Mutation preventing formation of hepatitis B e antigen in patients with chronic hepatitis B infection

Immunomodulatory Function of HBeAg Related to Short-Sighted Evolution, Transmissibility, and Clinical Manifestation of Hepatitis B Virus

Hepatitis B virus (HBV) infection, a global public health problem can be asymptomatic, acute or chronic and can lead to serious consequences of infection, including cirrhosis, and hepatocellular carcinoma. HBV, a partially double stranded DNA virus, belongs to the family Hepadnaviridae, and replicates via reverse transcription of an RNA intermediate. This reverse transcription is catalyzed by a virus-encoded polymerase that lacks proof reading ability, which leads to sequence heterogeneity. HBV is classified into nine genotypes and at least 35 subgenotypes, which may be characterized by distinct geographical distributions. This HBV diversification and distinct geographical distribution has been proposed to be the result of the co-expansion of HBV with modern humans, after their out-of-Africa migration. HBeAg is a non-particulate protein of HBV that has immunomodulatory properties as a tolerogen that allows the virus to establish HBV infection in vivo. During the natural course of infection, there is seroconversion from a HBeAg-positive phase to a HBeAg-negative, anti-HBe-positive phase. During this seroconversion, there is loss of tolerance to infection and immune escape-HBeAg-negative mutants can be selected in response to the host immune response. The different genotypes and, in some cases, subgenotypes develop different mutations that can affect HBeAg expression at the transcriptional, translational and post-translational levels. The ability to develop mutations, affecting HBeAg expression, can influence the length of the HBeAg-positive phase, which is important in determining both the mode of transmission and the clinical course of HBV infection. Thus, the different genotypes/subgenotypes have evolved in such a way that they exhibit different modes of transmission and clinical manifestation of infection. Loss of HBeAg may be a sign of short-sighted evolution because there is loss of tolerogenic ability of HBeAg and HBeAg-negative virions are less transmissible. Depending on their ability to lead to HBeAg seroconversion, the genotype/subgenotypes exhibit varying degrees of short-sighted evolution. The “arms race” between HBV and the immune response to HBeAg is multifaceted and its elucidation intricate, with transmissibility and persistence being important for the survival of the virus. We attempt to shed some light on this complex interplay between host and virus.

The Correlation Between Hepatitis B Virus Precore/Core Mutations and the Progression of Severe Liver Disease

Viral mutations acquired during the course of chronic hepatitis B virus (HBV) infection are known to be associated with the progression and severity of HBV-related liver disease. This study of HBV-infected Saudi Arabian patients aimed to identify amino acid substitutions within the precore/core (preC/C) region of HBV, and investigate their impact on disease progression toward hepatocellular carcinoma (HCC). Patients were categorized according to the severity of their disease, and were divided into the following groups: inactive HBV carriers, active HBV carriers, liver cirrhosis patients, and HCC patients. Two precore mutations, W28^* and G29D, and six core mutations, F24Y, E64D, E77Q, A80I/T/V, L116I, and E180A were significantly associated with the development of cirrhosis and HCC. Six of the seven significant core mutations that were identified in this study were located within immuno-active epitopes; E77Q, A80I/T/V, and L116I were located within B-cell epitopes, and F24Y, E64D, and V91S/T were located within T-cell epitopes. Multivariate risk analysis confirmed that the core mutations A80V and L116I were both independent predictors of HBV-associated liver disease progression. In conclusion, our data show that mutations within the preC/C region, particularly within the immuno-active epitopes, may contribute to the severity of liver disease in patients with chronic hepatitis. Furthermore, we have identified several distinct preC/C mutations within the study population that affect the clinical manifestation and progression of HBV-related disease. The specific identity of HBV mutations that are associated with severe disease varies between different ethnic populations, and so the specific preC/C mutations identified here will be useful for predicting clinical outcomes and identifying the HBV-infected patients within the Saudi population that are at high risk of developing HCC.

Clinical features of hepatitis B e-antigen positive chronic hepatitis B patients co-existing precore and/or basal core promoter mutations

Aim: Characterize the clinical features of treatment-naive hepatitis B e-antigen (HBeAg)-positive chronic hepatitis B (CHB) patients harboring either precore (PC) or basal core promoter (BCP; PC/BCP) mutations. Methods: Alanine aminotransferase, HBsAg, HBV-DNA, HBV genotypes, PC/BCP mutations and liver stiffness measurement were assessed for 186 treatment-naive HBeAg-positive CHB patients. Results: PC/BCP mutations were found in 40.31% of the treatment-naive HBeAg-positive CHB patients. Patients with PC/BCP mutations showed significantly higher alanine aminotransferase and liver stiffness measurement levels. The serum HBsAg and HBV DNA levels in patients with BCP mutations were significantly lower than those in patients with wild-type virus. PC/BCP mutations were more prevalent in patients in immune clearance phase than those in immune tolerance phase. Conclusion: The emergences of PC/BCP mutations possibly indicate that HBeAg positive patients are experiencing the phase of immune clearance.

Viral Biomarkers in Chronic HBeAg Negative HBV Infection

Viral biomarkers are important tools for monitoring chronic hepatitis B virus (HBV) hepatitis B early antigen (HBeAg) negative infection, both in its natural course as well as during and after treatment. The biomarkers consist of antibodies against viral epitopes, viral proteins, and molecular surrogate markers of the quantity and transcriptional activity of the stable episomal HBV covalently closed circular DNA (cccDNA) which is located in the nuclei of the infected hepatocytes. HBV deoxyribonucleic acid (DNA) or else viral load measurement in plasma or serum is a marker of HBV replication of major clinical importance. HBV DNA is used for staging and treatment monitoring as described in international scientific guidelines. Quantification of HBV antigens, mainly hepatitis B surface antigen (HBsAg) as well as Hepatitis B core related antigen (HBcrAg), play an important yet secondary role, especially in cases of low or undetectable HBV DNA and has been evaluated for the classification of the inactive carrier state, as a predictor of subsequent HBsAg clearance, treatment outcome, and development of hepatocellular carcinoma (HCC). The measurement of the replicative intermediate HBV RNA in serum is currently evaluated and may also prove to be a significant biomarker particularly in patients treated with nucleot(s)ide analogs. This review focuses on the viral biomarkers mentioned above and their role in HBV, HBeAg negative, infection.

Deep sequencing identifies hepatitis B virus core protein signatures in chronic hepatitis B patients

BACKGROUND

We aimed to identify HBc amino acid differences between subgroups of chronic hepatitis B (CHB) patients.

METHODS

Deep sequencing of HBc was performed in samples of 89 CHB patients (42 HBeAg positive, 47 HBeAg negative). Amino acid types were compared using Sequence Harmony to identify subgroup specific sites between HBeAg-positive and -negative patients, and between patients with combined response and non-response to peginterferon/adefovir combination therapy.

RESULTS

We identified 54 positions in HBc where the frequency of appearing amino acids was significantly different between HBeAg-positive and -negative patients. In HBeAg negative patients, 22 positions in HBc were identified which differed between patients with treatment response and those with non-response. The fraction non-consensus sequence on selected positions was significantly higher in HBeAg-negative patients, and was negatively correlated with HBV DNA and HBsAg levels.

CONCLUSIONS

Sequence Harmony identified a number of amino acid changes associated with HBeAg-status and response to peginterferon/adefovir combination therapy.

Clinical evaluation of hepatitis B core-related antigen in chronic hepatitis B and hepatocellular carcinoma patients

BACKGROUND

Hepatitis B core-related antigen (HBcrAg) has been revealed as an important marker of Hepatitis B virus (HBV) infection recently. We aimed to evaluate the HBcrAg assay for indication of HBV loads in chronic hepatitis B (CHB) and hepatocellular carcinoma (HCC) patients and assess the association between HBcrAg/cccDNA and HCC recurrence.

METHODS

HBcrAg was measured by chemiluminescence enzyme immunoassay. Intrahepatic covalently closed circular DNA (cccDNA) was measured by real-time PCR with TaqMan fluorescent probes based on liver specimens from 89 HCC patients.

RESULTS

HBcrAg correlated positively with HBV DNA irrespective of HBeAg status. Both HBcrAg and HBV DNA were associated with cccDNA in patients with elevated serum HBV DNA (>4 log IU/mL). In patients with non-elevated HBV DNA (≤4 log IU/mL), no relationship between HBV DNA and cccDNA was observed, but we still documented a modest correlation between HBcrAg and cccDNA. Finally, the recurrence-free survival rates were significantly lower in HCC patients with high intrahepatic cccDNA and serum HBcrAg levels than those with low cccDNA/HBcrAg levels (p = 0.035, p = 0.003 respectively).

