Exploring the biological basis of hepatitis B e antigen in hepatitis B virus infection

VHL-independent degradation of hepatitis B virus e antigen (HBeAg) by VHL-binding chimeric small molecules

Hepatitis B virus (HBV) is a leading cause of liver cancer worldwide, with current treatment options unable to provide lasting efficacy against chronic infection. A key viral protein, HBV e antigen (HBeAg), plays an important role in suppressing the cellular and humoral immune response during infection and its loss is a precursor to clearance of chronic HBV infection. Its structural similarity to capsid forming HBV core protein antigen (HBcAg) makes it an intriguing, yet understudied target for pharmaceutical intervention. Recently, targeted protein degradation has been successfully applied against several viral proteins. This work investigates the targeting of HBeAg using heterobifunctional degraders derived from reported HBcAg ligands known to interact with HBeAg. Multiple compounds designed to recruit the VHL E3 ligase were found to be capable of reducing recombinant HBeAg protein levels in a HiBiT reporter assay system. Surprisingly, this decrease was found to be independent of VHL recruitment but driven by structural motifs of the VHL recruiting ligand, VH032. Virological assessment of these compounds against wildtype virus revealed an equipotent capability to reduce secreted HBeAg compared to the parental inhibitor, however increased efficacy was observed against an inhibitor resistant strain. Together, this work provides an initial description of the feasibility of converting HBV capsid-targeting ligands into degraders and provides evidence that such degraders may harbour improved activity against mutated forms of target which are resistant to parental compounds.

Hepatitis B surface antigen: carcinogenesis mechanisms and clinical implications in hepatocellular carcinoma

Liver cancer is the third leading cause of death globally, with hepatitis B virus (HBV) infection being identified as the primary risk factor for its development. The occurrence of HBV-related hepatocellular carcinoma (HCC) is attributed to various mechanisms, such as chronic inflammation and liver cell regeneration induced by the cytotoxic immune response triggered by the virus, abnormal activation of oncogenes arising from HBV DNA insertion mutations, and epigenetic alterations mediated by viral oncoproteins. The envelope protein of the HBV virus, known as hepatitis B surface antigen (HBsAg), is a key indicator of increased risk for developing HCC in HBsAg-positive individuals. The HBsAg seroclearance status is found to be associated with recurrence in HCC patients undergoing hepatectomy. Additional evidence indicates that HBsAg is essential to the entire process of tumor development, from initiation to advancement, and acts as an oncoprotein involved in accelerating tumor progression. This review comprehensively analyzes the extensive effects and internal mechanisms of HBsAg during the various stages of the initiation and progression of HCC. Furthermore, it highlights the importance and potential applications of HBsAg in the realms of HCC early diagnosis and personalized therapeutic interventions. An in-depth understanding of the molecular mechanism of HBsAg in the occurrence and development of HCC is provided, which is expected to develop more precise and efficient strategies for the prevention and management of HCC in the future.

Up-regulation of MDSCs accumulation and Th2 biased response to co-stimulation of CsESP from Clonorchis sinensis and HBeAg in vitro

Co-infection with Clonorchis sinensis (C. sinensis) and Hepatitis B virus (HBV) are commonly observed in endemic areas of Clonorchiasis. Chronic infection of C. sinensis or HBV is more likely to happen. However, the immune mechanisms related to the pathogenesis of co-infection remain unknown. In the present study, Myeloid-derived suppressor cells (MDSCs) accumulation, bone marrow derived dendritic cells (BMDCs) reaction and the consequent effectors on Th1/Th2 polarization to co-incubation of excretory-secretory products from C. sinensis (CsESP) and Hepatitis B e antigen (HBeAg) in vitro were investigated for further understanding the immune response during co-infection. The results indicated that compared with CsESP or HBeAg alone, co-stimulation dominantly promoted MDSCs accumulation. Co-stimulation significantly downregulated the expression of CD80 and CD86, and reduced IL-12p70 release while augmented IL-10 levels of BMDCs. Higher transcription levels of mannose receptor (MR) while lower mRNA level of toll like receptor 4 (TLR-4) were detected among membrane receptors of BMDCs with co-treatment. In addition, after CD4 naïve T cells were stimulated by LPS-treated BMDCs with CsESP and HBeAg, the proportion of CD4+IL-4+ T cells and IL-4 increased, while CD4+INF-γ+ T cells percentage and INF-γ down-regulated. In conclusion, CsESP and HBeAg co-incubation more distinctly suppressed maturation of BMDCs resulting in increase of IL-10 and decrease of IL-12 highly possible by up-regulation of MR and down-regulation of TLR-4 of BMDCs, and successively induce Th2 immune skewing. These findings laid the cornerstone to further clarify immune responses during the co-infection contributing to the better precise treatment and progression assessment of co-infection patients.

Mechanism Research of QingReJieDu Formula for Treating Hepatitis B Virus Based on Network Pharmacology

BACKGROUND

Hepatitis B virus (HBV) is a DNA virus known to induce hepatitis and liver dysfunction, and is one of the main causes of liver cirrhosis and liver cancer. At present, there lacks a satisfactory optimal treatment plan for HBV in clinical practice, promoting the development of a novel Chinese formula, QingReJieDu Formula (QRJDF), as a potential solution.

PURPOSE

This study aims to explore the underlying mechanisms of QRJDF in the treatment of Hepatitis B virus (HBV) through a combination of network pharmacology and experimental validation.

METHODS/STUDY DESIGN

HepG2.2.15 cells were used to study the efficacy of QRJDF against HBV in vitro. Entecavir (ETV) was used as a positive control. Additionally, HBV transgenic mice served as subjects to study the in vivo efficacy of QRJDF against HBV, with serum and tissue samples analyzed post-euthanasia at 12 weeks to observe relevant indicators. UPLC-Q-TOF-MS technology was utilized to obtain the main ingredients in QRJDF. Network pharmacology was used to explore the potential ingredients and targets of QRJDF against HBV. Transcriptome sequencing was used to further explore the potential targets of QRJDF against HBV. Finally, integration of network pharmacology and transcriptomics results facilitated the screening of potential key targets and identification of potential pathways.

RESULTS

QRJDF demonstrated anti-HBV effects in HepG2.2.15 cells, compared to ETV control, QRJDF was more efficient in inhibiting HBV antigen levels, although it was less efficient in inhibiting HBV DNA level. In addition, the antiviral effect was verified in HBV transgenic mice. Network pharmacology results found three major active anti-HBV ingredients from QRJDF. Network pharmacology and transcriptomics revealed that QRJDF could act on the TGFβ1/Smad4 signaling pathway.

CONCLUSION

The study comprehensively evaluated the efficacy in vivo and in vitro, and fully confirmed that QRJDF was a potential therapeutic agent for HBV. In addition, the transcriptome technology was verified, and the key targets and approaches of QRJDF against hepatitis B were screened in combination with network pharmacology, which provided research ideas for the follow-up research of antiviral Chinese medicine.

HBeAg induces neutrophils activation impairing NK cells function in patients with chronic hepatitis B

BACKGROUND

The role of neutrophils in hepatitis B virus (HBV) infection has been a subject of debate due to their involvement in antiviral responses and immune regulation. This study aimed to elucidate the neutrophil characteristics in patients with chronic hepatitis B (CHB).

METHODS

Through flow cytometry and ribonucleic acid-sequencing analysis, the phenotypes and counts of neutrophils were analyzed in patients with CHB. Moreover, the effects of HBeAg on neutrophils and the corresponding pattern recognition receptors were identified. Simultaneously, the cross-talk between neutrophils and natural killer (NK) cells was investigated.

RESULTS

Neutrophils were activated in patients with CHB, characterized by higher expression levels of programmed death-ligand 1 (PD-L1), cluster of differentiation 86, and interleukin-8, and lower levels of CXC motif chemokine receptor (CXCR) 1 and CXCR2. Hepatitis B e antigen (HBeAg) partially induces neutrophil activation through the Toll-like receptor 2 (TLR2). A consistent upregulation of the TLR2 and HBeAg expression was observed in patients with CHB. Notably, the genes encoding molecules pivotal for NK-cell function upon NK receptor engagement enriched in neutrophils after HBeAg activation. The HBeAg-activated neutrophils demonstrated the ability to decrease the production of interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) in NK cells, while the PD-1 and PD-L1 pathways partially mediated the immunosuppression.

CONCLUSIONS

The immunosuppression of neutrophils induced by HBeAg suggests a novel pathogenic mechanism contributing to immune tolerance in patients with CHB.

Chronic hepatitis B virus infection in Eastern Ethiopia: Clinical characteristics and determinants of cirrhosis

BACKGROUND

Chronic hepatitis B (CHB) virus infection is a major cause of liver-associated morbidity and mortality, particularly in low-income countries. A better understanding of the epidemiological, clinical, and virological characteristics of CHB will guide appropriate treatment strategies and improve the control and management of CHB in Ethiopia.

AIM

To investigate the characteristics of CHB in Eastern Ethiopia and assess the efficacy and safety of antiviral treatment.

