes A and D occur frequently in Africa, Europe, and India, while genotypes B and C are prevalent in Asia. Genotype E is restricted to West Africa, and genotype F is found in Central and South America. The distribution of genotypes G and H is less clear. Accumulating evidence indicates a better sustained response to conventional interferon in patients with genotype B than those with C, and in patients with genotype A than those with D. In contrast, conflicting results exist regarding the response to pegylated interferon. On the other hand, the therapeutic responses to nucleoside/nucleotide analogues are comparable among patients with different HBV genotypes. The impact of HBV subgenotypes, mixed genotype infections, and recombinants of different genotypes on the response to antiviral treatments awaits further examinations.

CONCLUSION

Remarkable clinical and pathogenic differences do exist among HBV genotypes; however, researches on molecular and virologic mechanisms underlying the clinical phenotypes of different HBV genotypes are urgently needed.

Clinical characteristics and distribution of hepatitis B virus genotypes in Guangxi Zhuang population

AIM: To investigate the distribution of HBV genotypes and their YMDD mutations in Guangxi Zhuang population, China, and to study the relationship between HBV genotypes and clinical types of HB, ALT, HBV DNA, HBe system as well as the curative effect of Lamivudine (LAM) on hepatitis B.

METHODS: A total of 156 cases were randomly chosen as study subjects from 317 patients with chronic hepatitis B (CHB). HBV genotypes were determined by PCR-microcosmic nucleic acid cross-ELISA. YMDD mutations were detected by microcosmic nucleic acid cross-nucleic acid quantitative determination. HBV DNA was detected by fluorescence ratio PCR analysis. LAM was given to 81 cases and its curative effect was observed by measuring ALT, HBV DNA load, HBeAg, and HBeAg/HBeAb conversion rate.

RESULTS: HBV genotypes B, C, D, and non-classified genotypes were found in Guangxi Zhuang population. accounting for 25.6%, 47.4%, 58.3%, and 16.0%, respectively. Seventy-four cases were CD-, CB-, BD-mixed genotypes (47.7%). Forty-six (29.5%) cases had YMDD mutations. Genotype B was mostly found in mild and moderate CHB patients. Genotypes C, D and mixed genotype mostly occurred in severe CHB cases. Genotypes D and CD HBV-infected patients had higher ALT and HBV DNA than patients with other types of HBV infection. There was no significant difference among the genotypes in YMDD mutations, clinical types, ALT and HBV DNA level. Non-classified types geno had a significantly lower positive rate of HBeAg than other genotypes (χ²=12.841, P<0.05). There was no significant difference in ALT recovery rate, HBV DNA load, HBeAg, and HBeAg/HBeAb conversion rate, 48 wk after LAM treatment between groups of genotypes D, CD, and non-classified type.

CONCLUSION: Genotypes B, C, and D, non-classified and mixed genotype of HBV are identified in the Guangxi Zhuang population. Variations in genotypes are associated with clinical severity and serum ALT levels, but not with YMDD mutation or HBV DNA load. Therapeutic effects of LAM on clinical parameters are not influenced by differences in genotypes. Further studies are needed to gain an in-depth understanding of the relationship between HBV genotypes and serum HBeAb and HBeAg.

Complete genome sequence and phylogenetic analysis of hepatitis B virus isolated from Turkish patients with chronic HBV infection

