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

Comparison of hepatitis B virus genotype B and C patients in Japan in terms of family history and maternal age at birth

AIM

Hepatitis B virus of genotypes B (HBV/B) and C (HBV/C) prevails in Japan and patients with HBV/B have been known to be older than those with HBV/C, but the reason has remained unknown. We aimed to clarify the reason by focusing on the family history of HBV infection.

METHODS

In a total of 508 patients with chronic HBV infection, HBV genotype, patient age, and age of the mother at birth were compared.

RESULTS

Patient age was significantly older in HBV/B than in HBV/C, and the patient percentage with a family history of HBV infection was lower in HBV/B. When comparing maternal age at birth between the two genotypes, there was no significant difference in the overall patient population, but the proportion of older birth group (≥26 years old) was significantly lower in HBV/B (38.7% vs. 59.3%, p = 0.048) in patients with a family history of HBV infection in both mothers and siblings whose HBV were considered to be transmitted vertically. There was a negative correlation between maternal age at birth and patient age in this group, reflecting the fact that the age of childbearing is increasing recently in Japan. Because patients with HBV/B experience hepatitis B e antigen seroconversion at an earlier age, it was considered that HBV/B has become harder to transmit vertically in recent decades.

CONCLUSION

The recent decrease in vertical transmission of HBV/B associated with an older childbearing age in Japan might be one of the reasons for the finding that HBV/B patients were older than HBV/C patients.

Prevalence of HBV genotypes among patients attending Moi Teaching and Referral Hospital liver clinic

Hepatitis B virus (HBV) belongs to the genus Orthohepadnavirus, of Hepadnaviridae family, smallest human deoxyribonucleic acid (DNA) virus with 3200 bp in a partially double-stranded circular DNA. Globally, about 2 billion people are infected with over 65 million of the chronically infected residing in Africa. Ten HBV genotypes (A-J) have been reported across the globe. Based on the World Health Organization (WHO) African Regions including Kenya have high HBV prevalence rates yet the data on prevalence rates of the various HBV genotypes and their associated biomarkers is very scanty. A cross-sectional descriptive study with purposive sampling was conducted in which a census of patients with chronic Hepatitis B (CHB) with history >6-month were reviewed for eligibility. Demographics data was abstracted from patient files and blood samples drawn for genotyping, viral load using Rotor gene Q Polymerase Chain Reaction (PCR) equipment, Hepatitis B surface Antigen (HBsAg), Hepatitis B envelope antigen (HbeAg) and Hepatitis B core antibody (Anti-HBc) using Cobas e411 machine. Out of a total of 83 patients, 43 (52%) were eligible; males 29 (67.4%), females 14 (32.6%) with mean ages of 35.1±10.8 and 34.3±9.3 respectively. Genotypes A were 34(79.1%), B were 5(11.6%), C-D were 0 while E-J were 9(20.9%). All cases of genotype B were associated with co-infection of genotype A. Majority were HBeAg negative with HBV DNA >10 IU/ml (81.4% and 86.0% respectively) with distribution among all the genotypes. Across genotypes, viral load mean percentage comparisons were: A vs. A/B = 2600 (p = 0.09), A vs. E-J = 5260 (p = 0.09) and A/B vs. E-J = 200 (p = 0.28). The most prevalent genotype was A followed by mixed co-infection of genotype A/B. Genotype A was associated with HBV DNA viral loads > 10IU/ml and high rates of HBeAg negativity. Genotypes E-J were also detected though not characterized.

A Recent Prevalence of Hepatitis B Virus (HBV) Genotypes and Subtypes in Asia: A Systematic Review and Meta-Analysis

Background and Aim: Despite introducing the hepatitis B virus (HBV) vaccine, the incidence of the Hepatitis B virus globally is still a major health concern. This systematic review and meta-analysis were conducted to provide detailed information on the prevalence of HBV genotypes and subtypes in circulation in Asia. Methods: A systematic search for articles describing the prevalence of HBV genotypes and subtypes in Asia was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Results: Our search returned 207 eligible articles involving 49,279 genotypes and 7457 subtypes representing 28 Asian countries. A meta-analysis was performed on our eligible studies using the Random effect Model. The pooled prevalence of HBV genotypes showed that genotype C (30.9%) (95% CI, 27.5–34.5%; I2 = 97.57%; p < 0.001) was the most common HBV genotype in Asia, followed by genotype B (17.8%) (95% CI, 15.5–20.4%; I2 = 97.26%; p < 0.001) and genotype D (15.4%) (95% CI, 11.8–19.8%). Vietnam had the highest prevalence of genotype B, Lebanon had the highest prevalence of genotypes C, and Jordan had the highest prevalence of genotype D. There was variation in genotypic prevalence with respect to the target genes for HBV genotyping. Reverse dot blot hybridization had the highest estimate of genotypes B and C. HBV subtype C2 (40.0%) (95% CI, 33.3–47.0) is the most prevalent HBV subtype. Conclusion: Evidence from this study reveals that HBV genotypes C and B are the most dominant HBV genotypes in Asia, and HBV subtype C2 is more endemic in Asia.

Interpretation of HBV Serologies

Hepatitis B was discovered by researchers who were investigating jaundice associated with blood transfusions as well as parenterally administered medications. Through trial and error, the HBV was identified. There are specific tests that detect HBV infection, whether it is a previous exposure or active infection. The various HBV serologies are reviewed in this work as well. Hepatitis B surface antigen has emerged as a tool in defining treatment endpoint and its significance is reviewed. HBV genotypes are distributed uniquely throughout the world, in particular, genotype C is associated with higher rates of hepatocellular carcinoma. Various HBV genotypes and their impact on the clinical course are discussed. The relationship of HBV serologies and HBV DNA to disease progression is outlined. There are specific recommendations on monitoring those infected with HBV and this is reviewed here. HBV mutations have an impact on the disease course and those of significance are also discussed.

Association of interleukin-18 genotypes (-607C > A) and (-137 G > C) with the hepatitis B virus disease progression to hepatocellular carcinoma

Chronic infection with HBV has been reported to be associated with the development of HCC. The inflammation mounted by cytokine-mediated immune system plays an important role in the pathogenesis of HBV-associated HCC. IL-18 is a pro-inflammatory cytokine whose role in the development of HBV-associated chronic to malignant disease state has not been much studied. The present study was conceived to determine the role of genetic polymorphisms in IL-18, serum levels of IL-18, and expression level of its signal transducers in the HBV disease progression. A total of 403 subjects were enrolled for this study including 102 healthy subjects and 301 patients with HBV infection in different diseased categories. Polymorphism was determined using PCR-RFLP. Genotypic distributions between the groups were compared using odd's ratio and 95% CI were calculated to express the relative risk. Circulating IL-18 levels were determined by ELISA. Expression levels of pSTAT-1 and pNFƙB was determined by western blotting. In case of IL-18(- 607C > A), the heterozygous genotype (CA) was found to be a protective factor while in case of IL-18(- 137G > C) the heterozygous genotype (GC) acted as a risk factor for disease progression from HBV to HCC. Moreover, serum IL-18 levels were significantly increased during HBV disease progression to HCC as compared to controls. Also the levels of activated signal transducers (pSTAT-1 and pNF-κB) of IL-18 in stimulated PBMCs were significantly increased during HBV to HCC disease progression. These findings suggest that IL-18 has the potential to act as a biomarker of HBV-related disease progression to HCC.

The evolution and clinical impact of hepatitis B virus genome diversity

The global burden of hepatitis B virus (HBV) is enormous, with 257 million persons chronically infected, resulting in more than 880,000 deaths per year worldwide. HBV exists as nine different genotypes, which differ in disease progression, natural history and response to therapy. HBV is an ancient virus, with the latest reports greatly expanding the host range of the Hepadnaviridae (to include fish and reptiles) and casting new light on the origins and evolution of this viral family. Although there is an effective preventive vaccine, there is no cure for chronic hepatitis B, largely owing to the persistence of a viral minichromosome that is not targeted by current therapies. HBV persistence is also facilitated through aberrant host immune responses, possibly due to the diverse intra-host viral populations that can respond to host-mounted and therapeutic selection pressures. This Review summarizes current knowledge on the influence of HBV diversity on disease progression and treatment response and the potential effect on new HBV therapies in the pipeline. The mechanisms by which HBV diversity can occur both within the individual host and at a population level are also discussed.