METHODS

This cohort study included 193 adults who were human immunodeficiency virus-negative with CHB between June 2016 and December 2019. Baseline assessments included chemistry, serologic, and viral markers. χ 2 tests, Mann-Whitney U tests, and logistic regression analyses were used to identify the determinants of cirrhosis. Tenofovir disoproxil fumarate (TDF) was initiated using treatment criteria from the Ethiopian CHB pilot program.

RESULTS

A total of 132 patients (68.4%) were men, with a median age of 30 years [interquartile range (IQR): 24-38]. At enrollment, 60 (31.1%) patients had cirrhosis, of whom 35 (58.3%) had decompensated cirrhosis. Khat use, hepatitis B envelope antigen positivity, and a high viral load were independently associated with cirrhosis. Additionally, 66 patients (33.4%) fulfilled the treatment criteria and 59 (30.6%) started TDF. Among 29 patients who completed 24 months of treatment, the median aspartate aminotransferase to platelet ratio index declined from 1.54 (IQR: 0.66-2.91) to 1.10 (IQR: 0.75-2.53) (P = 0.002), and viral suppression was achieved in 80.9% and 100% of patients after 12 months and 24 months of treatment, respectively. Among the treated patients, 12 (20.3%) died within the first 6 months of treatment, of whom 8 had decompensated cirrhosis.

CONCLUSION

This study highlights the high prevalence of cirrhosis, initial mortality, and the efficacy of TDF treatment. Scaling up measures to prevent and control CHB infections in Ethiopia is crucial.

HBV PreC interacts with SUV39H1 to induce viral replication by blocking the proteasomal degradation of viral polymerase

Hepatitis B e antigen (HBeAg) seropositivity during the natural history of chronic hepatitis B (CHB) is known to coincide with significant increases in serum and intrahepatic HBV DNA levels. However, the precise underlying mechanism remains unclear. In this study, we found that PreC (HBeAg precursor) genetic ablation leads to reduced viral replication both in vitro and in vivo. Furthermore, PreC impedes the proteasomal degradation of HBV polymerase, promoting viral replication. We discovered that PreC interacts with SUV39H1, a histone methyltransferase, resulting in a reduction in the expression of Cdt2, an adaptor protein of CRL4 E3 ligase targeting HBV polymerase. SUV39H1 induces H3K9 trimethylation of the Cdt2 promoter in a PreC-induced manner. CRISPR-mediated knockout of endogenous SUV39H1 or pharmaceutical inhibition of SUV39H1 decreases HBV loads in the mouse liver. Additionally, genetic depletion of Cdt2 in the mouse liver abrogates PreC-related HBV replication. Interestingly, a negative correlation of intrahepatic Cdt2 with serum HBeAg and HBV DNA load was observed in CHB patient samples. Our study thus sheds light on the mechanistic role of PreC in inducing HBV replication and identifies potential therapeutic targets for HBV treatment.

Hepatitis B Virus Genotype Influence on Virological and Enzymatic Measures over Time-A Retrospective Longitudinal Cohort Study

HBV is a hepatotropic virus with multiple genotypes. It is uncertain if specific genotype(s) influence virological measures and/or liver markers over time. It is unclear whether nucleos(t)ide analogue therapy response is influenced by genotype. In this retrospective longitudinal study, we utilized data from The Ottawa Hospital Viral Hepatitis Program (TOHVHP) to evaluate the role of HBV genotype on viral load, liver enzymatic levels, fibrosis progression, and parenchymal inflammation and steatosis over time. HBV DNA, ALT, and AST levels, as well as transient elastography scores for fibrosis (E) and inflammation/steatosis (CAP), were modeled using mixed-effects linear regression. Interaction terms between HBV genotype and time were included to investigate if there was a difference in trends between genotypes. A total of 393 HBV patients infected with genotypes A-E were included. The mean age was 44.4 years, and 56% were male. Asian (50.5%), Black (29.1%), and White (6.4%) patients were well-represented. By multivariate analysis, we found no evidence that the trajectories of these commonly measured viral or liver measures varied over time by HBV genotype in those receiving HBV nucleos(t)ides and in those not on antiviral therapy.

The relationship of maternal hepatitis B e antigen and response to vaccination of infants born to women with chronic infection

BACKGROUND

The relationship of maternal HBeAg and infants' response to hepatitis B vaccine remains controversial. This study aims to observe the dynamic changes in infant birth HBV markers and study the time-varying effects of maternal HBeAg on vaccination response of infants born to women with chronic HBV infection.

METHODS

3163 infants born to HBsAg positive mothers including 1737 with maternal HBeAg positive in group A and 1426 negative in group B were enrolled eventually. Demographic information and laboratory tests were collected at birth, 7-12th and 24th month. The dynamic changes of infant HBV markers and HBsAb titers at different time points were compared between the two groups.

RESULTS

The infant HBV markers at birth displayed different modes. During the follow-up, we observed a significant downward trend in the positive rates of HBsAg, HBeAg, HBeAb and HBcAb. The HBsAg of two groups switched to negative at 7-12 months and HBeAg in Group A became negative at 24 months. The HBsAb titers of the infants in the two groups were 576.91(192.8-1000.0) vs 719.67(208.1-1000.0) at 7-12 months (Z = -3.049, P = 0.002) and 783.5(227.8-1000.0) vs 891.4(234.0-1000.0) at 24 months (Z = -0.853, P = 0.394). High HBV DNA viral load (OR 1.260, 95% CI 1.139-1.395, P < 0.001) and maternal HBeAg level (OR 1.003, 95% CI 1.002-1.003, P < 0.001) were associated with the higher HBeAg positive rate of infants.

CONCLUSIONS

Maternal HBeAg did affect the infants' immune response to vaccination and reduce the anti-response at 7-12th month temporarily, but these influences were negligible by 24th months after birth, which proved that the maternal HBeAg would not induce immune tolerance of infants from a long-term perspective.

Pre- and Post-Transcriptional Control of HBV Gene Expression: The Road Traveled towards the New Paradigm of HBx, Its Isoforms, and Their Diverse Functions

Hepatitis B virus (HBV) is an enveloped DNA human virus belonging to the Hepadnaviridae family. Perhaps its main distinguishable characteristic is the replication of its genome through a reverse transcription process. The HBV circular genome encodes only four overlapping reading frames, encoding for the main canonical proteins named core, P, surface, and X (or HBx protein). However, pre- and post-transcriptional gene regulation diversifies the full HBV proteome into diverse isoform proteins. In line with this, hepatitis B virus X protein (HBx) is a viral multifunctional and regulatory protein of 16.5 kDa, whose canonical reading frame presents two phylogenetically conserved internal in-frame translational initiation codons, and which results as well in the expression of two divergent N-terminal smaller isoforms of 8.6 and 5.8 kDa, during translation. The canonical HBx, as well as the smaller isoform proteins, displays different roles during viral replication and subcellular localizations. In this article, we reviewed the different mechanisms of pre- and post-transcriptional regulation of protein expression that take place during viral replication. We also investigated all the past and recent evidence about HBV HBx gene regulation and its divergent N-terminal isoform proteins. Evidence has been collected for over 30 years. The accumulated evidence simply strengthens the concept of a new paradigm of the canonical HBx, and its smaller divergent N-terminal isoform proteins, not only during viral replication, but also throughout cell pathogenesis.

Clinical isolates of hepatitis B virus genotype C have higher in vitro transmission efficiency than genotype B isolates

Serum samples were collected from 54 hepatitis B e antigen (HBeAg)-positive Chinese patients infected with hepatitis B virus (HBV) subgenotype B2 or C2. They were compared for transmission efficiency using same volume of samples or infectivity using same genome copy number. Adding polyethylene glycol (PEG) during inoculation did not increase infectivity of fresh samples but markedly increased infectivity following prolonged sample storage. Differentiated HepaRG cells infected without PEG produced more hepatitis B surface antigen (HBsAg) and higher HBsAg/HBeAg ratio than sodium taurocholate cotransporting polypeptide (NTCP)-reconstituted HepG2 cells infected with PEG. They better supported replication of core promoter mutant in contrast to wild-type (WT) virus by HepG2/NTCP cells. Overall, subgenotype C2 samples had higher viral load than B2 samples, and in general produced more HBeAg, HBsAg, and replicative DNA following same-volume inoculation. Precore mutant was more prevalent in subgenotype B2 and had reduced transmission efficiency. When same genome copy number of viral particles was inoculated, viral signals were not necessarily higher for three WT C2 isolates than four WT B2 isolates. Using viral particles generated from cloned HBV genome, three WT C2 isolates showed slightly reduced infectivity than three B2 isolates. In conclusion, subgenotype C2 serum samples had higher transmission efficiency than B2 isolates in association with higher viral load and lower prevalence of precore mutant, but not necessarily higher infectivity. PEG-independent infection by HBV viremic serum samples is probably attributed to a labile host factor.

