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

Genetic Diversity of Hepatitis B and C Viruses Revealed by Continuous Surveillance from 2015 to 2021 in Gabon, Central Africa

Viral hepatitis remains one of the largest public health concerns worldwide. Especially in Central Africa, information on hepatitis virus infections has been limited, although the prevalence in this region has been reported to be higher than the global average. To reveal the current status of hepatitis B and C virus (HBV and HCV) infections and the genetic diversity of the viruses, we conducted longitudinal surveillance in Gabon. We detected 22 HBV and 9 HCV infections in 2047 patients with febrile illness. Genetic analyses of HBV identified subgenotype A1 for the first time in Gabon and an insertion generating a frameshift to create an X-preC/C fusion protein. We also revealed that most of the detected HCVs belonged to the "Gabon-specific" HCV subtype 4e (HCV-4e), and the entire nucleotide sequence of the HCV-4e polyprotein was determined to establish the first reference sequence. The HCV-4e strains possessed resistance-associated substitutions similar to those of other HCV-4 strains, indicating that the use of direct-acting antiviral therapy may be complex. These results provide a better understanding of the current situation of hepatitis B and C virus infections in Central Africa and will help public health organizations develop effective countermeasures to eliminate chronic viral hepatitis in this region.

Clinical Utility of Quantitative HBV Core Antibodies for Solving Diagnostic Dilemmas

The present-day management of hepatitis B virus (HBV) infection relies on constant and appropriate monitoring of viral activity, disease progression and treatment response. Traditional HBV infection biomarkers have many limitations in predicting clinical outcomes or therapy success. Quantitation of HBV core antibodies (qAnti-HBc) is a new non-invasive biomarker that can be used in solving multiple diagnostic problems. It was shown to correlate well with infection phases, level of hepatic inflammation and fibrosis, exacerbations during chronic infection and presence of occult infection. Further, the level of qAnti-HBc was recognised as predictive of spontaneous or therapy-induced HBeAg and HBsAg seroclearance, relapse after therapy discontinuation, re-infection after liver transplantation and viral reactivation upon immunosuppression. However, qAnti-HBc cannot be relied upon as a single diagnostic test to solve all dilemmas, and its diagnostic and prognostic power can be much improved when combined with other diagnostic biomarkers (HBV DNA, HBeAg, qHBsAg and anti-HBs antibodies). The availability of commercial qAnti-HBc diagnostic kits still needs to be improved. The comparison of results from different studies and definitions of universal cut-off values continue to be hindered because many methods are only semi-quantitative. The clinical utility of qAnti-HBc and the methods used for its measurement are the focus of this review.

Whole genome analysis of hepatitis B virus before and during long-term therapy in chronic infected patients: Molecular characterization, impact on treatment and liver disease progression

Hepatitis B virus (HBV) infection remains a serious public health concern worldwide despite the availability of an efficient vaccine and the major improvements in antiviral treatments. The aim of the present study is to analyze the mutational profile of the HBV whole genome in ETV non-responder chronic HBV patients, in order to investigate antiviral drug resistance, immune escape, and liver disease progression to Liver Cirrhosis (LC) or Hepatocellular Carcinoma (HCC). Blood samples were collected from five chronic hepatitis B patients. For each patient, two plasma samples were collected, before and during the treatment. Whole genome sequencing was performed using Sanger technology. Phylogenetic analysis comparing the studied sequences with reference ones was used for genotyping. The mutational profile was analyzed by comparison with the reference sequence M32138. Genotyping showed that the studied strains belong to subgenotypes D1, D7, and D8. The mutational analysis showed high genetic variability. In the RT region of the polymerase gene, 28 amino acid (aa) mutations were detected. The most significant mutations were the pattern rtL180M + rtS202G + rtM204V, which confer treatment resistance. In the S gene, 35 mutations were detected namely sP120T, sT126S, sG130R, sY134F, sS193L, sI195M, and sL216stop were previously described to lead to vaccine, immunotherapy, and/or diagnosis escape. In the C gene, 34 mutations were found. In particular, cG1764A, cC1766G/T, cT1768A, and cC1773T in the BCP; cG1896A and cG1899A in the precore region and cT12S, cE64D, cA80T, and cP130Q in the core region were associated with disease progression to LC and/or HCC. Other mutations were associated with viral replication increase including cT1753V, cG1764A/T, cC1766G/T, cT1768A, and cC1788G in the BCP as well as cG1896A and cG1899A in the precore region. In the X gene, 30 aa substitutions were detected, of which substitutions xT36D, xP46S, xA47T, xI88F, xA102V, xI127T, xK130M, xV131I, and xF132Y were previously described to lead to LC and/or HCC disease progression. In conclusion, our results show high genetic variability in the long-term treatment of chronic HBV patients causing several effects. This could contribute to guiding national efforts to optimize relevant HBV treatment management in order to achieve the global hepatitis elimination goal by 2030.