Hepatitis B Virus Genotypes in the Kingdom of Bahrain: Prevalence, Gender Distribution and Impact on Hepatic Biomarkers

Background: Approximately 400 million people are infected with Hepatitis B virus (HBV) around the world, which makes it one of the world’s major infectious diseases. The prevalence of HBV genotypes and predictive factors for risk are poorly known in the Kingdom of Bahrain. Objectives: The aim of the present study was to investigate the prevalence of HBV genotypes, its correlation with demographic factor sand impacts on hepatic biomarkers. Materials and Methods: Venous blood samples were collected from 82 HBV positive patients (48 males, 34 females). The extraction of HBV DNA, PCR amplification, and genotyping were done to classify different genotypes (A, A/D, B, B/D, C, D, D/E, E). HBV genotypes association with gender, nationality, mode of transmission, and liver cirrhosis complication was determined by descriptive statistic and univariate analysis of variance (ANOVA). For liver function test, unpaired t-test and ANOVA were performed. Results: The predominant genotype among patients under study was genotype D (61%), followed by genotype A (10%), and lowest frequency was found for undetermined genotype (1%). In general, there was no significant association between the different genotypes and some demographical factors, serological investigations, and liver function test. The prevalence of HBV genotypes was higher in male patients as compared to female patients and higher in non-Bahraini than in Bahraini. Patients with the dominant genotype D showed higher than the normal maximum range for alanine aminotransferase (ALT) (mean = 45.89) and Gamma-glutamyl transferase (GGT) (mean = 63.36). Conclusions: The most common HBV genotype in Bahrain was genotype D, followed by genotype A. Further studies involving the sources of transmission and impact of hepatic biomarker in Bahrain are required to enhance the control measures of HBV infections.

Genotype characteristic and phylogenetic analysis of hepatitis B virus in northeast-Iran

Viral hepatitis is considered as a worldwide health problem and hepatitis B virus (HBV) infection is one of the major health concerns which are annually responsible for more than one million deaths. HBV can be classified into at least eight genotypes, A-H and four major subtypes. Predominant HBV genotype in Mediterranean and Middle East countries is genotype D, but there is a few studies have been performed on the HBV genotype in Iran. The genotype characteristic and phylogenetic analyses were determined in chronic HBV patients in the northeast of Iran. First, seventy-eight patients with chronic HBV infection were enrolled. Demographic features were reviewed and sera samples were collected. HBV genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, and results were confirmed by sequencing. Finally, a phylogenetic tree was obtained using Geneious software. Sixty-two (79.48%) of patients were males (mean age: 36.82 years). Twelve out of 78 patients (15.4%) were hepatitis B envelope antigen (HBeAg)-reactive. There were no significant differences between the clinical and HBeAg-positive serological data and HBeAb positive individuals. RFLP DNA sequencing and phylogenetic analysis showed that genotype D was the only genotype which observed in Mashhad, northeast of Iran. This is the first report of HBV genotyping in Mashhad. The results revealed that genotype D was the only genotype detected in this area which was consistence with previous studies in the Middle East, Mediterranean countries, southwest and center of Iran.

A genetic variant of the NTCP gene is associated with HBV infection status in a Chinese population

Background

To investigate whether genetic variants of the HBV receptor gene NTCP are associated with HBV infection in the Han Chinese population.

Methods

We sequenced the entire 23 kb NTCP gene from 111 HBeAg-positive HBsAg carriers (PSE group), 110 HBeAg-negative HBsAg carriers (PS group), and 110 control subjects. Then, we performed association analyses of suggestively significant SNPs with HBV infection in 1075 controls, 1936 PSs and 639 PSEs.

Results

In total, 109 rare variants (74 novel) and 38 single nucleotide polymorphisms (SNPs, one novel) were screened. Of the seven non-synonymous rare variants, six were singletons and one was a double hit. All three damaging rare singletons presented exclusively in the PSE group. Of the five SNPs validated in all 3650 subjects, the T allele of rs4646287 was significantly decreased (p = 0.002) in the PS group (10.1 %) and PSE group (8.1 %) compared to the controls (10.9 %) and was decreased to 7.4 % in the PSE hepatocellular carcinoma (HCC) subgroup. Additionally, rs4646287-T was associated with a 0.68-fold (95 % CI = 0.51–0.89, p = 0.006) decreased risk of PSE compared with the controls. The NTCP mRNA level was lower in HCC tissues in “CT + TT” carriers than in “CC” carriers.

Conclusions

We found a genetic variant (rs4646287) located in intron 1 of NTCP that may be associated with increased risk of HBV infection in Han Chinese.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2257-6) contains supplementary material, which is available to authorized users.

Male-specific hepatitis B virus large surface protein variant W4P potentiates tumorigenicity and induces gender disparity

BACKGROUND

The underlying mechanisms of carcinogenesis and gender disparity in hepatitis B virus (HBV)-induced hepatocellular carcinoma (HCC) remain unclear. Recently, we reported a novel HCC-related W4P/R mutation in the large surface protein (LHB) of HBV genotype C, which was found exclusively in male HCC patients.

METHODS

LHB sequences from a carrier (wild type; WT) and W4P variant LHB sequence from an HCC patient were cloned and used to generate NIH3T3 and Huh7 cell lines. Cell proliferation and in vitro tumorigenicity were assessed by cell growth and transformation assays. Male and female nude mice were injected with the cells to determine in vivo tumorigenicity. To confirm the effect of estrogen in W4P-mediated tumorigenicity, male mice were injected with estrogen and challenged with W4P-expressing cells. The serum levels of different cytokines from the mouse model and patients were analyzed by ELISA. A critical role of interleukin (IL)-6 signaling in W4P-mediated tumorigenicity was tested by inhibition of Jak2.

RESULTS

Although both WT and W4P variant LHBs enhanced cell proliferation by regulating the cell cycle and facilitated cell colony formation, the W4P variant demonstrated significantly higher activity. NIH3T3 cells expressing variant LHB, but not the WT, induced tumor in a nude mouse model. Tumor masses produced by variant LHB were significantly larger in male than female mice, and significantly reduced by estrogen. IL-6, but not tumor necrosis factor-α, was elevated in male mice harboring W4P-induced tumor, and was reduced by estrogen. IL-6 levels of HCC patients with the W4P variant were significantly higher than those of patients with WT LHB. W4P LHB induced higher production of IL-6 than WT LHB in cell lines, and the level was reduced by estrogen. The ability to reduce cell proliferation and colony formation of W4P LHB was hampered by inhibition of IL-6 signaling.

CONCLUSIONS

This study suggests that the W4P mutation during the natural course of chronic hepatitis B infection may contribute to HCC development, particularly in male patients, in an IL-6-dependent manner.

Mutations of Basal core promoter and precore regions in hepatitis B virus genotypes B and C

BACKGROUND

Mutations in basal core promoter (BCP) and precore regions of hepatitis B virus (HBV) are associated with course and treatment outcomes of chronic HBV infection. While BCP and precore mutation analysis have been carried out in adult patients between different genotypes, this analysis has rarely been performed for chronically infected children.

OBJECTIVES

The aim of this study was to assess the mutation profiles of BCP and precore regions in different HBV genotypes in chronically infected children.

PATIENTS AND METHODS

A cohort of 245 children and 92 adults with chronic HBV infection was included in this study. BCP and precore regions were analyzed by PCR amplification and sequenced.

RESULTS

Ten nucleotide positions, including nt1679, nt1721, nt1753, nt1757, nt1758, nt1762, nt1764, nt1775, nt1856 and nt1858 in BCP/precore regions of HBV genome, showed obviously higher frequencies of mutation in genotype C subjects than in genotype B subjects among children, while there were only three positions, including nt1679, nt1758 and nt1775 showing higher mutation frequencies in genotype C subjects than in genotype B subjects in adults. Several combined mutations were obviously highly distributed in children with chronic HBV genotype C infection, such as G1721A/A1775G/T1858C triple mutation; a novel combined mutation type, exclusively detected in children with chronic HBV genotype C infection. In addition, G1721A/A1775G/T1858C combined mutation was associated with higher viral load and lower age distribution.

