Role of anti-HBs in functional cure of HBeAg+ chronic hepatitis B patients infected with HBV genotype A

A three antigen hepatitis B vaccine induces T cells to Pres1 and Pres2 which correlate with anti HBs antibody titers: An investigation into the immunological mechanisms contributing to high anti-HBs titers

PreHevbrio® is a 3-antigen HBV vaccine (3-A-HBV) engineered to express the three HBV envelope proteins; the small 'S' hepatitis B surface antigen (SHBs or HBsAg), the middle pre-S2 + HBsAg (MHBs) and the large PreS1 + PreS2 + HBsAg (LHBs) antigens. 3-A-HBV has been shown to induce superior and more durable antibody responses relative to a 1-A-HBV despite containing half the 'S' antigen dose. To explain the mechanism(s) behind the high immunogenicity, the potential influence of mammalian glycosylation, HBs antigen conformation, anti-HBs epitope binding profiles and T-cell responses to the PreS antigens were investigated. In this paper, we demonstrate that glycosylation status does not play a role in the increased immunogenicity of the 3-A-HBV, but that the 3-A-HBV particles are able to induce T cell responses to PreS1 and PreS2 antigens. Epitope mapping demonstrated that the 3-A-HBV particles are inherently more antigenic than 1-A-HBV particles, leading to quantitative differences in the anti-HBs antibody response. Further, we demonstrate that the T cell responses significantly correlate with the higher observed anti-HBs titers and may contribute to the higher and more durable anti-HBs titers. This trial is registered at Clinicaltrials.gov (NCT03393754) and EudraCT (2017-001819-36).

HBV Antigen-Guided Switching Strategy From Nucleos(t)ide Analogue to Interferon: Avoid Virologic Breakthrough and Improve Functional Cure

Little is known for factors associated with virologic breakthrough (VBT) after switching from nucleos(t)ide analogue (NA) to pegylated interferon alpha (Peg-IFN-α) for patients with chronic hepatitis B (CHB). Eighty patients who received 48-week Peg-IFN-ɑ and NA combination therapy followed by Peg-IFN-ɑ monotherapy for additional 48 weeks were included in this study. HBV-related markers including HBV DNA, HBsAg, HBcrAg, HBeAg, cccDNA, and immunological biomarkers were dynamically evaluated. Twelve (15.0%) patients experienced VBT after switching to Peg-IFN-ɑ and exhibited significantly lower rates of HBsAg loss after therapy completion (0% vs. 35.3%, p = 0.014). The patients with HBcrAg≥ 5 log10U/mL and HBsAg≥ 100 IU/mL had the highest risk of VBT and failed to achieve subsequent HBsAg clearance. Intrahepatic cccDNA level was significantly higher in patients with HBcrAg≥ 5 log10U/mL than those with HBcrAg< 5 log10U/mL. Notably, in contrast to patients with HBcrAg< 5 log10U/mL or with HBsAg< 100 IU/mL who had obviously restored HBV-specific CD8+T cell, Tfh or B cell responses before NA cessation, those with HBcrAg≥ 5 log10U/mL or with HBsAg≥ 100 IU/mL exhibited lackluster immunities before NA cessation and notable diminished immune responses thereafter. Monitoring HBcrAg and HBsAg levels, which correlated with poor immune responses during sequential Peg-IFN-ɑ strategy, may help to avoid VBT and improve functional cure of CHB.

Circulating capsid-antibody-complexes (CACs) drive intrahepatic complement deposition and inform subclinical liver inflammation in chronic hepatitis B

Chronic infection with Hepatitis B Virus (HBV) often results in a dysfunctional virus-specific T cell response hampering viral clearance. Paradoxically, intrahepatic inflammatory responses that contribute more to liver histopathology than to viral suppression are commonly observed, which are widely believed to be cell mediated. The involvement of humoral immunity in this process however is not well documented. To investigate the possible roles of HBV Capsid-Antibody Complexes (CACs) in eliciting chronic liver inflammation, we developed a novel microplate-based assay for the quantification of CACs in serum. The CACs assay showed high sensitivity and specificity with its readout closely correlating with the molecular features of CACs. A cross-sectional study on untreated chronic hepatitis B (CHB) patients showed a 77% positive rate for CACs with significant association with alanine transaminase (ALT), intrahepatic inflammation, and complement deposition, suggestive of its functional role in hepatic injury. Multiple staining of complement activation fragment C4d with major leukocyte and myofibroblast markers revealed an intertwined picture in periportal area with a morphology reminiscent of "piecemeal necrosis". In a pooled cohort with ALT levels lower than 40 IU/ml, CACs alone revealed subclinical liver inflammation. We provide definitive evidence for a causative role for CACs in complement-mediated intrahepatic immunopathology, an additional mechanism contributing to liver damage in CHB. Assessment of CACs in serum complements current clinical markers for assessing CHB associated inflammation.