Analysis of hepatic fibrosis markers in the serum of chronic hepatitis B patients according to basal core promoter/precore mutants

The A1762T/G1764A double mutant in the basal core promoter (BCP) region of the hepatitis B virus (HBV) is associated with severe hepatic lesions while the G1899A mutation with the double mutant is associated with a significant reduction in the risk of severe fibrosis. This study aims to measure a number of markers in the serum of patients with chronic HBV infection and to assess relationships between these markers and BCP/precore mutants with consideration of the stage of fibrosis. The serum levels of resistin, TGF-β1, MMP-1, TIMP-1, collagen IA1 and PDGF-BB, which are markers that are known to be involved in the process of hepatic fibrosis, were assayed. The serum levels of PDGF-BB and TIMP-1, and the mutation profile were independently associated with advanced fibrosis. A higher level of TIMP-1 was associated with advanced fibrosis regardless of the mutation status, and a higher level of PDGF-BB was associated with nonsevere fibrosis in patients infected with viruses harboring the A1762T/G1764A or A1762T/G1764A/G1899A mutations. Our results suggest an impact of the A1762T/G1764A mutant on the biological pathway related to TGF-β1 and PDGF-BB. In vitro studies are needed to understand the impact of these mutants on the serum secretion of markers involved in fibrosis severity.

Viral quasispecies quantitative analysis: a novel approach for appraising the immune tolerant phase of chronic hepatitis B virus infection

Few non-invasive models were established for precisely identifying the immune tolerant (IT) phase from chronic hepatitis B (CHB). This study aimed to develop a novel approach that combined next-generation sequencing (NGS) and machine learning algorithms using our recently published viral quasispecies (QS) analysis package. 290 HBeAg positive patients from whom liver biopsies were taken were enrolled and divided into a training group (n = 148) and a validation group (n = 142). HBV DNA was extracted and QS sequences were obtained by NGS. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) based on viral operational taxonomic units (OTUs) were performed to explore the correlations among QS and clinical phenotypes. Three machine learning algorithms, including K-nearest neighbour, support vector machine, and random forest algorithm, were used to construct diagnostic models for IT phase classification. Based on histopathology, 90 IT patients and 200 CHB patients were diagnosed. HBsAg titres for IT patients were higher than those of CHB patients (p < 0.001). HCA and PCA analysis grouped IT and CHB patients into two distinct clusters. The relative abundance of viral OTUs differed mainly within the BCP/precore/core region and was significantly correlated with liver inflammation and fibrosis. For the IT phase classification, all machine-learning models showed higher AUC values compared to models based on HBsAg, APRI, and FIB-4. The relative abundance of viral OTUs reflects the severity of liver inflammation and fibrosis. The novel QS quantitative analysis approach could be used to diagnose IT patients more precisely and reduce the need for liver biopsy.

