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.

Update on epidemiology of hepatitis B and C in China

A high rate of chronic hepatitis B virus (HBV) infection in China is mainly caused by perinatal or early childhood transmission. Administration of universal HBV vaccination in infants has led to a dramatic decrease in HBV epidemiology, with hepatitis B surface antigen (HBsAg) prevalence declining from 9.75% in 1992 to 7.18% in 2006. The major HBV genotypes are B and C, with B being more prevalent in the southern part and C more prevalent in the northern part of China. A national survey carried out in 1992 showed that the hepatitis C virus (HCV) infection rate was 3.20% in general population in China. After implementation of mandatory HCV screening for blood transfusion and other precautions to prevent blood-borne disease since 1993, the new cases of HCV infection associated with blood or blood product has become very rare. Although the anti-HCV prevalence would be much higher in high-risk groups, a survey carried in 2006 showed that the anti-HCV prevalence rate was only 0.43% in general population. This sharp decline in HCV infection rate was mainly due to stringent administration and monitoring of blood donors and blood products, but may also be related to the remarkably improved specificity of anti-HCV test. The predominant HCV genotype in China is genotype 1b (60-70%), and the host interleukin-28b rs12979860 CC genotype is very frequent in Chinese population (over 80%).

HBsAg quantification to predict natural history and treatment outcome in chronic hepatitis B patients

There is a growing interest in serum HBsAg quantification (qHbsAg). HBsAg titers are negatively correlated with liver fibrosis in HBeAg(+) patients. In HBeAg(-) HBsAg level <1000 IU/ml and HBV-DNA titer <2000 IU/ml accurately identify inactive carriers. During PEG-IFN treatment qHBsAg identifies patients with no benefit from therapy at week 12, allowing stopping or switched- "week 12 stopping rule". During nucleos(t)ide analogues the role of qHBsAg need to be clarified. In clinical practice qHBsAg is a simple and reproducible tool that may be used in association with HBV-DNA to classify patients during the natural history of HBV and to monitor therapy.

Hepatitis B virus subgenotype C2- and B2-associated mutation patterns may be responsible for liver cirrhosis and hepatocellular carcinoma, respectively

The objective of this study was to examine hepatitis B virus (HBV) subgenotypes and mutations in enhancer II, basal core promoter, and precore regions of HBV in relation to risks of liver cirrhosis (LC) and hepatocellular carcinoma (HCC) in Southeast China. A case-control study was performed, including chronic hepatitis B (CHB; n=125), LC (n=120), and HCC (n=136). HBV was genotyped by multiplex polymerase chain reaction and subgenotyped by restriction fragment length polymorphism. HBV mutations were measured by DNA sequencing. HBV genotype C (68.2%) predominated and genotype B (30.2%) was the second most common. Of these, C2 (67.5%) was the most prevalent subgenotype, and B2 (30.2%) ranked second. Thirteen mutations with a frequency >5% were detected. Seven mutation patterns (C1653T, G1719T, G1730C, T1753C, A1762T, G1764A, and G1799C) were associated with C2, and four patterns (C1810T, A1846T, G1862T, and G1896A) were associated with B2. Six patterns (C1653T, G1730C, T1753C, A1762T, G1764A, and G1799C) were obviously associated with LC, and 10 patterns (C1653T, G1730C, T1753C, A1762T, G1764A, G1799C, C1810T, A1846T, G1862T, and G1896A) were significantly associated with HCC compared with CHB. Four patterns (C1810T, A1846T, G1862T, and G1896A) were significantly associated with HCC compared with LC. Multivariate regression analyses showed that HBV subgenotype C2 and C2-associated mutation patterns (C1653T, T1753C, A1762T, and G1764A) were independent risk factors for LC when CHB was the control, and that B2-associated mutation patterns (C1810T, A1846T, G1862T, and G1896A) were independent risk factors for HCC when LC was the control.

Hepatitis B virus (HBV)-specific T-cell responses to recombinant HBV core protein in patients with normal liver function and co-infected with chronic HBV and human immunodeficiency virus 1 (HIV-1)

Background

Little is known about HBV-specific T-cell responses in chronic Hepatitis B patients (HBV) that are co-infected with Human immunodeficiency virus type 1 (HIV-1), especially those with normal alanine aminotransferase (ALT) levels.

Methods

Twenty-five patients with chronic HBV (11 hepatitis B e antigen [HBeAg]-positive, 14 HBeAg-negative) were enrolled in a cross-sectional study. A longitudinal study as also conducted in which follow-up was done at 3, 12, and 24 months, after acute HIV-1 infection, in 11 individuals who also had chronic HBV. Peripheral blood mononuclear cells were stimulated with recombinant HBV surface protein (S protein), core protein (C protein) or gag peptide. IFN-γ-secreting T cells were identified by ELISPOT assay.

Results

In the cross-sectional study, co-infected chronic HBV patients had lower C protein-specific T-cell responses compared with mono-infected individuals, though the difference was not significant. In co-infected, chronic HBV patients, the magnitude of C protein-specific T-cell responses was significantly greater in HBeAg-positive subjects compared to HBeAg-negative subjects (p = 0.011). C protein-specific T-cell responses were positively correlated with HBV viral load (r_s = 0.40, p = 0.046). However, gag-specific T-cell responses were negatively correlated with HIV viral load (r_s = −0.44, p = 0.026) and positively correlated with CD4⁺ count (r_s = 0.46, p = 0.021). The results were different in mono-infected individuals. PBMCs from co-infected HBeAg-positive patients secreted more specific-IFN-γ in cultured supernatants compared with PBMCs from co-infected HBeAg-negative patients (p = 0.019). In the longitudinal study, S protein- and C protein-specific T-cell responses were decreased as the length of follow-up increased (p = 0.034, for S protein; p = 0.105, for C protein). Additionally, the S protein- and C protein-specific T-cell responses were significantly higher in HBeAg-positive patients than in HBeAg-negative patients at 3 and 12 months after HIV-1 infection (all p < 0.05), but not at 24 months. A positive correlation (trend) was found between C protein-specific T-cell responses and HBV viral load at 3 and 12 months after HIV-1 infection.

Conclusions

HBV-specific T-cell responses to recombinant HBV core protein were reduced in chronic HBV patients co-infected with HIV-1. The reduced C protein-specific T cell responses were positively correlated with HBV viral load in co-infected, chronic HBV patients.

A complete genomic analysis of hepatitis B virus isolated from 516 Chinese patients with different clinical manifestations

This study investigated features and clinical implications of HBV mutations in patients with different clinical manifestations. In total, 516 patients were enrolled in this study, including 131 patients with acute hepatitis B, 239 patients with chronic hepatitis B, and 146 patients with acute-on-chronic liver failure. HBV genotypes and mutations were analyzed by direct sequencing of complete viral genomes. Genotypes B2, C1, C2, and D1 accounted for 22.2%, 1.6%, 74.6%, and 1.6%, respectively. Genotype B was more frequently detected in patients with acute hepatitis B than those with chronic hepatitis B and acute-on-chronic liver failure. Deletion mutations were detected mostly in preS1 and preS2 regions and the detection rates were 3.8%, 19.7%, and 24.7% for acute hepatitis B, chronic hepatitis B and acute-on-chronic liver failure patients, respectively. Incidences of point mutation T53C (preS1F53L), G1613A (polR841K), G1775A and A1762T + G1764A in the basal core promoter region, G1896A and G1899A in precore region and A2189C (coreI97L) in core region increased along with acute hepatitis B, chronic hepatitis B, and acute-on-chronic liver failure. The mutation G1896A was independently associated with poor survival of patients with acute-on-chronic liver failure. The gradual increase of viral mutation incidences was also observed in three HLA-A2-restricted cytotoxic T lymphocyte epitopes from HLA-A2-positive patients, that is env188-196 (5.8%, 10.1%, 22.5%), core107-115 (4.3%, 4.6%, 19.7%), and x92-100 (1.4%, 20.2%, 33.8%). In conclusion, certain viral mutations in various regions of HBV genome are associated with disease progression of HBV infection.

Efficacy and safety of entecavir plus carnitine complex (GODEX®) compared to entecavir monotherapy in patient with ALT elevated chronic hepatitis B: randomized, multicenter open-label trials. The GOAL study

Background/Aims

Carnitine and vitamin complex (Godex®) is widely used in patients with chronic liver disease who show elevated liver enzyme in South Korea. The purpose of this study is to identify the efficacy and safety of carnitine from entecavir combination therapy in Alanine aminotransferase (ALT) elevated Chronic Hepatitis B (CHB) patients.

Methods

130 treatment-naïve patients with CHB were enrolled from 13 sites. The patients were randomly selected to the entecavir and the complex of entecavir and carnitine. The primary endpoint of the study is ALT normalization level after 12 months.