CONCLUSIONS

HBcrAg not only can serve as a biomarker to assess HBV loads in patients as well as provide a good method for monitoring cccDNA in HCC, but also can be used as a good prognostic predictor for HCC patients.

HBV pre-core mutant in genotype-D infected children is selected during HBeAg/anti-HBe seroconversion and leads to HBeAg negative chronic hepatitis B in adulthood

Selection of HBeAg defective HBV mutants (mt) during childhood might influence infection outcome in adults. Aim of this study was to correlate the dynamics of pre-core HBV mutant (pre-C mt) selection with virological/clinical outcomes in children followed-up until adulthood. Eighty subjects (50-M/30-F), 70 HBeAg-positive (87.5%), and 10 (12.5%) HBeAg-negative/anti-HBe-positive at the admission, mostly genotype D infected (91.2%), with median age of 6.5 (range: 0.2-17) years, were followed-up for 14.3 years (range: 1.1-24.5); 46 (57.5%) received IFN treatment. HBV-DNA and q-HBsAg were tested by commercial assays, Pre-Core 1896 mt by direct-sequence, oligo-hybridization-assay, and allele-specific-PCR (sensitivity: 30%, 10%, and 0.1% of total viremia). HBeAg/anti-HBe seroconversion (SC) occurred in 55/70 (78.6%) children. After SC, 8 (14.6%) developed HBeAg-negative chronic hepatitis (CHB), 41 (74.5%) remain with HBeAg-negative chronic infection, and 6 (10.9%) lost HBsAg. Baseline HBV-DNA and HBsAg were lower in SC than in no-SC children (median: 7.35 vs 8.95 Log IU/mL, P = 0.005, and 4.72 vs 5.04 Log IU/mL, P = 0.015). The prevalence of pre-C mt increased rapidly (10-40%) around SC. Eventually, pre-C mt was detected in 100% of CHB, in 33% of chronic infections without disease, and in 16% of subjects who cleared HBsAg (P < 0.001). HBV-DNA levels remained slightly higher in carriers of HBeAg negative infection with dominant/mixed pre-C mt populations, than in those with dominant pre-C wt (mean Log IU/mL: 3.83 and 3.42 vs 2.67, P = 0.007). In conclusion, pre-C-mt is selected during HBeAg/anti-HBe SC in children with poor control of HBV replication, leading to HBeAg-negative chronic-active-hepatitis during adulthood.

Virological and Clinical Characteristics of Hepatitis B Virus Genotype A

Hepatitis B virus (HBV) infection is one of the most prevalent chronic viral infections in humans. The overall prevalence of hepatitis B surface antigen (HBsAg) is reported to be 3.6%; however, it varies depending upon the geographic area. HBV is classified into ten genotypes (A through J) on the basis of an intergroup genomic divergence of > 8%. Specifically, HBV genotype A exhibits several unique virological and clinical characteristics and can be further classified into seven subtypes. Among them, subtype A2 or Ae (A2/[e]) is occasionally responsible for nosocomial infection and among homosexual males. Regarding virological factors, the G1896A precore mutation is rarely observed in genotype A as it would disrupt an essential stem-loop structure in the ε signal essential for pregenomic RNA packaging. HBV genotype A also harbors a 6-nucleotide C-terminal insertion in the hepatitis B-e antigen (HBeAg) precursor, resulting in a variable-length HBeAg protein product observed in serum of positive patients. These molecular traits likely contribute to the specific clinical presentation of genotype A-infected patients, such as mild acute hepatitis B (AHB), longer persistence of HBsAg positivity in AHB, and increased chronicity after AHB in adults. However, genotype A shows a better response to interferon than other genotypes in chronic hepatitis B patients. Here, we review the virological and clinical characteristics of HBV genotype A that will be useful in elucidating the association among persistent viral infection, host genetic factors, and treatment in future studies.

Molecular Microbiology

Background

Nucleic acid (NA) amplification techniques are now commonly used to diagnose and manage patients with infectious diseases. The growth in the number of Food and Drug Administration–approved test kits and analyte-specific reagents has facilitated the use of this technology in clinical laboratories. Technological advances in NA amplification techniques, automation, NA sequencing, and multiplex analysis have reinvigorated the field and created new opportunities for growth. Simple, sample-in, answer-out molecular test systems are now widely available that can be deployed in a variety of laboratory and clinical settings. Molecular microbiology remains the leading area in molecular pathology in terms of both the numbers of tests performed and clinical relevance. NA-based tests have reduced the dependency of the clinical microbiology laboratory on more traditional antigen detection and culture methods and created new opportunities for the laboratory to impact patient care.

Content

This chapter reviews NA testing as it applies to specific pathogens or infectious disease syndromes, with a focus on those diseases for which NA testing is now considered the standard of care and highlights the unique challenges and opportunities that these tests present for clinical laboratories.

Hepatitis B virus e antigen-negative chronic infection. Treatment based on glutamic pyruvic transaminase and hepatitis B virus deoxyribonucleic acid cut-off values

OBJECTIVES

To identify glutamic pyruvic transaminase (GPT) and hepatitis B virus DNA (HBV-DNA) cut-off values at diagnosis in patients with hepatitis B virus e antigen-negative chronic infection (HBeAg(-)), which may be predictors of clinical course, prognosis and/or the need for antiviral therapy.

METHODS

A retrospective and observational cohort study of patients diagnosed with HBeAg(-) chronic infection (2005-2012). A normal GPT cut-off value at diagnosis that predicts abnormal GPT values in the clinical course of the infection, a baseline HBV-DNA cut-off value that predicts an increase in HBV-DNA above 2,000IU/ml, and GPT and HBV-DNA as predictors of the need for treatment were investigated using ROC curves.

RESULTS

126 patients were enrolled (follow-up: 42.1±21.5months), 93 of which had normal GPT levels at diagnosis. In the ROC curve analysis, 900IU/ml was found to be the HBV-DNA cut-off value that best predicted this value's increase above 2,000IU/ml (sensitivity: 90%; specificity: 88%; PPV: 79%; NPV: 100%; diagnostic precision: 89%), while 25mU/ml was the normal GPT cut-off value at diagnosis that best predicted subsequently elevated GPT levels (sensitivity: 95.4%; specificity: 81.6%; PPV: 67%; NPV: 96%; diagnostic precision: 80.6%). Patients with GPT 26-40mU/ml at diagnosis presented with more complications or required more treatment than subjects with GPT≤25mU/ml (P<.05). The combined GPT and HBV-DNA values that elicited the highest treatment need were 38mU/ml of GPT and 6,000IU/ml of HBV-DNA (sensitivity: 75%; specificity: 93.4%; PPV: 60%; NPV: 96.6%).

CONCLUSION

HBeAg(-) patients with GPT<25mU/ml and HBV-DNA<900IU/ml at diagnosis have positive outcomes and may not require such stringent follow-up in the first years after diagnosis.

Sanger sequencing versus INNO-LiPA® HBV PreCore assay for routine detection of precore and basal core promoter mutations in hepatitis virus B chronically infected patients

We compared the Sanger sequencing and the commercial INNO-LiPA® HBV assay for the routine detection of precore (PC) and basal core promoter (BCP) mutations of hepatitis B virus in chronically infected patients. The overall agreement rate between assays was 94.2% and 98.8% for the detection of PC and BCP mutations, respectively.

How viral genetic variants and genotypes influence disease and treatment outcome of chronic hepatitis B. Time for an individualised approach?

Chronic hepatitis B virus (HBV) infection remains a global problem. Several HBV genotypes exist with different biology and geographical prevalence. Whilst the future aim of HBV treatment remains viral eradication, current treatment strategies aim to suppress the virus and prevent the progression of liver disease. Current strategies also involve identification of patients for treatment, namely those at risk of progressive liver disease. Identification of HBV genotype, HBV mutants and other predictive factors allow for tailoured treatments, and risk-surveillance pathways, such as hepatocellular cancer screening. In the future, these factors may enable stratification not only of treatment decisions, but also of patients at risk of higher relapse rates when current therapies are discontinued. Newer technologies, such as next-generation sequencing, to assess drug-resistant or immune escape variants and quasi-species heterogeneity in patients, may allow for more information-based treatment decisions between the clinician and the patient. This article serves to discuss how HBV genotypes and genetic variants impact not only upon the disease course and outcomes, but also current treatment strategies. Adopting a personalised genotypic approach may play a role in future strategies to combat the disease. Herein, we discuss new technologies that may allow more informed decision-making for response guided therapy in the battle against HBV.

