High prevalence and mapping of pre-S deletion in hepatitis B virus carriers with progressive liver diseases

The dynamic variation position and predominant quasispecies of hepatitis B virus: Novel predictors of early hepatocarcinoma

To find the predictors of early HCC based on the dynamic changes of HBV quasispecies, this study utilizing the second-generation sequencing (NGS) and high-order multiplex droplet digital PCR (ddPCR) technology to examine the HBV quasispecies in serum of total 247 subjects recruited from high-incidence area of HCC. In the discovery stage, 15 non-synonymous Single Nucleotide Polymorphisms (SNPs) with higher variant proportion in HCC case group were founded (all P<0.05). Furthermore, the variant proportions in some of these SNPs were observed changing regularly within 5 years before the onset of HCC, and 5 of them located in HBX, 2 in HBS and 2 in HBC. The HBV predominant quasispecies and their consensus sequences were identified by genetic evolution analysis, in which the high HBS and HBC quasispecies heterogeneity were found associated with the forming of multifarious quasispecies clones, and the HBX gene had the highest proportion of predominant quasispecies (46.7 % in HBX vs 12.7 % and 13.8 % in HBS and HBC respectively) with the key variations (G1512A, A1630G, T1753C/G/A, A1762T and G1764A) determined. In the validation stage, we confirmed that the combined double mutations of G1512A+A1630G, A1762T+G1764A, and the combined triple mutations of T1753C/G/A + A1762T+G1764A, all expressed higher in early HCC cases when comparing with control group (all P<0.05). We also demonstrated the advantages of ddPCR using in multi-variations detection in large-sample for early HCC surveillance and screening. So we think that the dynamic of key HBV variation positions and their different combinations determined by quasispecies anlysis in this study can act as the novel predictors of early hepatocarcinoma and suitable to popularize and apply in HCC screening.

NDP52 mediates an antiviral response to hepatitis B virus infection through Rab9-dependent lysosomal degradation pathway

Autophagy receptor NDP52 triggers bacterial autophagy against infection. However, the ability of NDP52 to protect against viral infection has not been established. We show that NDP52 binds to envelope proteins of hepatitis B virus (HBV) and triggers a degradation process that promotes HBV clearance. Inactivating NDP52 in hepatocytes results in decreased targeting of viral envelopes in the lysosome and increased levels of viral replication. NDP52 inhibits HBV at both viral entry and late replication stages. In contrast to NDP52-mediated bacterial autophagy, lysosomal degradation of HBV envelopes is independent of galectin 8 and ATG5. NDP52 forms complex with Rab9 and viral envelope proteins and links HBV to Rab9-dependent lysosomal degradation pathway. These findings reveal that NDP52 acts as a sensor for HBV infection, which mediates a unique antiviral response to eliminate the virus. This work also suggests direct roles for autophagy receptors in other lysosomal degradation pathways than canonical autophagy.

Regulation of Mitochondrial Metabolism by Hepatitis B Virus

Mitochondria play important roles in the synthesis of ATP, the production of reactive oxygen species, and the regulation of innate immune response and apoptosis. Many viruses perturb mitochondrial activities to promote their replication and cause cell damage. Hepatitis B virus (HBV) is a hepatotropic virus that can cause severe liver diseases, including cirrhosis and hepatocellular carcinoma (HCC). This virus can also alter mitochondrial functions and metabolism to promote its replication and persistence. In this report, we summarize recent research progress on the interaction between HBV and mitochondrial metabolism, as well as the effect this interaction has on HBV replication and persistence.

Cell Culture Systems for Studying Hepatitis B and Hepatitis D Virus Infections

The hepatitis B virus (HBV) and hepatitis D virus (HDV) infections cause liver disease, including hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). HBV infection remains a major global health problem. In 2019, 296 million people were living with chronic hepatitis B and about 5% of them were co-infected with HDV. In vitro cell culture systems are instrumental in the development of therapeutic targets. Cell culture systems contribute to identifying molecular mechanisms for HBV and HDV propagation, finding drug targets for antiviral therapies, and testing antiviral agents. Current HBV therapeutics, such as nucleoside analogs, effectively suppress viral replication but are not curative. Additionally, no effective treatment for HDV infection is currently available. Therefore, there is an urgent need to develop therapies to treat both viral infections. A robust in vitro cell culture system supporting HBV and HDV infections (HBV/HDV) is a critical prerequisite to studying HBV/HDV pathogenesis, the complete life cycle of HBV/HDV infections, and consequently identifying new therapeutics. However, the lack of an efficient cell culture system hampers the development of novel antiviral strategies for HBV/HDV infections. In vitro cell culture models have evolved with significant improvements over several decades. Recently, the development of the HepG2-NTCP sec+ cell line, expressing the sodium taurocholate co-transporting polypeptide receptor (NTCP) and self-assembling co-cultured primary human hepatocytes (SACC-PHHs) has opened new perspectives for a better understanding of HBV and HDV lifecycles and the development of specific antiviral drug targets against HBV/HDV infections. We address various cell culture systems along with different cell lines and how these cell culture systems can be used to provide better tools for HBV and HDV studies.

Pre-S1 Mutations as Indicated by Serum Pre-S1 Antigen Negative is Associated with an Increased Risk of Hepatocellular Carcinoma in Chronic Hepatitis B Patients

Objective

Pre-S1 antigen (pre-S1) is a component of hepatitis B virus large surface antigen (L-HBsAg). This study aimed to investigate the association between clinical pre-S1 antigen (pre-S1) status and adverse prognostic events in chronic hepatitis B (CHB) patients.

Methods

This study retrospectively enrolled 840 CHB patients with comprehensive clinical data, including 144 patients with multiple follow-up of pre-S1 status. All patients were tested for serum pre-S1 and divided into pre-S1 positive and negative groups. Single factor and logistic multiple regression analyses were performed to explore the association between pre-S1 and other HBV biomarkers with the risk of hepatocellular carcinoma (HCC) in CHB patients. The pre-S1 region sequences of HBV DNA were obtained from one pre-S1 positive and two pre-S1 negative treatment-naïve patients using polymerase chain reaction (PCR) amplification followed by Sanger sequencing.

Results

The quantitative HBsAg level was significantly higher in the pre-S1 positive group than that in the pre-S1 negative group (Z=-15.983, P<0.001). The positive rate of pre-S1 increased significantly with the increase in HBsAg level (χ 2=317.963, P<0.001) and HBV DNA load (χ 2=15.745, P<0.001). The pre-S1 negative group had a higher HCC risk than the pre-S1 positive group (Z=-2.00, P=0.045, OR=1.61). Moreover, patients in the sustained pre-S1 negative group had a higher HCC risk (Z=-2.56, P=0.011, OR=7.12) than those in the sustained pre-S1 positive group. The sequencing results revealed mutations in the pre-S1 region from samples of pre-S1 negative patients, including frameshift and deletion mutations.

Conclusion

Pre-S1 is a biomarker that indicates the presence and replication of HBV. Pre-S1 sustained negativity attributed to pre-S1 mutations in CHB patients may be associated with a higher risk of HCC, which has clinical significance and warrant further investigations.

Hepatocellular Carcinoma in Mongolia Delineates Unique Molecular Traits and a Mutational Signature Associated with Environmental Agents

PURPOSE

Mongolia has the world's highest incidence of hepatocellular carcinoma (HCC), with ∼100 cases/100,000 inhabitants, although the reasons for this have not been thoroughly delineated.

EXPERIMENTAL DESIGN

We performed a molecular characterization of Mongolian (n = 192) compared with Western (n = 187) HCCs by RNA sequencing and whole-exome sequencing to unveil distinct genomic and transcriptomic features associated with environmental factors in this population.

RESULTS

Mongolian patients were younger, with higher female prevalence, and with predominantly HBV-HDV coinfection etiology. Mongolian HCCs presented significantly higher rates of protein-coding mutations (121 vs. 70 mutations per tumor in Western), and in specific driver HCC genes (i.e., APOB and TSC2). Four mutational signatures characterized Mongolian samples, one of which was novel (SBS Mongolia) and present in 25% of Mongolian HCC cases. This signature showed a distinct substitution profile with a high proportion of T>G substitutions and was significantly associated with a signature of exposure to the environmental agent dimethyl sulfate (71%), a 2A carcinogenic associated with coal combustion. Transcriptomic-based analysis delineated three molecular clusters, two not present in Western HCC; one with a highly inflamed profile and the other significantly associated with younger female patients.

CONCLUSIONS

Mongolian HCC has unique molecular traits with a high mutational burden and a novel mutational signature associated with genotoxic environmental factors present in this country.

Genomic Variability of Hepatitis B Virus Circulating in Brazilian Western Amazon

The emergence of clinically relevant mutations in the hepatitis B virus (HBV) genome has been a matter of great debate because of the possibility of escape from the host’s immune system, the potential to cause more severe progression of liver diseases and the emergence of treatment-resistant variants. Here we characterized the circulating variants of HBV in Rondônia State, in the north of Brazil. Serum samples of 62 chronic HBV carriers were subjected to PCR assays and clinical data were collected. Mutations and genotypes were characterized through direct sequencing. The findings show the presence of subgenotypes A1 (54.83%, 34/62), D3 (16.13%, 10/62), F2 (16.13%, 10/62), A2 (4.84%, 3/62), D2 (3.23%, 2/62), D1 (1.61%, 1/62), D4 (1.61%, 1/62) and F4 (1.61%, 1/62). Deletions in the pre-S2 region were found in 13.79% (8/58) of the samples, mutations in the S gene in 59.68% (37/62) and RT mutations in 48.39% (30/62). We found a variable genotypic distribution in different locations and important mutations related to immune escape and drug resistance in Western Amazonia, which contributed to genetic surveillance and provided important information to help control the disease.