CONCLUSIONS

The mutation ratio difference between genotypes B and C in children was higher than that of adults and several combined mutations were exclusively detected in children with chronic HBV genotype C infection associated with higher viral load.

A description of the hepatitis B virus genomic background in a high-prevalence area in China

Background

Hepatitis B (HB) is an important disease worldwide. Almost 350 million people are positive for Hepatitis B virus surface antigen (HBsAg), and one-third of them live in China. According to a nation-wide serosurvey in China in 2006, the prevalence of HBsAg was higher in Northwest China than in other areas. However, the epidemic HBV strains in this area are poorly studied.

Results

In this study, 242 complete hepatitis B virus (HBV) genome sequences were obtained from HBV asymptomatic carriers in major cities of Northwest China. The 242 HBV sequences clustered into genotypes B, C and D. Through comparison of the genotype consensus sequences, 158 genotype-dependent positions were observed in P, S and X ORFs. Clinically relevant mutation screening in this study revealed that no HBV antiviral drug resistance mutations were observed and the vaccination failure mutations were heavily underrepresented.

Conclusions

The role of genotype D strains in HBV prevalence should not be ignored in Northwest China. Due to low prevalence of vaccination failure mutations, it can be inferred that the genotype B, C and D strains in Northwest China may have less likelihood of vaccine escape.

A population-based study examining hepatitis B virus infection and immunization rates in Northwest China

Background and Aim

Current baseline data regarding the prevalence of hepatitis B virus (HBV) infections and the immune status in hyperendemic areas is necessary in evaluating the effectiveness of ongoing HBV prevention and control programs in northwest China. This study aims to determine the prevalence of chronic HBV infections, past exposure rates, and immune response profiles in Wuwei City, northwest China in 2010.

Methods

Cross-sectional household survey representative of the Wuwei City population. 28,579 participants were interviewed in the seroepidemiological survey ≥1 year of age. House to house screening was conducted using a standard questionnaire. All serum samples were screened by enzyme-linked immunoassays for the presence of hepatitis B surface antigen, antibodies against HBV surface antigen, and antibodies to the hepatitis B core antigen.

Results

Among individuals ≥1 year of age, 7.2% (95%CI: 6.3–8.1%) had chronic HBV infections, 43.9% (CI: 40.4–47.4%) had been exposed to HBV, and 23.49% (CI: 21.6–25.3%) had vaccine-induced immunity. Multi-factor weighted logistic regression analysis showed that having household contact with HBV carriers (OR = 2.6, 95%CI: 2.3–3.0) and beauty treatments in public places (OR = 1.2, 95%CI: 1.1–1.3) were the risk factors of HBV infection in whole population. Having household contact with HBV carriers (OR = 3.8, 95% CI: 2.2–6.5) and lack of hepatitis vaccination (OR = 2.0, 95% CI: 1.4–3.3) were the risk factors for HBV infection in children aged 1–14 years.

Conclusions

Hepatitis B infection remains a serious public health problem in northwest China. Having household contact with HBV carriers and beauty treatments in public places represented HBV infection risk factors. Hepatitis B vaccine immunization strategies need further improvement, particularly by targeting the immunization of rural migrant workers.

Tackling hepatitis B virus-associated hepatocellular carcinoma--the future is now

Hepatocellular carcinoma (HCC) is one of the most lethal and prevalent cancers in many developing countries including India. Among the various etiological factors being implicated in the cause of HCC, the most important cause, however, is hepatitis B virus (HBV) infection. Among all HBV genes, HBx is the most critical carcinogenic component, the molecular mechanisms of which have not been completely elucidated. Despite its clinical significance, there exists a very elemental understanding of the molecular, cellular, and environmental mechanisms that drive disease pathogenesis in HCC infected with HBV. Furthermore, there are only limited therapeutic options, the clinical benefits of which are insignificant. Therefore, the quest for novel and effective therapeutic regimen against HBV-related HCC is of paramount importance. This review attempts to epitomize the current state of knowledge of this most common and dreaded liver neoplasm, highlighting the putative treatment avenues and therapeutic research strategies that need to be implemented with immediate effect for tackling HBV-related HCC that has plagued the medical and scientific fraternity for decades. Additionally, this review proposes a novel "five-point" management algorithm for HBV-related HCC apart from portraying the unmet needs, principal challenges, and scientific perspectives that are relevant to controlling this accelerating global health crisis.

Evaluation of PCR-RFLP in the Pre-S Region as Molecular Method for Hepatitis B Virus Genotyping

BACKGROUND

Hepatitis B virus (HBV) infection is a public health problem in developing countries. HBV genotypes play major role in the evolution of infection since they were involved in different clinical presentations and response to treatment.

OBJECTIVES

This study was conducted to evaluate the efficiency of restriction fragment length polymorphism (RFLP) analysis for HBV genotyping.

PATIENTS AND METHODS

We investigated 98 samples collected from patients chronically infected with HBV. HBV genotypes were determined by analysis of patterns obtained after amplification in Pre-S region and digestion of the amplicon by two endonucleases AvaII and DpnII. Obtained results were confirmed by partial sequencing in the same region.

RESULTS

Two different HBV genotypes were detected in this study, Genotype D (in 95. 9%) and Genotype A (in 4.1%). Seventy-four samples (75.5%) were successfully genotyped with RFLP analysis and all classified as genotype D. The remaining 24 samples (24.5%) which were un-genotyped by RFLP analysis, were classified by partial sequencing of the pre-S region as HBV genotype D (20 samples, 20.4%) and genotype A (4 samples, 4.1%). Atypical profiles were significantly associated with advanced liver disease (P = 0.001) as well as older age (P < 0.05).

CONCLUSIONS

Several previous studies used PCR-RFLP to genotype HBV; however, we showed the high risk to obtain atypical profiles, especially in advanced stages of chronic infection, with as results difficulties to genotype the virus. These profiles resulted from the accumulation of mutations during natural course of infection resulting in a modification in restriction sites for enzymes. So, we recommended completing the investigation by partial sequencing to confirm obtained results.

Molecular epidemiology and population dynamics of hepatitis B virus in Dianjiang County, Chongqing, China

Hepatitis B virus infection is highly endemic in China, especially in rural areas such as Dianjiang County with poor-quality health care and little local HBV information. Therefore, for the first time, the present study was carried out to investigate the molecular epidemiology, phylogeny and population dynamics of HBV based on 146 HBV-infected patients. A 435-bp portion of the HBV S region was sequenced, and the phylogeny was reconstructed, indicating that three genotypes, B, C and D of HBV were distributed in Dianjiang County. The predominant genotype is B (67.12 %), followed by C (32.19 %) and D (0.68 %). Patient demographic information and clinical outcomes were examined by genotypes, and no significant association was found. Population dynamics analysis suggested that both genotype B and C have experienced a tenfold expansion during the last five years for reasons that are unclear. Thus, a thorough molecular epidemiology investigation is strongly recommended in the future.

One single nucleotide difference alters the differential expression of spliced RNAs between HBV genotypes A and D

Hepatitis B virus (HBV) is generally classified into eight genotypes (A to H) based on genomic sequence divergence. The sequence variation among the different HBV genotypes suggests that the spliced RNAs should be different from genotype to genotype. However, the cis-acting element involved in the modulation of the distinct expression profiles of spliced HBV RNAs remains unidentified. Moreover, the biological role of splicing in the life cycle of HBV is not yet understood. In this study, spliced RNAs generated from genotypes A and D were carefully characterized in transfected HepG2 cells. The species and frequency of the spliced RNAs were dramatically different in the two genotypes. Of note, a population of multiply spliced RNAs with intron 2067-2350 excision was identified in HBV genotype A-transfected HepG2 cells, but not in genotype D transfected HepG2 cells. Further, we found a single nucleotide difference (2335) located within the polypyrimidine tract of the splice acceptor site 2350 between the two genotypes, and a single base substitution at 2335 was able to convert the splicing pattern of genotype D (or genotype A) to that of genotype A (or genotype D). These findings suggest that different unique splice sites may be preferentially used in different HBV genotypes resulting in distinct populations of spliced RNAs. The possible significance of the distinct spliced RNAs generated from the different HBV genotypes in HBV infection is discussed.