Prevalence and Characteristics of Precore Mutation in Iran and Its Correlation with Genotypes of Hepatitis B

Introduction

Mutation of the HBV precore gene prevents the production of HBeAg, which is an important target for immune responses. Distribution of this mutation varies along with frequency of HBV genotypes in accordance with geographic and ethnic variations. The general objective of this study was to evaluate the prevalence and characteristics of precore mutation in Iran and its correlation with genotypes of hepatitis B.

Methods

In this cross-sectional study, viral DNA of 182 Iranian hepatitis B surface antigen positive patients who were admitted to Bandar Abbas Blood Transfusion Organization in 2012 and 2013 was retrieved from their serum samples. HBeAg, anti-HBe, and anti-HBc IgM diagnostic tests were performed using ELISA kits. Precore and Pre-S regions were amplified using specific primers and PCR thereafter to determine the genotypes; precore mutation, PCR, and restriction fragment length polymorphism (RFLP) methods also were applied. SPSS version 12 was used for data analysis by Mann–Whitney U test, Fisher’s exact probability test, and t-test.

Results

A total of 62 patients (34.1%) had precore mutation (A1896G), and genotype D was the predominant genotype in these patients, which was followed by an unknown genotype that was suspected for genotype B. Interestingly, the relationships between precore mutation and HBeAg (p=0.037) and genotype D (p=0.005) were significant; however, no correlation was observed between this mutation and acute or chronic hepatitis and sex of patients.

Conclusion

This study found high prevalence of precore mutations in southern Iran, which was significantly associated with HBeAg and genotype D.

Novel non-canonical genetic rearrangements termed "complex structural variations" in HBV genome

BACKGROUNDS AND AIMS

Chronic hepatitis B virus (HBV) infection is an important worldwide public health issue. Further knowledge on the characteristics of HBV will facilitate its eradication. Genome structural variations (SVs) are defined by its canonical form such as duplication, deletion, and insertion. However, recent studies have reported complex SVs that cannot be explained by those canonical SVs. A HBV strain (UK2) with an unusual genome structure rearrangement that was completely different from known mutations or rearrangements was previously reported. Thus, this study was conducted to confirm the rearrangement in UK2 as a novel complex SV, and to find additional HBV strains with complex SVs. Further, the contribution of complex SVs in hepadnavirus variability was investigated.

METHODS

The genome rearrangement pattern in UK2 was analyzed. Further, a search of online databases retrieved additional HBV strains which were candidates to harbor complex SVs. The architecture of each rearrangement in the candidate strains was analyzed by bioinformatical tools. In addition, alignment of woolly monkey hepatitis virus (WMHV) and HBV from human and non-human primates was performed to investigate the contribution of complex SVs to variability of hepadnavirus.

RESULTS

The rearrangement in UK2 was confirmed as a complex SV. An additional 15 HBV strains were retrieved from databases, and confirmed as harboring complex SVs. Complex combinations of deletion, insertion, and duplication characterized the novel rearrangements. The complex SVs in six strains (37.5%) were composed of deletion, insertion, and duplication. The complex SVs in another six strains (37.5%) consisted of deletion and insertion, followed by insertions and duplication in three strains (18.8%), and deletion and duplication in one strain (6.3%). In addition, unique preS1 promoter insertions, which contained the hepatocyte nuclear factor 1 binding site, were observed in seven (43.8%) of 16 strains. Further, analysis of the genetic sequences of WMHV and HBV from human and non-human primates showed that complex combinations of deletions and insertions accounted for their genetic differences.

CONCLUSIONS

Non-canonical genetic rearrangements termed complex SVs were observed in HBV. Further, complex SVs accounted for the genetic differences of WMHV and HBV from human and non-human primates.

Hepatitis B virus sequencing and liver fibrosis evaluation in HIV/HBV co-infected Nigerians

OBJECTIVES

Molecular characteristics of hepatitis B virus (HBV), such as genotype and genomic mutations, may contribute to liver-related morbidity and mortality. The association of these characteristics with liver fibrosis severity in sub-Saharan Africa is uncertain. We aimed to characterise molecular HBV features in human immunodeficiency virus (HIV)/HBV co-infected Nigerians and evaluate associations between these characteristics and liver fibrosis severity before and after antiretroviral therapy (ART) initiation.

METHODS

HIV/HBV co-infected Nigerians underwent liver fibrosis estimation by transient elastography (TE) prior to and 36 months after ART initiation. Basal core promoter/precore (BCP/PC) and preS1/preS2/S regions of HBV were sequenced from baseline plasma samples. We evaluated associations between HBV mutations and liver fibrosis severity by univariate and multivariable regression.

RESULTS

At baseline, 94 patients underwent TE with median liver stiffness of 6.4 (IQR 4.7-8.7) kPa. Patients were predominantly infected with HBV genotype E (45/46) and HBe-antigen negative (75/94, 79.8%). We identified BCP A1762T/G1764A in 15/35 (43%), PC G1896A in 20/35 (57%), 'a' determinant mutations in 12/45 (26.7%) and preS2 deletions in 6/16 (37.5%). PreS2 mutations were associated with advanced fibrosis in multivariable analysis. At follow-up, median liver stiffness was 5.2 (IQR 4.1-6.6) kPa. No HBV molecular characteristics were associated with lack of fibrosis regression, although HIV virologic control, body mass index (BMI) and baseline CD4+ T-cell count were associated with a decline in fibrosis stage.

CONCLUSION

Frequent BCP/PC and preS1/preS2/S mutations were found in ART-naïve HIV/HBV co-infected Nigerians. Median liver stiffness declined after initiation of ART, regardless of pre-ART HBV mutational pattern or virologic characteristics.

Hepatitis B Virus e Antigen Activates the Suppressor of Cytokine Signaling 2 to Repress Interferon Action

Hepatitis B virus (HBV) infection causes acute hepatitis B (AHB), chronic hepatitis B (CHB), liver cirrhosis (LC), and eventually hepatocellular carcinoma (HCC). The presence of hepatitis B e antigen (HBeAg) in the serum generally indicates ongoing viral replication and disease progression. However, the mechanism by which HBeAg regulates HBV infection remains unclear. Interferons (IFNs) are pleiotropic cytokines that participate in host innate immunity. After binding to receptors, IFNs activate the JAK/STAT pathway to stimulate expression of IFN-stimulated genes (ISGs), leading to induction of antiviral responses. Here, we revealed that HBeAg represses IFN/JAK/STAT signaling to facilitate HBV replication. Initially, HBeAg stimulates the expression of suppressor of cytokine signaling 2 (SOCS2). Subsequently, SOCS2 impairs IFN/JAK/STAT signaling through reducing the stability of tyrosine kinase 2 (TYK2), downregulating the expression of type I and III IFN receptors, attenuating the phosphorylation and nucleus translocation of STAT1. Finally, SOCS2 inhibits the expression of ISGs, which leads to the repression of IFN action and facilitation of viral replication. These results demonstrate an important role of HBeAg in the regulation of IFN action, and provide a possible molecular mechanism by which HBV resists the IFN therapy and maintains persistent infection.

Differential regulation of hepatitis B virus core protein expression and genome replication by a small upstream open reading frame and naturally occurring mutations in the precore region

Hepatitis B virus (HBV) transcribes two subsets of 3.5-kb RNAs: precore RNA for hepatitis B e antigen (HBeAg) expression, and pregenomic RNA for core and P protein translation as well as genome replication. HBeAg expression could be prevented by mutations in the precore region, while an upstream open reading frame (uORF) has been proposed as a negative regulator of core protein translation. We employed replication competent HBV DNA constructs and transient transfection experiments in Huh7 cells to verify the uORF effect and to explore the alternative function of precore RNA. Optimized Kozak sequence for the uORF or extra ATG codons as present in some HBV genotypes reduced core protein expression. G1896A nonsense mutation promoted more efficient core protein expression than mutated precore ATG, while a +1 frameshift mutation was ineffective. In conclusion, various HBeAg-negative precore mutations and mutations affecting uORF differentially regulate core protein expression and genome replication.