Hepatitis viruses are the leading causes of chronic liver disease resulting in chronic hepatitis, cirrhosis, and hepatocellular carcinoma in the world and also in Turkey. Although Turkey has an intermediate rate of hepatitis B virus (HBV) infection with a prevalence reported as 5%, a complete HBV genome sequence has not been published. In this study, the molecular characterization and phylogenetic analysis are described of 11 complete HBV genomes isolated from 11 naïve patients (5 male, 6 female; ages: 18--54 years old, median 35 years old) with chronic HBV infection. Of 11 patients, 7 and 4 were HBeAg positive/anti-HBe negative and HBeAg negative/anti-HBe positive, respectively. All patients had no co-infection with HCV, HDV, or HIV. HBV DNA was extracted from the sera of the patients. The complete genome was amplified by PCR and cloned into a TA vector. The PCR products were sequenced directly and the complete HBV genome sequences were determined. Ten HBV genomes were 3182 base pairs in length. There was a 183 bp deletion (between nucleotides 2987--3169) in pre-S region in one HBeAg positive patient. There were two pre-core stop codons (G1896A) in two HBeAg negative and three core promoter dual mutations (T1762/A1764) in one HBeAg positive and two HBeAg negative patients' HBV genomes. Phylogenetic analysis of all complete genomes yielded that all Turkish sequences were clustered in genotype D branch (ten in subgenotype D1 and one in subgenotype D2). The analysis of S gene amino acid sequences revealed that surface gene subtypes of one and ten HBV strains were subtype ayw3 and ayw2, respectively. This study indicates that Turkish patients with chronic hepatitis B infection show very little genotypic heterogeneity. Genotype D of HBV DNA and subtype ayw2 of surface gene represent almost the whole Turkish patient population infected with HBV.

Geographic distribution, virologic and clinical characteristics of hepatitis B virus genotypes in China

The significance of hepatitis B virus (HBV) genotypes for the heterogeneity of chronic HBV infection and severity of liver disease is not well understood. The aim of this study was to determine the distribution and virologic characteristics of HBV genotypes in China and possible association with the diversity of liver disease. The study includes 1096 chronic HBV carriers from nine provinces in China. We collected clinical and laboratory data and analysed the HBV strains in sera by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and nucleotide sequencing techniques. The most common HBV genotypes were B (41%) and C (53%), while genotypes A and D were also found. A North-South divide was identified in genotype B and C distribution - genotype C was predominant in northern China, while genotype B was more prevalent in southern provinces. Patients with genotype B were younger than those with genotype C, and had a lower prevalence of HBeAg - 65%vs 72%, respectively (P = 0.03). However, the severity of liver disease did not differ significantly between patients infected with genotype B or C - neither when comparing liver function tests (1024 patients), nor hepatic inflammation and fibrosis (264 patients). Amongst 47 patients with genotype D (by PCR-RFLP), 37 (79%) were infected with a new subtype (designated Dc), having a recombination fragment from genotype C precore/core region. This is the first large-scale HBV genotype study from China and convincing documentation of the North-to-South gradient of genotypes C vs B in this country. HBV DNA recombination over the surface and precore/core genes increases the diversity of HBV strains and may have diagnostic and clinical implications.

Hepatitis B virus genotype C prevails among chronic carriers of the virus in Korea

Hepatitis B virus (HBV) is one of the major causative agents of chronic liver diseases in Korea. HBV has been classified into 8 genotypes by a divergence of >8% in the entire genomic sequence, and have distinct geographic distributions. There are limited data on the relevance between HBV genotypes and clinical outcomes in Korea. To investigate the clinical feature relating to HBV genotype in Korea, a total 120 serum samples with HBsAg (65 from Seoul and 55 from the other city in Korea) were obtained from each 30 chronic HBV carriers with asymptomatic carrier (ASC), chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). HBV genotype was determined by either enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies against genotype-specific epitopes in the preS2-region or the direct sequencing of small S gene. HBV genotypes were determined in 105 (87.5%) of 120 samples. HBV genotype C was identified in all HBV carriers with ASC, CH, LC, and HCC. Genotypes A, B, D, E, F and G were not detected in any of them. Genotype C HBV prevails predominantly among chronic carriers of the virus in Korea, irrespective of their clinical stages of liver disease and geographic origin.

Relationship of genotypes of hepatitis B virus to mutations, disease progression and response to antiviral therapy

Phylogenetic analysis has led to the classification of hepatitis B virus into eight genotypes, designated A to H. The genotypes have differences in biological properties and show heterogeneity in their global distribution. These attributes of the genotypes may account not only for differences in the prevalence of hepatitis B virus mutants in various geographic regions, but also be responsible for differences in the clinical outcome and response to antiviral treatment in different population groups.

Hepatitis B virus genotypes in Korea: an endemic area of hepatitis B virus infection

OBJECTIVES

It has been reported that distribution of hepatitis B virus (HBV) genotypes shows geographic difference and are associated with clinical outcomes of HBV infection, including response to antiviral therapy and progression of chronic liver diseases. In this study, we analyzed the distribution of HBV genotypes according to the various clinical outcomes of chronic HBV infection in Korea, which is one of the most endemic areas of HBV infection.