Clinical features of hepatitis B patients at immune-tolerance phase with basal core promoter and/or precore mutations

Little data exist on basal core promoter/precore (BCP/PC) mutations in chronic hepatitis B (CHB) patients at the immune-tolerance (IT) phase. We studied consecutive treatment-naïve, CHBe-antigen (HBeAg)-positive patients who had undergone liver biopsy and genotyping. Those in the IT phase or immune-clearance (IC) phase were enrolled for comparison of the frequency of BCP/PC mutations and their clinical presentations. Subgroup analyses for the IT group were also performed between patients with and without mutations, and IC patients between fibrosis stages ≤2 vs fibrosis >2. Among 301 patients enrolled, 88/301 (29.24%) and 213/301 (70.76%) were at the IT and IC phase, respectively. The frequency of BCP/PC mutations in IT phase was significantly lower than those in IC phase (15.91% vs 64.79%, P < .001). The BCP mutation only was significantly more frequent than the PC mutation in both groups and also in all IC subgroups. IT patients with BCP/PC mutations had significantly higher quantitative anti-HBc levels compared with those of patients with wild-type virus (P < .05). They also had significantly lower mean levels of alanine transaminase, aspartate transaminase, total bilirubin and qAnti-HBc compared with those of IC patients (all P < .05). Additionally, they were significantly younger in mean age, had higher platelet count, higher levels of HBV DNA and surface antigen, as well as higher frequency of genotype B than those of IC patients with fibrosis >2 (all P < .05). BCP/PC mutations were found in IT patients with CHB. They had distinct clinical characteristics when compared with patients with wild-type or at IC phase. Further studies are needed to understand their natural history and treatment outcomes.

Impacts of the Percentage of Basal Core Promoter Mutation on the Progression of Liver Fibrosis After Hepatitis B e Antigen Seroconversion

BACKGROUND

We investigated the relationships among the percentage of hepatitis B virus (HBV) mutations and liver fibrosis after hepatitis B e antigen (HBeAg) seroconversion.

METHODS

We quantified the percentage of HBV mutants by pyrosequencing using serum samples obtained at inflammatory phase and after HBeAg seroconversion in 160 initially HBeAg-positive chronic HBV-infected patients. The relationships between antiviral agents, percentages of HBV mutations, and liver stiffness measurements (LSMs) were analyzed.

RESULTS

We demonstrated that the percentages of A1762T/G1764A mutation are significantly higher in subjects with an LSM >7 kPa than in those with an LSM ≤7 kPa after HBeAg seroconversion. Hepatitis B e antigen seroconversion age is positively correlated with the percentages of A1762T/G1764A mutation at inflammatory phase before HBeAg seroconversion. Subjects who underwent interferon, entecavir, or tenofovir disoproxil fumarate therapy before HBeAg seroconversion possessed a lower percentage of A1762T/G1764A mutation after HBeAg seroconversion. The percentage of A1762T/G1764A ≥20% after HBeAg seroconversion was predictive of an LSM >7 kPa (hazard ratio = 6.37, P = .001). The presence of A1762T/G1764A led to downregulated messenger ribonucleic acid and protein levels of programmed-death ligand-1 (PD-L1) in hepatocytes.

CONCLUSIONS

The percentage of A1762T/G1764A mutations after HBeAg seroconversion was associated with liver fibrosis. The A1762T/G1764A mutation may evoke hepatic inflammation by suppressing PD-L1 in hepatocytes.

Presence of Precore (C)/C Promoter Mutants in Peripheral Blood Mononuclear Cells of Chronic Hepatitis B (CHB) Carriers During Pregnancy Does Not Correlate with Increased Risk of Liver Disease in 4 Years of Follow-Up

PURPOSE

HBV precore (PC) and basal core promoter (BCP) mutants are associated with liver disease severity, yet have been suggested to protect against HBV vertical transmission. HBV within peripheral blood mononuclear cells (PBMC) has been reported in association with intrauterine HBV infection. We analyzed HBV replication status in PBMC and PC/BCP mutants in PBMC from pregnant chronic hepatitis B (CHB) patients.

METHODS

Pregnant CHB carriers were assessed for HBeAg, HBV-DNA, ALT in second-third trimester and liver stiffness measurement (LSM) postpartum. HBV-DNA, HBV-cccDNA, and HBV-mRNA were tested in PBMC by in-house PCR. BCP/PC variants were determined by Sanger sequencing and analyzed using MEGA7.