Intrahepatic plasma cells, but not atypical memory B cells, associate with clinical phases of chronic hepatitis B

Studies have traditionally focused on the role of T cells in chronic hepatitis B (CHB), but recent evidence supports a role for B cells. The enrichment of so-called atypical memory (AtM) B cells, which show reduced signaling and impaired differentiation, is believed to be a characteristic feature of CHB, potentially contributing to the observed dysfunctional anti-HBsAg B-cell responses. Our study, involving 62 CHB patients across clinical phases, identified AtM B cells expressing IFNLR1 and interferon-stimulated genes. Contrary to previous reports, we found relatively low frequencies of AtM B cells in the liver, comparable to peripheral blood. However, liver plasma cell frequencies were significantly higher, particularly during phases with elevated viral loads and liver enzyme levels. Liver plasma cells exhibited signs of active proliferation, especially in the immune active phase. Our findings suggest a potential role for plasma cells, alongside potential implications and consequences of local proliferation, within the livers of CHB patients. While the significance of AtM B cells remains uncertain, further investigation is warranted to determine their responsiveness to interferons and their role in CHB.

Overview of the immunological mechanisms in hepatitis B virus reactivation: Implications for disease progression and management strategies

Hepatitis B virus (HBV) reactivation is a clinically significant challenge in disease management. This review explores the immunological mechanisms underlying HBV reactivation, emphasizing disease progression and management. It delves into host immune responses and reactivation's delicate balance, spanning innate and adaptive immunity. Viral factors' disruption of this balance, as are interactions between viral antigens, immune cells, cytokine networks, and immune checkpoint pathways, are examined. Notably, the roles of T cells, natural killer cells, and antigen-presenting cells are discussed, highlighting their influence on disease progression. HBV reactivation's impact on disease severity, hepatic flares, liver fibrosis progression, and hepatocellular carcinoma is detailed. Management strategies, including anti-viral and immunomodulatory approaches, are critically analyzed. The role of prophylactic anti-viral therapy during immunosuppressive treatments is explored alongside novel immunotherapeutic interventions to restore immune control and prevent reactivation. In conclusion, this comprehensive review furnishes a holistic view of the immunological mechanisms that propel HBV reactivation. With a dedicated focus on understanding its implications for disease progression and the prospects of efficient management strategies, this article contributes significantly to the knowledge base. The more profound insights into the intricate interactions between viral elements and the immune system will inform evidence-based approaches, ultimately enhancing disease management and elevating patient outcomes. The dynamic landscape of management strategies is critically scrutinized, spanning anti-viral and immunomodulatory approaches. The role of prophylactic anti-viral therapy in preventing reactivation during immunosuppressive treatments and the potential of innovative immunotherapeutic interventions to restore immune control and proactively deter reactivation.

Characteristics and clinical treatment outcomes of chronic hepatitis B children with coexistence of hepatitis B surface antigen (HBsAg) and antibodies to HBsAg

BACKGROUND

The coexistence of hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (HBsAb) represents an uncommon serological pattern observed in patients with hepatitis B virus (HBV) infection, and its underlying mechanism and clinical significance have not been well established. The aim of this study was to investigate the association between this serological profile and clinical treatment outcomes in children with chronic hepatitis B (CHB).

METHODS

This retrospective cohort study included 372 treatment-naïve CHB children from the Hunan Children's Hospital. The participants were categorized into HBsAb-positive group and HBsAb-negative group. The associations between HBsAb positive status to clinical outcomes were assessed using Cox proportional hazard regression. Receiver operating characteristic curve was conducted to evaluate the prediction ability in HBsAg loss.

RESULTS

The coexistence of HBsAg and HBsAb accounted for 23.39% (87/372) of the participants. The crude incidence rates of HBsAg loss, hepatitis B e antigen (HBeAg) clearance, and HBV-DNA undetectability were higher in the HBsAb-positive group compared with the HBsAb-negative group (37.46 vs. 17.37, 49.51 vs. 28.66, 92.11 vs. 66.54 per 100 person-years, respectively, all P < 0.05). The Cox regression analysis revealed a significant association between this serological profile and an increased likelihood of HBsAg loss (HR = 1.78, P = 0.001), and HBeAg clearance (HR = 1.78, P = 0.001). In addition, a combination of HBsAb ≥ 0.84 log10 IU/L and age ≤ 5 years can help identify patients likely to achieve HBsAg loss after antiviral therapy, with an AUC of 0.71.

CONCLUSIONS

Children who are positive for both HBsAg and HBsAb demonstrate a higher probability of favorable outcomes after antiviral treatment. Thus, children with HBsAb-positive CHB should be actively treated to achieve functional cure.