Results

Among the 130 patients, 119 patients completed the study treatment. The ALT normalization at 3 months was 58.9% for the monotherapy and 95.2% for the combination therapy (P<0.0001). ALT normalization rate at 12 months was 85.7% for the monotherapy and 100% for the combination group (P=0.0019). The rate of less than HBV DNA 300 copies/mL at 12 months was not statistically significant (P=0.5318) 75.9% for the monotherapy, 70.7% for the combination and it was. Quantification of HBsAg level was not different from the monotherapy to combination at 12 months. Changes of ELISPOT value to evaluate the INF-γ secretion by HBsAg showed the increasing trend of combination therapy compare to mono-treatment.

Conclusions

ALT normalization rate was higher in carnitine complex combination group than entecavir group in CHB. Combination group was faster than entecavir mono-treatment group on ALT normalization rate. HBV DNA normalization rate and the serum HBV-DNA level were not changed by carnitine complex treatment.

Resolving ambiguity in the phylogenetic relationship of genotypes A, B, and C of hepatitis B virus

Background

Hepatitis B virus (HBV) is an important infectious agent that causes widespread concern because billions of people are infected by at least 8 different HBV genotypes worldwide. However, reconstruction of the phylogenetic relationship between HBV genotypes is difficult. Specifically, the phylogenetic relationships among genotypes A, B, and C are not clear from previous studies because of the confounding effects of genotype recombination. In order to clarify the evolutionary relationships, a rigorous approach is required that can effectively explore genetic sequences with recombination.

Result

In the present study, phylogenetic relationship of the HBV genotypes was reconstructed using a consensus phylogeny of phylogenetic trees of HBV genome segments. Reliability of the reconstructed phylogeny was extensively evaluated in agreements of local phylogenies of genome segments.

The reconstructed phylogenetic tree revealed that HBV genotypes B and C had a closer phylogenetic relationship than genotypes A and B or A and C. Evaluations showed the consensus method was capable to reconstruct reliable phylogenetic relationship in the presence of recombinants.

Conclusion

The consensus method implemented in this study provides an alternative approach for reconstructing reliable phylogenetic relationships for viruses with possible genetic recombination. Our approach revealed the phylogenetic relationships of genotypes A, B, and C of HBV.

Distinct quasispecies characteristics and positive selection within precore/core gene in hepatitis B virus HBV associated acute-on-chronic liver failure

BACKGROUND AND AIM

The cause of hepatitis B virus associated acute-on-chronic liver failure (ACLF) remains unclear. Quasispecies can contribute to virus persistence and pathogenesis. We used a bioinformatics-based molecular evolution approach to compare quasispecies characteristics and positive selection sites within HBV precore/core gene between ACLF and chronic hepatitis B (CHB) patients.

METHODS

HBV precore/core gene were amplified from 11 ACLF and 10 CHB patients harboring HBV genotype B; following DNA cloning and sequencing quasispecies complexity, diversity, and positive selection sites within the precore/core gene were determined by bioinformatics analysis, and compared between the patient groups.

RESULTS

Both quasispecies complexity (P=0.022 at nucleotide level and 0.008 at amino acid level) and diversity (P<0.05) were found to be significantly greater in ACLF than in CHB. The frequency of G1896/A mutation in ACLF (175/298 clones, 58.7%) was also significantly higher than in CHB (100/230 clones, 43.5%) (P=0.0005). Moreover, analysis of positive selection revealed that significantly more patients with such sites were present in ACLF than in CHB (8/11 VS 2/10, P=0.03); the majority of these positive selection sites lay within HLA-restricted epitopes.

CONCLUSIONS

The ACLF patients showed distinct quasispecies characteristics with higher complexity and diversity within the HBV precore/core gene. The increased HBV quasispecies complexity and diversity, together with a distinct set of positive selection sites, is likely associated with the development of ACLF.

Accumulation of the mutations in basal core promoter of hepatitis B virus subgenotype C1 increase the risk of hepatocellular carcinoma in Southern China

Hepatitis B virus (HBV) genotype C is associated with the development of hepatocellular carcinoma (HCC). In addition, HBV subgenotype C1 is the major subgenotype in Southern China. The aim of this study was to investigate whether there was the specific mutation patterns in HBV/C1 associated with Southern Chinese patients with HCC.

METHODS

Mutations in HBV basal core promoter (BCP) and their association with HCC were assessed in a matched cross-sectional control study of 102 HCC and 105 chronic hepatitis (CH) patients (from Guangdong, China) infected with HBV/C1. Functional analysis of HBx mutants was performed by the colony formation assay and the luciferase assays.

RESULTS

T1762/A1764 double mutations was frequently found in patients infected with HBV/C1, regardless of clinical status (64.7% in HCC and 51.4% in CH, P>0.05). Unexpectedly, the adjacent V1753 or A1768 mutation significantly increased the risk of HCC (P<0.05). Moreover, the prevalence of triple or quadruple mutations in BCP was significantly higher in patients with HCC than those with CH, particularly for HBeAg-positive-carriers (P<0.05). Functional analysis revealed that T1762/A1764 mutation alone did not alter the transcriptional activity and the inhibitory effects on cell proliferation of HBx, but triple or quadruple mutations largely abrogated this effect.

CONCLUSIONS

Accumulation of mutations involving V1753 or/and A1768 in addition to T1762/A1764 in BCP region were closely related to HCC among the patients infected with HBV/C1, particularly for HBeAg-positive-carriers. The increased risk of HCC caused by BCP variants may be attributable partially to modifying the biological functions of HBx.

Quantitative hepatitis B surface antigen titres in Chinese chronic hepatitis B patients over 4 years of entecavir treatment

BACKGROUND

The clinical value of quantitative hepatitis B surface antigen (qHBsAg) titre in patients taking nucleotide/nucleoside analogues (NAs) is still controversial. This study aims to investigate the dynamic changes of qHBsAg titres and their significance for predicting virological response (VR) and serological response (SR) to long-term entecavir (ETV) treatment.

METHODS

A total of 48 ETV-naive patients were enrolled and followed prospectively for 4 years, 32 of whom were hepatitis B e antigen (HBeAg)-positive at baseline. Serum alanine aminotransferase (ALT), qualitative HBV serological markers and HBV DNA were detected; qHBsAg titres were measured using Elecsys(®) HBsAg II Quant Assay (Roche Diagnostics, Penzberg, Germany).

RESULTS

The mean baseline HBV DNA and qHBsAg were 7.51 log10 copies/ml and 3.78 log10 IU/ml, respectively. After 48 months of ETV treatment, the rates of VR (<291 copies/ml), ALT normalization and SR (HBeAg/antibody to HBeAg [anti-HBe]) were 89.6% (43/48), 89.6% (43/48) and 34.4% (11/32), respectively. There was a decrease in qHBsAg titres from baseline to month 48, ranging from 3.78 to 3.10 log10 IU/ml. The greatest decrease of qHBsAg was observed in the first 3 months of treatment (0.47 log10 IU/ml), which was significantly correlated with corresponding HBV DNA decreases (3.89 log10 copies/ml; P=0.032). By using receiver operating characteristic (ROC) curve analysis, qHBsAg titres at baseline (area under the curve [AUROC]=0.647) and 3 months after treatment (AUROC=0.586) had poor power in predicting 48-month VR; qHBsAg titres at baseline (AUROC=0.779) and 3 months after ETV treatment (AUROC=0.658) had poor power in predicting 48-month SR in patients who were HBeAg-positive at baseline. Additionally, the decrease of qHBsAg in the first 3 months of treatment also had poor power in predicting either 48 month VR or SR.

CONCLUSIONS

ETV is efficacious in NA-naive patients, and qHBsAg titres decreased significantly in the first 3 months of ETV treatment. However, qHBsAg titre was not a good predictor of 4-year VR and HBeAg/anti-HBe SR in this cohort.

Correlation between hepatitis B virus genotypes and clinical outcomes

Hepatitis B virus (HBV) has been classified into 10 genotypes (A-J) according to genome sequence divergence. HBV genotypes have a distinct geographical distribution. As chronic HBV infection is endemic in the Asian region, genotypes B and C prevail there, and genotypes A and D are mainly found in the western world and Europe. Genotypes A, B, C, and D have been studied most extensively. In Europe and Asia, most patients with genotypes A and B have acute hepatitis B; however, some mutants may tend to cause fulminant hepatitis B. Many studies have indicated that the severity and outcomes of chronic hepatitis B infections are more serious in patients with genotypes C and D than in those with genotypes A and B. Cirrhosis and hepatocellular carcinoma (HCC) are more frequently diagnosed in carriers of genotypes C and D than in those of genotypes A and B. Accumulating evidence indicated that higher plasma HBV DNA levels, infection with HBV genotype C, as well as mutations at 1653T, 1753V, and A1762T/G1764A are independently associated with the risk of HCC in Asian men. However, the therapeutic responses differ with regard to the different HBV genotypes. For example, the response to interferon-α treatment in patients with genotypes A and B was better than that in patients with genotypes C, D, and mixed genotypes. Some studies have shown seroconversion after treatment, i.e., genotypes A and C may switch to genotypes D and B, respectively. Some reports indicated a correlation between the emergence of the hepatitis B e antigen-negative variant in patients with genotypes C and D and worsening of liver injury without sustained response. In order to provide better treatment options for these poorly responding patients, further studies, e.g, novel immunomodulatory therapies, are required. Many studies have shown that HBV genotypes have remarkable clinical and epidemical differences; however, HBV sub-genotypes, mixed genotype infections, and the effect of different genotypes on the treatment of HBV infections require further studies.