METHODS

A total of 200 patients with chronic HBV infection were enrolled. Clinical diagnoses of the 200 patients with chronic liver diseases were as follows: hepatitis B e antigen (HBeAg)-positive healthy carrier (defined as HBeAg(+), anti-HBe(-), HBV DNA(+) by hybridization, normal transaminase; n = 40); inactive HBsAg carrier (n = 40); chronic hepatitis B (n = 40); liver cirrhosis (n = 40); hepatocellular carcinoma (n = 40). HBV genotypes were determined by nested polymerase chain reaction using genotype-specific primers.

RESULTS

All patients except 2 (inactive HBsAg carriers) were positive for nested PCR and they have genotype C regardless of clinical outcomes.

CONCLUSIONS

HBV genotype was genotype C regardless of various clinical outcomes of chronic HBV infection in Korea. Considering that HBV genotypes have clinical relevance, distribution of HBV genotype in each area should be monitored when management for chronic HBV infection is planned.

Biological impacts of “hot-spot” mutations of hepatitis B virus X proteins are genotype B and C differentiated

AIM: To investigate the biological impacts of “hot-spot” mutations on genotype B and C HBV X proteins (HBx).

METHODS: Five types of “hot-spot” mutations of genotype B or C HBV X genes, which sequentially lead to the amino acid substitutions of HBx as I127T, F132Y, K130M+V131I, I127T+K130M+V131I, or K130M+V131I+F132Y, respectively, were generated by means of site-directed mutagenesis. To evaluate the anti-proliferative effects, HBx or related mutants’ expression vectors were transfected separately to the Chang cells by lipofectamine, and the cells were cultured in hygromycin selective medium for 14 d, drug-resistant colonies were fixed with cold methanol, stained with Giemsa dyes and scored (increase of the colonies indicated the reduction of the anti-proliferation activity, and vice versa). Different types of HBx expression vectors were co-transfected separately with the reporter plasmid pCMVβ to Chang cells, which were lysed 48 h post-transfection and the intra-cellular β-galactosidase activities were monitored (increase of the β-galactosidase activities indicated the reduction of the transactivation activity, and vice versa). All data obtained were calculated by paired-samples t-test.

RESULTS: As compared to standard genotype B HBx, mutants of I127T and I127T+K130M+V131I showed higher transactivation and anti-proliferative activities, while the mutants of F132Y, K130M+V131I, and K130M+V131I+F132Y showed lower activities. As compared to standard genotype C HBx, I127T mutant showed higher transactivation activity, while the other four types of mutants showed no differences. With regard to anti-proliferative activity, compared to standard genotype C HBx, F132Y and K130M+V131I mutants showed lower activities, and K130M+V131I +F132Y mutant, on the other hand, showed higher activity, while the mutants of I127T and I127T+K130M+V131I showed no differences.

CONCLUSION: “Hot-spot” mutations affect the anti-proliferation and transactivation activities of genotype B and/or C HBx, and the biological impacts of most “hot-spot” mutations on HBx are genotype B and C differentiated.

Genotypic variability of hepatitis viruses associated with chronic infection and the development of hepatocellular carcinoma

At least five hepatitis viruses are known to date. Infection by enterically transmitted viruses (HAV and HEV) is generally benign compared with the disease caused by parenterally transmitted viruses (HBV, HCV, and HDV). Chronic infection by HBV is common and may evolve to cirrhosis and hepatocellular carcinoma (HCC). Eight HBV genotypes (A-H) have been described, with the South American genotype F being the most divergent. Seven clades of HDV have been described; among them, the South American genotype III is associated to a high frequency of fulminant hepatitis. HCV infection leads to a high rate of chronicity and HCC. From the six HCV genotypes, infection with genotype 1 might have the worst prognostic. Chronic infection by HCV and HBV is the major risk factor for HCC, which occurs, in the majority of the cases, as a consequence of cirrhosis. However, there is growing evidence that some HBV and HCV proteins might contribute to the generation of HCC. Some HBV and HCV variants and specific mutations within the viral genomes might be more frequently associated with the evolution to HCC. Although more studies are needed, emerging evidence indicates that it might be important to address the genetic variability of these viruses and their contribution to the development of HCC.