Vertical Transmission of Hepatitis B Virus-An Update

Hepatitis B virus (HBV) infection is a major public health problem in the world. Approximately 296 million people are chronically infected. In endemic areas, vertical transmission is a common route of transmission. There are several strategies for the prevention of HBV vertical transmission, such as antiviral treatment during the third trimester of pregnancy and immunoprophylaxis to newborns that includes the administration of hepatitis B immune globulin (HBIG) and an HBV vaccine. Despite this, immunoprophylaxis failure can occur in up to 30% of infants born to HBeAg-positive mothers and/or with high viral load. Therefore, management and prevention of HBV vertical transmission is of paramount significance. In this article, we provided a review of the epidemiology, mechanisms of pathogenesis and risk factors of vertical transmission, as well as the strategies implemented to prevent the infection.

The Complex Role of HBeAg and Its Precursors in the Pathway to Hepatocellular Carcinoma

Hepatitis B virus (HBV) is one of the seven known human oncogenic viruses and has adapted to coexist with a single host for prolonged periods, requiring continuous manipulation of immunity and cell fate decisions. The persistence of HBV infection is associated with the pathogenesis of hepatocellular carcinoma, and various HBV proteins have been implicated in promoting this persistence. The precursor of hepatitis e antigen (HBeAg), is translated from the precore/core region and is post-translationally modified to yield HBeAg, which is secreted in the serum. HBeAg is a non-particulate protein of HBV and can act as both a tolerogen and an immunogen. HBeAg can protect hepatocytes from apoptosis by interfering with host signalling pathways and acting as a decoy to the immune response. By evading the immune response and interfering with apoptosis, HBeAg has the potential to contribute to the hepatocarcinogenic potential of HBV. In particular, this review summarises the various signalling pathways through which HBeAg and its precursors can promote hepatocarcinogenesis via the various hallmarks of cancer.

Design and Synthesis of (3-Phenylisoxazol-5-yl)methanimine Derivatives as Hepatitis B Virus Inhibitors

Series of (3-phenylisoxazol-5-yl)methanimine derivatives were synthesized, and evaluated for anti-hepatitis B virus (HBV) activity in vitro. Half of them more effectively inhibited HBsAg than 3TC, and more favor to inhibit secretion of HBeAg than to HBsAg. Part of the compounds with significant inhibition on HBeAg were also effectively inhibit replication of HBV DNA. Compound (E)-3-(4-fluorophenyl)-5-((2-phenylhydrazineylidene)methyl)isoxazole inhibited excellently HBeAg with IC₅₀ in 0.65 μM (3TC(Lamivudine) in 189.90 μM), inhibited HBV DNA in 20.52 μM (3TC in 26.23 μM). Structures of compounds were determined by NMR and HRMS methods, and chlorination on phenyl ring of phenylisoxazol-5-yl was confirmed by X-ray diffraction analysis, and the structure-activity relationships (SARs) of the derivatives was discussed. This work provided a new class of potent non-nucleoside anti-HBV agents.

Characterization of Intracellular Precore-Derived Proteins and Their Functions in Hepatitis B Virus-Infected Human Hepatocytes

Hepatitis B virus (HBV) precore protein is not essential for viral replication but is thought to facilitate chronic infection. In addition to the secreted precore products, including the hepatitis B e antigen (HBeAg) and PreC protein, intracellular precore-derived proteins in HBV-infected human hepatocytes remain poorly characterized, and their roles, if any, remain largely unknown. Here, we detected multiple precore derivatives, including the nonprocessed precursor p25 and the processing intermediate p22, in HBV-infected human hepatocytes as well as human hepatoma cells overexpressing the HBV precore protein. Both p25 and p22 showed phosphorylated and unphosphorylated forms, which were located in different intracellular compartments. Interestingly, precore expression was associated with decreases in intracellular HBV core protein (HBc) and secreted DNA-containing virions but was also associated with an increase in secreted empty virions. The decrease in HBc by precore could be attributed to cytosolic p22, which caused HBc degradation, at least in part by the proteasome, and consequently decreased HBV pregenomic RNA packaging and DNA synthesis. In addition, cytosolic p22 formed chimeric capsids with HBc in the cell, which were further secreted in virions. In contrast, the PreC antigen, like HBeAg, was secreted via the endoplasmic reticulum (ER)-Golgi secretory pathway and was thus unable to form capsids in the cell or be secreted in virions. Furthermore, p25, as well as p22, were secreted in virions from HBV-infected human hepatocytes and were detected in the sera of HBV-infected chimpanzees. In summary, we have detected multiple intracellular precore-derived proteins in HBV-infected human hepatocytes and revealed novel precore functions in the viral life cycle. IMPORTANCE Chronic hepatitis B remains a worldwide public health issue. The hepatitis B virus (HBV) precore protein is not essential for HBV replication but may facilitate viral persistence. In this study, we have detected multiple precore protein species in HBV-infected human hepatocytes and studied their functions in the HBV life cycle. We found that the HBV precore proteins decreased intracellular HBV core protein and reduced secretion of complete virions but enhanced secretion of empty virions. Interestingly, the cytosolic precore protein species formed chimeric capsids with the core protein and were secreted in virions. Our results shed new light on the functions of intracellular precore protein species in the HBV life cycle and have implications for the roles of precore proteins in HBV persistence and pathogenesis.

Farnesoid X Receptor Activation Decreases Toll-like Receptor 2 Expression by Upregulating HBeAg Production

Background: Previous investigations have demonstrated that hepatitis B virus (HBV) infection leads to elevated serum bile acid levels, which is considered to cause liver damage. Thus, we suppose that bile acids may be of considerable significance in inducing immune tolerance. Methods: In this investigation, we explored the functions of the farnesoid X receptor (FXR), a nuclear receptor activated by bile acids, in modulating hepatitis B e antigen (HBeAg) production and toll-like receptor (TLR) expression in vitro and in vivo. Results: The results showed that FXR activation promoted secreted and intracellular HBeAg expression in HepG2 and HEK293T cells. However, FXR antagonist Z-guggulsterone (Z-g) decreased the bile acid-mediated HBeAg production. Meanwhile, TLR2 expression significantly reduced in HepG2 cells transfected with pAAV/HBV1.2 plasmid comprising whole HBV genome and treated with bile acids, but not with mutant pAAV/HBV1.2 plasmid with defected HBeAg product. In the hydrodynamic injection HBV mouse model, the level of serum HBeAg was decreased, but intrahepatic TLR2 expression was elevated in FXR-/- mice. Conclusions: In conclusion, FXR activation inhibits TLR2-mediated innate immunity by upregulating HBeAg production. Our data indicate that a mild elevation of serum bile acids may cause immune tolerance and lead to virus persistence in HBV-infected patients.

Current Best Practice in Hepatitis B Management and Understanding Long-term Prospects for Cure

The hepatitis B virus (HBV) is a major cause of cirrhosis and hepatocellular carcinoma worldwide. Despite an effective vaccine, the prevalence of chronic infection remains high. Current therapy is effective at achieving on-treatment, but not off-treatment, viral suppression. Loss of hepatitis B surface antigen, the best surrogate marker of off-treatment viral suppression, is associated with improved clinical outcomes. Unfortunately, this end point is rarely achieved with current therapy because of their lack of effect on covalently closed circular DNA, the template of viral transcription and genome replication. Major advancements in our understanding of HBV virology along with better understanding of immunopathogenesis have led to the development of a multitude of novel therapeutic approaches with the prospect of achieving functional cure (hepatitis B surface antigen loss) and perhaps complete cure (clearance of covalently closed circular DNA and integrated HBV DNA). This review will cover current best practice for managing chronic HBV infection and emerging novel therapies for HBV infection and their prospect for cure.

A roadmap for serum biomarkers for hepatitis B virus: current status and future outlook

Globally, 296 million people are infected with hepatitis B virus (HBV), and approximately one million people die annually from HBV-related causes, including liver cancer. Although there is a preventative vaccine and antiviral therapies suppressing HBV replication, there is no cure. Intensive efforts are under way to develop curative HBV therapies. Currently, only a few biomarkers are available for monitoring or predicting HBV disease progression and treatment response. As new therapies become available, new biomarkers to monitor viral and host responses are urgently needed. In October 2020, the International Coalition to Eliminate Hepatitis B Virus (ICE-HBV) held a virtual and interactive workshop on HBV biomarkers endorsed by the International HBV Meeting. Various stakeholders from academia, clinical practice and the pharmaceutical industry, with complementary expertise, presented and participated in panel discussions. The clinical utility of both classic and emerging viral and immunological serum biomarkers with respect to the course of infection, disease progression, and response to current and emerging treatments was appraised. The latest advances were discussed, and knowledge gaps in understanding and interpretation of HBV biomarkers were identified. This Roadmap summarizes the strengths, weaknesses, opportunities and challenges of HBV biomarkers.

Understanding the genetics of viral drug resistance by integrating clinical data and mining of the scientific literature

Drug resistance caused by mutations is a public health threat for existing and emerging viral diseases. A wealth of evidence about these mutations and their clinically associated phenotypes is scattered across the literature, but a comprehensive perspective is usually lacking. This work aimed to produce a clinically relevant view for the case of Hepatitis B virus (HBV) mutations by combining a chronic HBV clinical study with a compendium of genetic mutations systematically gathered from the scientific literature. We enriched clinical mutation data by systematically mining 2,472,725 scientific articles from PubMed Central in order to gather information about the HBV mutational landscape. By performing this analysis, we were able to identify mutational hotspots for each HBV genotype (A-E) and gene (C, X, P, S), as well as the location of disulfide bonds associated with these mutations. Through a modelling study, we also identified a mutation position common in both the clinical data and the literature that is located at the binding pocket for a known anti-HBV drug, namely entecavir. The results of this novel approach show the potential of integrated analyses to assist in the development of new drugs for viral diseases that are more robust to resistance. Such analyses should be of particular interest due to the increasing importance of viral resistance in established and emerging viruses, such as for newly developed drugs against SARS-CoV-2.