Genotype D of hepatitis B virus and its subgenotypes: An update

AIM

The aim of the present study was to systematically and comparatively analyze the subgenotypes of genotype D of hepatitis B virus.

METHODS

In total, 304 complete genomes of all genotype D subgenotypes were downloaded from the public databases. The sequences were analyzed using nucleotide divergence calculations, phylogenetic analysis and bioinformatics to detect amino acids signature motifs for each subgenotype and to define their geographical distribution.

RESULTS

Intragroup divergence ranged from 0.8 ± 0.5 (%  standard deviation) for subgenotype D6 to 3.0 ± 0.3 for D8. Inter-subgenotype divergence mostly ranged 4-7.5%. Phylogenetic analysis of genotype D showed separation into six distinct clusters (subgenotypes D1, D2, D3/D6, D4, D5 and D7/D8) with good bootstrap support. The mean intergroup divergence between D3 and D6 was the lowest and fell below the threshold of 4%, which is required to define a subgenotype, suggesting that subgenotypes D3 and D6 belong to one subgenotype. "D8" is a genotype D/E recombinant, which clusters with D7. A number of signature amino acids were found in all four open reading frames that could differentiate the subgenotypes, which also showed distinct geographical distribution.

CONCLUSION

There are six and not eight subgenotypes of D, D1-D6, which can be differentiated by distinct clustering with high bootstrap support and signature amino acids. Subgenotypes D3 and "D6" should be reclassified as a single subgenotype D3 and it would be more correct to classify "D8" as a genotype D/E recombinant rather than a subgenotype.

New HBV subgenotype D9, a novel D/C recombinant, identified in patients with chronic HBeAg-negative infection in Eastern India

Genome diversity is a hallmark of hepatitis B virus (HBV), which allowed its classification into 10 genotypes (A-J) and numerous subgenotypes. Among them, Genotype D is currently segregated into eight subgenotypes (D1-D8). Here, we report the identification and characterization of a novel subgenotype within genotype D of HBV from chronic hepatitis B e antigen (HBeAg)-negative patients of Eastern India. Phylogenetic tree analysis based on complete genome sequences revealed that six of 39 HBV/D isolates formed a distinct cluster supported by high bootstrap value and had nucleotide divergence >4% relative to the known D subgenotypes (D1-D8), justifying their assignment into a new subgenotype (D9). By comparing the amino acid sequences of the four ORFs of HBV/D9 with D1-D8, 36 specific residues, including a unique one (E(112) in the core region), were identified that could be considered as a signature of D9. Further analysis by Simplot, BootScan and jpHMM demonstrated that D9 resulted from a discrete recombination with genotype C over the precore-core region. This type of recombination has not been described previously as all C/D recombinants reported so far possessed genotype C backbones with mosaic fragments derived from HBV/D. Interestingly, compared to other subgenotypes of HBV/D, D9 isolates had a higher frequency of mutations (A1762T and G1764A) in the basal core promoter region that had been implicated in the development of hepatocellular carcinoma. Further investigations are needed to determine the overall prevalence and clinical significance of these newly characterized D9 strains and to assess the impact of inter-genotypic recombination on viral properties.

Hepatitis B virus genetic variants: biological properties and clinical implications

Hepatitis B virus (HBV) causes a chronic infection in 350 million people worldwide and greatly increases the risk of liver cirrhosis and hepatocellular carcinoma. The majority of chronic HBV carriers live in Asia. HBV can be divided into eight genotypes with unique geographic distributions. Mutations accumulate during chronic infection or in response to external pressure. Because HBV is an RNA-DNA virus the emergence of drug resistance and vaccine escape mutants has become an important clinical and public health concern. Here, we provide an overview of the molecular biology of the HBV life cycle and an evaluation of the changing role of hepatitis B e antigen (HBeAg) at different stages of infection. The impact of viral genotypes and mutations/deletions in the precore, core promoter, preS, and S gene on the establishment of chronic infection, development of fulminant hepatitis and liver cancer is discussed. Because HBV is prone to mutations, the biological properties of drug-resistant and vaccine escape mutants are also explored.

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.

Correlation between viral load of HBV in chronic hepatitis B patients and precore and Basal core promoter mutations

BACKGROUND

More than two billion people have been exposed to hepatitis B virus (HBV) worldwide. Furthermore, four hundred million of them are infected with chronic HBV infection. The predominant mutation of the precore region involves a G to A change at nucleotide1896, which creates a premature stop codon at codon 28. Two mutations of A1762T and G1764A are reported as the most prevalent mutations in the basal core promoter (BCP).

OBJECTIVES

The purpose of this study was to investigate the relationship between mutations in precore (PC) and basal core promoter regions, and the viral load.

PATIENTS AND METHODS

Fifty serum samples from patients with hepatitis B were used. Levels of liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured at the same time of serological markers of hepatitis B by ELISA. HBV-DNA was extracted from the sera, and then PCR performed on the HBV-DNA extracted with the use of specific primer of gene C. HBV viral load was determined by real-time PCR. The PC/ BCP mutations were determined by applying Line Probe Assay technique. The data were analyzed using SPSS software, version 20.

RESULTS

Only 82% of the patients were HBeAb positive and 76% of the patients had basal core/ precore mutations and mean viral load was 3/7 × 106 ± 9/7 × 105 IU/ml. Prevalence of mutations in the precore and basal core promoter regions were 46% and 30%, respectively.

CONCLUSIONS

Our data indicated that there is a statistically significant relationship between HBV viral load and mutations in precore region (P < 0.05).

The role of HBsAg quantification for monitoring natural history and treatment outcome

Since its discovery by Blumberg in 1965, the hepatitis B virus antigen (HBsAg) is used as the fingerprint of hepatitis B infection. The HBsAg level is a reflection of the transcriptional activity of cccDNA. It is an important marker that not only indicates active hepatitis B infection but can also predict clinical and treatment outcomes. Assays for HBsAg quantification are fully automated and have high output. HBsAg titres are higher in HBe antigen (HBeAg)(+) than in HBeAg(-) patients and are negatively correlated with liver fibrosis in HBeAg(+) patients. In HBeAg(-) chronic hepatitis B, an HBsAg level <1000 IU/ml and an HBV DNA titre <2000 IU/ml accurately identify inactive carriers. During PEG-IFN treatment, HBsAg quantification is used to identify patients who will not benefit from therapy as early as week 12 on therapy, so that treatment may be stopped or switched- 'week 12 stopping rule'. With nucleos(t)ide analogues (NA), the role of HBsAg quantification must be clarified. Several studies show that baseline and on-treatment HBsAg levels might identify patients that can be treated with no subsequent risk of reactivation. In clinical practice, HBsAg quantification is a simple and reproducible tool that can be used in association with HBV DNA to classify patients during the natural history of HBV and to monitor therapy.

Hepatitis B e antigen-suppressing mutations enhance the replication efficiency of adefovir-resistant hepatitis B virus strains

Hepatitis B e antigen (HBeAg) negative hepatitis B virus (HBV) infections caused by precore (PC) or basal core promoter (BCP) mutations are associated with disease progression and complications. PC or BCP mutations may enhance the replication capacity of distinct drug-resistance-associated polymerase mutations, but their effect on adefovir-resistant HBV mutants is unclear. Importantly, BCP mutations were an independent risk factor for virological breakthrough in lamivudine-resistant patients treated with adefovir. We aimed at addressing the functional consequences of PC and BCP mutations on the replication and drug susceptibility of adefovir-resistant HBV mutants. Therefore, HBV constructs with wild type (WT) or adefovir-resistant rtN236T, rtA181V and rtA181T mutations, with or without concomitant PC or BCP mutations, were analysed in vitro using molecular assays. The adefovir-resistant polymerase mutations rtN236T, rtA181V and rtA181T showed a drastically reduced viral replication compared with WT. Interestingly, additional PC or BCP mutations enhanced the reduced replication efficacy of adefovir-resistant constructs and restored HBV replication to WT level. HBV rtA181T mutants displayed abolished hepatitis B surface antigen (HBsAg) secretion, owing to a sW172* stop codon in the overlapping envelope gene. All rtN236T- or rtA181V/T-containing constructs, regardless of concomitant PC or BCP mutations, were resistant to adefovir, but remained susceptible to telbivudine, entecavir and tenofovir. In conclusion, adefovir drug resistance mutations reduced viral replication, which can be significantly increased by additional HBeAg-suppressing PC or BCP mutations. Because increased HBV replication in HBeAg-negative patients has been associated with an unfavourable clinical course, close monitoring appears indispensable during adefovir treatment in HBeAg-negative patients.