Meta-analysis: The association of hepatitis B virus genotypes and hepatocellular carcinoma

BACKGROUND

A meta-analysis on the risk of hepatocellular carcinoma (HCC) among hepatitis B virus (HBV) genotypes is warranted as the current data are conflicting.

AIM

To investigate the relative risk of HCC among the four major HBV genotypes (A-D).

METHODS

A meta-analysis was performed based on literature search from electronic databases and bibliography between 1950 and 2012. All abstracts with keywords 'hepatitis B', 'hepatocellular carcinoma' and 'genotype' were screened. Studies were included if they reported HBV genotype as an exposure and HCC as an outcome.

RESULTS

Nine hundred and eighty-eight abstracts were found through literature search, among them 43 studies were eligible for this meta-analysis. A total of 14,545 patients with an average age of 43 years were included; 71% were male patients and 17% had cirrhosis. In 33 studies, HCC was found in 1541/6060 (25%) genotype C vs. 550/4417 (12%) genotype B HBV-infected patients [odds ratio (OR) = 2.05, 95% confidence interval (CI) = 1.52-2.76, P < 0.001]. No difference in the risk of HCC was found among genotype A (71/517, 14%) vs. genotype D (170/1506, 11%) HBV-infected patients in 14 studies (OR = 0.94, 95% CI = 0.67-1.32). In 10 studies, the risk of HCC was also found higher among genotype C (498/1659, 30%) than genotype A&D (103/1403, 7%) HBV-infected patients (OR = 2.34, 95% CI = 1.63-3.34, P < 0.001). Subgenotype Ce and Cs HBV-infected patients had similar risk on HCC (OR = 1.13, 95% CI = 0.76-1.67, P = 0.54). On funnel plot analysis, there was no significant publication bias in all comparisons.

CONCLUSION

Genotype C hepatitis B virus is associated with a higher risk of hepatocellular carcinoma than other major hepatitis B virus genotypes.

Chronic HBV infection among pregnant women and their infants in Shenyang, China

Background

The main transmission route of the hepatitis B virus (HBV) is mother to child transmission and contributes significantly to chronic HBV infection. Even though immunoprophylaxis with hepatitis B immunoglobulin (HBIG) and hepatitis B vaccine is administrated to neonates whose mothers are hepatitis B surface antigen (HBsAg) positive, about 10% of the neonates suffer from HBV infection in their early life.

Objectives

To survey chronic HBV infection among pregnant women and their infants and analyze the reason for immunoprophylaxis failure.

Methods

Serum HBsAg was tested in all pregnant women. HBVDNA and other serum HBV markers including hepatitis B e antigen (HBeAg), hepatitis B core antibody (anti-HBc) and hepatitis B surface antibody (anti-HBs) were tested among HBsAg positive pregnant women. All infants whose mothers were HBsAg positive were vaccinated with a standard immunoprophylaxis. Serum HBV markers and HBVDNA were tested among these infants at 7 months of age. HBV genotypes were analyzed among the infants and pregnant women who were HBVDNA positive.

Results

The prevalence of HBsAg, anti-HBc and anti-HBs among 4,536 pregnant women was 5.49%, 29.65% and 58.55%, respectively. The prevalence of HBsAg, anti-HBc and anti-HBs among pregnant women older than 20 years of age was significantly different compared to pregnant women younger than 20 years of age (4.54, 5.69 and 0.61 times, prevalence older vs. younger, respectively. P<0.05, 0.01, 0.05, respectively). Among 249 HBsAg positive pregnant women, 167 (67.07%) were HBeAg positive, 204 (81.93%) were HBVDNA positive and only 37 (14.86%) had HBVDNA >10⁷ IU/ml. Among the infants whose mothers were HBsAg positive, 214 (85.94%) infants were anti-HBs positive. There were 12 (4.82%) infants who were HBsAg and HBVDNA positive, and all 12 of these infants mothers were HBeAg positive and had HBVDNA >10⁷ IU/ml. Genotypes B and C were present among 165 pregnant women and genotype C was present in 85 pregnant women. There were 12 infants who were HBsAg positive and had the same HBV genotypes as their mothers. There was a significant difference in genotypes between the pregnant women whose infants were infected with HBV compared to those without HBV infection (P < 0.05).

Conclusions

There was a significant decline in HBsAg prevalence among pregnant women and their infants in Shenyang. Genotype C might be a risk factor for mother to child transmission of HBV.

Development of a novel genotype-specific loop-mediated isothermal amplification technique for Hepatitis B virus genotypes B and C genotyping and quantification

BACKGROUND

There is the need for a rapid, economical method for genotyping Hepatitis B virus (HBV) to support clinical practice.

OBJECTIVES

To develop a novel HBV genotyping process using genotype specific loop mediated isothermal amplification (LAMP).

STUDY DESIGN

HBV genotypes B and C specific LAMP methods were evaluated using standard panel. A comparative analysis of the LAMP test against Taqman assay using 105 clinical samples, was undertaken to evaluate the quantitation capacity of the method. 111 clinical samples were used to test the clinical applicability of the genotype specific LAMP method. The results were compared with those obtained by real-time PCR based genotyping and sequencing.

RESULTS

Using genotype-specific primers, the LAMP assay correctly identified all predefined genotypes B and C, and no cross-reaction was observed. Real-time format of this assay provides simultaneous identification and quantification of genotypes B and C. The detection sensitivity of the method was found to be 323 and 515 copies/ml for genotypes B and C specific LAMP assay respectively. High correlation (R(2)=0.91) and good agreement between the LAMP method and the real-time PCR test were achieved for HBV quantitation. Samples from 111 HBV-infected patients were genotyped with LAMP, revealing 53% HBV as genotype B, 36% as genotype C, and 12% as mixed genotypes B and C. LAMP method showed coincidence rates of 96.7% with the real-time PCR genotyping results.

CONCLUSION

This approach is a promising tool for HBV genotyping and quantitation. It appears to be useful for routine clinical practice even in field investigation.

Genotyping the hepatitis B virus with a fragment of the HBV DNA polymerase gene in Shenyang, China

The hepatitis B virus (HBV) has been classified into eight genotypes (A-H) based on intergenotypic divergence of at least 8% in the complete nucleotide sequence or more than 4% in the S gene. To facilitate the investigation of the relationship between the efficacy of drug treatment and the mutation with specific genotype of HBV, we have established a new genotyping strategy based on a fragment of the HBV DNA polymerase gene. Pairwise sequence and phylogenetic analyses were performed using CLUSTAL V (DNASTAR) on the eight (A-H) standard full-length nucleotide sequences of HBV DNA from GenBank (NCBI) and the corresponding semi-nested PCR products from the HBV DNA polymerase gene. The differences in the semi-nested PCR fragments of the polymerase genes among genotypes A through F were greater than 4%, which is consistent with the intergenotypic divergence of at least 4% in HBV DNA S gene sequences. Genotyping using the semi-nested PCR products of the DNA polymerase genes revealed that only genotypes B, C, and D were present in the 50 cases, from Shenyang, China, with a distribution of 11 cases (22%), 25 cases (50%), and 14 cases (28%) respectively. These results demonstrate that our new genotyping method utilizing a fragment of the HBV DNA polymerase gene is valid and can be employed as a general genotyping strategy in areas with prevalent HBV genotypes A through F. In Shenyang, China, genotypes C, B, and D were identified with this new genotyping method, and genotype C was demonstrated to be the dominant genotype.