Chemical-induced degradation of PreS2 mutant surface antigen via the induction of microautophagy

Naturally evolved immune-escape PreS2 mutant is an oncogenic caveat of liver cirrhosis and hepatocellular carcinoma (HCC) during chronic hepatitis B virus (HBV) infection. PreS2 mutant is prevalent in above 50% of patients with HCC. In addition, intrahepatic expression of PreS2 mutant large surface antigen (PreS2-LHBS) induces endoplasmic reticulum stress, mitochondria dysfunction, cytokinesis failure, and subsequent chromosome hyperploidy. As PreS2-LHBS has no enzymatic activity, the development of PreS2-specific inhibitors can be challenging. In this study, we aim to identify inhibitors of PreS2-LHBS via the induction of protein-specific degradation. We set up a large-scale protein stability reporter platform and applied an FDA-approved drug library for the screening. We identified ABT199 as a negative modulator of PreS2-LHBS, which induced the degradation of PreS2-LHBS without affecting the general cell viability in both hepatoma and immortalized hepatocytes. Next, by affinity purification screening, we found that PreS2-LHBS interacted with HSC70, a microautophagy mediating chaperone. Simultaneously, inhibitions of lysosomal degradation or microautophagy restored the expression of PreS2-LHBS, suggesting microautophagy is involved in ABT199-induced PreS2-LHBS degradation. Notably, a 24-hr treatment of ABT199 was sufficient for the reduction of DNA damage and cytokinesis failure in PreS2-LHBS expressing hepatocytes. In addition, a persistent treatment of ABT199 for 3 weeks reversed chromosome hyperploidy in PreS2-LHBS cells and suppressed anchorage-independent growth of HBV-positive hepatoma cells. Together, this study identified ABT-199 as a negative modulator of PreS2-LHBS via mediating microautophagy. Our results indicated that long-term inhibition of PreS2-LHBS may serve as a novel strategy for the therapeutic prevention of HBV-mediated HCC.

Review article: novel biomarkers in hepatitis B infection

BACKGROUND

Chronic hepatitis B remains a global health problem with an estimated 296 million people affected worldwide. Individuals are at risk of serious complications such as cirrhosis and hepatocellular carcinoma and accurately predicting these clinical endpoints has proven difficult. However, several viral biomarkers have recently been developed, including quantitative HBV surface antigen (qHBsAg), hepatitis B RNA (HBV RNA) and core-related antigen (HBcrAg), and shown promise in a range of clinical settings.

AIMS

To critically appraise these novel biomarkers, exploring their potential uses, availability of assays and areas for future development.

METHODS

We performed a literature search of PubMed, identifying articles published in the field of hepatitis B biomarkers between 2010 and 2022.

RESULTS

Novel biomarkers such as HBcrAg, HBV RNA and qHBsAg may be useful in predicting treatment outcomes, stratifying the risk of future complications and estimating off-treatment viral reactivation. Furthermore, HBV RNA and HBcrAg titres may accurately reflect cccDNA transcriptional activity, and this is particularly informative in the context of nucleoside analogue therapy. On a cautionary note, most studies have been performed in Caucasian or Asian populations, and methods for detecting HBV RNA lack standardisation.

CONCLUSION

Novel viral biomarkers have the potential to provide additional insights into the natural history of infection and allow a more bespoke, cost-effective framework of care. However, access remains limited, and further efforts are needed to validate their use in ethnically diverse populations, confirm predictive cut-off values, and establish their role in the era of novel antiviral therapies.

Sparse logistic regression revealed the associations between HBV PreS quasispecies and hepatocellular carcinoma

BACKGROUND

Chronic infection with hepatitis B virus (HBV) has been proved highly associated with the development of hepatocellular carcinoma (HCC).

AIMS

The purpose of the study is to investigate the association between HBV preS region quasispecies and HCC development, as well as to develop HCC diagnosis model using HBV preS region quasispecies.

METHODS

A total of 104 chronic hepatitis B (CHB) patients and 117 HBV-related HCC patients were enrolled. HBV preS region was sequenced using next generation sequencing (NGS) and the nucleotide entropy was calculated for quasispecies evaluation. Sparse logistic regression (SLR) was used to predict HCC development and prediction performances were evaluated using receiver operating characteristic curves.

RESULTS

Entropy of HBV preS1, preS2 regions and several nucleotide points showed significant divergence between CHB and HCC patients. Using SLR, the classification of HCC/CHB groups achieved a mean area under the receiver operating characteristic curve (AUC) of 0.883 in the training data and 0.795 in the test data. The prediction model was also validated by a completely independent dataset from Hong Kong. The 10 selected nucleotide positions showed significantly different entropy between CHB and HCC patients. The HBV quasispecies also classified three clinical parameters, including HBeAg, HBVDNA, and Alkaline phosphatase (ALP) with the AUC value greater than 0.6 in the test data.

CONCLUSIONS

Using NGS and SLR, the association between HBV preS region nucleotide entropy and HCC development was validated in our study and this could promote the understanding of HCC progression mechanism.

Association of Pre-S/S and Polymerase Mutations with Acute and Chronic Hepatitis B Virus Infections in Patients from Rio de Janeiro, Brazil

Several hepatitis B virus (HBV)-related factors, including the viral load, genotype, and genomic mutations, have been linked to the development of liver diseases. Therefore, in this study we aimed to investigate the influence of HBV genetic variability during acute and chronic infection phases. A real-time nested PCR was used to detect HBV DNA in all samples (acute, n = 22; chronic, n = 49). All samples were sequenced for phylogenetic and mutation analyses. Genotype A, sub-genotype A1, was the most common genotype in the study population. A total of 190 mutations were found in the pre-S/S gene area and the acute profile revealed a greater number of nucleotide mutations (p < 0.05). However, both profiles contained nucleotide mutations linked to immune escape and an increased risk of hepatocellular carcinomas (acute, A7T; chronic, A7Q). Furthermore, 17 amino acid substitutions were identified in the viral polymerase region, including the drug resistance mutations lamivudine and entecavir (rtL180M), with statistically significant differences between the mutant and wild type strains. Owing to the natural occurrence of these mutations, it is important to screen for resistance mutations before beginning therapy.

Pathogenicity and virulence of Hepatitis B virus

Hepatitis B virus (HBV) is a hepatotropic virus and an important human pathogen. There are an estimated 296 million people in the world that are chronically infected by this virus, and many of them will develop severe liver diseases including hepatitis, cirrhosis and hepatocellular carcinoma (HCC). HBV is a small DNA virus that replicates via the reverse transcription pathway. In this review, we summarize the molecular pathways that govern the replication of HBV and its interactions with host cells. We also discuss viral and non-viral factors that are associated with HBV-induced carcinogenesis and pathogenesis, as well as the role of host immune responses in HBV persistence and liver pathogenesis.

Alternative splicing of viral transcripts: the dark side of HBV

Regulation of alternative splicing is one of the most efficient mechanisms to enlarge the proteomic diversity in eukaryotic organisms. Many viruses hijack the splicing machinery following infection to accomplish their replication cycle. Regarding the HBV, numerous reports have described alternative splicing events of the long viral transcript (pregenomic RNA), which also acts as a template for viral genome replication. Alternative splicing of HBV pregenomic RNAs allows the synthesis of at least 20 spliced variants. In addition, almost all these spliced forms give rise to defective particles, detected in the blood of infected patients. HBV-spliced RNAs have long been unconsidered, probably due to their uneasy detection in comparison to unspliced forms as well as for their dispensable role during viral replication. However, recent data highlighted the relevance of these HBV-spliced variants through (1) the trans-regulation of the alternative splicing of viral transcripts along the course of liver disease; (2) the ability to generate defective particle formation, putative biomarker of the liver disease progression; (3) modulation of viral replication; and (4) their intrinsic propensity to encode for novel viral proteins involved in liver pathogenesis and immune response. Altogether, tricky regulation of HBV alternative splicing may contribute to modulate multiple viral and cellular processes all along the course of HBV-related liver disease.

The dynamic changes of HBV quasispecies diversity in infancy after immunoprophylaxis failure: a prospective cohort study

BACKGROUND

Previous works have observed that younger infants with chronic hepatitis B virus (HBV) infection are more responsive to antiviral treatment. However, the underlying mechanism remains unclear. In this study, the dynamic changes of HBV quasispecies in infants with immunoprophylaxis failure were investigated to provide virological explanations for clinical management on infantile antiviral therapy.

METHODS

Thirteen 7-month-old infants with immunoprophylaxis failure and their mothers were enrolled from a prospective cohort, and 8 of them were followed up to 3 years old. The sequences of HBV quasispecies were analyzed by the full-length genome clone-based sequencing, and compared among mothers and their infants at different ages.