Mitochondrial DNA haplogroup F confers genetic susceptibility to chronic HBV infection for the Yi nationality in Lijiang, China

Mitochondria are essential for hepatitis B virus (HBV) infection. Moreover, the findings of our previous study indicate that host mitochondrial genetic factors are associated with chronic hepatitis B (CHB) for the Han Chinese. However, in terms of genetic heterogeneity, the impact of mitochondria on host susceptibility to HBV infection in ethnic minorities in China remains unclear. Here, a total of 7070 subjects who had visited the hospital between June 1, 2019, and April 31, 2020, were enrolled for seroprevalence of HBV infection investigation. A total of 220 individuals with CHB (CHBs) and 223 individuals with a trace of HBV infection (spontaneously recovered subjects, SRs) were analyzed for mitochondrial DNA (mtDNA) sequence variations and classified into respective haplogroups. Haplogroup frequencies were compared between CHBs and SRs. Among eight nationalities, Yi nationality patients had the highest HBsAg prevalence rate (27.9% [95% CI: 25.3%-30.5%]) and the lowest vaccination rate (4.9% [95% CI: 3.7%-6.2%]). After adjustment for age and gender, haplogroup F was a risk factor for CHB infection (P = 0.049, OR = 2.079, 95% CI = 1.002-4.31), while D4 had a significant negative correlation with the HBeAg-positive rate (P = 0.024, OR = 0.215, 95% CI = 0.057-0.816). Together with our previous study, the findings indicate that different nationalities have different genetic susceptibility to HBV infection.

Identification of a Novel HBV Encoded miRNA Using Next Generation Sequencing

Hepatitis B Virus (HBV) encoded miRNAs were previously described and suggested to play a role in HBV replication and pathogenesis. In this study we aim to identify novel HBV encoded miRNAs in plasma and liver tissue samples from chronic hepatitis B (CHB) patients and determine their role in CHB pathogenesis and HBV replication. RNA next generation sequencing was performed on plasma and liver tissue samples from ten CHB patients and uninfected controls. The interaction of the potential miRNA-like structures with the RNA-induced silencing complex (RISC) was determined using RNA immunoprecipitation. Expression levels of the HBV encoded miRNAs were measured in liver tissue samples derived from a conformation cohort. The effect of HBV encoded miRNAs overexpression on HBV replication, expression of predicted target genes, and induction of interferon stimulated genes in cell lines were assessed. Three potential miRNA-like structures transcribed by HBV were identified in liver tissue, of which one miRNA, HBV-miR-6, was recognized using RISC. HBV-miR-6 expression was demonstrated in liver tissue samples from 52 of the 87 CHB patients. HBV-miR-6 levels correlated with hepatic HBV-DNA and plasma HBsAg levels. Overexpression of HBV-miR-6 in vitro did not affect HBV replication, and predicted both target genes expression and interferon stimulated genes expression after stimulation. A potential novel HBV encoded miRNA was identified and validated in liver tissue from CHB patients. It is suggested that HBV-miR-6 may play a role in the process of viral excretion or particle formation in vivo.

Role of Innate Immune Regulatory Genes, FOXP3 and FOS in Chronic Hepatitis B Infection

Persistence of hepatitis B virus (HBV) infection leading to chronic infection and its sequalae is responsible for over half a million deaths worldwide. The reason for persistence of chronic hepatitis B (CHB) infection is still not clearly understood. An attempt was made to understand the role of immune regulatory genes in CHB in comparison to spontaneously cleared HBV infection. Relative gene expression of 26 genes involved in innate immunity were studied using Real-Time Polymerase Chain Reaction Array. A total of 679 subjects from three different geographical regions of Northeast India (Assam, Arunachal Pradesh, and Tripura) were included in this case-control study. The cases were subdivided into CHB cases with HBeAg(+)(72), CHB with HBeAg(-)(278), spontaneously cleared controls (88), and healthy controls (228). Overall, 28.3% of the subjects had previous exposure with HBV, while 28.6% had protective antibodies IgG/IgM against HBV. There was a statistically higher number of CHB in men (66.4%) compared to women (33.6%) (p = 0.0001). Proto-oncogene FOS has been found to be moderately upregulated in CHB with HBeAg +ve (2.3-fold) and significantly upregulated (4.1-fold upregulation) in hepatocellular carcinoma. Further, FOXP3 was found to be significantly upregulated (3.0-fold, p = 0.01) in CHB with HBeAg (+) compared to spontaneously cleared HBV infection. In conclusion, CHB with HBeAg positivity was found to have disrupted immune response with upregulation of FOS and FOXP3. Thus, early induction of HBeAg seroconversion with interferon-based therapy or oral nucleos(t)ide analogs along with FOS inhibitors can have important clinical implications in the management of CHB and preventing cirrhosis and HCC.

Humoral immunity in hepatitis B virus infection: Rehabilitating the B in HBV

Insights into the immunopathogenesis of chronic HBV infections are fundamental in the quest for novel treatment approaches aimed at a functional cure. While much is known about the ineffective HBV-specific T-cell responses that characterise persistent HBV replication, B cells have been left largely understudied. However, an important role for humoral immunity during the natural history of HBV infections, as well as after functional cure, has been inadvertently revealed by the occurrence of HBV flares following B cell-depleting treatments. Herein, we review our current understanding of the role of the humoral immune response in chronic HBV, both at the level of HBV-specific antibody production and at the phenotypic and broader functional level of B cells. The recent development of fluorescently labelled HBV proteins has given us unprecedented insights into the phenotype and function of HBsAg- and HBcAg-specific B cells. This should fuel novel research into the mechanisms behind dysfunctional HBsAg-specific and fluctuating, possibly pathogenic, HBcAg-specific B-cell responses in chronic HBV. Finally, novel immunomodulatory treatments that partly target B cells are currently in clinical development, but a detailed assessment of their impact on HBV-specific B-cell responses is lacking. We plead for a rehabilitation of B-cell studies related to both the natural history of HBV and treatment development programmes.

Regulatory function of interferon-inducible 44-like for hepatitis B virus covalently closed circular DNA in primary human hepatocytes

AIM

Curing hepatitis B virus (HBV) infection requires elimination of covalently closed circular DNA (cccDNA). Interferon (IFN)-γ has noncytolytic antiviral potential; however, elimination of cccDNA could not be achieved. To enhance the regulatory effect, we comprehensively analyzed the host factors associated with cccDNA amplification and IFN-γ and IFN-α effects using an in vitro HBV infection system showing various transcription levels.

METHODS

Primary human hepatocytes were infected with HBV using genomic plasmids carrying the basic core promoter mutation A1762T/G1764A and/or the precore mutation G1896A and treated with IFN-γ and IFN-α. Comprehensive and functional studies involving microarray and small interfering RNA analysis revealed the host factors related to cccDNA regulation.

RESULTS

The HBV infection system reproduced the HBV life cycle and showed various propagation levels. Microarray analysis revealed 53 genes correlated with the cccDNA levels. Of the 53 genes, expression of IFN-induced protein 44-like (IFI44L) was significantly upregulated by IFN-γ and IFN-α. The anti-HBV effect of IFI44L is exerted regardless of IFN-γ or IFN-α by inhibiting the activation of nuclear factor-κB and signal transducer and activator of transcription 1 pathways.

CONCLUSIONS

Using the in vitro HBV infection system, an IFN-inducible molecule, IFI44L, associated with cccDNA amplification, was identified. These results suggest an innovative molecular strategy for the regulation of HBV cccDNA by controlling a novel host factor, IFI44L.

MAFLD is Associated with the Risk of Liver Fibrosis and Inflammatory Activity in HBeAg-Negative CHB Patients

PURPOSE

Chronic hepatitis B (CHB) and metabolic associated fatty liver disease (MAFLD) are both important public health problems. The effect of concomitant MAFLD on patients with CHB is still unclear. This study aimed to explore the influence of MAFLD on liver fibrosis and inflammation in CHB patients with different hepatitis B e antigen (HBeAg) status.

PATIENTS AND METHODS

We retrospectively collected the clinical data of 399 treatment-naïve CHB patients who underwent liver biopsy. All patients were divided into two groups (HBeAg± group). Logistic regression analysis was used to identify factors associated with liver inflammatory activity and significant fibrosis in patients with CHB. Multivariable logistic regressions were repeated in subgroups stratified by HBeAg status.