Hepatitis B virus strains from Rwandan blood donors are genetically similar and form one clade within subgenotype A1

BACKGROUND

Rwanda is a central African country with about 12 million inhabitants. The 1994 genocide against the Tutsi destroyed much of the infrastructure, including the health system. Although this has improved significantly, many challenges remain to be addressed. In this study, the prevalence of serological markers of past and ongoing hepatitis B virus (HBV) infection and HBV vaccine related immunity was investigated in samples from blood donors from all regions of Rwanda.

METHODS

The results from hepatitis B surface antigen (HBsAg) analyses of all (45,061) blood donations collected countrywide in 2014 from 13,637 first time and 31,424 repeat blood donors were compiled. Samples from 581 HBsAg negative blood donors were selected for further analysis for antibodies against HBV, anti-HBs and anti-HBc. Additional 139 samples from HBsAg positive donors were analyzed for HBeAg/anti-HBe (132 samples) and for HBV DNA. The S-gene was amplified by PCR, products sequenced, and phylogenetic analysis was performed.

RESULTS

HBsAg was found in 4.1% of first time donors with somewhat higher prevalence among those from the Central and Eastern regions than from other parts of the country. Indications of past infection was found in 21% of the HBsAg negative donors, 4.3% had only anti-HBs suggesting HBV vaccination. HBeAg was detected in 28 (21%), anti-HBe in 97 (73%), and both HBeAg and anti-HBe in 4 of 132 HBsAg positive donors. HBV DNA was found in 85 samples, and the complete S-gene was sequenced in 58 of those. Phylogenetic analysis of the sequences revealed that all HBV strains belonged to subgenotype A1, and formed one clade in the phylogenetic tree. In addition, 12 strains from first time donors had a unique 18 amino acid deletion in the N-terminal part of the pre-S2 region.

CONCLUSION

This study indicated that the prevalence of hepatitis B is intermediate in Rwanda and that the vaccination coverage is relatively low in young adults. All surveyed Rwandan blood donors were infected with similar subgenotype A1 strains, and a high frequency of those with anti-HBe had detectable HBV DNA. Several strains had in addition a unique pre-S2 deletion, the virulence of which needs to be further studied.

Core I97L mutation in conjunction with P79Q is associated with persistent low HBV DNA and HBs antigen clearance in patients with chronic hepatitis B

OBJECTIVES

When considering treatment for chronic hepatitis B (CHB), it is important to discriminate between patients with persistent low HBV DNA and patients with active hepatitis, who may proceed to cirrhosis. In this study, we sought to identify mutations in patients expected to have persistent low HBV DNA and ultimately exhibit clearance of hepatitis B surface antigen (HBsAg).

METHODS

Serum samples were obtained from 33 CHB genotype C patients, divided based on HBV DNA and alanine aminotransferase (ALT) levels following observation for >2 years: Group A (n=10), transient HBV DNA ≥5.0 log copies/mL and ALT ≥120 IU/L; Group B (n=11), persistent HBV DNA <5.0 and ALT <60; and Group C (n=12), persistent HBV DNA <4.0 and ALT <30. Full-length HBV sequences were compared among groups. Subsequently, 82 patients with CHB were evaluated for the I97L mutation and the additional mutation P79Q. We compared cumulative incidences of persistent low HBV DNA and HBsAg clearance in patients with or without I97L and P79Q by the Kaplan-Meier method.

RESULTS

Incidence of Core mutation I97L differed significantly among groups: A, 30% (3/10); B, 36.4% (4/11); C, 83.3% (10/12) (p = 0.021). Cumulative incidences of persistent low HBV DNA and HBsAg clearance were significantly higher in patients with I97L than in those with wild-type I97 (p = 0.003 and p = 0.016, respectively), and even higher in those with P79Q.

CONCLUSIONS

In patients with CHB, measurement of I97L and additional mutation P79Q would be useful for predicting persistent low HBV DNA, normal ALT, and HBsAg clearance.

Different precore/core mutations of hepatitis B interact with, limit, or favor liver fibrosis severity

BACKGROUND AND AIM

The impact of basal core promoter (BCP) and precore (PC) mutants of the hepatitis B virus (HBV) on liver disease severity remains controversial. The aim of the present study was to screen BCP and PC mutations in 252 HBV surface antigen (HBsAg) positive carriers in France and to assess relationships between these mutations and severe fibrosis.

METHODS

Direct sequencing of the precore/core gene was used to detect A1762T/G1764A and G1757A mutations in the BCP and G1896A and G1899A mutations in the PC region.

RESULTS

The prevalences of A1762T/G1764A, G1757A, G1896A, and G1899A mutations were 34.1%, 38.7%, 54.9%, and 29.3% (P < 0.001), respectively. The independent predictors of severe fibrosis (≥F3 Metavir) were older age (P < 0.001), male gender (P = 0.012), elevated alanine aminotransferase (P < 0.001), and the double A1762T/G1764A mutant with no other mutations (P = 0.011). Interestingly, the association of the G1899A mutation with the double A1762T/G1764A mutant significantly counteracted the deleterious effect of the sole double A1762T/G1764A mutant (odds ratio [OR] = 0.28 vs. OR = 3.55, respectively, P = 0.028).

CONCLUSIONS

Patients with the A1762T/G1764A mutation have a higher risk of severe fibrosis. The G1899A mutation is a protective factor against severe fibrosis that counteracted the deleterious effect of the A1762T/G1764A mutation. Finally, host phenotypic and HBV genotypic markers independently predict fibrosis severity.

Hepatitis B e antigen and its precursors promote the progress of hepatocellular carcinoma by interacting with NUMB and decreasing p53 activity

Hepatitis B viral infection is one of the leading causes of hepatocellular carcinoma (HCC) worldwide. Although several viral factors have been identified that may increase the risk for HCC development, the molecular mechanisms leading to the transformation of normal hepatocytes into cancer cells remain elusive. In this study, we demonstrated that the intracellular hepatitis B e antigen (HBeAg) and its precore precursors, but not their homologous core protein, could associate with NUMB and thereby impair the stability and transcriptional activity of tumor suppressor p53. HBeAg and its precursors could disrupt p53-NUMB and HDM2-NUMB interactions and tricomplex p53-HDM2-NUMB formation, inhibit the acetylation and translocation of p53 from cytosol to the nucleus, promote HDM2-mediated ubiquitination and degradation of p53, and suppress p53-dependent apoptosis. A xenograft tumorigenicity assay showed that expression of HBeAg and its precursors promoted carcinogenesis in a mouse model. Immunohistochemical analysis of the bioptic liver samples of HCC patients revealed that HBeAg positivity was associated with reduced transcriptional activity of p53. Taken together, the results suggest a role of intracellular HBeAg and its precursors in HCC development.

CONCLUSION

HBeAg and its precursors promote HDM2-mediated degradation and impair transcriptional activity of p53 by interacting with NUMB, consequently contributing to HCC development. (Hepatology 2016;64:390-404).

Enhanced pregenomic RNA levels and lowered precore mRNA transcription efficiency in a genotype A hepatitis B virus genome with C1766T and T1768A mutations obtained from a fulminant hepatitis patient

The viral factors associated with the development of fulminant hepatitis B are not fully understood. We recently found four unique mutations [G to A at nucleotide 1742 (G1742A), C1766T, T1768A and T1809C] in the basal core promoter (BCP) region of a genotype A hepatitis B virus (HBV) strain (FH) obtained from a 53-year-old man with fatal fulminant hepatitis. To elucidate the association of the mutations of the FH genome with the disease, we constructed a 1.3-fold FH genome and its five variants by replacing one or two mutated nucleotides with wild-type nucleotide(s) via site-directed mutagenesis, and transfected human hepatoma cells (HepG2/C3A) with the constructs. There were no discernible differences between FH and two variants (FH_A1742G and FH_C1809T) with regard to viral replication and protein expression. However, in comparison to three other variants (FH_T1766C, FH_A1768T and FH_T1766C/A1768T) with wild-type nucleotide(s) at 1766 and/or 1768, the FH genome exhibited a 2.5-5-fold enhancement of viral replication by heightened pregenomic RNA synthesis and a 1.5-2.5-fold reduction in the hepatitis B e antigen (HBeAg) synthesis by the downregulation of the precore mRNA level. An immunofluorescence analysis revealed the increased and predominant cytoplasmic localization of the core protein in the FH genome. The present study demonstrates that the C1766T/T1768A mutations in the BCP region of genotype A HBV enhance viral replication, downregulate HBeAg expression and are responsible for the predominant localization of the core protein in the cytoplasm, which are likely associated with the development of fulminant hepatitis.