RESULTS

The results revealed that the complexity, mutation frequency and genetic distance of HBV quasispecies decreased significantly at full-length, partial open reading frames and regulatory regions of HBV genome at nucleotide level in 7-month-old infants comparing with their mothers, whereas increased significantly to near the maternal level when infants grew up to 3 years old. Furthermore, similar changes were also found in Core, PreS2, RT and P regions of HBV genome at amino acid level, especially for potential NAs-resistant mutants in RT region and immune-escape mutants in Core and PreS2 regions.

CONCLUSIONS

This study uncovered the evolution of HBV quasispecies in infancy after mother-to-child transmission, which may provide the virological evidence for explaning that younger children are more responsive to antiviral therapy.

Controversies in Treating Chronic Hepatitis B Virus Infection: Discordant Serologic Results

Despite effective vaccines and approved therapeutic agents, hepatitis B virus (HBV) remains a prevalent global health problem. Current guidelines rely on a combination of serologic, virological, and biochemical markers to identify the phase in the natural history of chronic HBV infection. Discordant serologic results can occur, which may lead to misclassification. Commonly encountered results that differ from the typical profiles seen in chronic HBV infection are described. For each scenario, the frequency of occurrence, possible explanations, and recommendations for clinical management are discussed. Recognition of discordant serologic findings is crucial for optimal clinical decision.

Lost Small Envelope Protein Expression from Naturally Occurring PreS1 Deletion Mutants of Hepatitis B Virus Is Often Accompanied by Increased HBx and Core Protein Expression as Well as Genome Replication

Hepatitis B virus (HBV) transcribes coterminal mRNAs of 0.7 to 3.5 kb from the 3.2-kb covalently closed circular DNA, with the 2.1-kb RNA being most abundant. The 0.7-kb RNA produces HBx protein, a transcriptional transactivator, while the 3.5-kb pregenomic RNA (pgRNA) drives core and P protein translation as well as genome replication. The large (L) and small (S) envelope proteins are translated from the 2.4-kb and 2.1-kb RNAs, respectively, with the majority of the S protein being secreted as noninfectious subviral particles and detected as hepatitis B surface antigen (HBsAg). pgRNA transcription could inhibit transcription of subgenomic RNAs. The present study characterized naturally occurring in-frame deletions in the 3' preS1 region, which not only codes for L protein but also serves as the promoter for 2.1-kb RNA. The human hepatoma cell line Huh7 was transiently transfected with subgenomic expression constructs for envelope (and HBx) proteins, dimeric constructs, or constructs mimicking covalently closed circular DNA. The results confirmed lost 2.1-kb RNA transcription and HBsAg production from many deletion mutants, accompanied by increases in other (especially 2.4-kb) RNAs, intracellular HBx and core proteins, and replicative DNA but impaired virion and L protein secretion. The highest intracellular L protein levels were achieved by mutants that had residual S protein expression or retained the matrix domain in L protein. Site-directed mutagenesis of a high replicating deletion mutant suggested that increased HBx protein expression and blocked virion secretion both contributed to the high replication phenotype. Our findings could help explain why such deletions are selected at a late stage of chronic HBV infection and how they contribute to viral pathogenesis. IMPORTANCE Expression of hepatitis B e antigen (HBeAg) and overproduction of HBsAg by wild-type HBV are implicated in the induction of immune tolerance to achieve chronic infection. How HBV survives the subsequent immune clearance phase remains incompletely understood. Our previous characterization of core promoter mutations to reduce HBeAg production revealed the ability of the 3.5-kb pgRNA to diminish transcription of coterminal RNAs of 2.4 kb, 2.1 kb, and 0.7 kb. The later stage of chronic HBV infection often selects for in-frame deletions in the preS region. Here, we found that many 3' preS1 deletions prevented transcription of the 2.1-kb RNA for HBsAg production, which was often accompanied by increases in intracellular 3.5-, 0.7-, and especially 2.4-kb RNAs, HBx and core proteins, and replicative DNA but lost virion secretion. These findings established the biological consequences of preS1 deletions, thus shedding light on why they are selected and how they contribute to hepatocarcinogenesis.

Role of Small Envelope Protein in Sustaining the Intracellular and Extracellular Levels of Hepatitis B Virus Large and Middle Envelope Proteins

Hepatitis B virus (HBV) expresses co-terminal large (L), middle (M), and small (S) envelope proteins. S protein drives virion and subviral particle secretion, whereas L protein inhibits subviral particle secretion but coordinates virion morphogenesis. We previously found that preventing S protein expression from a subgenomic construct eliminated M protein. The present study further examined impact of S protein on L and M proteins. Mutations were introduced to subgenomic construct of genotype A or 1.1 mer replication construct of genotype A or D, and viral proteins were analyzed from transfected Huh7 cells. Mutating S gene ATG to prevent expression of full-length S protein eliminated M protein, reduced intracellular level of L protein despite its blocked secretion, and generated a truncated S protein through translation initiation from a downstream ATG. Truncated S protein was secretion deficient and could inhibit secretion of L, M, S proteins from wild-type constructs. Providing full-length S protein in trans rescued L protein secretion and increased its intracellular level from mutants of lost S gene ATG. Lost core protein expression reduced all the three envelope proteins. In conclusion, full-length S protein could sustain intracellular and extracellular L and M proteins, while truncated S protein could block subviral particle secretion.

Paradoxical HBsAg and anti-HBs coexistence among Chronic HBV Infections: Causes and Consequences

Hepatitis B surface antigen (HBsAg) and Hepatitis B surface antibody (anti-HBs) were reported simultaneously among Hepatitis B virus (HBV) infections. HBsAg is a specific indicator of acute or chronic HBV infections, while anti-HBs is a protective antibody reflecting the recovery and immunity of hosts. HBsAg and anti-HBs coexist during seroconversion and then form immune complex, which is rare detected in clinical cases. However, with the promotion of vaccination and the application of various antiviral drugs, along with the rapid development of medical technology, the coexistence of HBsAg and anti-HBs has become more prevalent. Mutations in the viral genomes, immune status and genetic factors of hosts may contribute to the coexistence. Novel HBsAg assays, with higher sensitivity and ability to detect mutations or immune complexes, can also yield HBsAg/anti-HBs coexistence. The discovery of coexistence has shattered the idea of traditional serological patterns and raised questions about the effectiveness of vaccines. Worth noting is that HBsAg/anti-HBs double positivity is strongly associated with progressive liver diseases, especially hepatocellular carcinoma. In conclusion, viral mutations, host factors, and methodology impacts can all lead to the coexistence of HBsAg and anti-HBs. This coexistence is not an indicator of improvement, as an increased risk of adverse clinical outcomes still exists.

Naturally occurring 5' preS1 deletions markedly enhance replication and infectivity of HBV genotype B and genotype C

BACKGROUND AND AIMS

Deletion of 15-nucleotide or 18-nucleotide (nt) covering preS1 ATG frequently arises during chronic infection with HBV genotypes B and C. Since the second ATG is 33nt downstream, they truncate large (L) envelope protein by 11 residues like wild-type genotype D. This study characterised their functional consequences.

METHODS

HBV genomes with or without deletion were amplified from a patient with advanced liver fibrosis and assembled into replication competent 1.1mer construct. Deletion, insertion or point mutation was introduced to additional clones of different genotypes. Viral particles concentrated from transfected HepG2 cells were inoculated to sodium taurocholate cotransporting polypeptide (NTCP)-reconstituted HepG2 (HepG2/NTCP) cells or differentiated HepaRG cells, and HBV RNA, DNA, proteins were monitored.

RESULTS

From transfected HepG2 cells, the 15-nt and 18-nt deletions increased HBV RNA, replicative DNA and extracellular virions. When same number of viral particles was inoculated to HepG2/NTCP cells, the deletion mutants showed higher infectivity. Conversely, HBV infectivity was diminished by putting back the 18nt into naturally occurring genotype C deletion mutants and by adding 33nt to genotype D. Infectivity of full-length genotype C clones was also enhanced by mutating the first ATG codon of the preS1 region but diminished by mutating the second in-frame ATG. Removing N-terminal 11 residues from preS1 peptide 2-59 of genotype C potentiated inhibition of HBV infection and enhanced binding to HepG2/NTCP cells.

CONCLUSIONS

The 15-nt and 18-nt deletions somehow increase HBV RNA, replicative DNA and virion production. Shortened L protein is more efficient at mediating HBV infection.