Response to long-term lamivudine treatment (up to 5 years) in patients with severe chronic hepatitis B, role of genotype and drug resistance

Lamivudine is effective in suppressing viral replication, normalizing alanine aminotransferase (ALT), and improving histological appearance in HBe positive and negative hepatitis. It is unclear whether hepatitis B virus (HBV) genotype influences the response to lamivudine. We report the long-term response of patients with chronic hepatitis B with and without cirrhosis at baseline treated with lamivudine according to HBV genotype. Retrospective review of charts of all patients treated with lamivudine monotherapy between 1993 and 2002. Response to therapy defined as ALT in the normal range, undetectable HBV DNA, and in the HBeAg positive group loss of HBeAg and/or the development of anti-HBe. HBV DNA measured by the Digene Hybrid capture assay (sensitivity 1.4 x 10(6) copies/mL). YMDD mutation at rtL180M and rtM204V/I measured by restriction digest of amplified products. Genotyping performed by sequencing and phylogenetic tree analysis of the preS region of the virus genome. Seventy-one patients treated with lamivudine for 6 months or more, 53 (75%) were male, average age 47 years, 38 (54%) were HBeAg+ and 33 (46%) HBeAg-. Mean baseline HBV DNA viral titre was 1280.2 copies/mL and 518 copies/mL respectively. Cirrhosis was present in 30 (42%). Sera were examined for YMDD mutations at last patient visit in 61 (86%), and were detected in 45 (74%), there being no association with a particular genotype. Data from up to 5 years on lamivudine indicated no difference in biochemical or virological response between genotypes. Cirrhosis was more prevalent with specific genotypes. We found no influence of HBV genotype on the development of resistance to lamivudine, however liver disease severity was influenced by genotype.

Transformation of hepatitis B serologic markers in babies born to hepatitis B surface antigen positive mothers

AIM: To better understand the clinical significance of hepatitis B serologic markers in babies born to hepatitis B surface antigen (HBsAg) positive mothers, the incidence of maternal serologic markers of hepatitis B via placenta and its transformation in these babies were investigated.

METHODS: Mothers with positive HBsAg were selected in the third trimester of pregnancy. Their babies received immunoprophylaxis with hepatitis B immunoglobulin and hepatitis B vaccine after birth, and were consecutively followed up for hepatitis B serologic markers and HBV DNA at birth, mo 1, 4, 7, 12, and 24.

RESULTS: Forty-two babies entered the study, including 16 born to hepatitis B e antigen (HBeAg)-positive HBsAg carrier mothers and 26 to HBeAg-negative HBsAg carrier mothers. Apart from four babies born to HBeAg-positive carrier mothers and demonstrated persistent positive HBeAg eventually became HBV carriers, all other babies developed anti-HBs before 12 mo of age. Among the other 12 babies born to HBeAg-positive carrier mothers, HBeAg was detected in 7 at birth, in 4 at mo 1, and in none of them thereafter. No antibody response to the transplacental HBeAg was detected. Among the babies born to HBeAg-negative carrier mothers, anti-HBe was detected 100% at birth and mo 1, in 88.5% at mo 4, in 46.2% at mo 7, in 4.2% at mo 12 and none in mo 24. Among all the immunoprophylaxis-protected babies born to either HBeAg-positive or HBeAg-negative carrier mothers, anti-HBc was detected in 100% at birth, mo 1 and mo 4, in 78.9% at mo 7, in 36.1% at mo 12 and in none at mo 24.

CONCLUSION: HBeAg can pass through human placenta from mother to fetus and become undetectable before 4 mo of age, but no antibodies response to the transplacental HBeAg can be detected till mo 24 in the immunoprophylaxis-protected babies. The sole existence of anti-HBe before 1 year of age or anti-HBc before 2 years of age in babies born to HBsAg carrier mothers may simply represent the transplacental maternal antibodies, instead of indicators of HBV infection status.