The clinical implications of hepatitis B virus genotypes and HBeAg in pediatrics

Although a successful vaccine against HBV has been implemented in 184 countries, eradication of hepatitis B virus (HBV) is still not on the horizon. There are over 240 million chronic carriers of HBV globally. The risk of developing chronic hepatitis ranges from >90% in newborns of hepatitis Be antigen (HBeAg)‐positive mothers, 25%–35% in children under 5 years of age and <5% in adults. HBeAg, a non‐particulate viral protein, is a marker of HBV replication. This is the only HBV antigen to cross the placenta, leading to specific unresponsiveness of helper T cells to the capsid protein and HBeAg in newborns. HBeAg is tolerated in utero and acts as a tolerogen after birth. Perinatal transmission is frequent when mothers are HBeAg‐positive, whereas it occurs less frequently when mothers are HBeAg‐negative. Sequence heterogeneity is a feature of HBV. Based on an intergroup divergence >7.5% across the complete genome, HBV is classified phylogenetically into at least nine genotypes. With between ~4% and 8% intergroup nucleotide divergence, genotypes A–D, F, H and I are classified further into subgenotypes. HBV genotypes/subgenotypes may have distinct geographical distribution and can develop different mutations in the regions of the HBV genome that code for HBeAg. These differences can be related to the role of HBV genotypes to the natural history of infection and mode of transmission. Thus genotypes/subgenotypes of HBV can be responsible for the different natural history of infection and modes of transmission in children, found in various regions of the world, where different genotypes/subgenotypes prevail. Copyright © 2016 John Wiley & Sons, Ltd.

Maternal-Derived Hepatitis B Virus e Antigen Alters Macrophage Function in Offspring to Drive Viral Persistence after Vertical Transmission

In contrast to horizontal transmission of hepatitis B virus (HBV) between adults, which often leads to self-limited acute infection, vertical transmission of HBV from mother to child often leads to chronic infection. However, the mechanisms linking vertical transmission with chronic infection are not known. We developed a mouse model to study the effect of maternal HBV infection on HBV persistence in offspring and found that HBV carried by the mother impaired CD8(+) T cell responses to HBV in her offspring, resulting in HBV persistence. This impairment of CD8(+) T cell responses was mediated by hepatic macrophages, which were predisposed by maternal HBV e antigen (HBeAg) to support HBV persistence by upregulation of inhibitory ligand PD-L1 and altered polarization upon restimulation with HBeAg. Depletion of hepatic macrophages led to CD8(+) T cell activation and HBV clearance in the offspring, raising the possibility of targeting macrophages to treat chronic HBV patients.

Hepatitis B virus basal core promoter mutations show lower replication fitness associated with cccDNA acetylation status

In chronic hepatitis B virus (HBV) infection, variants with mutations in the basal core promoter (BCP) and precore region predominate and associate with more severe disease forms. Studies on their effect on viral replication remain controversial. Increasing evidence shows that epigenetic modifications of cccDNA regulate HBV replication and disease outcome. Here we determined the transcription and viral replication efficiency of well-defined BCP and precore mutations and their effect on cccDNA epigenetic control. HBV monomers bearing BCP mutations A1762T/G1764A and A1762T/G1764A/C1766T, and precore mutations G1896A, G1899A and G1896A/G1899A, were transfected into HepG2 cells using a plasmid-free approach. Viral RNA transcripts were detected by Northern blot hybridization and RT PCR, DNA replicative intermediates by Southern blotting and RT PCR, and viral release was measured by ELISA. Acetylation of cccDNA-bound histones was assessed by Chromatin ImmunoPrecipitation (ChIP) assay and methylation of cccDNA by bisulfite sequencing. BCP mutations resulted in low viral release, mRNA transcription and pgRNA/cccDNA ratios that paralleled the acetylation of cccDNA-bound H4 histone and inversely correlated with the HDAC1 recruitment onto cccDNA. Independently of the mutations, cccDNA was a target for methylation, accompanied by the upregulation of DNMT1 expression and DNMT1 recruitment onto cccDNA. Our results suggest that BCP mutations decrease viral replication capacity possibly by modulating the acetylation and deacetylation of cccDNA-bound histones while precore mutations do not have a significant effect on viral replication. These data provide evidence that epigenetic factors contribute to the regulation of HBV viral replication.

Hepatitis B viral replication influences the expression of natural killer cell ligands

BACKGROUND

Hepatitis B virus (HBV) is accounting for over one million deaths annually due to immune-mediated chronic liver damage. Natural killer (NK) cells are abundant in the liver and contribute in HBV persistence. NK cytotoxic effects are controlled by signals from activating and inhibitory receptors. HBV may circumvent host antiviral immunity via the regulation of NK receptors and their ligands. We investigated the effect of viral replication and HBeAg mutations on NK mediators expression in the livers of chronic HBV (CHB) patients and in cell cultures.

METHODS

HBV monomers bearing hotspot mutations in the basal core promoter and precore region were transfected into HepG2 cells using a plasmid-free assay. Serum viremia and liver HBV RNA were measured in 19 CHB patients. The expression of HBV RNA and of NKG2D ligands, B7H6, DNAX accessory molecule-1, lectin-like transcript 1 (LLT1), LFA-1 and TRAIL was measured in the livers of CHB patients and transfected cells.

RESULTS

In general, high HBV replication in CHB patients and cell lines upregulated the mRNA of all NK cell ligands and particularly the inhibitory NK cell ligand, LLT1. The exception was the NKG2D ligand, MICA, that was significantly decreased in patients with high serum viremia and intrahepatic HBV RNA levels.

CONCLUSIONS

HBV replication has differential effects on NK cell ligands suggesting a potential escape mechanisms through up-regulation of LLT1 and down-regulation of MICA. A general trend towards upregulating NK cell ligands can be counteracted by decreasing MICA and hence weakening NK surveillance.

Overview of hepatitis B viral replication and genetic variability

Chronic infection with hepatitis B virus (HBV) greatly increases the risk for liver cirrhosis and hepatocellular carcinoma (HCC). HBV isolates worldwide can be divided into ten genotypes. Moreover, the immune clearance phase selects for mutations in different parts of the viral genome. The outcome of HBV infection is shaped by the complex interplay of the mode of transmission, host genetic factors, viral genotype and adaptive mutations, as well as environmental factors. Core promoter mutations and mutations abolishing hepatitis B e antigen (HBeAg) expression have been implicated in acute liver failure, while genotypes B, C, subgenotype A1, core promoter mutations, preS deletions, C-terminal truncation of envelope proteins, and spliced pregenomic RNA are associated with HCC development. Our efforts to treat and prevent HBV infection are hampered by the emergence of drug resistant mutants and vaccine escape mutants. This paper provides an overview of the HBV life cycle, followed by review of HBV genotypes and mutants in terms of their biological properties and clinical significance.

Mutation Changes in the preC/Core Promoter in HBeAg-Positive Patients With Chronic Hepatitis B During Interferon Therapy

To study the changes in 3 mutations related with hepatitis B e antigen (HBeAg) in patients with HBeAg-positive chronic hepatitis B (CHB) during interferon therapy.HBeAg seroconversion is a major therapeutic milestone for patients with HBeAg-positive CHB. The precore mutation G1896A and the basal core promoter mutations A1762T/G1764A are 3 important mutations that affect the expression of HBeAg; however, the change of these 3 mutations in CHB patients during interferon therapy has not yet been evaluated.Sixty-four treatment-naive patients with HBeAg-positive CHB were treated with interferon for 48 weeks and followed up for 24 weeks. Serum samples were collected from all of the participants at different time points and then subjected to viral DNA extraction. The precore and basal core promoter sequences were determined using nested PCR and direct sequencing. The treatment outcomes were confirmed both at the end of therapy and the follow-up period, and the results were compared between patients with mutant and wild-type virus.No significant difference in HBeAg loss and HBeAg seroconversion was observed between patients with mutant versus wild-type virus although the portion of patients who achieved HBeAg loss/seroconversion with mutant virus was a little higher than in patients with wild-type virus. Once a mutation exists, it is not replaced with the wild-type sequence during interferon therapy and follow-up; moreover, our results show that mutants stably coexist with the wild-type virus during interferon therapy.This study shows the changes in 3 mutations affecting the expression of HBeAg during interferon therapy. However, additional studies with a larger sample size and more sensitive detection methods are needed to uncover the underlying mechanism and clinical significance of these results.