Optimization of the algorithm diagnosis chronic hepatitis B markers in patients with newly diagnosed HIV infection

The possibility of modifying the algorithms for chronic viral hepatitis B laboratory diagnosis in individuals with newly diagnosed HIV infection is analyzed. Plasma samples were used from 196 patients residing in the Northwestern Federal District. Serological HBV markers were found in 79.6% of cases. However, HBsAg was detected in 5.6% of patients. Anti-HBcore IgG antibodies are found in 62.24% of cases, anti-HBe IgG antibodies in 27.55%, anti-HBs IgG antibodies in 52.55% of cases. Using a commercial kit with a 100 IU / ml sensitivity, HBV DNA was detected in 4.6% of patients, that is, 81.8% of HBsAg-positive individuals. Using the method developed by us, HBV DNA was found in 18.36% of HIV-infected individuals, including 12.75% of cases was HBsAg-negative (latent) disease form. In the examined group, HBV of genotype D prevailed (91.7%), genotype A was detected in 8.3% of cases. The distribution of subgenotypes is presented in the following ratios: D2 - 55.6%, D1 - 22.2%, D3 - 13.9%, A2 - 8.3%. Mutations were detected in the reverse transcriptase (RT) region in 91.6% of patients, in the SHB region in 83.3%, in the Core and Precore regions in 72.2% and in 27.7% of patients, respectively. Three HBV isolates (8.3%) were identified with drug resistance mutations to lamivudine, entericavir, telbivudine and tenofovir, which are amino acid substitutions in the HBV polymerase gene at positions L180M, T184A, M204V. Vaccine escape mutations were detected in 61.1% of patients. In all samples with drug resistance mutations, escape-mutants were simultaneously present. When analyzing the basal nucleus promoter, Precore and Core regions, 22.2% of patients with the double mutation A1762T / G1764A, 25% with the mutation G1896A were identified. In one person, all three substitutions were found. In the Core region, 77.7% of patients showed mutations in one of the hot spots (codons 87, 97, 112, and 130 substitution), which can play a role in immunomodulation in CHB. Analysis of the HBV genetic structure, mutations detection early in the virus in patients with HBV can help predict the clinical course and disease progression, and ART complications. To reduce the HIV HBV co-infection burden and to appointer anti-HBV therapy, it is necessary to introduce detection the occult HBV to modify the algorithm for CHB laboratory diagnosis.

Mechanisms of Hepatitis B Virus-Induced Hepatocarcinogenesis

Hepatitis B virus (HBV) is a major cause of hepatocellular carcinoma (HCC). There are approximately 250 million people in the world that are chronically infected by this virus, resulting in nearly 1 million deaths every year. Many of these patients die from severe liver diseases, including HCC. HBV may induce HCC through the induction of chronic liver inflammation, which can cause oxidative stress and DNA damage. However, many studies also indicated that HBV could induce HCC via the alteration of hepatocellular physiology that may involve genetic and epigenetic changes of the host DNA, the alteration of cellular signaling pathways, and the inhibition of DNA repair mechanisms. This alteration of cellular physiology can lead to the accumulation of DNA damages and the promotion of cell cycles and predispose hepatocytes to oncogenic transformation.

Meta-analysis: Association between hepatitis B virus preS mutation and hepatocellular carcinoma risk

Previous observational studies suggested that hepatitis B virus (HBV) preS mutation plays an important role in the existence of HBV-related hepatocellular carcinoma (HCC). However, the results are still debatable. With an increasing number of studies about this topic, this study employed a meta-analysis to identify the association between HBV preS mutation and HCC risk. We searched for eligible studies from PubMed, ProQuest, CINAHL, ScienceDirect and Springer databases to assess the association between HBV mutation and HCC risk. This meta-analysis was conducted using RevMan 5.3 to provide pooled estimate for odds ratio (ORs) with 95% confidence intervals (95% CIs). Twenty-one clinical studies were included in this meta-analysis study which consisted of 1738 participants with HBV-related HCC and 3740 HBsAg-positive patients without HCC. All studies used samples of Asian population. PreS deletion was the most common mutation found in all studies. We found that ORs of HBV overall preS deletion was associated with HCC (OR = 3.28; 95% CI = 2.32-4.65; P < .00001; random-effects model). Each preS1 and preS2 deletion was associated with increased risk of HCC, with OR 2.42 (95% CI = 1.25-4.68, P = .008) and 3.36 (95% CI = 2.04-5.55, P < .00001), respectively. PreS2 start codon mutation was also significantly associated with HCC risk (OR = 2.47; 95% CI: 1.15-5.27; P = .02; random-effect model). The result of this meta-analysis suggested that HBV preS deletion (all, preS1 and preS2) and preS2 start codon mutation might contribute to the increased risk of HBV-related HCC.

Mutations and methods of analysis of mutations in Hepatitis B virus

Immunization programmes against hepatitis-B are being carried out since more than three decades but still HBV is a major public health problem. Hepatitis B virus (HBV) genome consists of circular and partial double stranded DNA. Due to partial double stranded DNA, it uses an RNA intermediate during replication. This replicative strategy of HBV and lack of polymerase proofreading activity give rise to error occurrences comparable to retroviruses. The low fidelity of polymerase, overlapping reading frames and high replication rate produces many non-identical variants at every cycle of replication. Therefore, HBV spreads with mutations and variations. The mutations have been reported both in non-structural as well as structural genes of HBV genome. Recent advances in molecular biology have made easier to analyse these mutations. Hepatitis B antiviral therapy and immunization are all influenced by genetic variability. The analysis and understanding of these mutations are important for therapy against hepatitis B and updating of diagnostic tools. The present review discusses about mutations occurring in whole HBV genome. The mutation occurring both in structural and non-structural genes and non-coding regions have been described in details. It is much more informative because most of literature available, covers only individual gene or DNA regions of HBV.

Comparison and Correlation of Genetic Variability of the HBV Pre-S Region in HIV/HBV Co-Infected Patients: Quasispecies Perspective

Background

Human immunodeficiency virus (HIV)/hepatitis B virus (HBV) co-infection can accelerate HBV-induced liver disease. A previous study showed that variation in the HBV pre-S region and quasispecies heterogeneity (Sn, mean genetic distance, dS, dN, and dS/dN) are both related to HBV-induced terminal liver disease in HBV mono-infection. Currently, data are lacking on quasispecies variation of the HBV pre-S region in HIV/HBV co-infection. Investigating the quasispecies variation of the HBV pre-S region and its related factors in HIV/HBV co-infection will help to better explore the pathogenic mechanism of HIV/HBV co-infection.

Methods

According to the HIV antibody results obtained before treatment, chronic HBV-infected patients were divided into HIV/HBV co-infected and HBV mono-infected groups. The clinical characteristics of all patients were collected, and DNA was extracted from the serum. The HBV pre-S region was amplified by nested PCR and was further TA cloned. BioEdit software 7.0 was used for sequence alignment with reference to the standard sequence of the matched HBV genotype. We used 1:1 propensity score matching (PSM) to control for baseline confounding factors between the two groups.

Results

After 1:1 PSM, we identified 100 patients with similar propensities: 50 HIV/HBV co-infected patients and 50 HBV mono-infected patients. HBV quasispecies indices were lower in the HIV/HBV co-infected group than those in the HBV mono-infected group. A significant correlation was observed between all quasispecies indices and soluble cluster of differentiation 163 (sCD163) and interleukin-18 (IL-18) in the HIV/HBV co-infected group; however, this phenomenon was not found in the HBV mono-infected group.

Conclusion

Combined HIV infection reduces quasispecies heterogeneity in the HBV pre-S region, and the quasispecies heterogeneity is related to the sCD163 and IL-18 levels.

Hepatitis B virus preS2Δ38-55 variants: A newly identified risk factor for hepatocellular carcinoma

BACKGROUND & AIMS

Although HBV is a major cause of death in Africa, its genetic variability has been poorly documented. This study aimed to address whether HBV genotype and surface gene variants are associated with HBV-related liver disease in The Gambia.

METHODS

We conducted a case-control study nested in the Prevention of Liver Fibrosis and Cancer in Africa programme. Consecutive treatment-naive patients with chronic HBV infection and detectable viral load were recruited: 211 controls with no significant liver disease and 91 cases (56 cirrhosis and 35 HCC cases). HBV genotypes and surface gene variants were determined by Sanger sequencing or next-generation sequencing (NGS) in serum DNA. Aflatoxin B1 (AFB1)-specific codon 249 TP53 mutation was determined by NGS in circulating cell-free plasma DNA.

RESULTS

In phylogenetic analysis, 85% of individuals carried HBV genotype E, 14% genotype A, and 1% A/E recombinant viruses. Surface gene variants were more frequently observed in cases (43% and 57% in cirrhosis and HCC cases, respectively) than controls (25%; p <0.001), with preS2 deletions between nucleotides 38-55 (preS2Δ38-55) being the main genetic variant detected. In multivariable analysis, HBeAg seropositivity, low HBsAg levels, and HDV seropositivity were significantly associated with cirrhosis and HCC, whilst older age, higher viral load, genotype A, preS2Δ38-55, and AFB1 exposure were only associated with HCC. There was a multiplicative joint effect of preS2Δ38-55 variants with HBeAg seropositivity (odds ratio [OR] 43.1 [10.4-177.7]), high viral load >2,000 IU/ml (OR 22.7 [8.0-64.9]), HBsAg levels <10,000 IU/ml (OR 19.0 [5.5-65.3]), and AFB1 exposure (OR 29.3 [3.7-230.4]) on HCC risk.

CONCLUSIONS

This study identified a hotspot for HBV preS2 deletions as a strong independent factor for HCC in The Gambia, with HBV genotypes and AFB1 exposure contributing to the high liver cancer risk.

LAY SUMMARY

Although HBV-related liver disease is highly prevalent in sub-Saharan Africa, the associated virological characteristics are poorly studied. Using clinical data from African patients chronically infected with HBV, an assessment of the virological variability (genotypes and mutations) and exposure to AFB1, a toxin often contaminating food, was carried out. Our results show that HBV genotypes, the presence of a highly prevalent mutant form of HBV, and AFB1 exposure contribute to the high liver cancer risk in this population.