Basal core-promoter mutant of hepatitis B virus and progression of liver disease in hepatitis B e antigen-negative chronic hepatitis B

BACKGROUND/AIMS

The long-term outcomes in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B are distinct from those in HBeAg-positive chronic hepatitis. However, the molecular virological factors that contribute to the progression of liver disease in this special clinical setting remain largely unknown. We thus investigated the association of hepatitis B virus (HBV) genotypes as well as precore/basal core-promoter mutations with the clinical and virological characteristics of patients with HBeAg-negative chronic hepatitis B in Taiwan.

METHODS

HBV genotypes and sequences of precore and basal core-promoter regions of the HBV genome were determined in 174 HBeAg-negative chronic HBV infection patients including 62 inactive carriers and 112 with different stages of liver disease.

RESULTS

HBV carriers with older age (> 50 years) (odds ratio, 9.09; 95% confidence interval (CI), 3.22-25, P < 0.001) and basal core-promoter mutant of HBV (odds ratio, 4.12; 95% CI, 1.41-12.03, P = 0.01) were associated with the development of liver cirrhosis and hepatocellular carcinoma (HCC). The gender-related risk factors associated with the development of liver cirrhosis and HCC were further analyzed, and basal core-promoter mutant was only associated with the development of liver cirrhosis and HCC in male carriers (odds ratio, 4.35; 95% CI, 1.30-14.52, P = 0.02).

CONCLUSIONS

The risk of development of liver cirrhosis and HCC is significantly increased in patients with advanced age as well as with basal core-promoter mutant of HBV. In addition, basal core-promoter mutant might contribute to the gender difference of the progression of liver disease in HBeAg-negative chronic hepatitis B in Taiwan.

Molecular epidemiology of hepatitis B virus in Spain: identification of viral genotypes and prediction of antigenic subtypes by limited sequencing

The hepatitis B virus (HBV) genotypes were studied by a line probe assay (LiPA) and by direct sequencing of a 339 nucleotide fragment from the S region of the viral genome in samples from 269 carriers living in Spain, either native to Spain (231) or immigrants from Africa, Asia, and Eastern Europe (38). The sequences were also used to predict the HBV surface antigen (HBsAg) subtype on the basis of the amino acids specified at selected positions of the HBsAg molecule. Agreement between the two genotyping methods was found in most cases (98.1%) and a HBV genotype could be assigned to all samples. The viral groups D/ayw2 (30.1%), D/ayw3 (28.6%), and A/adw2 (21.2%) were prevalent, with an additional participation of the groups D/ayw4 (4.8%), F/adw4q- (1.9%), A/ayw1 (1.9%), and D/adw3 (0.7%), all of them present among the autochthonous carriers. Strains from genotypes B and C were found exclusively among Chinese immigrants. Genotype E strains were found in immigrants from Central Africa and in one patient native of Spain. Point mutations leading to amino acid changes of residues involved in the expression of the HBsAg subtype determinants were found in 12 samples (4.5%). Some mutations would predict the putative novel genotype-subtype associations A/adw4q+, A/ayr, D/ayr, and E/ayw1, while others would suggest the loss of subtype-specific determinants. The finding of HBV strains characteristic for Africa among the autochthonous carriers confirms the emergence of African HBV strains in Spain.

Viral hepatitis and hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. The incidence of HCC varies considerably with the geographic area because of differences in the major causative factors. Chronic hepatitis B and C, mostly in the cirrhotic stage, are responsible for the great majority of cases of HCC worldwide. The geographic areas at the highest risk are South-East Asia and sub-Saharan Africa, here hepatitis B is highly endemic and is the main cause of HCC. In areas with an intermediate rate of HCC such as Southern Europe and Japan, hepatitis C is the predominant cause, whereas in low rate areas such as Northern Europe and the USA, HCC is often related to other factors as alcoholic liver disease. There is a rising incidence in HCC in developed countries during the last two decades, due to the increasing rate of hepatitis C infection and improvement of the clinical management of cirrhosis.

METHODS

This article reviews the literature on hepatitis and hepatocellular carcinoma. The Medline search was carried out using these key words and articles were selected on epidemiology, risk factors, screening, and prevention of hepatocellular carcinoma.