Effects of hepatitis B virus mutations on its replication and liver disease severity

Hepatitis B virus (HBV), nowadays, is one of the major human pathogens worldwide. Approximately, 400 million people worldwide have chronic HBV infection. Only 5% of persons infected during adulthood develop chronic infection. The reverse is true for those infected at birth or in early childhood, i.e. more than 90% of these persons progress to chronic infection. Currently, eight different genotypes o f HBV have been identified, differing in nucleotide sequence by greater than 8%. In addition, numerous subgenotypes have a l s o been recognized based on the nucleotide sequence variability of 4- 8%. It has invariably been found that these genotypes and mutations play a pivotal role in the liver disease aggravation and virus replication. The precore mutations (G1896A) and the double mutation (T1762/A1764) in the basal core promoter are important mutations that alter expression of the hepatitis B e antigen (HBeAg). The HBeAg is important for establishing viral persistence. The precore G1896A mutation abrogates the expression of HBeAg. Numerous other mutations alter the disease severity and progression. It is predictive that the infected patient has high risk of hepatocellular carcinoma if the genotype C is incriminated or if HBV possesses basal core promoter double mutation. Association of the remaining genotypes have been noted but with less degree than genotype C. Phenotypic assays of the different HBV protein markers with different molecular techniques illustrate the replication efficiency of the virus in cell lines. This review will discuss various mutations into their association with liver disease severity and progression as well as virus replication.

Deep sequencing of the hepatitis B virus in hepatocellular carcinoma patients reveals enriched integration events, structural alterations and sequence variations

Chronic hepatitis B virus (HBV) infection is epidemiologically associated with hepatocellular carcinoma (HCC), but its role in HCC remains poorly understood due to technological limitations. In this study, we systematically characterize HBV in HCC patients. HBV sequences were enriched from 48 HCC patients using an oligo-bead-based strategy, pooled together and sequenced using the FLX-Genome-Sequencer. In the tumors, preferential integration of HBV into promoters of genes (P < 0.001) and significant enrichment of integration into chromosome 10 (P < 0.01) were observed. Integration into chromosome 10 was significantly associated with poorly differentiated tumors (P < 0.05). Notably, in the tumors, recurrent integration into the promoter of the human telomerase reverse transcriptase (TERT) gene was found to correlate with increased TERT expression. The preferred region within the HBV genome involved in integration and viral structural alteration is at the 3'-end of hepatitis B virus X protein (HBx), where viral replication/transcription initiates. Upon integration, the 3'-end of the HBx is often deleted. HBx-human chimeric transcripts, the most common type of chimeric transcripts, can be expressed as chimeric proteins. Sequence variation resulting in non-conservative amino acid substitutions are commonly observed in HBV genome. This study highlights HBV as highly mutable in HCC patients with preferential regions within the host and virus genome for HBV integration/structural alterations.

Elecsys hepatitis B surface antigen quantitative assay: performance evaluation and correlation with hepatitis B virus DNA during 96 weeks of follow-up in chronic hepatitis B patients

Background

Treatment for chronic hepatitis B aims to suppress virus replication and virus sequestration in hepatocytes. Covalently closed circular (ccc) DNA is the template for transcription of viral genes and is responsible for viral persistence. However, limited data are available for quantification of hepatitis B surface antigen (HBsAg) in Korea.

Methods

We evaluated the Elecsys HBsAg II quant assay (Roche Diagnostics, USA) for within-run, between-run, and between-day precisions, linearity, carryover, and clinical specificity. In total, 156 serum samples were evaluated for correlation between HBsAg and hepatitis B virus (HBV) DNA. Serial samples were obtained from 10 patients at 0, 12, 24, 48, 72, and 96 weeks during follow-up.

Results

The assay detected HBsAg in a linear range of 0.5-48,696 IU/mL. Within-run, between-run, and between-day CVs were 2.9-4.1%, 0-1.5%, and 1.5-4.9%, respectively. Cross-reactivity between potentially interfering substances was absent, and the carryover rate was 0.00002%. The correlation of measurements between the Elecsys assay and HBV DNA PCR was weak (r=0.438, P=0.002). For predicting virologic response, cutoff values of 10,275 IU/mL and 3,846 IU/mL at 12 and 24 weeks after treatment initiation showed positive predictive values of 77.1% and 85% and negative predictive values of 84.6% and 50%, respectively.

Conclusions

The Elecsys HBsAg II quant assay showed good performance for precision, linearity, carryover rate, and specificity. HBsAg level at baseline, 12 weeks, and 24 weeks after treatment initiation can predict virologic response, and the assay can be used for HBsAg quantification in clinical practice.

Subgenotyping of genotype C hepatitis B virus: correcting misclassifications and identifying a novel subgenotype

Background

More than ten subgenotypes of genotype C Hepatitis B virus (HBV) have been reported, including C1 to C16 and two C/D recombinant subgenotypes (CD1 and CD2), however, inconsistent designations of these subgenotypes still exist.

Methodology/Principal Findings

We performed a phylogenetic analysis of all full-length genotype C HBV genome sequences to correct the misclassifications of HBV subgenotypes and to study the influence of recombination on HBV subgenotyping. Our results showed that although inclusion of the recombinant sequences changed the topology of the phylogenetic tree, it did not affect the subgenotyping of the non-recombinant sequences, except subgenotype C2. In addition, most of the subgenotypes have been properly designated. However, several misclassifications of HBV subgenotypes have been identified and corrected. For example, C11 proposed by Utsumi and colleagues in 2011 was found to be grouped with C12 proposed by Mulyanto and colleagues. Two sequences, GQ358157 and GU721029, previously designated as C6 have been re-designated as C12 and C7, respectively. Moreover, a quasi-subgenotype C2 was proposed, which included the old C2, several previously unclassified sequences and previously designated C14. In particular, we identified a novel subgenotype, tentative C14, which was well supported by phylogenetic analysis and sequence divergence of >4%.

Conclusions/Significance

A number of misclassifications in the subgenotyping of genotype C HBV have been identified in this study. After correcting the misclassifications, we proposed a better classification for the subgenotyping of genotype C HBV, in which a novel quasi-subgenotype C2 and a novel subgenotype, tentative C14, were described. Based on this large-scale analysis, we propose that a novel subgenotype should only be reported after a complete comparison of all relevant sequences rather than a few representative sequences only.

Restored function of HBV-specific T cells after long-term effective therapy with nucleos(t)ide analogues

BACKGROUND & AIMS

In patients with chronic hepatitis B virus (HBV) infection, persistent exposure to high concentrations of antigen can disrupt T-cell functions. It is not clear to what extent long-term suppression of HBV by nucleos(t)ide analogues can restore antiviral T-cell functions. We compared HBV-specific T-cell responses of patients treated with nucleos(t)ide analogues with those detected in other conditions of HBV control.

METHODS

We analyzed intracellular levels of interferon gamma, interleukin-2, and tumor necrosis factor α in HBV-specific T cells after 10 days of stimulation with peptides covering the overall HBV genotype D sequence and ex vivo with selected CD8 epitopes and the corresponding HLA-A2 dextramers. Findings from patients treated with nucleos(t)ide analogues who had complete (HBV DNA negative/antibody to hepatitis B surface antigen positive) or partial (HBV DNA negative/hepatitis B surface antigen positive) control of their infections were compared with those of patients with spontaneous or interferon alfa-induced resolution of acute or chronic infections, inactive HBV carriers, or untreated hepatitis B e antigen-negative patients with chronic infections.

RESULTS

Although HBV-specific T cells from nucleos(t)ide analogue-treated patients with complete control of infection were dysfunctional ex vivo, they had efficient responses after in vitro expansion. These responses were comparable to those of patients who spontaneously resolved acute HBV infection. Nucleos(t)ide analogue-treated patients who were HBV DNA negative but hepatitis B surface antigen positive had lower levels of T-cell responses but responses greater than those of untreated patients with chronic infection.

CONCLUSIONS

In vitro reactivity can be restored to T cells from patients with suppressed HBV infection following long-term treatment with nucleos(t)ide analogues, despite prolonged exposure to large loads of antigen. Immune therapies that increase the antiviral T-cell response might increase the likelihood of complete HBV control in patients undergoing long-term nucleos(t)ide analogue treatment.