Association of the Hepatitis B Virus Large Surface Protein with Viral Infectivity and Endoplasmic Reticulum Stress-mediated Liver Carcinogenesis

Hepatitis B is the most prevalent viral hepatitis worldwide, affecting approximately one-third of the world’s population. Among HBV factors, the surface protein is the most sensitive biomarker for viral infection, given that it is expressed at high levels in all viral infection phases. The large HBV surface protein (LHBs) contains the integral pre-S1 domain, which binds to the HBV receptor sodium taurocholate co transporting polypeptide on the hepatocyte to facilitate viral entry. The accumulation of viral LHBs and its prevalent pre-S mutants in chronic HBV carriers triggers a sustained endoplasmic reticulum (ER) overload response, leading to ER stress-mediated cell proliferation, metabolic switching and genomic instability, which are associated with pro-oncogenic effects. Ground glass hepatocytes identified in HBV-related hepatocellular carcinoma (HCC) patients harbor pre-S deletion variants that largely accumulate in the ER lumen due to mutation-induced protein misfolding and are associated with increased risks of cancer recurrence and metastasis. Moreover, in contrast to the major HBs, which is decreased in tumors to a greater extent than it is in peritumorous regions, LHBs is continuously expressed during tumorigenesis, indicating that LHBs serves as a promising biomarker for HCC in people with CHB. Continuing efforts to delineate the molecular mechanisms by which LHBs regulates pathological changes in CHB patients are important for establishing a correlation between LHBs biomarkers and HCC development.

[The prevalence clinically significant virus mutations among patients with chronic viral hepatitis B.]

The prevalence of clinically significant virus mutations in patients with chronic viral hepatitis B from the Kyrgyz Republic was analyzed. Blood plasma samples of 64 patients with verified chronic viral hepatitis B obtained from Kyrgyzstan indigenous people were used in the work. Asymmetric PCR was carried out with extended oligonucleotides and the first reaction amplification product was further used in a new PCR with one of the nested pairs overlapping primers that flanked the entire HBV genome together, followed by sequencing. Based on the phylogenetic analysis of 64 HBV isolates obtained from patients from the Kyrgyz Republic, it was shown that only the genotype D virus was present in the examined group, the HBV subgenotype D1 (68.75%) prevailed compared with the HBV subgenotype D2 (18.75%) and subgenotype D3 (12.5%). For all subgenotypes, several independent infection sources are obvious, subclusters that include isolates from Kyrgyzstan, Kazakhstan and Uzbekistan are distinguished, as well as subclusters that include isolates only from Kyrgyzstan, which are less similar to isolates previously deposited in the international database, which probably indicates an independent HBV homologous evolution in the region. Clinically significant mutations were identified in 26.5% of patients. Including 12.5% with escape mutations that prevent the virus detection and / or allow the virus to replicate despite the vaccine (122K, 128V, 133I, 134N). Another 12.5% of the isolates are characterized by mutations that are independently associated with the liver cirrhosis and hepatocellular carcinoma development, including 21, 24, 27 nucleotides deletions in the Pre-S2 region and the S11F mutation in the PreCore region. In one case, unusual 236S and 250P mutations were found in the positions described as drug resistance sites of the P region associated with the resistance development to adefovir, tenofovir, and entecavir. The hepatitis B virus genetic structure analysis, early virus mutations detection in patients with chronic hepatitis B virus can help to choose the right vaccination strategy, antiviral and immunosuppressive therapy, as well as predict the clinical course and disease progression.

Pre-S Deletions are Predominant Quasispecies in HIV/HBV Infection: Quasispecies Perspective

Background

Combined HIV infection can accelerate HBV-induced liver disease. It is known that HBV Pre-S deletion is closely related to HBV-associated terminal liver disease in HBV mono-infection. Currently, data on HBV Pre-S quasispecies feature deletion in HIV/HBV co-infected patients are lacking.

Methods

The characteristics and blood samples of patients with chronic HBV infection were collected and classified into an HIV/HBV co-infection group and an HBV mono-infection group according to HIV antibody results before treatment. HBV DNA in serum was extracted. The HBV Pre-S region was amplified by nested-PCR and was further T-A cloned. Using the standard sequence of the matched genotype HBV as a reference, BioEdit 7.0 software was employed for sequence alignment.

Results

HBV Pre-S regions were successfully amplified from 147 patients, including 71 cases in the HIV/HBV co-infected group and 76 cases in the HBV mono-infected group. The proportion of the HIV/HBV co-infected group with Pre-S quasispecies deletion was lower than that of the HBV mono-infected group. By analyzing the frequency of Pre-S quasispecies in the two groups, the frequency of Pre-S quasispecies in HIV/HBV co-infected patients with Pre-S quasispecies was higher than HBV mono-infected patients. The frequency of Pre-S quasispecies deletion of the S protein promoter region in the HIV/HBV co-infected group was significantly higher than that in the HBV mono-infected group.

Conclusion

High-frequency Pre-S quasispecies deletions are predominant in HIV/HBV co-infected patients; however, low-frequency Pre-S deletions are predominant in HBV mono-infected patients, providing a reference for the pathogenesis of the accelerated progression of liver disease in HIV/HBV co-infection.

Biological features of hepatitis B virus strains associated with fulminant hepatitis

Accumulating evidence suggests that hepatitis B virus (HBV) biological features may influence the course and clinical manifestations of infection and possibly the development of fulminant hepatitis (FH). Since HBV is not a cytocidal virus, virus-induced liver damage results from an interplay between the virus replication and the host's defense. Therefore, viral factors contributing to enhanced replication, induction of a stronger immune attack or apoptosis of hepatocytes could be crucial in development of FH. Numerous mutations in basal core promoter, pre-C, C and S regions of the HBV genome contribute to development of FH by different mechanisms, including enhanced viral replication, the loss of a decoy for immune response, unbalanced expression of viral proteins and retention of unprocessed cytotoxic proteins in hepatocytes.

Molecular characterization of hepatitis B virus isolated from Black South African cancer patients, with and without hepatocellular carcinoma

In South Africa (SA), hepatitis B virus (HBV) infection is strongly associated with hepatocellular carcinoma (HCC). As HBV genotypes/subgenotypes and mutations can influence disease manifestation and progression, our aim was to molecularly characterize HBV in Black cancer patients, with and without HCC. The basal core promoter/precore (BCP/PC) and complete surface (S) regions of HBV isolates were amplified and sequenced from 55 HCC cases and 22 non-HCC cancer controls. Phylogenetic analysis of 43 polymerase/complete S region amplicons showed that the majority (88.4%) clustered with subgenotype A1, 4.7% with A2, and 7% with A3. The following mutations were significantly more frequent in HCC cases than in controls (p < 0.05): in the BCP/PC 1753C/G (22.5% vs. 0%), 1764A (69.4% vs. 38.1%), and T64C (51.5% vs. 20%) in the preS2, which results in a F22L substitution. PreS1 and preS2 start codon mutants were detected only in HCC cases, occurring in two and 16 isolates, respectively. PreS deletion mutants were isolated from 11 HCC cases, which had a HBV viral load > 10,000 IU/mL and were significantly younger than non-HCC controls (34 ± 7.1 vs. 41.2 ± 9.5 years, p = 0.05). The 1762T/1764A double mutation was detected in the majority (90.9%) of the isolates from HCC cases with preS deletions. Black HBV carriers were mainly infected with subgenotype A1, with HCC cases carrying BCP/PC and preS mutant strains that are associated with hepatocarcinogenesis. This is the first study to compare the molecular characteristics of HBV from HCC and non-HCC cancer patients in SA.

Do the circulating Pre-S/S quasispecies influence hepatitis B virus surface antigen levels in the HBeAg negative phase of HBV infection?

BACKGROUND

Virus, host factors and their interplay influence Hepatitis B surface Antigen serum levels during Hepatitis B Virus (HBV) infection course and treatment.

AIM

To study the Pre-S/S circulating quasispecies in a cohort of untreated, HBeAg negative, genotype-D, HBsAg carriers.

METHODS

We studied 260 carriers: 71 with HBeAg negative infection (ENI; HBV-DNA ≤2000 IU/mL); 42 Grey Zone (GZ; HBV-DNA ≤20 000 IU/mL); 82 chronic hepatitis (CH) and 65 cirrhosis (CI) (HBV-DNA > 20 000 IU/mL). Population sequencing was applied to identify Pre-S/S gene mutations responsible for any amino acid substitution or potential biological/antigenic implications (M-muts) on HBsAg.