Hepatitis B: 50 years after the discovery of Australia antigen

It is an honour to be invited to recount the progress in our understanding and management of hepatitis B 50 years after the discovery of Australia antigen (Au Ag). During this half century, we have gone from identifying the causative agent--hepatitis B virus (HBV), understanding its biology and the disease it causes, to having vaccines that can prevent HBV infection and antiviral therapy that can suppress HBV replication and prevent progression of HBV-related liver disease. As a result of the progress, prevalence of HBV infection and morbidity and mortality from chronic HBV infection has declined.

Deep sequencing of hepatitis B virus basal core promoter and precore mutants in HBeAg-positive chronic hepatitis B patients

Mutants in the basal core promoter (BCP) and precore (PC) regions of hepatitis B virus (HBV) genome are associated with the progression of chronic hepatitis B (CHB) infection. However, quasispecies characteristics of naturally occurring mutants in those regions in HBeAg-positive CHB patients has not been well described, partly limited by quantitative assay. This study aimed to develop an Ion Torrent deep sequencing assay to determine BCP and PC mutant percentages in HBeAg-positive CHB patients who were treatment naïve and correlate them with different viral and host factors. Our results showed that Ion Torrent deep sequencing could achieve high accuracy (R²>0.99) within a dynamic range between 1% and 100%. Twelve hotspots with prevalence of greater than 20% were observed in EnhII/BCP/PC regions. G1719T, T1753V, A1762T and G1764A were genotype C related. BCP A1762T/G1764A double mutants were generally accompanied with PC 1896 wild type or lower PC G1896A mutant percentage. Lower serum HBeAg and HBsAg levels were associated with higher BCP A1762T/G1764A mutant percentages (≥50%). ALT levels were higher in patients with PC G1896A mutant percentage greater than 10%. In conclusion, deep sequencing such as Ion Torrent sequencing could accurately quantify HBV mutants for providing clinical relevant information during HBV infection.

G1896A Precore Mutation and Association With HBeAg Status, Genotype and Clinical Status in Patients With Chronic Hepatitis B

BACKGROUND

Precore stop codon (G1896A) mutation is one of the commonest mutations found in patients with chronic hepatitis B. However, over the years, this mutation was not reported much in Malaysia.

OBJECTIVES

We therefore investigated the presence of G1896A mutation in Malaysian population and its association with HBeAg status, clinical stage, hepatitis B virus (HBV) genotype and e-seroconversion rate.

PATIENTS AND METHODS

Serum samples from 93 patients confirmed as hepatitis B carriers were collected for molecular assay. The whole genome of HBV was amplified by polymerase chain reaction and directly sequenced. The precore and basal core promoter regions were analyzed for presence of mutations.

RESULTS

The most commonly observed mutation in the precore region was C1858T with 64.5% prevalence. The precore mutation of interest (G1896A) was identified in 25.8% of isolates. The basal core promoter mutations detected were A1762T-G1764A (26.9%), C1653T (8.6%), A1752G (10.8%) and C1766T (2.2%). No significant association was observed between G1896A mutation and HBeAg-negativity. Nonetheless, G1896A was highly prevalent among HBV genotype B. Clinical association revealed that subjects with G1896A mutations were mainly detected in asymptomatic chronic hepatitis B (58.3%) and liver cirrhosis (41.7%). One subject was diagnosed with fulminant hepatitis (4.2%) and 8.3% had hepatocellular carcinoma (HCC).

CONCLUSIONS

Our data suggested an intermediate prevalence of G1896A mutation among Malaysian hepatitis B carriers. The stop codon mutation has a significant association with genotype B and patients with chronic hepatitis B and liver cirrhosis.

Lamivudine Resistance and Precore Variants in Iranian Patients With Chronic Hepatitis B: Correlation With Virological and Clinical Features

Background:

Long-term lamivudine therapy, despite its initial effectiveness against hepatitis B virus (HBV), is associated with the emergence of drug resistance mutations in polymerase protein.

Objectives:

The aim of the present study was to determine the prevalence of precore and lamivudine drug resistance mutations in lamivudine treated patients with chronic B hepatitis.

Patients and Methods:

Sequential sera were obtained from 88 chronic HBV carriers who received lamivudine for more than 24 months. Polymerase and precore regions were directly sequenced for these groups: I (before treatment), II, and III (12 and 24 months after treatment, respectively).

Results:

All patients (100%) were contained genotype D, subtype ayw2. One (1.1%), 12 (13.6%), and 22 (25%) members of groups I, II, and III had the replacement of either isoleucine or valine instead of methionine in tyrosine-methionine-aspartate-aspartate (YMDD) motif, respectively. The frequency of mutations from 0 time point to 12 and 24 months showed that there was an increasing trend between sequential samples (P < 0.001). In group I, 31 (35.2%); II, 36 (41.0%) and III, 41 (46.6%) members had the precore stop codon mutations. The frequency of mutations from 0 time point to 12 and 24 months showed that there was an ascending trend between sequential samples. Indeed, frequency of precore stop codon was significantly increased with the passage of time (P < 0.001).

Conclusions:

Presence of drug resistance mutations among the patients was significant. Precore mutations were common amongst Iranian HBV chronic carriers under lamivudine therapy and these mutations were accompanied by clinical relapse.

Cost-Effectiveness Analysis of Alternative Antiviral Strategies for the Treatment of HBeAg-Positive and HBeAg-Negative Chronic Hepatitis B in the United Kingdom

BACKGROUND

Seven drugs are licensed for the treatment of chronic hepatitis B (CHB) in the United Kingdom. Which initial treatment, secondary therapy, and whether antivirals should be given alone or in combination are questions of considerable uncertainty.

OBJECTIVE

The aim of this model was to undertake a comprehensive economic evaluation of all antiviral treatments for CHB to recommend the most cost-effective therapeutic sequence.

METHODS

We developed a probabilistic Markov model to compare the cost-effectiveness of all clinically relevant antiviral treatment sequences for nucleos(t)ide-naive adults with hepatitis B e-antigen (HBeAg)-positive or HBeAg-negative CHB. Relative rates of HBeAg seroconversion and viral suppression were obtained from a network meta-analysis. Data on mortality, antiviral drug resistance, durability of response, adverse events, and costs were obtained from published literature. Results are reported in terms of lifetime costs, quality-adjusted life-years (QALYs), and expected net benefit.

RESULTS

In the base-case analysis, pegylated interferon alpha-2a (peg-IFN α-2a) followed by tenofovir disoproxil fumarate was most effective and cost-effective in HBeAg-positive patients, with a cost of £7488 per QALY gained compared with no treatment. In HBeAg-negative patients, peg-IFN α-2a followed by entecavir was most effective and cost-effective, with a cost of £6981 per QALY gained. The model was robust to a wide range of sensitivity analyses.

CONCLUSIONS

Peg-IFN α-2a followed by tenofovir disoproxil fumarate or entecavir is the most effective antiviral treatment strategy for people with both variants of CHB. At a cost of less than £10,000 per QALY gained, these sequences are considered cost-effective in England and Wales. The results of this analysis were used to inform 2013 National Institute for Health and Care Excellence guideline recommendations.

Studies of nosocomial outbreaks of hepatitis B in nursing homes in Germany suggest a major role of hepatitis B e antigen expression in disease severity and progression

Hepatitis B virus (HBV) causes acute or chronic hepatitis B. Local outbreaks of HBV infections in skilled nursing facilities is a matter of growing concern in developed countries. Here, we investigated two outbreaks of hepatitis B that recently occurred in nursing homes in Germany. The outbreak at location A was associated with acute fulminant hepatitis with fatal outcome in several cases, while individuals infected at location B developed asymptomatic or mild hepatitis B. Sequence analysis of viruses involved in these outbreaks revealed different, but unique HBV strains for each location. Each of the strains produced high viremia of more than 10(9) virions/mL serum. We found that the mild course of hepatitis B at location B was caused by a circulating wild-type HBV genotype A2 strain, which is commonly found in Central Europe. Complete genome sequences of isolates obtained from infected patients revealed nearly 100% sequence identity at the nucleotide level as well as expression of HBV e protein (HBeAg), a known T cell tolerogen in the incubation or chronic phases of HBV infection. By contrast, the outbreak at location A was associated with an HBV genotype D2 variant that lacked HBeAg expression, suggesting that immunopathology and selection of specific HBV variants played a major role in the severe (or even fulminant) acute hepatitis observed at location A. Importantly, all patients were diagnosed with type 2 diabetes mellitus, a known risk factor for healthcare-associated transmission of HBV. The study leads us to suggest that, besides strict adherence to hygiene standards, additional efforts are required to reduce the risk of HBV transmission and fulminant disease progression in healthcare settings and nursing homes. In this context, a general screening for HBsAg and active hepatitis B vaccination should be considered for people living in nursing homes, especially for those with diagnosed diabetes or other predisposing factors for HBV transmission.