Genotyping and molecular characterization of hepatitis B virus from human immunodeficiency virus-infected individuals in southern Africa

Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) are hyperendemic in sub-Saharan Africa. The HBV genotypes prevailing in HIV-infected Africans are unknown. Our aim was to determine the HBV genotypes in HIV-infected participants and to identify clinically significant HBV mutations. From 71 HBV DNA^+ve HIV-infected participants, 49 basic core promoter/precore (BCP/PC) and 29 complete S regions were successfully sequenced. Following phylogenetic analysis of 29 specimens in the complete S region, 28 belonged to subgenotype A1 and one to D3. Mutations affecting HBeAg expression at the transcriptional (1762T1764A), translational (Kozak 1809–1812, initiation 1814–1816, G1896A with C1858T), or post translational levels (G1862T), were responsible for the high HBeAg-negativity observed. The G1862T mutation occurred only in subgenotype A1 isolates, which were found in one third (7/21) of HBsAg^−ve participants, but in none of the 18 HBsAg^+ve participants (p<0.05). Pre-S deletion mutants were detected in four HBsAg^+ve and one HBsAg^−ve participant/s. The following mutations occurred significantly more frequently in HBV isolated in this study than in strains of the same cluster of the phylogenetic tree: ps1F25L, ps1V88L/A; ps2Q10R, ps2 R48K/T, ps2A53V and sQ129R/H, sQ164A/V/G/D, sV168A and sS174N (p<0.05). ps1I48V/T occurred more frequently in females than males (p<0.05). Isolates with sV168A occurred more frequently in participants with viral loads >200 IU per ml (p<0.05) and only sS174N occurred more frequently in HBsAg^−ve than in HBsAg^+ve individuals (p<0.05). Prior to initiation of ART, ten percent, 3 of 29 isolates sequenced, had drug resistance mutations rtV173L, rtL180M+rtM204V and rtV214A, respectively. This study has provided important information on the molecular characteristics of HBV in HIV-infected southern Africans prior to ART initiation, which has important clinical relevance in the management of HBV/HIV co-infection in our unique setting.

Full genome characterization of hepatitis B virus strains from blood donors in Iran

Iran is a low to medium endemic country for hepatitis B virus (HBV), depending on the region, where genotype D is dominant. Samples from 170 asymptomatic HBsAg-positive blood donors were quantified and the median viral load was 6.7 × 10(2)  IU/ml with 10.6% samples unquantifiable. Fifty complete genome sequences of these strains were characterized. Phylogenetic analysis identified 98% strains as subgenotype D1 and 2% as D2. Deduced serotypes were ayw2 (94%), ayw1 (4%), and adw (2%). The nucleotide diversity of the complete genome subgenotype D1 Iranian strains was limited (2.8%) and comparison with D1 strains from Egypt and Tunisia revealed little variation between strains from these three countries (range 1.9-2.8%). The molecular analysis of the individual genes revealed that the G1896A mutation was present in 86.2% of the strains and in 26 strains (29.9%) this mutation was accompanied by the G1899A mutation. The double mutations A1762T/G1764A and G1764T/C1766G were found in 20.7% and 24.1% of the strains, respectively. The pre-C initiation codon was mutated in five strains (5.8%). One strain had a 2-amino acid (aa) insertion at position s111 and another sP120Q substitution suggesting a vaccine escape mutant.

T1846 and A/G1913 are associated with acute on chronic liver failure in patients infected with hepatitis B virus genotypes B and C

The aim of this study was to determine whether mutations in the hepatitis B virus (HBV) genome are associated with the onset of acute on chronic liver failure (ACLF). For the longitudinal study, full-length HBV genomes were cloned and sequenced from four ACLF patients and compared with sequences from matching samples collected before ACLF. For the cross-sectional study, 166 serum samples were obtained, including 49 samples from patients with ACLF. The results of longitudinal study showed that C53T, A1846T, and G1896A were the most common mutations in association with ACLF. In the cross-sectional study 61.2% patients with ACLF presented with T1846, which was higher than patients with chronic hepatitis B (CHB) (11.1%), liver cirrhosis (LC) (31.1%), and hepatocellular carcinoma (HCC) (33.3%). Prevalence of A/G1913 was 42.9% in patients with ACLF, also higher than patients with CHB (2.2%), LC (17.8%), and HCC (11.1%). There were no differences in HBV genotype and patients' HBeAg status among patients with ACLF, LC, and HCC. However, prevalence of T1846 was much higher in patients infected with genotype B (57.1%) than genotype C (30.4%). A/G1913 was higher in HBeAg negative patients (28%) than HBeAg positive patients (13.2%). Results of a multivariable analysis showed that T1846 and A/G1913 were independent factors for ACLF (OR = 3.373 and 4.244, respectively). Interestingly, T1846 destroys an ATG codon of a small open reading frame in the preC region, which may increase core protein expression. We conclude that T1846 and A/G1913 in the preC/C gene are closely associated with ACLF.

Hepatitis B virus basal core promoter mutations A1762T/G1764A are associated with genotype C and a low serum HBsAg level in chronically-infected HBeAg-positive Chinese patients

The present study was aimed to obtain baseline information of basal core promoter A1762T/G1764A and precore G1896A mutations of hepatitis B virus (HBV) in 192 HBeAg-positive chronically-infected Chinese patients, who were potential candidates for antiviral treatment. The detection of these mutations (including minor mutant subpopulations) was achieved by direct sequencing, whose sensitivity for minor mutant subpopulations identification was confirmed by clone sequencing. Patients enrolled were infected with either genotype B (46.35%) or C (53.65%) HBV identified by routine tests in our laboratory. The A1762T/G1764A or G1896A mutations were detected in 125specimens (125/192, 65.10%), in which 77 (77/125, 61.60%) existed as subpopulations. The A1762T/G1764A mutations were found to be more prevalent in genotype C than that in genotype B HBV [62.14% (64/103) vs. 20.22% (18/89), P<0.0001]. There is no statistically significant link between G1896A and genotypes. The emergence of A1762T/G1764A mutations was also found to be associated with an older age, an elevated ALT/AST level, and a lower HBsAg level in serum [wild-type vs. mutant: 4.57 (3.46-5.42) vs. 3.93 (2.51-5.36), P<0.0001]. In conclusion, HBV basal core promoter mutations A1762T/G1764A are associated with genotype C and a low serum HBsAg level in chronically-infected HBeAg-positive Chinese patients.

Subgenotype D5, BCP and MHR mutations in hepatic complications among hepatitis B virus infected patients from Orissa, India

The study was undertaken to investigate the clinical implications of hepatitis B virus (HBV) genotypes, basal core promoter (BCP), precore (PC) and surface gene mutations in HBV infected patients from Orissa, southeastern India. HBV infections were identified by serology testing and HBV DNA amplification by polymerase chain reaction among the 152 patients. After sequencing, surface gene mutation were studied by sequence analysis as well as by using BLOSUM scores and BCP mutations were studied only by sequence analysis. A high proportion of HBV/D5 (66.0%) was found among the study samples having significant relation with liver cirrhosis (LC) and hepatocellular carcinoma (HCC) patients (p<0.05). The BCP mutation, TA (81.4%) and C1753/TA (75.0%) was found in significant proportion (p<0.05) among HCC cases and in fact a gradual increase in these mutations were noted between inactive carriers (IC) to HCC group and also showed higher viral load. An increasing trend of major hydrophilic region (MHR) mutations in S gene was also observed from IC (56.0%) to chronic liver disease (CLD) (60.4%) to LC (72.4%) to HCC (95.0%) patients. In conclusion, our study suggests that the predominant HBV subgenotype HBV/D5 with high viral load and BCP mutations (double and triple) and high mutations in MHR region was significantly associated with advanced liver disease (LC and HCC) and might act as predictor of severe hepatic complications.

Hepatitis B virus gene mutations in liver diseases: a report from New Delhi

OBJECTIVES

The study was designed to characterize the surface, core promoter, precore/core region sequences for the presence of mutations in hepatitis B virus (HBV) associated with different liver diseases.

METHODS

567 HBV associated patients with different liver diseases were enrolled in this study. All samples were analyzed for HBV surface, core promoter, precore/core region mutations and genotypes using PCR and direct sequencing.