Ethnogeographical structure of hepatitis B virus genotype distribution in Indonesia and discovery of a new subgenotype, B9

The distribution of hepatitis B virus (HBV) in the populations of island Southeast Asia is of medical and anthropological interest and is associated with an unusually high genetic diversity. This study examined the association of this HBV genetic diversity with the ethnogeography of the populations of the Indonesian archipelago. Whole genome analysis of 21 HBV isolates from East Nusa Tenggara and Papua revealed two recently reported HBV/B subgenotypes unique to the former, B7 (7 isolates) and B8 (5 isolates), and uncovered a further novel subgenotype designated B9 (4 isolates). Further isolates were collected from 419 individuals with defined ethnic backgrounds representing 40 populations. HBV/B was predominant in Austronesian-language-speaking populations, whereas HBV/C was the major genotype in Papua and Papua-influenced populations of Moluccas; HBV/B3 was the predominant subgenotype in the western half of the archipelago (speakers of the Western Malayo-Polynesian [WMP] branch of Austronesian languages), whereas B7, B8 and B9 were specific to Nusa Tenggara (Central Malayo-Polynesian (CMP)). The result provides the first direct evidence that the distribution of HBV genotypes/subgenotypes in the Indonesian archipelago is related to the ethnic origin of its populations and suggests that the HBV distribution is associated with the ancient migratory events in the peopling of the archipelago.

Recent advances in the research of hepatitis B virus-related hepatocellular carcinoma: epidemiologic and molecular biological aspects

Hepatocellular carcinoma (HCC) is one of the commonest cancers worldwide, and more than half of HCC patients are attributable to persistent hepatitis B virus (HBV) infections. The best and cheapest way to prevent HBV-related HCC is the implementation of universal hepatitis B vaccination program, by which the incidence rates of childhood HCC have been reduced in several countries, including Taiwan. However, there are still hundreds of millions of HBV carriers in the world that remain a global health challenge. In the past decade, several hepatitis B viral factors such as serum HBV DNA level, genotype, and naturally occurring mutants have already been identified to influence liver disease progression and HCC development in HBV carriers. Several easy-to-use scoring systems based on clinical and viral characteristics are developed to predict HCC risk in HBV carriers and may facilitate the communication between practicing physicians and patients in clinical practice. In addition, the role of nonviral factors in HBV-related HCC has also been increasingly recognized. On the basis of these emerging data, it is recommended that HBV carriers should be screened and monitored to identify those who have a higher risk of liver disease progression and require antiviral treatments. Regarding the molecular carcinogenesis of HCC development, despite some progress in the research of cell biology of HCC in the past decade, aberrant pathways involved in maintaining HCC phenotypes have not been completely elucidated yet. In the future, through comprehensive and integrated approaches to analyze the genomes of human HCC, novel target genes or pathways critically involved in hepatocarcinogenesis may hopefully be identified.

HBsAg seroclearance in chronic hepatitis B: implications for hepatocellular carcinoma

GOALS AND BACKGROUND

The long-term clinical course, including the development of hepatocellular carcinoma (HCC) after hepatic B surface antigen (HBsAg) seroclearance is not established. We discovered that the incidence of HCC and the risk factors for HCC in chronic hepatitis B (CHB) patients after HBsAg seroclearance.

STUDY

During 28 years, 96 CHB patients with HBsAg seroclearance were retrospectively reviewed. These patients continued to undergo HCC surveillance. The median follow-up time from initial visit was 166.5 months (range, 7 to 321 mo).

RESULTS

The mean age at the initial visit and at the time of seroclearance was 39.2 ± 10.6 years and 46.4 ± 9.9 years, respectively. The mean age at the time of HBsAg seroclearance was significantly lower (P=0.03) in patients with spontaneous HBsAg seroclearance than patients with treatment-associated HBsAg seroclearance. During a median of 56 months (range, 7 to 238 mo) of follow-up after HBsAg seroclearance, 6 (6.5%) patients developed HCC. The mean age at the time of developing HCC was 55.8 ± 10.3 years. On univariate analysis, the evidence of liver cirrhosis from the time of HBsAg seroclearance and age more than 45 years at the time of HBsAg seroclearance were significant risk factors for HCC development. In multivariate analysis, the evidence of liver cirrhosis at HBsAg seroclearance was the only significant risk factor for HCC development.

CONCLUSIONS

HCC can develop after HBsAg seroclearance in patients with known cirrhosis. Patients who achieved HBsAg seroclearance at older age (>45) may have undiagnosed cirrhosis and hence remain at risk for HCC. HCC surveillance should be carried out for both of those patient populations.

Change in serum hepatitis B surface antigen level and its clinical significance in treatment-naïve, hepatitis B e antigen-positive patients receiving entecavir

BACKGROUND/AIM

We investigated changes in hepatitis B surface antigen (HBsAg) level and its correlation with clinical outcomes in treatment-naive chronic hepatitis B (CHB) patients undergoing entecavir therapy.

PATIENTS AND METHODS

Among 51 hepatitis B e antigen (HBeAg)-positive treatment-naive CHB patients receiving entecavir for more than 1 year, 28 were enrolled. HBsAg levels were measured at baseline, 6 months, and 12 months after treatment using the Architect HBsAg QT assay (Abbott, dynamic; range: 0.05 to 125,000 IU/mL). Serum alanine aminotransferase, HBeAg, anti-HBe, and hepatitis B virus (HBV) DNA (Cobas Taqman: low detection limit 1.84 log10 copies/mL) were measured at baseline and every 3 months. The HBsAg response was defined as an HBsAg level that decreased more than 1 log10 IU/mL from baseline level at 12 months after entecavir treatment.

RESULTS

Twenty-eight patients were treated for a median period of 21 months (range: 18 to 24 mo). Serum HBsAg level showed a mean of 4.0, 3.7, and 3.6 log10 IU/mL at pretreatment, 6, and 12 months, respectively, and declined significantly (P<0.001). Serum HBV DNA level showed a mean of 8.1, 3.1, and 2.4 log10 copies/mL at pretreatment, 6, and 12 months, respectively, and declined significantly (P<0.001). The decline in HBsAg level was significantly correlated with that of the HBV DNA level at 12 months from baseline (γ=0.391, P=0.044). Five patients showed an HBsAg response, and cumulative incidence of HBeAg loss at 1 year after entecavir treatment was 80% versus 30% in patients with an HBsAg response and those without, respectively (P=0.034).

CONCLUSIONS

Monitoring changes in quantitative HBsAg level could be a useful parameter for assessing the response to entecavir therapy in HBeAg-positive treatment-naive CHB patients.

Hepatitis B virus genotypes and precore and core mutants in UAE patients

Background

Knowledge of the HBV genotype with which a patient is infected is crucial information for a physician to have when planning clinical treatment for that patient. Previous studies have suggested that there are possible differences in the pathogenicity and therapeutic response of different HBV genotypes. However, the prevalence of the various HBV genotypes and Precore and Core mutations is unknown in the UAE. Therefore, we sought to determine the prevalence of the different HBV genotypes in the UAE population.

Methodology/Principal Findings

A total of 88 HBsAg-positive patients were included in the study.

A method for genotyping and subtyping HBV by partial HBsAg gene sequencing using primers that are complementary to all known genotypes was used. Precore and core region of these viruses were also sequenced in 88 patients.

HBV genotype D was the most prevalent (79.5%) genotype identified in our study population, followed by genotypes A (18.2%) and C (2.3%). The following subtypes were isolated: ayw2 (80.7%), adw2 (14.8%), and adw (2.3%). The HBV-DNA viral load was higher in HBeAg-positive patients than it was in patients who were HBeAg-negative. Precore mutants were found in 51 (58.0%) of 88 patients. Mutations in the basal core promotor were found in 22 (25.3%) of 88 patients.

Conclusion/Significance

HBV infection is a major health problem in the UAE, and while genotypes B and C are the most prevalent HBV genotypes in the Asian population, our study reveals that genotype D is the predominant genotype that is present in the UAE. More patients were HBeAg-negative than were HBeAg-positive in our study sample, which could be due to the duration of infection of the included patients. Additionally, the viral loads of the HBeAg-positive patients were higher those of the HBeAg-negative patients. Analysis of nucleotide 1858 showed presence of thymine in all patients with genotypes C, and D and in a few patients with genotypes A. This nucleotide was closely related to the presence of precore mutants. Mutations in the basal core promoter were found in 22 of 88 (25.3%) samples. These mutations were more frequent in patients infected with genotype A (37.5%) and not found in patients infected with genotype C.