RESULTS

Screening of patients with advanced chronic hepatitis B and C with hepatic ultrasound and determination of serum alfa-fetoprotein may improve the detection of HCC, but further studies are needed whether screening improves clinical outcome. Hepatitis B and C viruses (HBV/HCV) can be implicated in the development of HCC in an indirect way, through induction of chronic inflammation, or directly by means of viral proteins or, in the case of HBV, by creation of mutations by integration into the genome of the hepatocyte.

CONCLUSION

The most effective tool to prevent HCC is avoidance of the risk factors such as viral infection. For HBV, a very effective vaccine is available. Preliminary data from Taiwan indicate a protective effect of universal vaccination on the development of HCC. Vaccination against HBV should therefore be a health priority. In patients with chronic hepatitis B or C, interferon-alfa treatment in a noncirrhotic stage is protective for HCC development in responders, probably by prevention of cirrhosis development. When cirrhosis is already present, the protective effect is less clear. For cirrhosis due to hepatitis B, a protective effect was demonstrated in Oriental, but not in European patients. For cirrhosis due to hepatitis C, interferon-alfa treatment showed to be protective in some studies, especially in Japan with a high incidence of HCC in untreated patients. Virological, but also merely biochemical response, seems to be associated with a lower risk of development of HCC. As most studies are not randomized controlled trials, no definitive conclusions on the long-term effects of interferon-alfa in HBV or HCV cirrhosis can be established. Especially in hepatitis C, prospective studies should be performed using the more potent reference treatments for cirrhotics, namely the combination of peginterferon and ribavirin.

Hepatitis B virus genotypes and hepatocellular carcinoma in Thailand

AIM

The role of hepatitis B virus (HBV) genotypes on the clinical features and prognosis of patients with hepatocellular carcinoma (HCC) is currently unknown. The aim of the present study was to evaluate the distribution of HBV genotypes and their clinical relevance in Thai patients.

METHODS

HBV genotypes were determined by PCR-RFLP in stored sera of 93 asymptomatic carriers, 103 patients with chronic hepatitis, 60 patients with cirrhosis and 76 patients with HCC. The clinical data were analyzed in relation to the HBV genotype.

RESULTS

HBV genotypes C and B were predominant in Thailand, accounting for 73% and 21%, respectively. The distributions of genotypes B and C were similar in HCC patients compared to the other groups. Genotype C was significantly more common in HCC patients who were under 40 years old than genotype B (18% vs 0%, P = 0.03), but was significantly less common in patients older than 60 years (26% vs 56.5%, P = 0.01). The positive rate of hepatitis B e antigen (HBeAg) in patients with genotype C was significantly higher than that in patients with genotype B (71.6% vs 44.4%, P = 0.03 in chronic hepatitis; 56.8% vs 11.1%, P = 0.01 in cirrhosis). There were no differences between HCC patients with genotypes B and C regarding tumor staging by CLIP criteria and the overall median survival. Multivariate analyses showed that HBV genotype was not an independent prognostic factor of survival in HCC patients.

CONCLUSION

Patients with genotype C had a higher positive rate of HBeAg and exhibited earlier progression of cirrhosis and HCC than those with genotype B. However, there were no differences in the risk of developing HCC and its prognosis between patients with these genotypes.

Hepatitis B virus: significance of genotypes

Hepatitis B Virus (HBV) genotypes have come of age. The concept that HBV genotypes may influence the course of disease and relevant biological differences has now been recognised. However, there are still major gaps in our knowledge. Most clinical data come from Asia and describe findings in patients infected with genotypes B and C. Large scale studies with genotypes A and D as found in Europe or A, D and E from Africa are urgently needed to broaden our understanding. Experimental data which explain in vivo findings in terms of differences in molecular biology in vitro are still in the beginning. The succeeding years will see many interesting studies which will aid our understanding of how variants and genotypes of HBV influence the spectrum of disease in people infected with HBV.