RESULTS

HBV genotype D (72.8%) was the predominant type followed by genotype A (27.2%). The serum viral load of HBV was highest in HBsAg carriers group and lowest in patients with hepatocellular carcinoma. 17.9% patients with cirrhosis and 24.6% hepatocellular carcinoma cases were ADV-resistant with rtA181T/V mutations in the S-gene. A1896T was found more frequently in fulminant hepatic failure compared to acute viral hepatitis patients (p = 0.038). T1753V mutation was significantly higher in patients with cirrhosis of liver (34.6%) than in chronic hepatitis (18.9%) and hepatocellular carcinoma patients (21.2%; p = 0.001). T1762/A1764 mutation was observed in all the groups. C1914G core gene mutation was associated with the hepatocellular carcinoma (32.2%) compared to other groups. HBV genotype D predominated in comparison to genotype A. An increased frequency of precore mutation and BCP double mutations amongst the population studied was also observed.

CONCLUSION

Mutations such as T1762/A1764, T1753V and C1914G were usually associated with advanced forms of liver disease and had an increased risk of HCC. The nucleotide variability in the basal core promoter and precore regions possibly plays a role in the progression of HBV disease. Prospective studies on the sequence variations of the preC/C region of the HBV genome and the molecular mechanisms in relation to progression of liver disease would aid in better understanding of the biological significance of HBV strains in India.

Novel evidence of HBV recombination in family cluster infections in western China

Two hepatitis B virus (HBV) C/D recombinants were isolated from western China. No direct evidence indicates that these new viruses arose as a result of recombination between genotype C and D or a result of convergence. In this study, we search for evidence of intra-individual recombination in the family cluster cases with co-circulation of genotype C, D and C/D recombinants. We studied 68 individuals from 15 families with HBV infections in 2006, identified individuals with mixed HBV genotype co-infections by restriction fragment length polymorphism and proceeded with cloning and DNA sequencing. Recombination signals were detected by RDP3 software and confirmed by split phylogenetic trees. Families with mixed HBV genotype co-infections were resampled in 2007. Three of 15 families had individuals with different HBV genotype co-infections in 2006. One individual (Y2) had a triple infection of HBV genotype C, D and C/D recombinant in 2006, but only genotype D in 2007. Further clonal analysis of this patient indicated that the C/D recombinant was not identical to previously isolated CD1 or CD2, but many novel recombinants with C2, D1 and CD1 were simultaneously found. All parental strains could recombine with each other to form new recombinant in this patient. This indicates that the detectable mixed infection and recombination have a limited time window. Also, as the recombinant nature of HBV precludes the possibility of a simple phylogenetic taxonomy, a new standard may be required for classifying HBV sequences.

Spatial and temporal dynamics of hepatitis B virus D genotype in Europe and the Mediterranean Basin

Hepatitis B virus genotype D can be found in many parts of the world and is the most prevalent strain in south-eastern Europe, the Mediterranean Basin, the Middle East, and the Indian sub-continent. The epidemiological history of the D genotype and its subgenotypes is still obscure because of the scarcity of appropriate studies. We retrieved from public databases a total of 312 gene P sequences of HBV genotype D isolated in various countries throughout the world, and reconstructed the spatio-temporal evolutionary dynamics of the HBV-D epidemic using a bayesian framework.The phylogeographical analysis showed that India had the highest posterior probability of being the location of the tree root, whereas central Asia was the most probable location of the common ancestor of subgenotypes D1-D3. HBV-D5 (identified in native Indian populations) diverged from the tree root earlier than D1-D3. The time of the most recent common ancestor (tMRCA) of the tree root was 128 years ago, which suggests that the common ancestor of the currently circulating subgenotypes existed in the second half of the XIX century. The mean tMRCA of subgenotypes D1-D3 was between the 1940s and the 1950-60s. On the basis of our phylogeographic reconstruction, it seems that HBV-D reached the Mediterranean area in the middle of the XX century by means of at least two routes: the first pathway (mainly due to the spread of subgenotype D1) crossing the Middle East and reaching north Africa and the eastern Mediterranean, and the second pathway (closely associated with D2) that crossed the former Soviet Union and reached eastern Europe and the Mediterranean through Albania. We hypothesise that the main route of dispersion of genotype D was the unsafe use of injections and drug addiction.

HBV/D1: a major HBV subgenotype circulating in Uyghur patients with chronic HBV infection in Xinjiang, China

Each hepatitis B virus (HBV) genotype and subgenotype is associated with a particular geographic distribution, ethnicity, and anthropological history. The present study investigated the genomic characteristics of HBV from Uyghur patients with chronic HBV infection in Xinjiang, China. Among the 53 Uyghur patients enrolled, HBV/D was found to be the dominant strain, with 64.2 % (34/53), 60.4 % (32/53) with HBV/D1 and 3.8 % (2/53) with HBV/D3. In addition to these findings, 3.8 % HBV/B (2/53), 5.7 % HBV/C (3/53), 11.3 % C+D (6/53), 7.5 % B+D (4/53), 3.8 % B+C (2/53) and 3.8 % B+C+D (2/53) were also detected. The full-length genome of seven HBV/D1 isolates and 144 reference sequences retrieved from GenBank were compared and analyzed by biological information methods. These results demonstrate that the D1 isolates from Xinjiang and Central Asia show a close genetic proximity (0.013±0.0007). Furthermore, four unique amino acid substitutions (sp82(Asn), sp89(His), rt129(Leu), rt151(Leu)) representing background polymorphisms rather than drug resistance mutations or immune escape variants were found in the Uyghur patients of Xinjiang, but these were seldom found in HBV/D1 strains from other regions (0 %-14.3 %). This study indicates that in Xinjiang, unlike HBV-infected Han patients, HBV/D1 is the predominant strain among HBV-infected Uyghur people. Although genetic distance analysis suggests that the HBV/D1 isolates from Xinjiang are closely related to those from Central Asia, unique amino acid substitutions suggest independent evolution of HBV in the Uyghur patients of Xinjiang.

Long-term monitoring drug resistance by ultra-deep pyrosequencing in a chronic hepatitis B virus (HBV)-infected patient exposed to several unsuccessful therapy schemes

The aim of this study was to analyze the spectrum and dynamics of low-prevalent HBV mutations in the reverse transcriptase (rt) and S antigen by ultra-deep pyrosequencing (UDPS). Samples were obtained from a chronically infected patient who was followed throughout a thirteen-year period. This technology enabled simultaneous analysis of 4084 clonally amplified fragments from the patient allowing detecting low prevalent (<1%) mutations during the follow-up. At baseline, HBV sequences were predominately wild-type. Under sequential HBV monotherapies including lamivudine, adefovir and entecavir, a high frequency of rtM204I mutation was detected initially as unique and then coexisting with rtM204V. Both mutations were statistically associated with rtA200V and rtV207I, respectively. Once the entecavir and tenofovir combined therapy was started, polymerase and consequently envelope gene mutations appeared at several positions at a higher frequency than before, including the entecavir resistance-associated mutation rtT184L.

[Quantification of hepatitis B virus HBsAg: clinical implications]

The surface antigen of hepatitis B virus (HBsAg) is the main serological marker of HBV infection since its discovery almost 50 years ago. Currently the quantification of HBsAg has acquired special relevance as there are commercial tests to measure its levels. Several studies have shown that in patients treated with pegylated interferon alfa the fall of HBsAg levels predicts the loss of HBsAg and persistent virologic response. The role of the quantification of HBsAg in the treatment with nucleoside analogues is still not well understood and requires further studies.

Establishment of rapid and specific real-time PCR assays for the detection of hepatitis B viral genotype in tibet

Hepatitis B virus (HBV) with a C/D recombinant genotype is dominant in Tibet. A rapid, simple and specific genotyping system, consisting of three real-time PCR assays, was developed for the determination of genotypes C and D as well as two forms of recombinant C/D. Overall, 95% of the 22 samples were genotyped accurately. This system is considered to be a useful method for large-scale genotype surveys in Tibet.

Identification of novel inter-genotypic recombinants of human hepatitis B viruses by large-scale phylogenetic analysis

Recombination plays an important role in the evolutionary history of Hepatitis B virus (HBV). We performed a phylogenetic analysis of 3403 full-length HBV genome sequences isolated from humans to define the genotype. The genome sequences were divided into 13 sub-datasets, each approximately 250 bp in length. Genotype designations obtained from the sub-datasets that differed from the genotype defined by the whole genome were assigned as putative recombinants. Our results showed that 3379 out of 3403 sequences belonged to the previously described and putative genotypes A to J respectively, with 315 sequences defined in this analysis. The remaining 24 viruses had sequence divergence of less than 8% with both genotypes B and C and were provisionally assigned genotype "BC". 1047 out of 3403 sequences were identified to be putative recombinants, of which 72 were identified to be novel recombinants. Notably, all viruses of the herein described genotype "BC" were identified to be B/C recombinants.