RESULTS

HBsAg serum levels were lower in ENI + GZ than in CH + CI (2.61 [-1.10/4.06] vs 3.62 [2.41/4.92] log₁₀ IU/mL, P < 0.001) and in CI than CH (3.48 [2.41/4.38] vs 3.66 [2.57/4.92] log₁₀ IU/mL, P < 0.001). M-muts were found in 73 (28.1%) cases: 5 (7.0%) ENI, 3 (7.1%) GZ, 26 (31.7%) CH, 39 (60.0%) CI (P < 0.001) and mostly in Pre-S2 (17.6%) than Pre-S1 (5.8%) and Small-S (10.8%; P < 0.001). Overall HBsAg serum levels were higher in carriers with M-muts (3.56 [0.95/4.38] vs 3.17 [-1.10/4.92] log₁₀ IU/mL, P < 0.001), but comparable in carriers with or without M-mut when considering separately ENI + GZ (2.84 [0.95/3.89] vs 2.61 [-1.10/4.06] log₁₀ IU/mL, P = 0.330] and CH + CI (3.57 [2.67/4.38] vs 3.63 [2.41/4.92] log₁₀ IU/mL, P = 0.37). Infection phase (β: 0.422, P < 0.001), age (β: -0.260, P < 0.001), ALT (β: -0.103, P = 0.045), liver stiffness (β: -0.118, P = 0.039) and HBV-DNA (β: 0.384, P < 0.001), but not M-mut were independently associated with HBsAg serum levels.

CONCLUSIONS

In HBeAg negative, genotype-D, carriers Pre-S/S heterogeneity increases with severity of liver disease, but does not influence HBsAg serum levels, that in low viraemic carriers are associated with an effective control of HBV.

Long-term outcomes of HBsAg/anti-HBs double-positive versus HBsAg single-positive patients with chronic hepatitis B

The coexistence of HBsAg and anti-HBs has been reported in some chronic hepatitis B patients; however, the long-term outcomes of this serological profile have not been elucidated. We aimed to evaluate the long-term outcomes of HBsAg/anti-HBs double-positive chronic hepatitis B patients. Chronic hepatitis B patients who underwent baseline abdominal ultrasonography and follow-up (HBsAg/anti-HBs assessment and abdominal ultrasonography) at our healthcare center were included. The "coexistence group" included patients positive for both HBsAg and anti-HBs and the "control group" included patients positive for only HBsAg during follow-up. The outcomes were hepatocellular carcinoma (HCC) incidence, HBsAg seroclearance and overall mortality. Kaplan-Meier and Cox proportional hazard regression analyses were performed. Of the 2,341 eligible patients, 166 (7.1%) were in the coexistence group. The total follow-up duration was 5.4 years. The coexistence group had a 3.08-fold higher risk of HCC than the control group [hazard ratio (HR) 3.08, 95% confidence interval(CI) 1.26-7.55, P = 0.014] in multivariate analysis. The coexistence group had more HBsAg seroclearance than the control group (HR 1.43, 95% CI 1.01-2.03, P = 0.046). However, overall mortality did not significantly differ between the 2 groups. The coexistence group is heterogeneous and includes subjects with unfavorable outcomes (incidence of HCC) and favorable outcomes (more HBsAg seroclearance).

Formation of semi-enveloped particles as a unique feature of a hepatitis B virus PreS1 deletion mutant

BACKGROUND

Naturally occurring variants with deletions or mutations in the C-terminal PreS1 domain from hepatitis B virus (HBV) chronically infected patients have been shown to promote HBsAg retention, inhibit HBsAg secretion and change the extracellular appearance of PreS1-containing HBV particles (filaments and virions).

AIMS

To study the impact of N-terminal deletion in preS1 domain on viral secretion and morphogenesis.

METHODS

An HBV mutant with 15 amino acids (aa 25-39) deletion in N-terminal preS1 was isolated. Intracellular and extracellular HBsAg were quantified by Western blot. Subcellular HBsAg distribution was analysed by confocal laser scanning microscopy. The viral morphology was characterised by sucrose density gradient ultracentrifugation, Western blot, electron microscopy, HBV mixed ELISA and HBV particle gel essay.

RESULTS

Expression of this mutant genome released higher amounts of HBsAg in the form of shorter filaments. A significant fraction of semi-enveloped virions was observed in the supernatant that has been unprecedented so far. Stepwise insertion of aa 25-31, aa 32-39 and aa 25-39 increased the length of filaments. The rescue of aa 25-31 and aa 25-39 drastically reduced the amounts of extracellular HBsAg and semi-enveloped virions, while such effects could not be observed after insertion of aa 32-39, arguing against a simple spacer function of this region. The deletion and rescued mutants do not differ in subcellular HBsAg distribution and colocalisation with ER, Golgi and multivesicular bodies markers arguing against differences in release pathways.

CONCLUSION

N-terminal PreS1-domain (aa 25-31) determines HBsAg secretion and triggers proper assembly of PreS1-containing particles.

Non-invasive biomarkers for chronic hepatitis B virus infection management

Chronic hepatitis B virus (HBV) infection remains a major health burden with over 250 million cases worldwide. This complex infection can lead to chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Complete recovery is seldom achieved due to the persistence in infected hepatocytes of covalently closed circular (ccc)DNA, which is not targeted by current antiviral therapies. Routine circulating biomarkers used for clinical monitoring of patients do not accurately reflect the cccDNA pool and transcriptional activity. New biomarkers, such as serum HB core-related Ag and circulating HBV RNAs, are under development. In this review, we discuss surrogate non-invasive biomarkers for evaluating intrahepatic cccDNA abundance and transcriptional activity. We also present their relevance for improving the classification of patients with regards to their natural history and for evaluating novel compounds to assess target engagement and to define new virological endpoints.

Hepatitis B Virus Molecular Epidemiology, Host-Virus Interaction, Coinfection, and Laboratory Diagnosis in the MENA Region: An Update

Hepatitis B virus (HBV) is an enveloped partial double-stranded DNA virus that can cause acute and chronic hepatitis. According to the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), 257 million people are living with HBV. Moreover, 20,900 acute hepatitis B cases were reported in 2016. Hepatitis B is highly prevalent in the African, Western Pacific, Eastern Mediterranean, South-East Asia, and European regions, respectively. Due to the high mutational rate of HBV and lack of reverse transcriptase proofreading activity, ten different genotypes with different geographical distributions have been identified. HBV pathogenesis and severity of infection depend on several host and viral factors, particularly, the genetic variability of both the host and virus. Although HBV infection is a global health concern, there is a lack of adequate studies and reports in the Middle East and North Africa (MENA) region. Here, we provide a review on HBV epidemiology, pathogenesis, host-pathogen interactions, coinfection with selected viruses, and laboratory diagnosis, focusing on studies conducted in the MENA region to determine the current situation of the HBV infection and outline the future study areas.

A substitution in the pre-S1 promoter region is associated with the viral regulation of hepatitis B virus

Background

Much evidence has demonstrated the influence of Hepatitis B virus (HBV) mutations on the clinical course of HBV infection. As large (L) protein plays a crucial role for viral entry, we hypothesized that mutations in the pre-S1 promoter region might affect the expression of L protein and subsequently change the biological characters of virus.

Methods

Patients infected with genotype C HBV were enrolled for analysis. HBV DNA sequences were inserted into a TA cloning vector and analyzed. To evaluate the effects of mutations in the pre-S1 promoter region, promoter activity and the expression of mRNA and L protein were analyzed using HepG2 cells.

Results

In total, 35 patients were enrolled and 13 patients (37.1%) had a single base substitution in the pre-S1 promoter region; the most frequent substitution was a G-to-A substitution at the 2765th base (G2765A) in the Sp1 region. The HBV viral load showed a negative correlation with the substitution ratio of the Sp1 region or G2765A (r = − 0.493 and − 0.473, respectively). Among those with a viral load ≤5.0 log IU/ml, patients with the G2765A substitution showed a significantly lower HBV viral load than those with the wild-type sequence. HepG2 cells transfected with the G2765A substitution vector showed reduced luciferase activity of the pre-S1 promoter, as well as reduced expression of pre-S1 mRNA and L protein. Furthermore, the G2765A substitution greatly reduced the L protein expression level of vector-produced virus particles.

Conclusion

G2765A substitution in the pre-S1 promoter reduced the expression of L protein and resulted in a low viral load and less severe disease in chronic HBV infections.

Variants of hepatitis B virus surface antigen observed during therapy with nucleic acid polymer REP 2139-Ca have no influence on treatment outcome and its detection by diagnostic assays

The treatment of patients suffering from HBeAg-positive chronic hepatitis B with REP 2139-Ca resulted in potent reductions in HBsAg and HBV DNA, seroconversion to anti-HBs and the establishment of functional control of infection. In this cohort of 12 patients, we investigated whether differences between HBsAg sequences might explain the lack of response to REP 2139-Ca observed in 3 of 12 patients. We also assessed if the reduction or complete loss of HBsAg in serum observed during therapy were caused by mutations in the "a" determinant preventing the detection of HBsAg by standard diagnostic assays. The complete pre-S/S open reading frame (ORF) was sequenced and pre-S1, pre-S2 and S amino acid sequences were analysed. We found no major differences between pre-S1, pre-S2 and S sequences in responders and nonresponders correlated with low reduction in HBsAg. In addition, we found no mutations in the "a" determinant that would significantly affect the reactivity of HBsAg in diagnostic assays. These results demonstrate that the amino acid sequence of complete pre-S/S ORF has no direct influence on response to REP 2139-Ca therapy.