Hepatitis B virus genotypes

Eight genotypes of hepatitis B virus (A-H) are currently recognized, and subgenotypes have recently been described in four of these genotypes (A, B, C and F). The genotypes show a distinct geographical distribution between and even within regions, and are proving to be an invaluable tool in tracing the molecular evolution and patterns and modes of spread of hepatitis B virus. Structural and functional differences between genotypes can influence the severity, course and likelihood of complications, and response to treatment of hepatitis B virus infection and possibly vaccination against the virus. Although the number of studies on these genotypes has increased dramatically during recent years, much remains to be learnt about their full implications.

Strong association between genotype F and hepatitis B virus (HBV) e antigen-negative variants among HBV-infected argentinean blood donors

A number of reports have indicated an increased risk of cirrhosis and hepatocellular carcinoma in hepatitis B virus (HBV)-infected individuals carrying HBV e antigen (HBeAg)-negative variants. Although distinct core promoter and precore mutations distributed according to geographical locality and viral genotype have been reported, epidemiological data from South America are still scarce. The prevalences of HBV genotypes and core promoter and precore polymorphisms in 75 HBeAg-negative Argentinean blood donors were surveyed. The observed frequencies of HBV genotypes were 64.0% for genotype F, 17.3% each for genotypes A and D, and 1.3% for genotype C. Genotype F strains were widely distributed and significantly more prevalent in the northern region of the country (P < 0.001). An overall high proportion of a stop codon mutation (UAG) at precore codon 28 (66.7%) was observed. Wild-type codon 28 (UGG) was present in 29.3% of the samples, and the remaining 4.0% of samples had mixed variants. The combination of A at nucleotide (nt) 1762 and G at nt 1764 of the core promoter was found in 58.7% of the samples. The variant profiles--T at nt 1762 and A at nt 1764 or A at nt 1762 and A at nt 1764--were detected in 28.0 and 1.3% of the samples, respectively. The observed core promoter polymorphisms could not be related to the ratio of HBeAg to anti-HBeAg antibody, HBV genotype, or precore codon 28 status. Nevertheless, a clear association of genotype F and a precore stop codon mutation was found (P < 0.05). In conclusion, HBV genotype F and mutant codon 28 strains predominated and were strongly associated in a geographically broad Argentinean blood donor population.

Epidemiology and Prevention of Hepatitis B Virus Infection

Hepatitis B is one of the most common infectious diseases globally. It has been estimated that there are 350 million chronic hepatitis B virus (HBV) carriers worldwide. The prevalence of chronic HBV infection varies geographically, from high (>8%), intermediate (2-7%) to low (<2%) prevalence. HBeAg-negative chronic hepatitis B (e-CHB) and occult HBV infection are two special clinical entities, and the prevalence and clinical implications remain to be explored. The predominant routes of transmission vary according to the endemicity of the HBV infection. In areas with high HBV endemicity, perinatal transmission is the main route of transmission, whereas in areas with low HBV endemicity, sexual contact amongst high-risk adults is the predominant route. HBV has been classified into 7 genotypes, i.e. A to G, based on the divergence of entire genome sequence and HBV genotypes have distinct geographical distributions. Three main strategies have been approved to be effective in preventing HBV infection. They are behavior modification, passive immunoprophylaxis, and active immunization. The implement of mass HBV immunization program is recommended by the WHO since 1991, and has dramatically decreased the prevalence of HBV infection and HCC in many countries.

Long-term results of lamivudine monotherapy in Korean patients with HBeAg-positive chronic hepatitis B: response and relapse rates, and factors related to durability of HBeAg seroconversion

OBJECTIVE

The aim of this study was to evaluate retrospectively the long-term effects of lamivudine in 461 Korean patients with chronic hepatitis B who were treated for more than 12 months.

METHODS

The annual rates of virological response and breakthrough were examined and the predictive factors for post-treatment relapse in 114 patients who achieved hepatitis B e antigen (HBeAg) loss or seroconversion after lamivudine therapy were also analyzed.