Detection of hepatitis B virus genotypes A to D by the fluorescence polarization assay based on asymmetric PCR

The hepatitis B virus genotypes A and D have global distributions, while the hepatitis B genotypes B and C are predominant in Asia. Individuals infected with genotype C or D have a lower response rate to therapy than individuals infected with genotype A or B. The conventional detections of hepatitis B genotypes A to D, however, have not been used routinely due to technical difficulties and high costs. A simple and cost-effective method for simultaneous detection of the hepatitis B genotypes A to D has been developed. A pair of general primers in the preS region of the hepatitis B were used in an asymmetric PCR. Four probes specific for the hepatitis B genotypes A to D labeled with different fluorophores hybridized, respectively with their target amplicons, and the hybridization increased the fluorescence polarization (FP) values. The genotypes were determined by the increased fluorescence polarization values. DNA extracted from 1398 samples was detected by the FP and the type-specific PCR assay in parallel. No significance difference was found between the two methods.

Management of chronic hepatitis B: experience from China

Chronic hepatitis B infection is a significant health problem throughout the world, and particularly in China. It is estimated that more than half a million Chinese people die annually from end-stage hepatitis B complications, which is associated with huge healthcare costs and a heavy socioeconomic burden. In China, the implementation of a hepatitis B vaccination programme has come into effect, and there has been a one-third decrease of the hepatitis B virus (HBV) carrier population since 1992. This great achievement changes China from a highly endemic area for HBV infection to an intermediate one. The predominant HBV genotypes in China are B and C, which might predispose patients to a poor antiviral response. Patients and physicians from China have been actively involved in the global research into and development of new antiviral agents. Patients have been recruited for global and domestic clinical trials on antiviral agents, including lamivudine, adefovir dipivoxil, entecavir, telbivudine and two pegylated interferon-alpha. In the future, more important data, focussing on optimization of the efficacy of antiviral agents, will be released from China, based on the newly launched National Eleven Five Plan Project on Hepatitis Research. Both economic development and healthcare system reform, including a new reimbursement policy, will make antiviral agents more accessible to Chinese patients. Ultimately, this will allow physicians greater opportunities to follow international and Chinese treatment recommendations.

Geographical and genetic diversity of the human hepatitis B virus

Hepatitis B virus (HBV) is one of the most widely distributed viruses that infect humankind. Distinct clinical and virological characteristics of the HBV-infection have been reported in different geographical parts of the world and are increasingly associated with genetic diversity of the infecting virus. HBV is classified into genotypes and subgenotypes that are associated with ethnicity and geography. The genetic diversity of HBV in its various aspects has been the subject of extensive investigations during the last few decades. Since molecular epidemiology research tools have become widely available, the number of new publications in this field has grown exponentially. This review summarises the recent publications on the geographical distribution of genetic variants of HBV, and proposes updated criteria for the identification of new genotypes and subgenotypes of the virus.

Cloning and sequence analysis of complete genome of hepatitis B virus isolates of genotypes B, C, D/C and A from Chinese patients with chronic hepatitis B

AIM: To clone and sequence the complete genome of hepatitis sequence of hepatitis B virus (HBV) isolates of genotypes B, C, D/C and A from the sera of Chinese patients with chronic hepatitis B (CHB).

METHODS: Long-distant polymerase chain reaction (L-PCR) technique was used to amplify the complete genome of HBV isolates from Chinese patients with CHB. After the resulting amplicons were cloned into the TA vector and sequenced, the complete sequences of HBV isolates of genotypes B, C, D/C and A were analyzed using the DNAStar and Simpot software.

RESULTS: The complete genome sequences of HBV isolates of genotypes B, C, D/C and A, which had been deposited into GenBank, were composed of 3215, 3215, 3215 and 3182 bp, respectively. A 33-bp deletion mutation at position 2853-2885 and two point mutations at positions 1762A-T and 1764G-A were observed in one of four clones of sample H3. The coexistence of wild-type and mutant HBV strains in a patient with chronic hepatitis B may provide a molecular basis for the development of drug resistance during antiviral therapy.

CONCLUSION: The complete genome sequences of HBV isolates of genotypes B, C, D/C and A are successfully cloned and can be used as reference sequences for the study of HBV in Chinese patients with chronic hepatitis B.

Hepatitis B virus: molecular genotypes and HBeAg serological status among HBV-infected patients in the southeast of Brazil

BACKGROUND

Knowledge of HBV genotype is very important for clinical treatment. Studies have suggested possible pathogenic and therapeutic differences among HBV genotypes. The aim of this study was to determine HBV subtypes and genotypes in HBV-infected patients in our region (southeast Brazil) and to correlate results with clinical and histopathological data.

METHODS

One hundred and thirty-nine HBsAg-positive patients were included in the study. All patients were anti-HCV and anti-HIV negative (64% male; mean age 42 +/- 14.5 years; range 7-80 years; 84% Caucasian) and were followed up at the University Hospital. A method for genotyping and subtyping HBV by partial HBsAg gene sequencing with primers common to all known genotypes was used. The viral load was measured by Amplicor Monitor assay (Roche).

RESULTS

HBV genotype A was the most prevalent (55%), while genotypes C, D and F were found in 3%, 38% and 4% of HBV-infected patients, respectively. Among the patients infected by genotype A, 18.3% (14/76) were African descendents and, among the patients infected by genotype D, 11.3% (6/53) were also African descendents. In the four patients infected with genotype C, 2 were Asian descendents and 2 were Caucasians. All (7) genotype F infected patients were Caucasians. Seventy percent of our HBsAg-positive patients were HBeAg negative (62% genotypes A; 26.2% D; 7.1% C and 4.7%F). The viral load of HBV-DNA was about 5 times higher in HBeAg-positive than in HBeAg-negative patients. About 40% of these patients had alanine aminotransferase of up to 1.5 times the normal level. The mean stage of fibrosis in genotype A patients (2.8) was significantly higher than the mean stage of fibrosis in genotype D patients (2.0) (P = 0.0179).

CONCLUSION

The genotypes encountered in our HBV-infected patients were apparently a consequence of the types of immigration that occurred in our region, where European and African descendents predominate. The HBeAg-negative status predominated, possibly due to the length of time of infection. The viral load in HBeAg-positive patients was higher than in HBeAg-negative individuals. The fibrosis grade in genotype A-infected patients was more advanced than genotype D-infected patients.

Durability of antiviral response in HBeAg-positive chronic hepatitis B patients who maintained virologic response for one year after lamivudine discontinuation

The purpose of this study is to determine the long-term relapse rate and associated risk factors in HBeAg-positive chronic hepatitis B (CHB) patients who had maintained virologic response (VR) for 1 year after lamivudine (LMV) discontinuation. We enrolled 55 treatment-naive HBeAg-positive CHB patients who achieved and maintained VR until 1 year after LMV discontinuation. Delayed relapse was defined as an elevation of HBV DNA after sustained VR for 1 year. During follow-up, 16 of 55 patients (29%) showed delayed relapse. Beginning 1 year after LMV discontinuation, the cumulative rates of relapse after 2 and 4 years were 29 and 44%, respectively. In multivariate analysis, age (P = 0.029) and >2,000 copies/ml HBV DNA 3 months after LMV discontinuation (P = 0.047) were significant predictors of delayed relapse. Delayed relapse is not infrequent, even in patients who maintain VR for 1 year after LMV discontinuation. Therefore, LMV maintenance therapy might be considered in HBeAg-positive CHB patients who achieve VR.

The loss of HBeAg without precore mutation results in lower HBV DNA levels and ALT levels in chronic hepatitis B virus infection

BACKGROUND

The aim of this study was to investigate the correlation between precore (PC)/basal core promoter (BCP) mutations and the viral loads or activity of hepatitis in patients with chronic hepatitis B virus (HBV) infection.

METHODS

HBV genotypes, PC mutations, BCP mutations, HBV DNA levels, and serological markers of HBV were analyzed in all the patients with chronic HBV infection seen in Fujita Health University Hospital from June 2004 to November 2008 (n=215).