The incidence rate over 10 years of naturally occurring, cancer related mutations in the basal core promoter of hepatitis B virus

•

The annual incidence rate of the basal core promoter (BCP) double mutations is 3.8%.

•

The incidence rate tends to decrease with age and the peak appeared early in the life.

•

Nucleotide (nt) 1762 is the favoured site of the first mutation.

•

Viruses with a single mutation at nt 1762 or 1764 are more prone to develop double mutations.

Cross-sectional analyses showed that the prevalence of basal core promoter (BCP) double mutations (nt 1762T, 1764A) of hepatitis B virus (HBV) gradually increases with age. We aimed to determine the incidence rate of the mutations over 10 years. Study subjects were selected from the Long An cohort established in 2004, including 59 with HBV with single mutations at nt 1762 or 1764 in the BCP and 342 with wild type BCP sequences at baseline. Their serum samples for analysis were obtained at the 3rd and 10th annual visits, respectively. The results showed that the annual incidence rate of BCP double mutations is 3.8% (95% confidence interval [CI]: 1.4–6.2) and tends to decrease with age. The peak incidence is in the 30–34 years age-group. The incidence rate in HBeAg positive individuals (5.5%) is significantly higher than in those without HBeAg (3.4%) (P < 0.05). The incidence rate is significantly higher in genotype C (4.8%) than in genotype B (2.8%) or I (3.1%). The incidence rate of the mutations (6.8%) developing from a single mutation at nt 1762 or 1764 is significantly higher than that (3.8%) from the wild type sequence (P < 0.005). The difference in incidence of single mutations between nt 1762 (0.7%) and 1764 (0.03%) is significant (P < 0.05). In conclusion, the incidence rate of BCP double mutations tends to decrease with age after the age of 35 years. Viruses with a single mutation at nt 1762 or 1764 are more prone to develop double mutations. Nt 1762 is the more common site of the first mutation.

Identification of Novel Recombinant Forms of Hepatitis B Virus Generated from Genotypes Ae and G in HIV-1-Positive Japanese Men Who Have Sex with Men

The rare hepatitis B virus (HBV) genotype G (HBV/G) coinfects HIV-1-positive individuals along with HBV/A and generates recombinants. However, the circulation of HBV A/G recombinants remains poorly understood. This molecular epidemiologic study examined HBV A/G recombinants in Japanese HIV-1-positive men who have sex with men (MSM). Initially, blood specimens submitted for confirmatory tests of HIV infection in Osaka and Tokyo, Japan, from 2006 to 2013 were examined for HIV-1, and HIV-1-positive specimens were screened for HBV. Among 817 specimens from HIV-1-positive individuals, HBsAg was detected in 59 specimens; of these, HBV/Ae (alternatively A2), a subgenotype of HBV/A prevalent in Europe and North America, was identified in 70.2%, HBV/C in 17.5%, and HBV/G in 10.5%, and HBV/E in 1.8% according to the core gene sequence. The full-length genome analysis of HBV was performed on HBV/G-positive specimens because some HBV A/G recombinants were historically overlooked by genotyping based on a partial genome analysis. It revealed that five of the specimens contained novel Ae/G recombinants, the core gene of which had a high sequence similarity to HBV/G. Detailed analyses showed that novel recombinants were coinfected with HBV/Ae in a recombinant-dominant fashion. No major drug-resistant mutations were found in the newly identified HBV Ae/G recombinants. Some of the individuals asymptomatically coinfected with HIV/HBV suffered mild liver injury. This study demonstrated that novel Ae/G HBV recombinants were identified in Japanese HIV-1-positive MSM. The pathogenicity of novel HBV Ae/G recombinants should be examined in a future longitudinal study. Surveillance of such viruses in HIV-1-positive individuals should be emphasized.

Accurate Detection of Hepatitis B Virus G1896A Mutant by Developed Taqman-ARMS Followed a Strict Control System

BACKGROUND

Hepatitis B virus (HBV) G1896A mutation was associated with HBeAg seronegativity and hepatitis B related acute-on-chronic liver failure. In this study, we developed Taqman amplification refractory mutation system (Taqman-ARMS) and established a strict control system to detect HBV G1896A mutant.

METHODS

HBV viral DNA was isolated from 60 patient serum samples, and full-length HBV genome was cloned. Then, Taqman-ARMS was used to detect HBV G1896A mutant.

RESULTS

The assay has the sensitivity of 1E+3 IU/ml G1896A template, and 0.1% weak population virus with G1896A could be found in mixtures. Total of all 60 clinical samples random collected were detected by Taqman-ARMS, the results were consistent with those by DNA sequencing.

CONCLUSION

The proposed Taqman-ARMS real-time PCR method for the detection of G1896A mutation of HBV was rapid, simple, sensitive, specific, and applicable in the clinical setting.

Lower mutation frequency of BCP/precore regions in e antigen-negative chronic HBV-infected children instead of adults patients

To describe the Hepatitis B e antigen(HBeAg) seroconversion related mutation profiles of the basal core promoter(BCP)/precore regions in e antigen seroconverted child patients, a cohort of 245 child patients with CHB and a control patients group of 92 adult patients with CHB were recruited. The mutation frequencies of six nucleotides or nucleotide combinations including nucleotide (nt)1896, nt1762/1764, nt1752, nt1846, nt1899 and nt1753 showed significant differences between HBeAg positive and HBeAg-negative child patients groups. The frequencies of these HBeAg seroconversion-related mutations were significantly lower in HBeAg-negative children with CHB than in HBeAg-negative adults with CHB, especially for the mutation G1896A (41.1% vs 91.7%, P<0.001), and the average number of BCP/precore region mutations in samples from HBeAg-negative child patients was also obviously lower than in HBeAg-negative adult patients(3.62±3.03 vs 4.89±2.09, P<0.001), suggesting less impact of mutations in the BCP/precore region on HBeAg seroconversion in child patients than adult patients.

Variations and mutations in the hepatitis B virus genome and their associations with clinical characteristics

Hepatitis B virus (HBV) infection is major global issue, because chronic HBV infection is strongly associated with liver cancer. HBV spread worldwide with various mutations and variations. This variability, called quasispecies, is derived from no proof-reading capacity of viral reverse transcriptase. So far, thousands of studies reported that the variety of genome is closely related to the geographic distribution and clinical characteristics. Recent technological advances including capillary sequencer and next generation sequencer have made in easier to analyze mutations. The variety of HBV genome is related to not only antigenicity of HBs-antigen but also resistance to antiviral therapies. Understanding of these variations is important for the development of diagnostic tools and the appropriate therapy for chronic hepatitis B. In this review, recent publications in relation to HBV mutations and variations are updated and summarized.

Mutations of pre-core and basal core promoter before and after hepatitis B e antigen seroconversion

AIM: To investigate the role of pre-core and basal core promoter (BCP) mutations before and after hepatitis B e antigen (HBeAg) seroconversion.

METHODS: The proportion of pre-core (G1896A) and basal core promoter (A1762T and G1764A) mutant viruses and serum levels of hepatitis B virus (HBV) DNA, hepatitis B surface antigen (HBsAg), and HB core-related antigen were analyzed in chronic hepatitis B patients before and after HBeAg seroconversion (n = 25), in those who were persistently HBeAg positive (n = 18), and in those who were persistently anti-HBe positive (n = 43). All patients were infected with HBV genotype C and were followed for a median of 9 years.

RESULTS: Although the pre-core mutant became predominant (24% to 65%, P = 0.022) in the HBeAg seroconversion group during follow-up, the proportion of the basal core promoter mutation did not change. Median HBV viral markers were significantly higher in patients without the mutations in an HBeAg positive status (HBV DNA: P = 0.003; HBsAg: P < 0.001; HB core-related antigen: P = 0.001). In contrast, HBV DNA (P = 0.012) and HBsAg (P = 0.041) levels were significantly higher in patients with the pre-core mutation in an anti-HBe positive status.

CONCLUSION: There is an opposite association of the pre-core mutation with viral load before and after HBeAg seroconversion in patients with HBV infection.