RESULTS

In patients with CHB, MAFLD was independently associated with a risk of moderate-to-severe liver activity and significant fibrosis (P <0.05). In the HBeAg-negative group, patients with MAFLD had significantly higher levels of alanine aminotransferase (ALT) (P <0.05) and more severe liver inflammatory activity and fibrosis (P <0.05) compared to those without MAFLD. MAFLD was independently associated with a risk of moderate-to-severe liver activity (A ≥3: OR 3.97, 95% CI 1.71-9.22, P =0.001) and significant fibrosis (F ≥2: OR 2.02, 95% CI 1.09-3.73, P =0.026). In the HBeAg-positive group, MAFLD was found to be independently associated with moderate-to-severe liver activity (OR 2.44, 95% CI 1.03-5.79, P =0.044) but not fibrosis (P =0.618).

CONCLUSION

MAFLD is associated with the risk of liver fibrosis and inflammatory activity in HBeAg-negative CHB patients. Sufficient attention should be paid to the prevention and treatment of MAFLD in patients with CHB, especially in HBeAg-negative patients.

Genotype E: The neglected genotype of hepatitis B virus

Hepatitis B virus (HBV) (sub)genotypes A1, D3 and E circulate in sub-Saharan Africa, the region with one of the highest incidences of HBV-associated hepatocellular carcinoma globally. Although genotype E was identified more than 20 years ago, and is the most widespread genotype in Africa, it has not been extensively studied. The current knowledge status and gaps in its origin and evolution, natural history of infection, disease progression, response to antiviral therapy and vaccination are discussed. Genotype E is an African genotype, with unique molecular characteristics that is found mainly in Western and Central Africa and rarely outside Africa except in individuals of African descent. The low prevalence of this genotype in the African descendant populations in the New World, phylogeographic analyses, the low genetic diversity and evidence of remnants of genotype E in ancient HBV samples suggests the relatively recent re-introduction into the population. There is scarcity of information on the clinical and virological characteristics of genotype E-infected patients, disease progression and outcomes and efficacy of anti-HBV drugs. Individuals infected with genotype E have been characterised with high hepatitis B e antigen-positivity and high viral load with a lower end of treatment response to interferon-alpha. A minority of genotype E-infected participants have been included in studies in which treatment response was monitored. Of concern is that current guidelines do not consider patients infected with genotype E. Thus, there is an urgent need for further large-scale investigations into genotype E, the neglected genotype of HBV.

Biogenesis of hepatitis B virus e antigen is driven by translocon-associated protein complex and regulated by conserved cysteine residues within its signal peptide sequence

Hepatitis B virus uses e antigen (HBe), which is dispensable for virus infectivity, to modulate host immune responses and achieve viral persistence in human hepatocytes. The HBe precursor (p25) is directed to the endoplasmic reticulum (ER), where cleavage of the signal peptide (sp) gives rise to the first processing product, p22. P22 can be retro-translocated back to the cytosol or enter the secretory pathway and undergo a second cleavage event, resulting in secreted p17 (HBe). Here, we report that translocation of p25 to the ER is promoted by translocon-associated protein complex. We have found that p25 is not completely translocated into the ER; a fraction of p25 is phosphorylated and remains in the cytoplasm and nucleus. Within the p25 sp sequence, we have identified three cysteine residues that control the efficiency of sp cleavage and contribute to proper subcellular distribution of the precore pool.

Amino acid residues at core protein dimer-dimer interface modulate multiple steps of hepatitis B virus replication and HBeAg biogenesis

The core protein (Cp) of hepatitis B virus (HBV) assembles pregenomic RNA (pgRNA) and viral DNA polymerase to form nucleocapsids where the reverse transcriptional viral DNA replication takes place. Core protein allosteric modulators (CpAMs) inhibit HBV replication by binding to a hydrophobic "HAP" pocket at Cp dimer-dimer interfaces to misdirect the assembly of Cp dimers into aberrant or morphologically "normal" capsids devoid of pgRNA. We report herein that a panel of CpAM-resistant Cp with single amino acid substitution of residues at the dimer-dimer interface not only disrupted pgRNA packaging, but also compromised nucleocapsid envelopment, virion infectivity and covalently closed circular (ccc) DNA biosynthesis. Interestingly, these mutations also significantly reduced the secretion of HBeAg. Biochemical analysis revealed that the CpAM-resistant mutations in the context of precore protein (p25) did not affect the levels of p22 produced by signal peptidase removal of N-terminal 19 amino acid residues, but significantly reduced p17, which is produced by furin cleavage of C-terminal arginine-rich domain of p22 and secreted as HBeAg. Interestingly, p22 existed as both unphosphorylated and phosphorylated forms. While the unphosphorylated p22 is in the membranous secretary organelles and the precursor of HBeAg, p22 in the cytosol and nuclei is hyperphosphorylated at the C-terminal arginine-rich domain and interacts with Cp to disrupt capsid assembly and viral DNA replication. The results thus indicate that in addition to nucleocapsid assembly, interaction of Cp at dimer-dimer interface also plays important roles in the production and infectivity of progeny virions through modulation of nucleocapsid envelopment and uncoating. Similar interaction at reduced p17 dimer-dimer interface appears to be important for its metabolic stability and sensitivity to CpAM suppression of HBeAg secretion.

Biological Characterization of Hepatitis B virus Genotypes: Their Role in Viral Replication and Antigen Expression

Hepatitis B virus (HBV) inter-host evolution has resulted in genomic diversification reflected in the existence of nine genotypes (A-I) and numerous subgenotypes. There is growing evidence that genotypes influence HBV natural history, clinical outcomes, and treatment response. However, the biological characteristics underlying these differences have not yet been established. By transfecting HuH-7 cells with unit-length constructs of genotypes A2, B2, C1, D1, and F1b, we identified major differences in HBV replicative capacity and antigen expression across genotypes. Genotypes B2 and F1b showed a 2-fold increase in cccDNA levels compared to the other genotypes (p<0.005). Genotype A2 expressed the lowest pgRNA levels, with a 70-fold decrease in relation to the other genotypes (p<0.0001), while genotype B2 showed the lowest Precore RNA levels, with a 100-fold reduction compared to genotype A2 (p<0.0001). The highest intracellular HBV DNA levels were observed for genotype B2 and the lowest for genotypes A2 and C1 (p<0.0001). Regarding antigen expression, genotype F1b secreted the highest HBsAg levels and genotype D1 the lowest (p<0.0001), while genotypes A2 and B2 showed the highest intracellular HBsAg levels (p<0.0001). Interestingly, genotype C1 secreted the highest HBeAg levels, while genotype A2 showed the highest intracellular levels (p<0.0001). Finally, the analysis of the intra/extracellular antigen ratios revealed that most genotypes retained intracellularly 5-20% of the antigens, except the genotype A2 that retained 50% of the total expressed antigens. In conclusion, this study provides new insights into the biological characteristics of HBV genotypes, being the first study to comparatively analyze European (A and D) and Asian (B and C) genotypes with the Latin American (F) genotype. The differences in HBV replication and antigen expression might contribute to understand the differential role of genotypes in pathogenesis.

Prospects for the Global Elimination of Hepatitis B

Chronic hepatitis B virus (HBV) infection is the leading cause of liver cirrhosis and hepatocellular carcinoma, estimated to be globally responsible for ∼800,000 deaths annually. Although effective vaccines are available to prevent new HBV infection, treatment of existing chronic hepatitis B (CHB) is limited, as the current standard-of-care antiviral drugs can only suppress viral replication without achieving cure. In 2016, the World Health Organization called for the elimination of viral hepatitis as a global public health threat by 2030. The United States and other nations are working to meet this ambitious goal by developing strategies to cure CHB, as well as prevent HBV transmission. This review considers recent research progress in understanding HBV pathobiology and development of therapeutics for the cure of CHB, which is necessary for elimination of hepatitis B by 2030.

The Functions of Hepatitis B Virus Encoding Proteins: Viral Persistence and Liver Pathogenesis

About 250 million people worldwide are chronically infected with Hepatitis B virus (HBV), contributing to a large burden on public health. Despite the existence of vaccines and antiviral drugs to prevent infection and suppress viral replication respectively, chronic hepatitis B (CHB) cure remains a remote treatment goal. The viral persistence caused by HBV is account for the chronic infection which increases the risk for developing liver cirrhosis and hepatocellular carcinoma (HCC). HBV virion utilizes various strategies to escape surveillance of host immune system therefore enhancing its replication, while the precise mechanisms involved remain elusive. Accumulating evidence suggests that the proteins encoded by HBV (hepatitis B surface antigen, hepatitis B core antigen, hepatitis B envelope antigen, HBx and polymerase) play an important role in viral persistence and liver pathogenesis. This review summarizes the major findings in functions of HBV encoding proteins, illustrating how these proteins affect hepatocytes and the immune system, which may open new venues for CHB therapies.