RESULTS

HBV genotype was C in 169 patients, B in 16, A in 3, F in 1, and unclassifiable in 5. Among the patients with genotype C, the prevalence of PC wild type was significantly lower in hepatitis B envelope antigen (HBeAg)(-) patients than in HBeAg(+) patients (9.5% versus 49.0%, P<0.0001). Among HBeAg(-) patients, the patients with PC wild type had significantly lower serum viral loads and alanine aminotransferase (ALT) levels compared with those with PC mutant (P<0.001). Among HBeAg(-) patients, the patients with genotype B had lower serum viral loads compared with those with genotype C (3.6+/-0.9 versus 4.6+/-1.6, P<0.05), and the prevalence of BCP wild type was significantly higher in those with genotype B than in those with genotype C (58.3% versus 10.8%, P<0.05).

CONCLUSIONS

Among HBeAg(-) patients with genotype C, the patients with PC wild type had significantly lower viral loads and ALT levels than those with PC mutant. This suggests that the patients with PC wild type may have better prognosis than those with PC mutant among HBeAg(-) patients with genotype C.

Hepatitis B and hepatocellular carcinoma

Chronic infection with the hepatitis B virus has been linked epidemiologically to the development of hepatocellular carcinoma for more than 30 years. Although the mechanisms by which chronic hepatitis B viral infection results in hepatocellular carcinoma are unclear, there is good evidence that the virus itself exerts a direct hepatocarcinogenic effect, and this has implications for prevention. First, programs of universal infant vaccination have been shown to be effective in reducing the rate of hepatocellular carcinoma among children. This benefit should be translated into adulthood among vaccine recipients. Second, it has been suggested that antiviral therapy against hepatitis B may reduce the risk of hepatocellular carcinoma. Antiviral therapy against hepatitis B is effective in causing prolonged lowering of serum levels of hepatitis B virus DNA. There are emerging data showing that prolonged antiviral therapy may reduce the risk of hepatocellular carcinoma among certain patients with chronic hepatitis B.

Distribution of hepatitis B virus genotypes among patients with chronic infection in Japan shifting toward an increase of genotype A

Acute hepatitis B virus (HBV) infection has been increasing through promiscuous sexual contacts, and HBV genotype A (HBV/A) is frequent in patients with acute hepatitis B (AHB) in Japan. To compare the geographic distribution of HBV genotypes in patients with chronic hepatitis B (CHB) in Japan between 2005 and 2006 and between 2000 and 2001, with special attention to changes in the proportion of HBV/A, a cohort study was performed to survey changes in genotypes of CHB patients at 16 hospitals throughout Japan. Furthermore, we investigated the clinical characteristics of each genotype and examined the genomic characteristics of HBV/A isolates by molecular evolutionary analyses. Of the 1,271 patients, 3.5%, 14.1%, and 82.3% were infected with HBV/A, -B, and -C, respectively. In comparison with our previous survey during 2000 and 2001, HBV/A was twice as frequent (3.5% versus 1.7%; P = 0.02). The mean age was lower in the patients with HBV/A than in those with HBV/B or -C. Based on phylogenetic analyses of 11 full-length genomes and 29 pre-S2/S region sequences from patients, HBV/A isolates were imported from Europe and the United States, as well as the Philippines and India. They clustered with HBV/A from AHB patients and have spread throughout Japan. HBV/A has been increasing in CHB patients in Japan as a consequence of AHB spreading in the younger generation through promiscuous sexual contacts, aided by a tendency of HBV/A to induce chronic hepatitis. The spread of HBV/A infection in Japan should be prevented by universal vaccination programs.

Genotype D amongst injection drug users with acute hepatitis B virus infection in British Columbia

The eight genotypes of hepatitis B virus (HBV) exhibit distinct geographical distributions. This study identified HBV genotypes and transmission modes associated with acute infection in British Columbia (BC), Canada, from 2001 to 2005. Seventy cases of acute HBV in BC were identified from laboratory reports using a standardized case definition. Interviews for risk factors and hepatitis history were conducted for each case. HBV genotypes were determined by BLAST comparison analysis of the surface (S) or preS gene sequence. To illustrate the distribution of genotypes identified amongst acute cases in BC, an annotated map was produced showing the global occurrence of HBV genotypes. The majority of acute HBV cases occurred in Caucasian, Canadian-born males, with 30% of cases reporting injection drug use (IDU) and 21% reporting incarceration. The most common genotype observed was genotype D (62.9%), followed by genotypes A (18.6%), C (11.4%), B (4.3%), and E (1.4%). A significant association was observed between Genotype D and IDU (P = 0.0025) and previous incarceration (P = 0.0067). Phylogenetic analysis of the S gene sequence demonstrated identical or high genetic relatedness amongst genotype D viral strains (86% sub-genotype D3), thus verifying transmission clustering amongst BC injection drug users. The association between acute HBV genotype and reported transmission modes has not been previously described in North America. Tracking of genotypes can help identify disease transmission patterns and target at-risk populations for preventive immunization.

Inspection and analysis of hepatitis B virus genotypes among the korean nationality of Yanbian area in China

AIM: To investigate the distribution and clinical significance of hepatitis B virus (HBV) genotypes among the Korean Chinese of Yanbian area in China.

METHODS: A total of 215 Korean Chinese with HBV infection in Yanbian area included symptomatic carrier (SC, n = 36), acute hepatitis B (AHB, n = 5), chronic hepatitis B (CHB, n = 106), hepatitis-induced cirrhosis (HC, n = 50), and primary hepatic carcinoma (HCC, n = 18). Specific primer-polymerase chain reaction was used to detect the HBV genotypes in this cases.

RESULTS: Of the 215 cases, genotype B and C were found in 61 (28.0%) and 154 (72.0%) cases, respectively. The ratio of genotype C was markedly higher in CHB (79.0%), HC (84.0%), HCC (89.0%) than that in SC (25.0%) and AHB (60.0%), respectively (P < 0.05). In SC, the proportion of genotype B was significantly higher than that of genotype C (75.0% vs 25.0%, P < 0.01). The rate of genotype C was higher in the HBeAg-positive cases than that in the HbeAg-negative cases (73.0% vs 54.0%, P < 0.05), but the rate of genotype B was the other way around (46.0% vs 27.0%, P < 0.01).

CONCLUSION: Genotype C HBV infection is predominant in the Korean Chinese of Yanbian area in China, and genotype B is the second. Genotype C is mostly found in CHB, HC and HCC.

Construction and expression of eukaryotic plasmids containing lamivudine-resistant or wild-type strains of Hepatitis B Virus genotype C

AIM: To construct eukaryotic expression plasmids of full-length Hepatitis B Virus (HBV) genotype C genome, which contain lamivudine-resistant mutants (YIDD, YVDD) or wild-type strain (YMDD), and to observe the expression of HBV DNA and antigens [hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg)] of the recombinant plasmids in HepG2 cells.

METHODS: Three HBV full-length genomes were amplified from the plasmids pMD18T-HBV/YIDD, pMD18T-HBV/YVDD and pMD18T-HBV/YMDD, using PCR. Three recombinant plasmids were generated by inserting each of the PCR products into the eukaryotic expression vector pcDNA3.1 (+), between the EcoRI and HindIII sites. After being characterized by restriction endonuclease digestion, and DNA sequence analysis, the recombinant plasmids were transfected into HepG2 cells. At 48 and 72 h post-transfection, the levels of intracellular viral DNA replication were detected by real-time PCR, and the expression of HBsAg and HBeAg in the cell culture supernatant was determined by ELISA.

RESULTS: Restriction endonuclease digestion and DNA sequence analysis confirmed that the three recombinant plasmids were correctly constructed. After transfecting the plasmids into HepG2 cells, high levels of intracellular viral DNA replication were observed, and HBsAg and HBeAg were secreted into the cell culture supernatant.

CONCLUSION: Eukaryotic expression plasmids pcDNA3.1 (+)-HBV/YIDD, pcDNA3.1 (+)-HBV/YVDD or pcDNA3.1 (+)-HBV/YMDD, which contained HBV genotype C full-length genome, were successfully constructed. After transfection into HepG2 cells, the recombinant plasmids efficiently expressed HBV DNA, HBsAg and HBeAg. Our results provide an experimental basis for the further study of HBV lamivudine-resistant mutants.