Novel Assays to Solve the Clinical and Scientific Challenges of Chronic Hepatitis B

Chronic infection with Hepatitis B is a common, incurable, and deadly infection. Despite inexpensive laboratory tests for diagnosis and management that have been established for decades, the worldwide rate of diagnosis is only ∼10%, and ∼5% of people are under treatment. Novel assays have been developed to improve linkage to care by providing more flexible approaches to determine a patient's health status. Other assays have been established to better investigate intrahepatic host-virus interactions to support clinical trials for cure research. This review outlines the clinical and scientific challenges still to be solved and the upcoming methods used to address them.

Editorial: HBsAg seroclearance after pegylated interferon treatment-The beginning of the end. Authors' reply

This article is linked to Gao et al papers. To view these articles, visit https://doi.org/10.1111/apt.17670 and https://doi.org/10.1111/apt.17690

The Multiple Facets and Disorders of B Cell Functions in Hepatitis B Virus Infection

Chronic hepatitis B virus (HBV) infection continues to be a global public health burden. B cells play a pivotal role in mediating HBV clearance and can participate in the development of anti-HBV adaptive immune responses through multiple mechanisms, such as antibody production, antigen presentation, and immune regulation. However, B cell phenotypic and functional disorders are frequently observed during chronic HBV infection, suggesting the necessity of targeting the disordered anti-HBV B cell responses to design and test new immune therapeutic strategies for the treatment of chronic HBV infection. In this review, we provide a comprehensive summary of the multiple roles of B cells in mediating HBV clearance and pathogenesis as well as the latest developments in understanding the immune dysfunction of B cells in chronic HBV infection. Additionally, we discuss novel immune therapeutic strategies that aim to enhance anti-HBV B cell responses for curing chronic HBV infection.

Effect of Anti-HBs on Mortality Among Resolved HBV Infection: a Population-Based Prospective Cohort Study

INTRODUCTION

Surveillance programs after hepatitis B surface antigen (HBsAg) loss are not yet well established, and the role of hepatitis B surface antibodies (anti-HBs) remains controversial. We aimed to evaluate the risk factors for increased mortality and the association between anti-HBs and all-cause and cause-specific mortality in a representative US (United States) population of patients with resolved HBV (Hepatitis B virus) infections.

METHODS

Data were taken from the US National Health and Nutrition Examination Survey (NHANES) 1999-2018. A total of 3455 US adults with resolved HBV infection [defined as hepatitis B surface antigen (HBsAg) negative/anti-hepatitis B core antigen (anti-HBc) positive] were enrolled in this study. The primary outcome measures were all-cause and cause-specific mortality from baseline until 31 December 2019.

RESULTS

During a mean follow-up of 10.3 years, 741 deaths occurred. Age, race, marital status, smoking status, physical activity level, and presence of cirrhosis, diabetes, cardiovascular diseases, chronic obstructive pulmonary diseases, cancer, and anti-HBs were significant factors for increased mortality, and a nomogram tool was developed and validated for the risk stratification of mortality. Compared with participants who were anti-HBs positive, those who were anti-HBs negative had a 23% (hazard ratio 1.23, 95% CI 1.02-1.46) higher risk of all-cause mortality in NHANES 1999-2018. For cause-specific mortality, the fully adjusted hazard ratios of participants who were anti-HBs negative were 0.71 (95% CI 0.48-1.06) for heart disease, 1.44 (95% CI 1.01-2.05) for cancer, and 1.44 (95% CI 1.13-1.83) for other conditions, compared to those of participants who were anti-HBs positive.

CONCLUSIONS

Among US adults with resolved HBV infections, anti-HBs-negative status was associated with an increased risk of death from all causes and cancer, implying that the role of anti-HBs in resolved HBV infection should not be ignored. On the public health level, more rigorous surveillance was needed for populations of individuals who were isolated anti-HBc positive.

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.

The Investigation of Hepatitis B Vaccine Immune Responses in Occult Hepatitis B Virus-Infected Patients

Objectives

There is no effective treatment for occult hepatitis B virus infection (OBI) patients, and immunotherapy may be one of the most promising options. We aim to investigate the underlying mechanism and therapeutic potential of hepatitis B vaccine immunotherapy for OBI patients.

Methods

Outpatient OBI patients were screened and randomly divided into treatment (Group A) and control (Group B) groups. At weeks 0, 4, and 24, patients in Group A received a subcutaneous/intramuscular injection of hepatitis B vaccine (Engerix-B, 20 μg/time) according to the standard vaccination schedule; patients in Group B served as blank control. The patients were followed for 36 weeks, with clinical, biochemical, virological, immunological, and imaging data collected and analyzed at weeks 0, 12, 24, and 36, respectively, and the relation between the virology and immunology results was analyzed.