Effect of intestinal microbiota imbalance associated with chronic hepatitis B virus infection on the expression of microRNA‑192 and GLP‑1

It has been reported that hepatitis B virus (HBV) infection has an impact on intestinal microbiota imbalance to induce diabetes mellitus (DM), but the underlying mechanisms still remain to be explored. The present study aimed to investigate the regulatory role of microRNA‑192 (miR‑192‑5p) and glucagon‑like peptide‑1 (GLP‑1) in intestinal microbiota imbalance by recruiting patients with DM infected with HBV. In the present study, patients with HBV infection and different levels of alanine transaminase (ALT) were recruited and divided into three groups. Intestinal microbiota analysis was performed to evaluate the fecal bacterial composition of patients in various groups. Quantitative PCR was performed to explore the differential expression of miR‑192‑5p and GLP‑1 in the feces, peripheral blood and intestinal mucosal tissue samples of each patient. Immunohistochemistry was used to assess the expression of GLP‑1 protein in the intestinal mucosal tissue samples. Luciferase assays were performed by cell transfection of miR‑192‑5p mimics/precursors/inhibitors to study the inhibitory effect of miR‑192‑5p on GLP‑1 expression. Intestinal microbiota imbalance was observed in hepatitis B surface antigen (HBsAg)‑positive patients with high ALT. The expression of miR‑192‑5p was significantly elevated in the feces, peripheral blood and intestinal mucosal tissue samples of HBsAg‑positive patients with high ALT along with decreased GLP‑1 mRNA and protein expression. Luciferase activity of GLP‑1 vector was inhibited by miR‑192‑5p mimics and promoted by miR‑192‑5p inhibitors. Transfection of miR‑192‑5p precursors resulted in upregulation of miR‑192‑5p and downregulation of GLP‑1, while miR‑192‑5p inhibitors remarkably suppressed the expression of miR‑192‑5p and notably induced the expression of GLP‑1. These results showed a regulatory network involving HBV infection, intestinal microbiota imbalance, and miR‑192‑5p and GLP‑1 expression.

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 core protein mutations in the development of occult HBV infection

BACKGROUND & AIMS

Occult HBV infection (OBI) is associated with transfusion-transmitted HBV infection and hepatocellular carcinoma. Studies on OBI genesis have concentrated on mutations in the S region and the regulatory elements. Herein, we aimed to determine the role of mutations in the core region on OBIs.

METHODS

An OBI strain (SZA) carrying 9 amino acid (aa) substitutions in the core protein/capsid (Cp) was selected by sequence alignment and Western blot analysis from 26 genotype B OBI samples to extensively explore the impact of Cp mutations on viral antigen production in vitro and in vivo.

RESULTS

A large panel of 30 Cp replicons were generated by a replication-competent pHBV1.3 carrying SZA or wild-type (WT) Cp in a 1.3-fold over-length of HBV genome, in which the various Cp mutants were individually introduced by repairing site mutations of SZA-Cp or creating site mutations of WT-Cp by site-directed mutagenesis. The expression of HBcAg, HBeAg, and HBsAg and viral RNA was quantified from individual SZA and WT Cp mutant replicons in transfected Huh7 cells or infected mice, respectively. An analysis of the effect of Cp mutants on intracellular or extracellular viral protein production indicated that the W62R mutation in Cp had a critical impact on the reduction of HBcAg and HBeAg production during HBV replication, whereas P50H and/or S74G mutations played a limited role in influencing viral protein production invivo.

CONCLUSIONS

W62R and its combination mutations in HBV Cp might massively affect HBcAg and HBeAg production during viral replication, which, in turn, might contribute to the occurrence of OBI.

LAY SUMMARY

Occult hepatitis B virus infections (OBIs) have been found to be associated with amino acid mutations in the S region of the HBV, but the role of mutations in the core protein (Cp) remains unclear. In this study, an OBI strain (SZA) carrying 9 amino acid substitutions in Cp has been examined comprehensively in vitro and in vivo. The W62R mutation in Cp majorly reduces HBcAg and HBeAg production during HBV replication, potentially contributing to the occurrence of OBI.

Diagnostic performance evaluation of hepatitis B e antigen rapid diagnostic tests in Malawi

Background

The World Health Organization (WHO) has targeted a reduction in viral hepatitis-related mortality by 65% and incidence by 90% by 2030, necessitating enhanced hepatitis B treatment and prevention programmes in low- and middle-income countries. Hepatitis B e antigen (HBeAg) status is used in the assessment of eligibility for antiviral treatment and for prevention of mother-to-child transmission (PMTCT). Accordingly, the WHO has classified HBeAg rapid diagnostic tests (RDTs) as essential medical devices.

Methods

We assessed the performance characteristics of three commercially available HBeAg RDTs (SD Bioline, Alere, South Africa; Creative Diagnostics, USA; and Biopanda Reagents, UK) in two hepatitis B surface antigen-positive cohorts in Blantyre, Malawi: participants of a community study (n = 100) and hospitalised patients with cirrhosis or hepatocellular carcinoma (n = 94). Two investigators, blinded to the reference test result, independently assessed each assay. We used an enzyme-linked immunoassay (Monolisa HBeAg, Bio-Rad, France) as a reference test and quantified HBeAg concentration using dilutions of the WHO HBeAg standard. We related the findings to HBV DNA levels, and evaluated treatment eligibility using the TREAT-B score.

Results

Among 194 HBsAg positive patients, median age was 37 years, 42% were femaleand 26% were HIV co-infected. HBeAg prevalence was 47/194 (24%). The three RDTs showed diagnostic sensitivity of 28% (95% CI 16–43), 53% (38–68) and 72% (57–84) and specificity of 96–100% for detection of HBeAg. Overall inter-rater agreement κ statistic was high at 0.9–1.0. Sensitivity for identifying patients at the threshold where antiviral treatment is recommended for PMTCT, with HBV DNA > 200,000 IU/ml (39/194; 20%), was 22, 49 and 54% respectively. Using the RDTs in place of the reference HBeAg assay resulted in 3/43 (9%), 5/43 (12%) and 8/43 (19%) of patients meeting the TREAT-B treatment criteria being misclassified as ineligible for treatment. A relationship between HBeAg concentration and HBeAg detection by RDT was observed. A minimum HBeAg concentration of 2.2–3.1 log₁₀IU/ml was required to yield a reactive RDT.

Conclusions

Commercially available HBeAg RDTs lack sufficient sensitivity to accurately classify hepatitis B patients in Malawi. This has implications for hepatitis B public health programs in sub-Saharan Africa. Alternative diagnostic assays are recommended.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06134-3.

Increased hepatitis B virus quasispecies diversity is correlated with liver fibrosis progression

Host immune response and viral factors are involved in disease progression in patients with chronic hepatitis B virus (HBV) infection. However, the relationship between HBV quasispecies and liver fibrosis progression remains unclear. In this study, 447 patients with chronic HBV infection, including 239 with chronic hepatitis B (CHB), 104 with liver cirrhosis (LC) and 104 with hepatocellular carcinoma (HCC) were enrolled. The 239 CHB patients were divided into groups F1, F2, and F3 according to liver fibrosis score. Four fragments of the HBV genome were determined and analyzed using next-generation sequencing. Specific mutations, such as A1762T, G1764A and G1896A, in the BCP/PC region were more common in patients with advanced liver disease and formed the majority of the viral quasispecies pool in patients with LC and HCC. The viral complexity and diversity increased as the fibrosis progressed, especially in patients with CHB who were comparable in age but at different stages of fibrosis. Patients with early-stage fibrosis experienced higher purifying selection pressure in the four sequenced regions, whereas different protein-coding region experienced different negative selection with disease progression. HBV quasispecies diversity may increase fibrosis progression in CHB patients with aging under immune selection.

In vitro expression of precore proteins of hepatitis B virus subgenotype A1 is affected by HBcAg, and can affect HBsAg secretion

HBeAg, a non-particulate protein of hepatitis B virus (HBV), is translated from the precore/core region as a precursor, which is post-translationally modified. Subgenotype A1 of HBV, which is a risk factor for hepatocellular carcinoma (HCC), has unique molecular characteristics in the basic core promoter/precore regions. Carriers of A1 exhibit early HBeAg loss. We sought to further characterize the precore proteins of A1 in vitro. HuH-7 cells were transfected with subgenomic constructs expressing individual precore proteins. Western blot analysis using DAKO anti-core antibody showed the expected sizes and a 1 kDa larger band for P22, P20 and P17. Using confocal microscopy, a cytoplasmic accumulation of HBeAg and precursors was observed with P25-expressing plasmid, whereas P22 localized both in the cytoplasm and nucleus. P20 and P17, which lack the carboxy end of P22 showed strong nuclear accumulation, implicating a nuclear localization signal in the N-terminal 10 amino acids. G1862T, unique to subgenotype A1, is frequently found in HBV from HCC patients. P25 with G1862T showed delayed and reduced HBeAg expression/secretion. Knock-out of core in the replication competent clones led to precore protein accumulation in the cytoplasm/perinuclear region, and decreased HBeAg secretion. Knock-out of precore proteins increased HBsAg secretion but intracellular HBsAg expression was unaffected. Over-expression of precore proteins in trans led to decreased HBsAg expression and secretion. Intracellular trafficking of HBV A1 precore proteins was followed. This was unaffected by the CMV promoter and different cell types. In the viral context, precore protein expression was affected by absence of core, and affected HBsAg expression, suggesting an interrelationship between precore proteins, HBcAg and HBsAg. This modulatory role of HBeAg and its precursors may be important in viral persistence and ultimate development of HCC.