Pretreatment HBeAg level and an early decrease in HBeAg level predict virologic response to entecavir treatment for HBeAg-positive chronic hepatitis B

There are few reports on hepatitis B e antigen (HBeAg) titres during nucleos(t)ide analogues treatment. We investigated the changes in HBeAg levels in patients treated with entecavir and the usefulness of HBeAg quantification for predicting antiviral response. Ninety-five consecutive HBeAg-positive patients treated with entecavir for more than 48 weeks were enrolled. Serum levels of hepatitis B surface antigen (HBsAg), HBeAg and HBV DNA were assessed at 4-week intervals to week 24 and thereafter at 12-week intervals. Virologic response (Y1VR) was defined as an undetectable HBV DNA level at week 48 of therapy. During 48 weeks, HBeAg and HBV DNA level decreased significantly in a biphasic manner and HBsAg level tended to decease. Fifty-three patients (55.8%) attained Y1VR. Pretreatment HBeAg levels were significantly lower in the Y1VR group than in no Y1VR group. At week 4 and 12 of therapy, 25% and 41.4% of patients showed a decrease of HBeAg levels with >0.5 log(10) and >1.0 log(10) from baseline, respectively. These patients achieved more Y1VR than those with less decrease of HBeAg levels (97.7%vs 22.2% and 86.2%vs 29.3%, respectively). HBeAg level at week 12 had higher predictive values for Y1VR than HBV DNA level. Multivariate analysis revealed that a pretreatment HBeAg level of <360 PEIU/mL and the reduction in HBeAg level >1.0 log(10) at week 12 were associated with Y1VR. These results suggest that pretreatment HBeAg level and an early decrease in HBeAg level are useful measurements for predicting one-year virologic response during entecavir treatment.

Factors associated with serum hepatitis B surface antigen levels and its on-treatment changes in patients under lamivudine therapy

BACKGROUND

We aimed to investigate factors associated with serum hepatitis B surface antigen (HBsAg) levels and its kinetics under lamivudine treatment in chronic hepatitis B patients.

METHODS

HBsAg levels were measured with the Architect HBsAg assay (Abbott laboratories, Abbott Park, IL, USA) in genotype B (HBV/B) or C (HBV/C) patients (n=218). Early HBsAg kinetics in 86 hepatitis B e antigen (HBeAg)-positive patients and long-term HBsAg changes in 45 patients with rapid and sustained viral suppression were further analysed.

RESULTS

Mean HBsAg levels were higher in male (n=181) than in female (n=37) patients (3.59 versus 3.23 log(10) IU/ml; P=0.036), and higher in 121 HBV/B than in 97 HBV/C patients (3.68 versus 3.34 log(10) IU/ml; P=0.006). In addition to HBV DNA loads (P<0.001), male gender (P=0.012) and HBV/B infection (P=0.035) were independently associated with higher HBsAg levels in antiviral-naive patients. HBsAg increases (0.00-0.87 log(10)) were found in 28/86 patients who obtained viral suppression under 12 weeks of lamivudine therapy. Higher baseline HBsAg levels (P=0.046), HBV/B infection (P=0.007) and faster HBV DNA declines (P=0.006) independently contributed to greater HBsAg decreases under 12 weeks treatment. An apparent dissociation between HBsAg and HBV DNA changes were found in 14/45 patients with rapid and sustained viral suppression, who had low baseline HBsAg levels and predominant HBV/C infection.

CONCLUSIONS

HBV/B and male gender were associated with higher HBsAg levels in antiviral-naive patients. Higher baseline HBsAg levels and HBV/B infection contributed to greater early HBsAg declines in HBeAg-positive patients, and might correlate with discordance between HBsAg and HBeAg or HBV DNA under long-term lamivudine treatment.

The X protein of hepatitis B virus activates hepatoma cell proliferation through repressing melanoma inhibitory activity 2 gene

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer deaths globally. Chronic hepatitis B virus (HBV) infection accounts for over 75% of all HCC cases; however, the molecular pathogenesis of HCC is not well understood. In this study, we found that the expression of the newly identified gene melanoma inhibitory activity 2 (MIA2) was reduced by HBV infection in vitro and in vivo, and that HBV X protein (HBx) plays a major role in this regulation. Recent studies have revealed that MIA2 is a potential tumor suppressor, and that, in most HCCs, MIA2 expression is down-regulated or lost. We found that the knock-down of MIA2 in HepG2 cells activated cell growth and proliferation, suggesting that MIA2 inhibits HCC cell growth and proliferation. In addition, the over-expression of HBx alone induced cell proliferation, whereas MIA2 over-expression impaired the HBx-mediated induction of proliferation. Taken together, our results suggest that HBx activates hepatoma cell growth and proliferation through repression of the potential tumor suppressor MIA2.

The influence of HLA alleles and HBV subgenotyes on the outcomes of HBV infections in Northeast China

Hepatitis B virus (HBV) infection has a wide variety of clinical outcomes, it could be spontaneouly recovered and also could develop fulminant liver failure or cirrhosis with hepatocellular carcinoma. Human leukocyte antigen (HLA) polymorphism and HBV (sub)genotypes have been speculated to associate with the outcome of HBV infection because the data obtained from various populations who bear different HLA alleles have shown a HLA polymorphism associated outcome of HBV infection. However, as the most important viral and host genetic factors, the impact of HBV (sub)genotypes in combination with HLA polymorphism on the clinical outcomes of HBV infections remains unclear. To demonstrate the association of HLA allele polymorphism in combination with HBV subgenotypes with the outcome of HBV infection in Northeastern Han Chinese population, a total of 230 HBV-infected individuals (Infection group) were compared to 210 random selected controls (Control group) who are negative for HBV infection for their HLA alleles frequency as well as the associations with the virus infection, clearance and persistence in combination with HBV subgenotypes. Of the 230 HBV-infected subjects, 54 were acute self-limited hepatitis (ASH) with HBV subgenotype C2 (ASH-C2), 144 were chronic hepatitis (CH) with HBV subgenotype C2 and B2 (CH-C2 and CH-B2), and 32 were spontaneously recovered (SR) without subgenotype results. When two groups are compared, the results suggest that B*48, B*51 and DRB1*12 carrier may have a high risk for HBV infection, but B*51 is likely association with spontaneous recovery and DRB1*07, 12 may be implied in viral persistence. HLA-B*15, DRB1*11 and 14 associated with viral clearance in the cases of HBV-C2 infection; HLA-B*54 carriers in chronic group are more sensitive to with the infection of HBV subgenotype B2; HLA-B*07 and DRB1*13 may protect subjects from HBV infection. The data presented a link between HLA polymorphism and HBV pathogenesis and suggested potential therapeutic targets for hepatitis B.

Quantitative hepatitis B surface antigen levels in patients with chronic hepatitis B after 2 years of entecavir treatment

OBJECTIVES

The role of quantitative hepatitis B surface antigen (HBsAg) levels in patients receiving oral antiviral therapy is controversial. We aimed to determine the HBsAg response in chronic hepatitis B patients treated with entecavir 0.5 mg daily for 2 years.

METHODS

A total of 166 patients were included. Liver biochemistry, hepatitis B virus (HBV) serological markers, HBV DNA, and quantitative HBsAg levels were performed at baseline, year 1, and year 2 after commencing entecavir. Additional HBsAg levels were measured at 12 and 24 weeks in patients with available sera.

RESULTS

In all, 68 patients were hepatitis B e-antigen (HBeAg) positive. Age, HBV DNA, and alanine aminotransferase (ALT) were significantly correlated with HBsAg levels at baseline (r=-0.429, 0.607, and 0.254, respectively, all P<0.05). The correlation with HBV DNA and ALT levels was reduced by entecavir treatment, and was lost after 2 years of treatment. There was an overall decline in HBsAg levels from baseline to year 1 to year 2 (3,377.4 vs. 2,316.5 vs. 1,903.0 IU/ml, respectively, P<0.001). However, at year 2, 102 patients (61%) had no significant changes (<0.5 log difference), 50 (30%) had significant decline (≥0.5 log decrease), whereas 14 (9%) had significant increase (≥0.5 log increase). Of the patients, 151 (91%) had undetectable HBV DNA; 25 (37%) underwent HBeAg seroconversion. Neither HBsAg at baseline nor early decline at weeks 12 or 24 was predictive of HBeAg seroconversion at 2 years.

CONCLUSIONS

Despite HBV DNA suppression, the majority did not show significant decline in HBsAg levels. Early decline of HBsAg levels at 12/24 weeks was not associated with HBV DNA suppression or HBeAg seroconversion.

Enhanced replication of hepatitis B virus with frameshift in the precore region found in fulminant hepatitis patients

BACKGROUND

The genotype B of hepatitis B virus (HBV) was reported to associate with fulminant hepatitis (FH). We aimed to clarify the characteristics of HBV obtained from FH patients in an area of Japan where genotype B HBV is prevalent.

METHODS

Using serum samples of 16 HBV-associated FH patients, partial HBV sequences were determined. The effects of HBV mutation/insertion/deletion were evaluated using an in vitro HBV replication system.