RESULTS

In 37 CHB pregnant carriers, median age 32 years, 53% Asian, median ALT 19 versus 26 U/L, median HBV-DNA 2.6 versus 8.1 logIU/mL (untreated vs. treated), eight HBeAg⁺, with genotype 10%A, 29%B, 21%C, 10%D, 19%E, eight received tenofovir in pregnancy to reduce vertical transmission risk. HBV-DNA was detected in ~ 55% (25/45) PBMC, and PC/BCP mutations were found in 36% (9/25) and 4% (1/25), respectively. All infants received HBV immunoprophylaxis and tested HBV surface antigen negative at 9-12 months of age. During a median 4 years (IQR 3-5), follow-up all mothers showed normal LSM, with no significant change in ALT, HBeAg status, or HBV-DNA levels compared to baseline in untreated CHB carriers.

CONCLUSION

In this multiethnic cohort of pregnant CHB carriers, HBV replicative intermediates and PC/BCP mutants were found in significant proportion of PBMC, but were not associated with increased risk of HBV immunoprophylaxis failure or liver disease severity over long-term follow-up.

Nucleotide Substitutions in Hepatitis B Viruses Derived from Chronic HBV Patients

Background

Mutations in the S gene (HBsAg), pre-core (PC), and basic core promoter (BCP) of the hepatitis B virus (HBV) infection are correlated with disease progression. This study assessed the frequency of mutations in the S gene, PC, and BCP regions in chronic hepatitis B (CHB) patients.

Methods

104 formerly known CHB patients who visited Tehran Hepatitis centers, were included. The viral load of samples was determined based on the TaqMan method. Regions of the S gene, PC and BCP were amplified by the nested PCR. Positive PCR products were sequenced and analyzed.

Results

33 successfully sequenced S gene region revealed all the derived strains were genotype D, with the majority (90.9%) belonging to the ayw2 subtype, and the rest (9.1%) to the ayw1 subtype. The prevalence of mutations was found to be 51.0% and 18.0% in the HBsAg and the Major Hydrophilic Region, respectively. 70.0% of amino acid changes within HBsAg occurred in different immune epitopes, of which 27.0% and 72.0% were located in B cell and Th epitopes, respectively. 26 successfully sequenced PC and BCP regions showed at least one mutation in 84.6% of the HBV strains. The PC and BCP mutations were G1896A (61.0%), G1899A (23.0%), A1762T/G1764A (23.0%) and G1764T/C1766G (26.0%). None of the strains with A1762T/G1764A mutation carried the G1764T/C1766G mutant.

Conclusions

Our results showed common mutations within HBsAg, occurring in immune epitopes, a high rate of G1896A mutations in the PC region, and a negative correlation between the emergence of A1762T/G1764A mutation and the G1764T/C1766G mutant in the BCP region.

Management of Hepatitis B Virus Infection: 2018 Guidelines from the Canadian Association for the Study of Liver Disease and Association of Medical Microbiology and Infectious Disease Canada

Hepatitis B virus (HBV) infection is an important public health problem in Canada. In keeping with evolving evidence and understanding of HBV pathogenesis, the Canadian Association for the Study of Liver Disease periodically publishes HBV management guidelines. The goals of the 2018 guidelines are to (1) highlight the public health impact of HBV infection in Canada and the need to improve diagnosis and linkage to care, (2) recommend current best-practice guidelines for treatment of HBV, (3) summarize the key HBV laboratory diagnostic tests, and (4) review evidence on HBV management in special patient populations and include more detail on management of HBV in pediatric populations. An overview of novel HBV tests and therapies for HBV in development is provided to highlight the recent advances in HBV clinical research. The aim and scope of these guidelines are to serve as an up-to-date, comprehensive resource for Canadian health care providers in the management of HBV infection.