Highly multiplexed 2-dimensional imaging mass cytometry analysis of HBV-infected liver

Studies of human hepatitis B virus (HBV) immune pathogenesis are hampered by limited access to liver tissues and technologies for detailed analyses. Here, utilizing imaging mass cytometry (IMC) to simultaneously detect 30 immune, viral, and structural markers in liver biopsies from patients with hepatitis B e antigen⁺ (HBeAg⁺) chronic hepatitis B, we provide potentially novel comprehensive visualization, quantitation, and phenotypic characterizations of hepatic adaptive and innate immune subsets that correlated with hepatocellular injury, histological fibrosis, and age. We further show marked correlations between adaptive and innate immune cell frequencies and phenotype, highlighting complex immune interactions within the hepatic microenvironment with relevance to HBV pathogenesis.

Transcriptome analysis of hepatoma cells transfected with Basal Core Promoter (BCP) and Pre-Core (PC) mutant hepatitis B virus full genome construct

Infections with Basal Core Promoter (BCP) (A1762T/G1764A) and Pre-Core (PC) (G1896A) hepatitis B virus HBeAg mutants are associated with severe liver injury. We analysed host cell responses in HepG2/C3A, hepatoma cells transfected with infectious clones developed from genotype D wild type (WT) and BCP/PC mutant (MT) viruses isolated from an acute resolved and an acute liver failure hepatitis B case respectively. Cells transfected with MT virus construct showed ~55 % apoptosis and with WT ~30 % apoptosis at 72 h. To determine possible roles of HBe and HBx proteins in apoptosis, we cloned these genes and co-transfected cells with WT+HBe/HBx or MT+HBe/HBx constructs. Co-expression of HBe protein improved cell viability significantly in both WT and MT virus constructs, indicating an important role of HBe in protecting cells. RNA sequencing analysis carried out at 12 and 72 h post-transfection with WT virus construct showed enrichment of innate/adaptive immune response-activating signal transduction, cell survival and amino acid/nucleic acid biosynthetic pathways at 12 and 72 h. By contrast, MT virus construct showed enrichment in host defence pathways and some biosynthetic pathways at the early time point (12 h), and inflammatory response, secretary granule, regulation of membrane potential and stress response regulatory pathways at the late time point (72 h). There was a significant down-regulation of genes involved in endoplasmic reticulum and mitochondrial functions and metabolism with MT construct and this possibly led to induction of apoptosis in cells. Considering rapid apoptotic changes in cells transfected with MT construct, it can be speculated that HBeAg plays a crucial role in cell survival. It enhances induction of metabolic and synthetic pathways and facilitates management of cellular stress that is induced due to hepatitis B virus infection/replication.

Hepatitis B Core-Related Antigen as Surrogate Biomarker of Intrahepatic Hepatitis B Virus Covalently-Closed-Circular DNA in Patients with Chronic Hepatitis B: A Meta-Analysis

Hepatitis B virus (HBV) covalently-closed-circular (ccc)DNA is the key molecule responsible for viral persistence within infected hepatocytes. The evaluation of HBV cccDNA is crucial for the management of patients with chronic HBV infection and for the personalization of treatment. However, the need for liver biopsy is the principal obstacle for the assessment of intrahepatic HBV cccDNA. In the last decade, several studies have investigated the performance of hepatitis B core-related antigen (HBcrAg) as a surrogate of HBV cccDNA amount in the liver. In this meta-analysis, we collected 14 studies (1271 patients) investigating the correlation between serum HBcrAg and intrahepatic HBV cccDNA. Serum HBcrAg showed a high correlation with intrahepatic HBV cccDNA (r = 0.641, 95% confidence interval (CI) 0.510-0.743, p < 0.001). In a head-to-head comparison, we observed that the performance of HBcrAg was significantly superior to that of hepatitis B surface antigen (r = 0.665 vs. r = 0.475, respectively, p < 0.001). Subgroup analysis showed that the correlation between HBcrAg and intrahepatic HBV cccDNA was high, both in hepatitis B e antigen-positive and -negative patients (r = 0.678, 95% CI 0.403-0.840, p < 0.001, and r = 0.578, 95% CI 0.344-0.744, p < 0.001, respectively). In conclusion, the measurement of serum HBcrAg qualifies as a reliable non-invasive surrogate for the assessment of an intrahepatic HBV cccDNA reservoir.

Characterization of Hepatitis B Precore/Core-Related Antigens

Current therapies rarely cure chronic hepatitis B virus (HBV) infection due to the persistence of the viral episome, the covalently closed circular DNA (cccDNA), in hepatocytes. The hepatitis B virus core-related antigen (HBcrAg), a mixture of the viral precore/core gene products, has emerged as one potential marker to monitor the levels and activities of intrahepatic cccDNA. In this study, a comprehensive characterization of precore/core gene products revealed that HBcrAg components included the classical hepatitis B virus core antigen (HBc) and e antigen (HBeAg) and, additionally, the precore-related antigen, PreC, retaining the N-terminal signal peptide. Both HBeAg and PreC antigens displayed heterogeneous proteolytic processing at their C termini resulting in multiple species, which varied with viral genotypes. HBeAg was the predominant form of HBcrAg in HBeAg-positive patients. Positive correlations were found between HBcrAg and PreC, between HBcrAg and HBeAg, and between PreC and HBeAg but not between HBcrAg and HBc. Serum HBeAg and PreC shared similar buoyant density and size distributions, and both displayed density and size heterogeneity. HBc, but not HBeAg or PreC antigen, was found as the main component of capsids in DNA-containing or empty virions. Neither HBeAg nor PreC protein was able to form capsids in cells or in vitro under physiological conditions. In conclusion, our study provides important new quantitative information on levels of each component of precore/core gene products as well as their biochemical and biophysical characteristics, implying that each component may have distinct functions and applications in reflecting intrahepatic viral activities.IMPORTANCE Chronic hepatitis B virus (HBV) infection afflicts approximately 257 million people, who are at high risk of progressing to chronic liver diseases, including fibrosis, cirrhosis, and hepatocellular carcinoma. Current therapies rarely achieve cure of HBV infection due to the persistence of the HBV episome, the covalently closed circular DNA (cccDNA), in the nuclei of infected hepatocytes. Peripheral markers of cccDNA levels and transcriptional activities are urgently required to guide antiviral therapy and drug development. Serum hepatitis B core-related antigen (HBcrAg) is one such emerging peripheral marker. We have characterized the components of HBcrAg in HBV-infected patients as well as in cell cultures. Our results provide important new quantitative information on levels of each HBcrAg component, as well as their biochemical and biophysical characteristics. Our findings suggest that each HBcrAg component may have distinct functions and applications in reflecting intrahepatic viral activities.

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.

Distinct Cytokine Profiles Correlate with Disease Severity and Outcome in Longitudinal Studies of Acute Hepatitis B Virus and Hepatitis D Virus Infection in Chimpanzees

Historical studies conducted in chimpanzees gave us the opportunity to investigate the basis for the different severities of liver damage and disease outcome associated with infection with wild-type hepatitis B virus (HBV) versus a precore HBV mutant, HBV/hepatitis D virus (HDV) coinfection, and HDV superinfection. Weekly samples from 9 chimpanzees were studied for immune responses by measuring plasma levels of 29 cytokines in parallel with alanine aminotransferase (ALT) levels and viral kinetics. Comparison of classic acute hepatitis B (AHB) with severe or progressive AHB and HBV/HDV coinfection or superinfection identified distinct cytokine profiles. Classic AHB (mean ALT peak, 362 IU/liter) correlated with an early and significant induction of interferon alpha-2 (IFN-α2), IFN-γ, interleukin-12 p70 (IL-12 p70), and IL-17A. In contrast, these cytokines were virtually undetectable in severe AHB (mean ALT peak, 1,335 IU/liter), characterized by significant elevations of IL-10, tumor necrosis factor alpha (TNF-α), and MIP-1β. In progressive AHB (mean ALT peak, 166 IU/liter), there was a delayed and lower-magnitude induction of cytokines. The ALT peak was also delayed (mean, 23.5 weeks) compared to those of classic (13.5 weeks) and severe AHB (7.5 weeks). HBV/HDV coinfection correlated with significantly lower levels of IFN-α2, IFN-γ, and IL-17A, associated with the presence of multiple proinflammatory cytokines, including IL-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, and IL-15. Conversely, HDV superinfection induced the highest ALT peak (1,910 IU/liter) and was associated with a general suppression of cytokines. Our data demonstrate that the most severe liver damage, caused by an HBV precore mutant and HDV, correlated with restricted cytokine expression and lack of Th1 response, raising the question of whether these viruses are directly cytopathic.IMPORTANCE Studies performed in chimpanzees at the National Institutes of Health (NIH) demonstrated a significant difference in ALT levels during acute hepatitis of different viral etiologies, with a hierarchy in the extent of liver damage according to the infecting virus: the highest level was in HDV superinfection, followed by infection with a precore HBV mutant, HBV/HDV coinfection, and, lastly, wild-type HBV infection. Our study demonstrates that both the virus and host are important in disease pathogenesis and offers new insights into their roles. We found that distinct cytokine profiles were associated with disease severity and clinical outcome. In particular, resolution of classic acute hepatitis B (AHB) correlated with a predominant Th1 response, whereas HBV/HDV coinfection showed a predominant proinflammatory response. Severe AHB and HDV superinfection showed a restricted cytokine profile and no evidence of Th1 response. The lack of cytokines associated with adaptive T-cell responses toward the precore HBV mutant and HDV superinfection argues in favor of a direct cytopathic effect of these viruses.