Prevalence of mutations in basal core promoter and precore region of hepatitis B virus in vaccinated and nonvaccinated individuals of the aboriginal Nicobarese tribe of Car Nicobar Island, India

The aim of this study was to explore the prevalence of basal core promoter (BCP) and precore gene (PC) mutations in hepatitis B virus (HBV) isolates among the Nicobarese tribe and their relationship with genotypes and HBeAg status. A total of 726 blood samples were collected from two villages of the Car Nicobar Island where mass vaccination was performed in the year 2000. HBV DNA was isolated and the BCP and PC regions were amplified and sequenced directly. The samples positive for HBV DNA were tested for HBsAg, HBeAg and anti-HBe. Among the 211 and 515 samples collected from vaccinated and nonvaccinated persons, 16 and 82 were positive for HBV DNA, respectively. Among the vaccinated individuals, only 1 had a mutation in both the BCP and PC gene. Among the nonvaccinated subjects, 3 (4.5%) had an A1762T mutation, 8 (12.1%) had a G1764A mutation, 11 (16.7%) had a G1896A mutation and 4 (6.1%) had a G1899A mutation. The HBeAg-negative subjects had a significantly higher frequency of BCP and PC mutations than the HBeAg-positive subjects. The prevalence of a PC mutation was higher than that of a BCP mutation. The present study stresses the need for the continuous surveillance of subjects with BCP and PC mutations, as the mutations may contribute to the progression of liver disease.

Short- and long-term outcome of interferon therapy for chronic hepatitis B infection

Hepatitis B virus (HBV) infection is a serious clinical problem worldwide. Conventional interferon (IFN)-α has been approved for the treatment of chronic hepatitis B (CHB). Short-term studies have demonstrated that IFN-based therapy is moderately effective in inducing the loss of hepatitis e antigen (HBeAg) or seroconversion (30%-40%) in HBeAg-positive patients and also produces sustained HBV DNA suppression (20%-30%) in HBeAg-negative patients. Many studies have reported a correlation between the HBV genotype and response to IFN treatment. The highest response rate to IFN treatment was found in patients infected with HBV genotype A, followed by HBV genotypes B, C, and D. The long-term effect of IFN-α on CHB has not yet been elucidated. The ability of IFN-α treatment to prevent new cirrhosis, complications associated with cirrhosis, and development of hepatocellular carcinoma (HCC) is controversial. The beneficial effect of IFN-α treatment in reducing the development of HCC has mainly been observed in treatment responders who already have cirrhosis. These inconsistent findings may be attributed to the inevitable limitations of comparisons across studies, including differences in the baseline characteristics of the study and the moderate suppression of HBV replication by IFN-α relative to nucleoside/nucleos(t)ide analogs.

Characteristics and prediction of hepatitis B e-antigen negative hepatitis following seroconversion in patients with chronic hepatitis B

AIM

We analyzed the characteristics of alanine aminotransferase (ALT) abnormality after achieving hepatitis B e-antigen (HBeAg) seroconversion (SC) and other factors associated with the occurrence of HBeAg negative hepatitis.

METHODS

We followed 36 patients with chronic hepatitis B from 3 years prior to at least 3 years after SC (mean, 11.6 years) and examined ALT, hepatitis B virus (HBV) DNA, HB surface antigen, HB core-related antigen (HBcrAg) levels and mutations related to HBeAg SC.

RESULTS

ALT normalization (<31 IU/L for at least 1 year) was primarily observed until 2 years following SC, after which it became more infrequent. We next divided patients into abnormal (≥31 IU/L, n = 20) and normal (<31 IU/L, n = 16) groups based on integrated ALT level after the time point of 2 years from SC, and considered the former group as having HBeAg negative hepatitis in the present study. Although changes in median levels of ALT and HBcrAg differed significantly between the groups, multivariate analysis showed ALT normalization within 2 years after SC to be the only significant determining factor for this disease (P = 0.001). We then assessed the 19 patients whose ALT was normal at 2 years following SC, four of whom developed HBeAg negative hepatitis. Increased levels of HBV DNA (P = 0.037) and HBcrAg (P = 0.033) were significant factors of potential relevance.

CONCLUSION

ALT abnormality after 2 years of SC may be evaluated as HBeAg-negative hepatitis. ALT, HBV DNA and HBcrAg levels may be useful in predicting the outcome of patients who achieve HBeAg SC.

Correlation between the promoter basal core and precore mutations and HBsAg quantification in French blood donors infected with hepatitis B virus

Hepatitis B virus (HBV) basal core promoter (BCP) and precore (PC) mutations, HBV viral load and HBV surface antigen (HBsAg) quantitation were screened to assess correlations between these HBV markers in asymptomatic chronic hepatitis B carriers in France. From January 2006 to July 2007, 200 sera were collected from patients who were discovered to be HBsAg-positive when they volunteered to give blood. Direct sequencing of precore/core gene was used to detect A1762T/G1764A mutations in the BCP and G1896A in the PC region. HBV viral load and HBsAg were quantified with two commercials assays. The prevalence of the BCP and PC mixed/mutants were 37% and 60% respectively (P = 0.0001). HBV DNA level and HBsAg titer were significantly lower in subjects harboring the mixed/mutant PC virus compared to those infected by the wild phenotype. No significant difference was observed in HBV viral loads of blood donors infected by wild or mixed/mutant BCP viruses. Mutant or mixed PC virus was associated with male gender, HBeAb-positive status and HBV/D and HBV/E genotypes. BCP mutations were associated with age, and both HBV/A-HBV/E genotypes.The genetic properties of HBV in this cohort showed that most of the blood donors had a negative HBeAg serological status and harbored the PC mutant phenotype in combination with low levels of both HBV DNA and HBsAg. As the study was conducted in healthy subjects who could be considered as asmptomatic carriers, these results suggest a possible protective effect of the G1896A mutation against severe liver lesions.

Early termination of immune tolerance state of hepatitis B virus infection explains liver damage

AIM: To assess an early termination of immune tolerance state of chronic hepatitis B virus infection in Bangladesh and its clinical significance.

METHODS: From a series of 167 treatment-naive chronic hepatitis B patients aged between 12 to 20 years (mean ± SD; 17.5 ± 2.8 years), percutaneous liver biopsies of 89 patients who were all hepatitis B e antigen negative at presentation were done. Of them, 81 were included in the study. They had persistently normal or raised serum alanine aminotransferase (ALT) values. A precore mutation (PCM) study was accomplished in 8 patients who were randomly selected.

RESULTS: Forty-four (53.7%) patients had significant necroinflammation (HAI-NI > 7), while significant fibrosis (HAI-F ≥ 3) was seen in 15 (18.5%) patients. Serum ALT (cut off 42 U/L) was raised in 29 (35.8%) patients, while low HBV DNA load (< 10⁵ copies/mL) was observed in 57 (70.4%) patients. PCM was negative in all 8 patients.

CONCLUSION: This study indicates that the current concept of age-related immune tolerance state of HBV infection deserves further analyses in different population groups.

Molecular analysis of the interspousal transmission of hepatitis B virus in two Japanese patients who acquired fulminant hepatitis B after 50 and 49 years of marriage

A 71-year-old (C1I) and 69-year-old (C2I) Japanese female contracted fulminant hepatitis B after 50 and 49 years of marriage, respectively. Both index cases exhibited high levels of anti-HBc IgM antibodies (24.2 and 31.5 S/CO, respectively), suggestive of acute hepatitis B virus (HBV) infection, although they had no discernible risk factors for HBV infection, except for chronically HBV-infected spouses with detectable HBV DNA (3.3 log copies/ml [C1S: 72-year-old] and 7.2 log copies/ml [C2S: 71-year-old]). The HBV genotype/subgenotype was identical in each couple (B/B1 or C/C2). The HBV isolates from the index cases and spouses shared a nucleotide sequence identity of 99.5% and 99.7%, respectively, over the entire genome, and these four isolates had the highest nucleotide sequence identity of only 97% to HBV isolates deposited in DNA databases. Phylogenetic trees confirmed a close relationship of the HBV isolates between C1I and C1S and between C2I and C2S, supported by a high bootstrap value of 100% within each couple, indicating the transfer of HBV infection between spouses. These four isolates shared a precore mutation of G1896A known to be associated with fulminant hepatitis B. Although the history of sexual contact within a reasonable incubation period was obscure for one stable, monogamous couple (C1I and C1S), the other couple had a monogamous sexual relationship within six months prior to disease onset. This study indicates that two elderly Japanese patients with fulminant hepatitis B acquired HBV infection via interspousal (most likely sexual) transmission during long-lasting marriages.