RESULTS

During follow-up, the rates of HBeAg seroconversion after 1, 2, 3, 4 and 5 years of treatment were 22.9, 33.2, 47.6, 54.2 and 58.8%, respectively, while those for virological breakthrough at 1, 2, 3 and 4 years were 8.2, 41.7, 55.7 and 64.8%, respectively. Ninety-five patients (20.6%) had HBeAg seroconversion and 19 (4.1%) showed HBeAg loss alone with disappearance of hepatitis B virus DNA in serum. Seroconversion was higher with prolonged treatment in patients who had elevated serum alanine aminotransferase. The cumulative relapse rates in the seroconversion group were 52.0 and 55.7% 1 and 2 years after treatment, respectively. Age and the duration of additional treatment were significant predictive factors for post-treatment relapse. Patients aged 12 months after seroconversion had the lowest relapse rate (p < 0.001).

CONCLUSIONS

These results suggest that additional treatment for over 12 months after HBeAg seroconversion in younger patients may produce a better long-term outcome.

Differences of hepatocellular carcinoma patients with hepatitis B virus genotypes of Ba, Bj or C in Japan

Hepatitis B virus (HBV) genotypes B (HBV/B) and C (HBV/C) are prevalent in Asia. Recently HBV/B has been classified into two subtypes, HBV/Ba which is ubiquitously found in Asia, and HBV/Bj which is specific in Japan. In addition, the frequency of positive HBeAg has been reported to be higher in patients with HBV/Ba than those with HBV/Bj. However, little is known about the differences between patients with various genotypes who developed hepatocellular carcinoma (HCC). In 296 serum samples of HCC patients collected from all over Japan, HBV genotypes were determined with the restriction fragment length polymorphism. HBV/A was detected in 1.0%, HBV/Ba in 4.4%, HBV/Bj in 7.4%, and HBV/C in 86.5%. In the Tohoku district and Okinawa, HBV/Ba, HBV/Bj and HBV/C were found in 6.7, 40.0 and 48.9%, compared to 4.0, 1.6 and 93.2% in the other districts in Japan. HBV/Bj patients were more frequently found in the group older than 65 years while HBV/Ba patients were found in all age groups. The frequency of positive HBeAg in HBV/Bj patients was significantly low compared to that in the other patients. More than 60% of the patients with HCC had cirrhosis as the underlying liver diseases. However, in HBV/Ba patients aged 50 years or younger, 80% of them had chronic hepatitis, while 87.5% of those aged older than 50 years had cirrhosis. These data suggest that great differences exist among patients with HCC infected with different genotypes.

Hepatitis B virus genotypes, phylogeny and occult infection in a region with a high incidence of hepatocellular carcinoma in China

AIM: To determine the genotypes and phylogeny of hepatitis B viruses (HBVs) in asymptomatic HBV carriers, and the prevalence of occult HBV infection in Long An County, Guangxi Zhuang Autonomous Region, an area with a high incidence of hepatocellular carcinoma.

METHODS: A nested polymerase chain reaction (nPCR) was used for detection of HBV DNA in serum samples from 36 blood donors with asympmatic HBV infection, and in serum samples from 52 HBsAg negative family members of the children who did not receive hepatitis B vaccination in Long An County. PCR products were sequenced, and the genotype of each HBV sequence was determined by comparison with sequences of known genotypes in the GenBank and EMBL nucleotide databases using the BLAST programme. Phylogenetic trees were constructed by the quartet maximum likelihood analysis using the TreePuzzle software.

RESULTS: Twenty (55.56%) of 36 HBV asymptomatic carriers were positive for HBV DNA. They were all genotype C by comparison with sequences of known genotypes in the GenBank and EMBL nucleotide databases. The full-length HBV DNA sequence isolated from the sample No. 624 contained 3215 bases. No interesting mutations were found in this isolate. The homology analysis showed that this strain was closer to the Vietnamese HBV genotype C strain, with a homology of 97%, compared its relation to the same genotype of HBV isolated in Shanghai. Six (11.5%) of the 52 HBsAg negative family members were positive for HBV DNA. A point mutation was found in the sample No. 37, resulting in the substitution of amino acid glycine to arginine in the “a” determinant. Other samples with positive HBV DNA did not have any unusual amino acid substitutions in or around the “a” determinant, and were attributed to the wild-type HBV.

CONCLUSION: The HBVs isolated from asymptomatic carriers of Long An County were all identified as genotype C, and the prevalence of occult HBV infection in the population of the county is as high as 11.5%. It is suggested that genotype C and persistent occult HBV infection may play an important role in the development of HCC in the county.