Bimodal distribution and set point HBV DNA viral loads in chronic infection: retrospective analysis of cohorts from the UK and South Africa

Hepatitis B virus (HBV) viral load (VL) is used as a biomarker to assess risk of disease progression, and to determine eligibility for treatment. While there is a well recognised association between VL and the expression of the viral e-antigen protein, the distributions of VL at a population level are not well described. We here present cross-sectional, observational HBV VL data from two large population cohorts in the UK and in South Africa, demonstrating a consistent bimodal distribution. The right skewed distribution and low median viral loads are different from the left-skew and higher viraemia in seen in HIV and hepatitis C virus (HCV) cohorts in the same settings. Using longitudinal data, we present evidence for a stable 'set-point' VL in peripheral blood during chronic HBV infection. These results are important to underpin improved understanding of HBV biology, to inform approaches to viral sequencing, and to plan public health interventions.

Global and regional dispersal patterns of hepatitis B virus genotype E from and in Africa: A full-genome molecular analysis

Description of the spatial characteristics of viral dispersal is important in understanding the history of infections. Nine hepatitis B virus (HBV) genotypes (A-I), and a putative 10th genotype (J), with distinct geographical distribution, are recognized. In sub-Saharan Africa (sub)-genotypes A1, D3 and E circulate, with E predominating in western Africa (WA), where HBV is hyperendemic. The low genetic diversity of genotype E (HBV/E) suggests its recent emergence. Our aim was to study the dispersal of HBV/E using full-length, non-redundant and non-recombinant sequences available in public databases. HBV/E was confirmed, and the phylogeny reconstruction performed using maximum likelihood (ML) with bootstrapping. Phylogeographic analysis was conducted by reconstruction of ancestral states using the criterion of parsimony on the estimated ML phylogeny. 46.5% of HBV/E sequences were found within monophyletic clusters. Country-wise analysis revealed the existence of 50 regional clusters. Sequences from WA were located close to the root of the tree, indicating this region as the most probable origin of the HBV/E epidemic and expanded to other geographical regions, within and outside of Africa. A localized dispersal was observed with sequences from Nigeria and Guinea as compared to other WA countries. Based on the sequences available in the databases, the phylogenetic results suggest that European strains originated primarily from WA whereas a majority of American strains originated in Western Central Africa. The differences in regional dispersal patterns of HBV/E suggest limited cross-border transmissions because of restricted population movements.

Hepatitis B envelope antigen increases Tregs by converting CD4+CD25- T cells into CD4+CD25+Foxp3+ Tregs

Hepatitis B virus (HBV) can establish a lifelong chronic infection in humans, leading to liver cirrhosis, liver failure and hepatocellular carcinoma. Patients with chronic hepatitis B (CHB) exhibit a weak virus-specific immune response. Regulatory T cells (Tregs) play a key role in regulating the immune response in patients with CHB. Patients with hepatitis B envelope antigen (HBeAg)-positive CHB harbored a higher percentage of Tregs in their peripheral blood than those with HBeAg-negative CHB. However, whether and how HBeAg manipulates the host immune system to increase the population of Tregs remains to be elucidated. The present manuscript describes a preliminary immunological study of HBeAg in a mouse model. Multiple potential CD4⁺ T cell epitopes in HBeAg were identified using Immune Epitope Database consensus binding prediction. It was demonstrated that HBeAg treatment increased the numbers of Tregs in mouse spleens in vitro and in vivo. Furthermore, it was indicated that the HBeAg-mediated increase in Tregs occurred through the conversion of CD4⁺CD25^- T cells into CD4⁺CD25⁺Foxp3⁺ Tregs. Additionally, in vitro study illustrated that HBeAg stimulated murine spleen cells to produce increased transforming growth factor-β, which is required to enable HBeAg to convert T cells into Tregs. The results of the present study may provide further evidence of the effect of HBeAg on Tregs and aid in the development of novel HBeAg-based immunotherapy for CHB.

Distinct disease features in chimpanzees infected with a precore HBV mutant associated with acute liver failure in humans

Transmission to chimpanzees of a precore hepatitis B virus (HBV) mutant implicated in acute liver failure (ALF) in humans did not cause ALF nor the classic form of acute hepatitis B (AHB) seen upon infection with the wild-type HBV strain, but rather a severe AHB with distinct disease features. Here, we investigated the viral and host immunity factors responsible for the unusual severity of AHB associated with the precore HBV mutant in chimpanzees. Archived serial serum and liver specimens from two chimpanzees inoculated with a precore HBV mutant implicated in ALF and two chimpanzees inoculated with wild-type HBV were studied. We used phage-display library and next-generation sequencing (NGS) technologies to characterize the liver antibody response. The results obtained in severe AHB were compared with those in classic AHB and HBV-associated ALF in humans. Severe AHB was characterized by: (i) the highest alanine aminotransferase (ALT) peaks ever seen in HBV transmission studies with a significantly shorter incubation period, compared to classic AHB; (ii) earlier HBsAg clearance and anti-HBs seroconversion with transient or undetectable hepatitis B e antigen (HBeAg); (iii) limited inflammatory reaction relative to hepatocellular damage at the ALT peak with B-cell infiltration, albeit less extensive than in ALF; (iv) detection of intrahepatic germline antibodies against hepatitis B core antigen (HBcAg) by phage-display libraries in the earliest disease phase, as seen in ALF; (v) lack of intrahepatic IgM anti-HBcAg Fab, as seen in classic AHB, but at variance with ALF; and (vi) higher proportion of antibodies in germline configuration detected by NGS in the intrahepatic antibody repertoire compared to classic AHB, but lower than in ALF. This study identifies distinct outcome-specific features associated with severe AHB caused by a precore HBV mutant in chimpanzees, which bear closer resemblance to HBV ALF than to classic AHB. Our data suggest that precore HBV mutants carry an inherently higher pathogenicity that, in addition to specific host factors, may play a critical role in determining the severity of acute HBV disease.

Hepatitis Flares Are Associated With Better Outcomes Than No Flare in Patients With Decompensated Cirrhosis and Chronic Hepatitis B Virus Infection

BACKGROUND & AIMS

Little is known about the effects of baseline hepatitis flares (level of alanine aminotransferase ≥5-fold above the upper limit of normal) on the outcomes of patients with chronic hepatitis B virus (HBV) infection with decompensated cirrhosis treated with nucleos(t)ide analogues. We aimed to investigate these effects.

METHODS

We performed a cohort study of 511 consecutive patients (78.1% men; 58.7% with flares at baseline) with chronic HBV infection and decompensated cirrhosis who were treated with nucleos(t)ide analogues as soon as decompensation was noted. Patients were enrolled from January 2002 to March 2018 at a tertiary care center in Taiwan and followed up for 16 years.

RESULTS

Patients with hepatitis flares had higher mean baseline levels of HBV DNA (6.44 ± 1.52 vs 6.08 ± 1.46 log₁₀ IU/mL; P = .003), hepatitis B surface antigen, and total bilirubin; prolonged prothrombin time; higher platelet counts (108.0 ± 42.9 vs 83.6 ± 44.7 103/μL; P < .001); and a higher proportion were infected with HBV genotype B, compared with patients without flares. Patients with flares had lower ratios of neutrophils to lymphocytes than patients with flares (6.14 ± 9.18 vs 9.12 ± 1.36; P = .019); were less likely than patients without flares to be positive for hepatitis B e antigen, ascites, esophageal varices, or splenomegaly; and a lower proportion died or underwent liver transplantation (46.5% vs 73.2% of patients without flares; P < .001), even though the patients without flares had similar short-term (<3 mo) outcomes. Factors associated independently with baseline flares were esophageal varices (odds ratio [OR], 0.165; 95% CI, 0.067-0.406), ascites (OR, 0.415; 95% CI, 0.178-0.969), levels of total bilirubin (OR, 1.158; 95% CI, 1.041-1.269), prolonged prothrombin time (OR, 1.095; 95% CI, 1.033-1.168), and higher platelet counts (OR, 1.009; 95% CI, 1.00-1.018). After we used propensity score matching to match patients with and without baseline flares, factors associated with the cumulative incidence of death or liver transplantation were flares (hazard ratio [HR], 0.491; 95% CI, 0.317-0.76), ratio of neutrophils to lymphocytes (HR, 1.278; 95% CI, 1.027-1.591), and prolonged prothrombin time (HR, 1.223; 95% CI, 1.052-1.423).

CONCLUSIONS

In a 16-year study of patients with chronic HBV infection and decompensated cirrhosis treated with nucleos(t)ide analogues, a baseline flare of hepatitis was associated independently with better long-term (≥3 mo) outcomes than no flare.

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.