Precore G1896A mutation is associated with reduced rates of HBsAg seroclearance in treated HIV hepatitis B virus co-infected patients from Western Africa

The nucleotide substitution G1896A on the precore (pc) region has been implicated in virological and serological responses during treatment in hepatitis B virus (HBV)-infected patients. Whether this mutation affects the therapeutic course of HIV-HBV co-infected patients, especially from Western Africa, is unknown. In this prospective cohort study, 86 antiretroviral (ARV)-naïve HIV-HBV co-infected patients from Côte d'Ivoire, initiating ARV-treatment containing lamivudine (n = 53) or tenofovir (n = 33), had available baseline pc sequences. Association of the pcG1896A mutation with time to undetectable HBV-DNA, hepatitis B "e" antigen (HBeAg) seroclearance (in HBeAg-positive patients), and hepatitis B surface antigen (HBsAg) seroclearance was evaluated using Cox proportional hazards regression. At ARV-initiation, median HBV-DNA was 6.04 log₁₀ copies/mL (IQR = 3.70-7.93) with 97.7% harbouring HBV genotype E. Baseline pcG1896A mutation was identified in 51 (59.3%) patients, who were more commonly HBeAg-negative (P < .001) and had basal core promotor A1762T/G1764A mutations (P < .001). Patients were followed for a median 36 months (IQR = 24-36). Cumulative proportion of undetectable HBV-DNA was significantly higher in patients with baseline mutation (pcG1896A = 86.6% vs no pcG1896A = 66.9%, P = .04), but not after adjusting for baseline HBV-DNA levels and anti-HBV agent (P = .2). No difference in cumulative proportion of HBeAg seroclearance was observed between mutation groups (pcG1896A = 57.1% vs no pcG1896A = 54.3%, P = .7). Significantly higher cumulative proportion of HBsAg seroclearance was observed in patients without this mutation (pcG1896A = 0% vs no pcG1896A = 36.9%, P < .001), even after adjusting for baseline HBsAg quantification and anti-HBV agent (P < .001). In conclusion, lacking the pcG1896A mutation before ARV initiation appeared to increase HBsAg seroclearance rates during treatment. The therapeutic implications of this mutation need further exploration in this setting.

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.

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.

Low incidence of precore W28* mutant variants in treated hepatitis B virus and human immunodeficiency virus co-infected patients

The precore (pc) W28* mutation arises from immune-selective pressures during the hepatitis B "e" antigen (HBeAg)-positive phase of chronic hepatitis B virus (HBV) infection and has been linked to severe liver-related morbidity. Here, we examined the determinants of harboring this mutation and its rate of emergence in treated patients co-infected with human immunodeficiency virus (HIV) and HBV. In a three-year prospective cohort of 165 HIV-HBV co-infected patients, pcW28* mutation was determined via DNA-chip during yearly sampling. In a subgroup with liver biopsies, HBV covalently-closed circular (ccc)-DNA and total intrahepatic (IH)-DNA were quantified by real-time PCR. From respective inclusion to year-3 visits, median HBV-DNA levels decreased (5.88 log₁₀ IU/mL to <1.78 log₁₀ IU/mL, p < 0.001) and tenofovir-use increased (15.8%-71.4%, p < 0.001). At baseline, 47 of 162 (29.0%) patients had the pcW28* mutation and were more frequently HBeAg-negative (adjusted-OR = 4.37, 95%CI = 1.76-10.86) and had non-A HBV genotypes (adjusted-OR = 9.14, 95%CI = 4.05-20.66). No association with HIV-related factors was observed. In 114 patients without baseline mutation and available data, four developed incident pcW28* mutation by the end of follow-up (cumulative 3.5%, 95%CI = 1.3-9.1%). In the 32 patients with liver biopsies, 10 (31.3%) patients harboring the pcW28* mutation had significantly lower adjusted mean cccDNA (0.05 versus without = 0.43 copies/cell, p < 0.001) and total IH-DNA levels (2.31 versus without = 18.59 copies/cell, p = 0.006). In conclusion, the pcW28* mutation infrequently appeared in this co-infected study population with increased use of potent antivirals and suppressed levels of circulating virus.