Clinical Outcome and Viral Genome Variability of Hepatitis B Virus-Induced Acute Liver Failure

Acute hepatitis B virus (HBV) infection remains a frequent cause of acute liver failure (ALF) worldwide. ALF occurs in 0.1%-0.5% of infected patients. The aim of this study was to scrutinize the outcome of patients with HBV-induced ALF and mutational patterns of HBV variants, which might contribute to ALF. From 2005 to 2016, 42 patients were treated for HBV-induced ALF in the University Hospital Essen, Germany. Clinical and virological data from these patients were collected. As a control, 38 patients with acute hepatitis B (AHB) without liver failure were included. The HBV genome was sequenced by next-generation sequencing (NGS). Mutations that were found by NGS were analyzed in vitro. Of 42 patients, 8 had ALF without spontaneous recovery (NSR): Seven patients underwent liver transplantation (LT) and one patient died before LT. Of 42 patients, 34 (81%) had spontaneous recovery (SR) and cleared the infection, achieving either anti-HBs seroconversion or hepatitis B surface antigen (HBsAg) loss. HBV genotype (GT)-D was the most frequent GT in patients with ALF. Mutations in HBV core, preS2, and small hepatitis B surface antigen (SHB) were more frequent in patients with ALF-NSR compared with those with ALF-SR or AHB. Amino acid deletions (del; 16-22 and 20-22) in preS2 and SHB mutation L49R were exclusively detected in patients with ALF-NSR. In vitro analyses reveal that these mutations did not influence HBsAg secretion or infectivity. Conclusion: HBV GT-D and increased variability in HBV core, preS2 region, and SHB are associated with a worse clinical outcome of acute HBV infection.

HBV preS deletion mapping using deep sequencing demonstrates a unique association with viral markers

Aim

Deletions are observed frequently in the preS1/S2 region of hepatitis B virus (HBV) genome, in association with liver disease advancement. However, the most significant preS1/S2 region and its influences on viral markers are unclear.

Methods

The preS1/S2 HBV regions of 90 patients without antiviral therapy were subjected to deep sequencing and deleted regions influencing viral markers were investigated.

Results

From the deletion frequency analysis in each patient, deletions were observed most frequently in the preS2 codon 132–141 region. When the patients were divided into three groups (0–0.1%: n = 27, 0.1%-10%: n = 34, 10–100%: n = 29), based on the deletion frequency, FIB-4 (p < 0.01), HBV DNA (p < 0.01), HBcrAg (p < 0.01) and preS1/S2 start codon mutations (p < 0.01, both) were significantly associated with the deletion. When clinical and viral markers were investigated by multivariate analysis for their association with the deletion, FIB-4 (p < 0.05), HBcrAg (p < 0.05), and preS1 start codon mutation (p < 0.01) were extracted as independent variables. When the influence of the preS codon 132-141deletions on HBsAg and HBcrAg, relative to HBV DNA, was investigated, the HBsAg/HBV DNA ratio was lower (0–10% vs. 10%-100%, p<0.05), while the HBcrAg/HBV DNA rati o was higher (0–0.1% vs. 10%-100%, p<0.05) in the presence of the preS codon 132-141deletions.

Conclusion

The preS codon.132-141 deletions have a significant influence on the clinical characteristics and viral markers, even when present as a minor population. Importantly, the preS codon 132–141 deletions have a clear influence on the viral life cycle and pathogenesis.

Response of hepatitis B virus to antiretroviral treatment containing lamivudine in HBsAg-positive and HBsAg-negative HIV-positive South African adults

Both hepatitis B virus (HBV) and human immunodeficiency virus (HIV) infection are highly endemic in sub-Saharan Africa. This study examined serological and clinical follow-up data from 39 HBV DNA-positive, HIV-positive black South African adults, who returned for follow-up at 3, 6, 12, and 18 months post-initiation of antiretroviral therapy (ART). Of the 39 participants, 10 experienced full suppression of HBV and 29 experienced no suppression, with 10 of these showing a virological breakthrough. All 10 patients who fully suppressed were HBsAg-negative, with 16 of the 29 who did not suppress being HBsAg-positive and 13 HBsAg-negative (P < 0.05). Participants fully suppressing the virus had significantly lower aminotransferase levels and were all HBsAg-negative compared to those who did not suppress (P < 0.05). HBV viral loads between HBsAg-positive and HBsAg-negative samples were similar at baseline and at the final time-point. In these South African patients with HBV/HIV coinfection, HBsAg-negative status at baseline was a predictor of the outcome of HBV suppression in response to ART containing lamivudine.

Taiwan consensus statement on the management of chronic hepatitis B

The experts of Taiwan Association for the Study of Liver (TASL) have actively participated and led the guidelines on hepatitis B virus (HBV) management by Asian Pacific Association for the Study of Liver (APASL) which is the first international association for the study of liver to publish the statement on HBV management before. However, there are more and more new data on the natural history and treatment of HBV infection in the past decade. These include new application of an old biomarker (quantitative HBsAg), clinical significance of HBV genotype and naturally occurring mutations, the role of non-invasive examination in evaluating severity of hepatic fibrosis, clinical significance of outcome calculators, new drug or new combination strategies towards more effective therapy and organ transplantation including liver and non-liver transplantation. It is time to publish the guidelines on HBV management of Taiwan. Hence, TASL have conducted an expert meeting to review, to discuss and to debate the relevant literatures, followed by draft the manuscript of HBV management guidelines and recommendations. The guidelines include general management, indications for fibrosis assessment, time to start or stop drug therapy, choice of drug to initiate therapy, when and how to monitor the patients during and after stopping drug therapy. Recommendations on the therapy of patients in special circumstances, including women in childbearing age, patients with antiviral drug resistance, concurrent viral infection, hepatic decompensation, patient receiving immune suppression or chemotherapy and patients in the setting of liver transplantation and hepatocellular carcinoma, are also included.

CTL-associated and NK cell-associated immune responses induce different HBV DNA reduction patterns in chronic hepatitis B patients

The activation of hepatitis B virus (HBV)-related hepatitis is associated with both natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). We analyzed the association between the immune response and changes in the proportion of Pre-S deletion variants. We quantified Pre-S deleted HBV (HBV-del) and wild-type HBV (HBV-wt) DNA levels in sera obtained from HBV-infected mice and chronic hepatitis B patients. In chronic hepatitis B patients, the HBV-del proportion usually increased during or after ALT elevation but did not occur during all ALT elevations. To clarify this difference in the immunological responses, we performed in vivo analyses using HBV-infected human hepatocyte chimeric mice. Although HBV-del proportions did not change in mice with NK cell-associated hepatitis or in mice treated with entecavir, the proportions sharply increased in mice with CTL-associated hepatitis. Furthermore, the number of patients in which HBV-del proportions were greater than 5% was significantly higher in chronic hepatitis B patients than in asymptomatic carriers (P = 0.023). We identified associations between virological response in chronic hepatitis B patients and two different immune responses. The proportion of HBV-del variants could be a useful biomarker for distinguishing between chronic hepatitis and asymptomatic carriers.

Hepatitis B virus infection: Defective surface antigen expression and pathogenesis

Hepatitis B virus (HBV) infection is a global public health concern. HBV causes chronic infection in patients and can lead to liver cirrhosis, hepatocellular carcinoma, and other severe liver diseases. Thus, understanding HBV-related pathogenesis is of particular importance for prevention and clinical intervention. HBV surface antigens are indispensable for HBV virion formation and are useful viral markers for diagnosis and clinical assessment. During chronic HBV infection, HBV genomes may acquire and accumulate mutations and deletions, leading to the expression of defective HBV surface antigens. These defective HBV surface antigens have been found to play important roles in the progression of HBV-associated liver diseases. In this review, we focus our discussion on the nature of defective HBV surface antigen mutations and their contribution to the pathogenesis of fulminant hepatitis B. The relationship between defective surface antigens and occult HBV infection are also discussed.

Genetic variability in coding regions of the surface antigen and reverse transcriptase domain of hepatitis B virus polymerase, Colombia, 2002-2014

Introduction: Despite the availability of an effective vaccine and treatment to reduce the viral load and progressive hepatocellular injury, approximately 240 million people worldwide are chronically infected with the hepatitis B virus (HBV). In Colombia, the circulation of different viral genotypes has been confirmed. Mutations in the genome have been associated to antiviral therapy resistance, viral escape to neutralizing antibodies, occult infection and progression to hepatocellular carcinoma. Objective: To identify the genotypes and the presence of mutations in the coding region of the surface (S) antigen and the reverse transcriptase (RT) domain of the polymerase of HBV obtained from serum samples for hepatitis B diagnosis received by the Instituto Nacional de Salud during the period 2002-2014. Materials and methods: A total of 495 serum samples with previous HBsAg reactive result were used for molecular detection. A fragment of 1,591 nucleotides was sequenced, and the corresponding phylogenetic analysis was performed. Results: We detected the viral genome of HBV in 66 samples and 28 were successfully sequenced. The phylogenetic analysis allowed the identification of subgenotypes F3 and A2. The L180M and M204V resistance mutations were simultaneously identified in one sample, while the I169L resistance mutation was identified in another one. A single escape mutation, P120Q, was identified in one more. Two samples showed a deletion of 105 nucleotides in the preS1-preS2 region. Conclusions: The circulation of genotypes/subgenotypes F3 and A2 of HBV in Colombia was corroborated, as well as the presence of some resistance and escape mutations. The present study constitutes a contribution to the molecular epidemiology of HBV in Colombia.