Transforming growth factor beta 1 gene variants increase transcription and are associated with liver cirrhosis in Chinese

BACKGROUND AND AIMS

Transforming growth factor beta1 (TGFbeta1) acts as an important profibrogenic cytokine in liver fibrogenesis. The aim of this study was to explore the association between TGFbeta1 gene polymorphisms and liver cirrhosis.

METHODS

Totally 118 Chinese suffering from liver cirrhosis induced by HBV infection and 104 healthy controls were recruited. The polymorphisms at positions -988, -800, -509 and codon10, codon25, codon263 of the TGFbeta1 gene were genotyped by ARMS-PCR or LightCycler. Enzyme immunoassay was used for TGFbeta1 measurement. The promoter activities and DNA-binding capacities containing -509C>T were analyzed by reporter gene and EMSA.

RESULTS

The allele frequencies of CAT -509 and of T at codon10 were elevated in patients at severe Child-Pugh grade. Elevated concentrations of TGFbeta1 were observed in patients, especially in those with -509CC/CT and codon10 TT/TC. Flanking sequences containing -509C showed higher promoter activities than -509T. EMSA showed one nucleotide change at -509C>T influenced nuclear protein binding to the putative binding site.

CONCLUSIONS

The C allele at -509 and the T allele at codon10 could play important roles in progression of liver cirrhosis. The C allele at -509 mediates higher transcriptional activity than the T allele providing a potential explanation for the clinical findings.

Genotype determination in Moroccan hepatitis B chronic carriers

BACKGROUND

In Morocco, chronic liver disease related to hepatitis B virus (HBV) is a public health burden. Treatment of chronic hepatitis B is often complicated by the appearance of escape mutants after treatment with nucleoside analogs, especially with genotypes responsible for the more severe form of the disease.

OBJECTIVES

In the present study we investigate the prevalence of the different HBV genotypes in Morocco since no previous careful study has been attempted.

METHODS

Epidemiological data from 91 chronically infected patients (45 women and 46 men) were collected prospectively. Sera were tested for anti-HBc IgG, HBeAg, anti-HBe antibody and liver enzymes. Restriction Fragment Length Polymorphism (RFLP) analysis was confirmed by subsequent sequencing of the pre-S and S region of the viral genome in order to determine which HBV genotypes were prevalent among Moroccan patients.

RESULTS

The mean age was 41+/-12.4 years. Ten patients (11%) were positive for hepatitis B e antigen (HBeAg) and 81 (89%) were positive for anti-HBe antibodies. By the RLFP method, genotype D, pattern D2, was found in the 77 cases where HBV was successfully amplified. Phylogenetic analysis based on pre-S/S sequences revealed that genotype D in Morocco differed from others D strains subgenotypes (D1, D2, D3 and D4). In addition, the pre-core mutant defined as HBeAg-negative/anti-HBe-positive and HBV DNA positive was detected in 86% of cases.

CONCLUSIONS

Our results clearly show that genotype D and pre-core mutant are highly prevalent in Morocco.

Viral hepatocarcinogenesis: from infection to cancer

Hepatocellular carcinoma (HCC) is a worldwide health issue that has started receiving attention but is still poorly understood. However, the hepatitis B virus (HBV) and the hepatitis C virus (HCV) are known to be two major causative agents of HCC. They differ in their modes of infection, their treatment options, their genomes and their carcinogenic abilities. However, both share a link with HCC through alterations of the host genome. In order to continue in our search for the mechanisms behind viral hepatocarcinogenesis, the individual entities (HBV, HCV, HCC and host), their natural history, treatment options and genomic properties must be further understood. Additionally, an understanding of the genomics, the link between the entities, is crucial for the success of the ongoing search for therapeutic options for HCC. Similar to most types of cancer, hepatocarcinogenesis is a multistep process involving different genetic alterations that ultimately lead to malignant transformation of the hepatocyte. As technology advances and research continues, the genetic changes and influences among these entities will prove essential to improved diagnostic and therapeutic options. It remains a challenge to provide a clear picture of the connection between virus and cancer. We review (i) the epidemiological link between HBV/HCV infection to HCC; (ii) prevention and control of chronic hepatitis B or C in reducing HCC risk; and (iii) genetic characters of viruses and hosts and the mechanisms associated with HCC susceptibilities, with the intention of providing a direction for future research and treatment.

A population-based study to investigate host genetic factors associated with hepatitis B infection and pathogenesis in the Chinese population

BACKGROUND

Hepatitis B virus (HBV) infection is a significant public health problem that may lead to chronic liver disease, cirrhosis, and hepatocellular carcinoma (HCC). Approximately 30% of the world's population has been infected with HBV and approximately 350 million (5-6%) are persistent carriers. More than 120 million Chinese are infected with HBV. The role of host genetic factors and their interactions with environmental factors leading to chronic HBV infection and its complications are not well understood. We believe that a better understanding of these factors and interactions will lead to more effective diagnostic and therapeutic options.

METHODS/DESIGN

This is a population-based, case-control study protocol to enroll 2200 Han Chinese from medical centers in northern and western China. Adult subjects in the following groups are being enrolled: healthy donors (n = 200), HBV infected persons achieving virus clearance (n = 400), asymptomatic HBV persistent carriers (n = 400), chronic hepatitis B cases (n = 400), decompensated liver cirrhosis with HBV infection cases (n = 400), and hepatocellular carcinoma with HBV infection cases (n = 400). In addition, for haplotype inference and quality control of sample handling and genotyping results, children of 1000 cases will be asked to provide a buccal sample for DNA extraction. With the exception of adult patients presenting with liver cirrhosis or HCC, all other cases and controls will be 40 years or older at enrollment. A questionnaire is being administered to capture dietary and environmental risk factors. Both candidate-gene and genome-wide association approaches will be used to assess the role of single genetic factors and higher order interactions with other genetic or environmental factors in HBV diseases.

CONCLUSION

This study is designed and powered to detect single gene effects as well as gene-gene and environmental-gene interactions. The identification of allelic polymorphisms in genes involved in the pathway leading to chronic viral infection, liver cirrhosis and, ultimately, hepatocellular carcinoma would provide insights to those factors leading to HBV replication, liver inflammation, fibrosis, and the carcinogenic process. An understanding of the contribution of host genetic factors and their interactions may inform public health policy, improve diagnostics and clinical management, and provide targets for drug development.

Basal core promoter T1762/A1764 and precore A1896 gene mutations in hepatitis B surface antigen-positive hepatocellular carcinoma: a comparison with chronic carriers

BACKGROUND

Chronic hepatitis B virus (HBV) infection is associated with hepatocellular carcinoma (HCC), and specific viral factors have been identified that may increase the risk for HCC development. However, the differences in these viral factors in chronic carriers who seldom develop HCC compared with HCC patients have not been adequately evaluated.

METHODS

From 1989 to 2005, 101 hepatitis B surface antigen-positive patients presented to our clinic with HCC. Baseline basal core promoter (BCP) T1762/A1764 mutants, precore (PC) A1896 mutants, HBV genotypes and HBV DNA in HCC patients were compared with 67 chronic carriers who had been followed for a mean of 112.1+/-77.7 standard deviation months.

RESULTS

At baseline, HCC patients had lower levels of serum albumin, but higher values of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, bilirubin and alpha-foetoprotein than those of chronic carriers (P<0.001 for all comparisons). The presence of genotype C, higher frequencies of PC A1896 mutants, BCP T1762/A1764 mutants and higher circulating levels of HBV DNA were more frequently detected in HCC patients than that in chronic carriers (P<0.001 for all observations). Logistic regression analysis revealed that BCP T1762/A1764 mutants [odds ratio (OR) 11.14, 95% confidence interval (CI) 3.05-40.72; P<0.001] and PC A1896 mutants (OR 3.75, 95% CI 1.14-12.34; P<0.05) were significantly associated with HCC development.

CONCLUSION

Our results indicate that the presence of BCP and PC mutations significantly increases the risk for HCC in chronic hepatitis B patients. These mutations were less often detected in chronic carriers who seldom develop HCC.