Results

Of the 228 OBI patients, 28 were excluded, and 200 were enrolled for observation. In the end, 44 patients were included in Group A and 39 in Group B after excluding lost cases. At week 0 (baseline), some patients in two groups had liver disease symptoms, HBV-related liver function damage, and liver fibrosis. 86.36% (38/44) and 82.05% (32/39) patients were positive for serum hepatitis B surface antibodies (anti-HBs) in Group A and Group B, respectively, with the median (quartile) of 42.47 (16.85, 109.1) and 39.27 (16.06, 117.4) mIU/ml, respectively. Reduced peripheral blood CD4⁺T, CD8⁺T, and B lymphocytes were found in some patients in two groups. These results were not statistically different between Group A and Group B (P>0.05). At week 36, all patients were serum anti-HBs (+) in Group A, with a median (quartile) of 1000 (483.9, 1000) mIU/ml, which was significantly higher than that at week 0 (P<0.05) and that in Group B (P<0.05). Compared to week 0, the number of CD8⁺ T and B lymphocytes increased significantly and were significantly higher than Group B at the same point. Two patients in Group B were found to have hepatitis B virus reactivation from week 12 to week 36.

Correlation Analysis

Anti-HBs in Group A patients were positively correlated with B lymphocytes (r=0.3431, 0.3087, and 0.3041, respectively) and positively correlated with CD8⁺ T lymphocytes (r=0.4954, 0.3054, and 0.3455, respectively) at weeks 12, 24, and 36.

Conclusion

Virological reactivation is a risk for OBI patients. Serum hepatitis B surface antibodies were significantly increased after hepatitis B vaccine treatment, the same as the numbers of peripheral blood B and CD8⁺ T lymphocytes; changes in hepatitis B surface antibody levels were positively correlated with the changes in peripheral blood B and CD8⁺ T lymphocytes.

Longitudinal mapping of hepatitis B vaccine-induced B-cell linear epitopes in healthy individuals

The elimination of hepatitis B virus (HBV) infection is partially facilitated by the prophylactic HB vaccine. As the loss of seroprotection over time remains a conundrum for long-lasting protection, a comprehensive dynamic analysis of immunogenic targets of the HB vaccine will provide novel insights into the improvement and design of potential targets. In this study, 36 healthy subjects without prior history of hepatitis B infection and negative for hepatitis B surface antibody (anti-HBs) were enrolled. Participants were given a series of three doses of HB vaccine on a 0-, 1-, and 6-month schedule and longitudinally followed up. We systematically mapped 55 overlapping 15-mer peptides covering the small S protein of hepatitis B virus (SHBs) of vaccinees' serum samples at seven time points by performing an ELISA assay. Additionally, the frequencies and function dynamics of adaptive immune response were assessed by flow cytometry. We found that the SHBs peptide coverage presented an overall upward trend along with the vaccination progress, and the individual subpartition recognition was strongly correlated with the anti-HBs titers. Moreover, we identified one dominant epitope (S29) located on "a determinant region" associated with effective vaccine response. Besides, significant correlations between the proportion of plasmablasts and proliferating B cells and levels of anti-HBs were ascertained. Taken together, our data characterized the dynamics of HB vaccine-induced neutralizing antibodies against B-cell linear epitopes on SHBs and adaptive immune response, which will be constructive to develop the next-generation vaccine.

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.

Hepatitis B Flare in Hepatitis B e Antigen-Negative Patients: A Complicated Cascade of Innate and Adaptive Immune Responses

Chronic hepatitis B virus (HBV) infection is a dynamic process involving interactions among HBV, hepatocytes, and the host immune system. The natural course of chronic hepatitis B (CHB) is divided into four chronological phases, including the hepatitis B e antigen (HBeAg)-positive and HBeAg-negative phases. During HBV flare, alanine aminotransferase (ALT) levels abruptly rise to >5× the upper limit of normal; this is thought to occur due to the immune response against an upsurge in serum HBV DNA and antigen levels. Hepatitis flares may occur spontaneously, during or after antiviral therapy, or upon immunosuppression or chemotherapy in both HBeAg-positive and HBeAg-negative patients. The clinical spectrum of HBV flares varies from asymptomatic to hepatic decompensation or failure. HBeAg seroconversion with ≥ 1 year of consolidation therapy is accepted as an endpoint of oral antiviral therapy in HBeAg-positive patients, but recommendations for treating HBeAg-negative patients differ. Thus, the management of HBeAg-negative patients has attracted increasing interest. In the current review, we summarize various types of HBV flares and the associated complex cascade of innate and adaptive immune responses, with a focus on HBeAg-negative CHB patients. Hopefully, this review will provide insight into immunopathogenesis to improve the management of HBV flares in HBeAg-negative CHB patients.