RESULTS

Of the 16 HBV isolates, 31% belonged to subgenotype B1/Bj, 38% were subgenotype B2/Ba, and 31% were subgenotype C2/Ce. Notably, the single nucleotide insertion/deletion that resulted in a frameshift of the precore protein was found exclusively in 60% of B1/Bj strains. An in vitro study showed that all of the frameshift mutants had significantly higher amounts of HBV DNA than did the wild type. One of the isolates had a novel insertion of A between nucleotides 1900 and 1901, which resulted in a 3-nucleotide change within the Kozak sequence of the core protein and enhanced the core protein expression in vitro.

CONCLUSIONS

The frameshift insertion/deletion in the precore region enhanced HBV replication and might be associated with the development of FH by the subgenotype B1/Bj HBV.

Virologic and clinical characteristics of HBV genotypes/subgenotypes in 487 Chinese pediatric patients with CHB

Background

The association of hepatitis B virus (HBV) genotypes/subgenotypes with clinical characteristics is increasingly recognized. However, the virologic and clinical features of HBV genotypes/subgenotypes in pediatric patients remain largely unknown.

Methods

Four hundred and eighty-seven pediatric inpatients with CHB were investigated, including 217 nucleos(t)ide analog-experienced patients. HBV genotypes/subgenotypes and reverse transcriptase (RT) mutations were determined by direct sequencing. The stage of fibrosis and degree of inflammatory activity were evaluated by the Metavir score system.

Results

Among 487 enrolled pediatric patients, HBV genotype C2 and B2 were the most two prevalent (73.7% and 21.1%). Comparing with HBV/B2 infected patients, no significant difference was observed in the incidence rate and mutant patterns of lamivudine- or adefovir-resistant mutations in HBV/C2 infected patients (P > 0.05). Importantly, we found that the degree of hepatic inflammation degree, fibrosis stage and ALT level were significantly higher in HBV/C2-infected HBeAg positive patients than it was in HBV/B2-infected ones.

Conclusions

The pediatric patients with HBV/C2 infection might be more susceptible to develop severe liver pathogenesis.

Identification of four novel subgenotypes (C13-C16) and two inter-genotypic recombinants (C12/G and C13/B3) of hepatitis B virus in Papua province, Indonesia

Four novel subgenotypes (C6, C11, C12, and D6) of hepatitis B virus (HBV) were identified in Papua, a multiethnic province of Indonesia. To characterize the HBV strains in Papua, serum samples collected from 515 indigenous inhabitants (mean age: 26.6±9.6 years) in a previously unexamined area, Nabire, located in northern Papua, were used in the present study. Among 46 samples whose 1.6-kilobase (kb) HBV DNA sequence was amplified, 38 (83%) were typeable into known subgenotypes [B3 (n=4), C1 (n=2), C5, (n=1), C6 (n=5), C12 (n=13), and D6 (n=13)]. An analysis of the full-length sequence of the eight remaining HBV/C isolates whose sequence was either unclassifiable or uncertain within the 1.6-kb sequence showed no significant evidence of recombination in six isolates, and inter-genotypic recombination in two isolates (NAB20 and NAB46). By pairwise comparisons and a maximum-likelihood phylogenetic analysis, six non-recombinant isolates were considered significantly remote from known HBV/C isolates of subgenotypes C1-C12, and were classifiable into four novel subgenotypes (tentatively designated C13-C16). NAB20 and NAB46 were hybrids of C13/B3 and C12/G, respectively, displaying recombination breakpoints in the 5'-terminus of the P gene. Notably, the distribution of presumably indigenous subgenotypes C11-C16 was associated with particular language speakers in Papua.

Hepatitis B virus genotype B with G1896A and A1762T/G1764A mutations is associated with hepatitis B related acute-on-chronic liver failure

The existence of statistical associations between hepatitis B-related acute-on-chronic liver failure and both hepatitis B virus (HBV) genotype and mutations in the basal core promoter (BCP) and precore (PC) regions needs to be confirmed. A total of 322 patients with a chronic HBV infection, including 77 with hepatitis B-related acute-on-chronic liver failure, 109 with hepatocellular carcinoma (HCC) and 136 with chronic hepatitis B (CHB) were enrolled. The HBV genotype and the presence of mutations in the BCP/PC regions were determined by direct sequencing, and the frequencies were compared in the three patient groups. Overall, 198/322 (61.5%) were infected with genotype B and 124/322 (38.5%) with genotype C. Genotype B was significantly more frequent in patients with acute-on-chronic liver failure than CHB (92.2% vs. 60.3%, P < 0.001). As a contrast, genotype C was more common in patients with HCC than CHB (58.7% vs. 39.7%, P = 0.003). In genotype B patients, the A1762T/G1764A, A1846T, and G1896A mutations were significantly more prevalent in patients with acute-on-chronic liver failure than CHB (50.7% vs. 28.0%, P = 0.004; 59.2% vs. 34.1%, P = 0.002; 69.0% vs. 41.5%, P = 0.001, respectively). In multivariate analysis, the risk factors for acute-on-chronic liver failure were genotype B, A1762T/G1764A, and G1896A. In conclusion, CHB patients with genotype B, G1896A, and A1762T/G1764A had a higher tendency to develop liver failure than patients with genotype C. Therefore, HBV genotyping and detecting G1896A and A1762T/G1764A mutations might have important clinical implications as predictive risk factors for hepatitis B-related acute-on-chronic liver failure.

Clinical and virological characteristics of chronic hepatitis B with concurrent hepatitis B E antigen and antibody detection

The concurrent detection of hepatitis B e antigen (HBeAg) and its corresponding antibody (anti-HBe) in patients with chronic hepatitis B virus (HBV) infection is well established but the clinical features remain poorly understood. Demographic information, clinical and laboratory data were collected from 1624 consecutive inpatient records of patients with chronic hepatitis B. Viral genotype, basic core promoter and precore mutations were determined by direct sequencing. In vitro HBeAg and anti-HBe binding experiments were conducted with three pairs of HBeAg-positive and anti-HBe-positive serum samples, which were mixed at variable ratios and incubated at 37°C for 3-24h. Of the 1624 chronic patients, 169 (10.4%) had concurrent HBeAg and anti-HBe positivity, and this was associated with intermediate age and HBV-DNA load, higher alanine aminotransferase level and more pronounced liver damage compared with HBeAg-positive or anti-HBe-positive patients alone. HBeAg and anti-HBe titres (median and interquartile range, S/CO) in the concurrent positive group were 4.2 (1.8-9.6) and 0.54 (0.27-0.72), which were closer to their respective cut-off values than those of HBeAg-positive or anti-HBe-positive groups alone. For the cases successfully sequenced, 110/134 (82.1%) harboured T1762/A1764 or/and A1896 mutants. The binding experiments showed that HBeAg and anti-HBe could be concurrently observed provided an optimal ratio (HBeAg to anti-HBe) was chosen. In antiviral treatment-naive patients, concurrence of HBeAg and anti-HBe was not uncommon, and such patients had profound liver disease. An optimal ratio between HBeAg and anti-HBe led to their concurrent detection when sera were tested by sensitive assays.

Hepatitis B virus genotype C isolates with wild-type core promoter sequence replicate less efficiently than genotype B isolates but possess higher virion secretion capacity

Infection by hepatitis B virus (HBV) genotype C is associated with a prolonged viremic phase, delayed hepatitis B e antigen (HBeAg) seroconversion, and an increased incidence of liver cirrhosis and hepatocellular carcinoma compared with genotype B infection. Genotype C is also associated with the more frequent emergence of core promoter mutations, which increase genome replication and are independently associated with poor clinical outcomes. We amplified full-length HBV genomes from serum samples from Chinese and U. S. patients with chronic HBV infection and transfected circularized genome pools or dimeric constructs of individual clones into Huh7 cells. The two genotypes could be differentiated by Western blot analysis due to the reactivities of M and L proteins toward a monoclonal pre-S2 antibody and slightly different S-protein mobilities. Great variability in replication capacity was observed for both genotypes. The A1762T/G1764A core promoter mutations were prevalent in genotype C isolates and correlated with increased replication capacity, while the A1752G/T mutation frequently found in genotype B isolates correlated with a low replication capacity. Importantly, most genotype C isolates with wild-type core promoter sequence replicated less efficiently than the corresponding genotype B isolates due to less efficient transcription of the 3.5-kb RNA. However, genotype C isolates often displayed more efficient virion secretion. We propose that the low intracellular levels of viral DNA and core protein of wild-type genotype C delay immune clearance and trigger the subsequent emergence of A1762T/G1764A core promoter mutations to upregulate replication; efficient virion secretion compensates for the low replication capacity to ensure the establishment of persistent infection by genotype C.