Development of a fibrosis index including hepatitis B virus basal core promoter A1762T mutation for pretherapeutic evaluation

BACKGROUND AND AIM

Commonly used non-invasive fibrosis scores usually included serum transaminase levels in the equations, including Aspartate transaminase to Platelet Ratio Index (APRI) and fibrosis-4 (FIB-4). Transaminases fluctuated significantly in chronic hepatitis B patients with exacerbations, leading to unsteady score values. As such, here, we aim to develop a transaminase-free score suitable for pretherapeutic evaluation of fibrosis stages.

METHODS

Firstly, 1082 treatment-naïve chronic hepatitis B patients were enrolled and divided into modeling (n = 541) and verification (n = 541) cohorts. Secondly, 265 patients having received liver biopsy, with known Ishak fibrosis stages, were included for independent correlation.

RESULTS

Cross-sectional analysis of 1082 patients revealed age-dependent variation of association between virological factors and cirrhosis. A fibrosis score including Anti-hepatitis B e antibody, Basal core promoter (BCP) A1762T mutation, and Platelet count Index (named ABPI) was derived from the modeling cohort. ABPI performed better than APRI and FIB-4 in the verification cohort for identifying cirrhotic patients (comparison of area under the receiver operating characteristic curves: ABPI vs APRI and FIB-4 = 0.785 vs 0.563 [P < 0.001] and 0.700 [P = 0.026], respectively). The performance of ABPI was even better in young (< 40 years old) hepatitis B patients (area under the receiver operating characteristic curves: 0.856 vs 0.402 [P < 0.001] and 0.599 [P = 0.009], respectively). Finally, in the independent cohort of 265 patients with known Ishak fibrosis stages, it was found that ABPI effectively distinguished between Ishak fibrosis stages 3 and > 3 and between 4 and > 4 (P < 0.001 for each).

CONCLUSIONS

We developed a transaminase-free fibrosis score (ABPI) utilizing basal core promoter A1762T data, which outperformed APRI and FIB-4.

Three types of preS1 start codon deletion variants in the natural course of chronic hepatitis B infection

BACKGROUND AND AIM

Naturally occurring hepatitis B virus variants carrying a deletion in the preS1 start codon region may evolve during long-lasting virus-host interactions in chronic hepatitis B (CHB). The aim of this study was to determine the immune phase-specific prevalent patterns of preS1 start codon deletion variants and related factors during the natural course of CHB.

METHODS

A total of 399 CHB patients were enrolled. Genotypic analysis of three different preS1 start codon deletion variants (classified by deletion size: 15-base pair [bp], 18-bp, and 21-bp deletion variants) was performed.

RESULTS

PreS1 start codon deletion variants were detected in 155 of 399 patients (38.8%). The predominant variant was a 15-bp deletion in the immune-tolerance phase (18/50, 36%) and an 18-bp deletion in the immune-clearance phase (69/183, 37.7%). A 21-bp deletion was the predominant variant in the low replicative phase (3/25, 12.0%) and reactivated hepatitis Be antigen (HBeAg)-negative phase (22/141, 15.6%). The 15-bp and 18-bp deletion variants were more frequently found in HBeAg-positive patients (P < 0.010 and P < 0.001, respectively), whereas the 21-bp deletion variant was more frequently found in HBeAg-negative patients (P < 0.001). On multiple logistic regression analyses, the 21-bp deletion variant was independently associated with liver cirrhosis (P = 0.006), and the 15-bp deletion variant was significantly related to an incomplete response to antiviral agents (P = 0.012).

CONCLUSIONS

The predominant type of preS1 start codon deletion variants changes according to the immune phases of CHB infection, and each variant type is associated with different clinical parameters. PreS1 start codon deletion variants might interact with the host immune response differently according to their variant types.

Review article: the prevention of hepatitis B-related hepatocellular carcinoma

BACKGROUND

Ample evidence indicates an aetiological association of persistent hepatitis B virus (HBV) infection with hepatocellular carcinoma (HCC). Several viral, host and external risk factors for the development of HBV-related HCC have been documented.

AIMS

To summarise and discuss the risk stratification and the preventive strategies of HBV-related HCC.

METHODS

Recent published studies identified from PubMed were comprehensively reviewed. The key words included chronic hepatitis B, HBV, hepatocellular carcinoma, prevention and antiviral therapy.

RESULTS

The incidence of HCC is extremely high in HBV hyperendemic areas. For HBV patients left untreated, significant risk factors for HCC include male gender, aging, advanced hepatic fibrosis, persistent serum transaminase elevation, specific HBV entry receptor (NTCP) genotype, PM2.5 exposure, HBeAg positivity, HBV genotype C/D/F, high proportion of core promoter mutation, pre-S deletion, high serum levels of HBV DNA and HBsAg as well as co-infection with HCV, HDV and HIV. Primary prevention of HBV-related HCC can be achieved through universal HBV vaccination and anti-viral prophylaxis for high viraemic mothers. The goal of secondary prevention has been reached by effective anti-viral therapy to reduce the risk of HCC development in chronic hepatitis B patients. However, whether HCC is prevented or delayed deserves further examination. Finally, several studies confirmed the tertiary preventive effect of anti-viral therapy in reducing risk of HCC recurrence after curative therapies.

CONCLUSIONS

Through the strategies of three-level prevention, the global burden of HBV-related HCC should decline over time and even be eliminated in conjunction with HBV cure.

Applications of next-generation sequencing analysis for the detection of hepatocellular carcinoma-associated hepatitis B virus mutations

BACKGROUND

Next-generation sequencing (NGS) is a powerful and high-throughput method for the detection of viral mutations. This article provides a brief overview about optimization of NGS analysis for hepatocellular carcinoma (HCC)-associated hepatitis B virus (HBV) mutations, and hepatocarcinogenesis of relevant mutations.

MAIN BODY

For the application of NGS analysis in the genome of HBV, four noteworthy steps were discovered in testing. First, a sample-specific reference sequence was the most effective mapping reference for NGS. Second, elongating the end of reference sequence improved mapping performance at the end of the genome. Third, resetting the origin of mapping reference sequence could probed deletion mutations and variants at a certain location with common mutations. Fourth, using a platform-specific cut-off value to distinguish authentic minority variants from technical artifacts was found to be highly effective. One hundred and sixty-seven HBV single nucleotide variants (SNVs) were found to be studied previously through a systematic literature review, and 12 SNVs were determined to be associated with HCC by meta-analysis. From comprehensive research using a HBV genome-wide NGS analysis, 60 NGS-defined HCC-associated SNVs with their pathogenic frequencies were identified, with 19 reported previously. All the 12 HCC-associated SNVs proved by meta-analysis were confirmed by NGS analysis, except for C1766T and T1768A which were mainly expressed in genotypes A and D, but including the subgroup analysis of A1762T. In the 41 novel NGS-defined HCC-associated SNVs, 31.7% (13/41) had cut-off values of SNV frequency lower than 20%. This showed that NGS could be used to detect HCC-associated SNVs with low SNV frequency. Most SNV II (the minor strains in the majority of non-HCC patients) had either low (< 20%) or high (> 80%) SNV frequencies in HCC patients, a characteristic U-shaped distribution pattern. The cut-off values of SNV frequency for HCC-associated SNVs represent their pathogenic frequencies. The pathogenic frequencies of HCC-associated SNV II also showed a U-shaped distribution. Hepatocarcinogenesis induced by HBV mutated proteins through cellular pathways was reviewed.

CONCLUSION

NGS analysis is useful to discover novel HCC-associated HBV SNVs, especially those with low SNV frequency. The hepatocarcinogenetic mechanisms of novel HCC-associated HBV SNVs defined by NGS analysis deserve further investigation.

The preS deletion of hepatitis B virus (HBV) is associated with liver fibrosis progression in patients with chronic HBV infection

BACKGROUND AND AIMS

Limited data are available regarding the association of hepatitis B virus (HBV) mutations with liver fibrosis in HBV infection. The study aimed to clarify whether HBV preS deletion mutation is associated with liver fibrosis progression.

METHODS

A total of 469 patients were enrolled, including 324 with chronic hepatitis B (CHB), 28 with HBV-related compensated liver cirrhosis (LC), and 117 with HBV-related decompensated LC. All CHB and compensated LC patients received liver biopsy. Fibrosis grade was assessed using METAVIR score. HBV preS deletion was determined by direct sequencing and verified by clonal sequencing.

RESULTS

Overall preS deletion was detected in 12.6% (59/469) patients, specifically, in 7.51% (13/173), 10.60% (16/151), and 20.69% (30/145) of patients with no-to-mild liver fibrosis (F0-1), moderate-to-severe liver fibrosis (F2-3), and cirrhosis (F4), respectively (p < 0.01). Patients with preS-deleted HBV had lower serum HBV DNA and albumin levels compared to patients with wild-type HBV. The median length of preS deletion was 39-base pairs (bp) (3-204 bp) and the deletion most frequently emerged in preS2 initial region. Multivariate analysis identified the preS2 deletion rather than preS1 deletion to be an independent risk factor of significant fibrosis, i.e., METAVIR F ≥ 2 (p = 0.007). In addition, preS-deleted viral sequences were detected in the pool of intrahepatic HBV covalently closed circular DNA.

CONCLUSIONS

HBV preS deletion is positively associated with liver fibrosis progression in chronic HBV-infected patients. HBV preS2 deletion may serve as a warning indicator for liver fibrosis progression.