Incubation phase of acute hepatitis B in man: dynamic of cellular immune mechanisms

Disease Progression Mathematical Modeling With a Case Study on Hepatitis B Virus Infection

Chronic Hepatitis B presents a significant health and socioeconomic burden. The risk of hepatocellular carcinoma remains elevated although treatments are available. Achieving an optimal treatment regimen necessitates a deep comprehension of the dynamic relationship between the virus and its host across disease states. This tutorial elucidates essential considerations for establishing a disease modeling platform to facilitate informed decision-making in hepatitis B treatment strategies. We review several published models of varying complexity and describe the context that motivated each model's structure and assumptions. Several of the models are made available in an interactive RShiny app to demonstrate the influence of model choice and sensitivity to the choice of parameter values.

The immune response in chronic HBV infection

Hepatitis B virus (HBV) is an ancient virus that has evolved unique strategies to persist as a chronic infection in humans. Here, I summarize the innate and adaptive features of the HBV-host interaction, and I discuss how different profiles of antiviral immunity cannot be predicted only on the basis of virological and clinical parameters.

Early application of IFNγ mediated the persistence of HBV in an HBV mouse model

The antiviral activity of interferon gamma (IFNγ) against hepatitis B virus (HBV) was demonstrated both in vivo and in vitro in a previous study. IFNγ can suppress HBV replication by accelerating the decay of replication-competent nucleocapsids of HBV. However, in this study, we found that the direct application of the mouse IFNγ (mIFNγ) expression plasmid to the liver of an HBV hydrodynamic injection (HI) mouse model led to the persistence of HBV, as indicated by sustained HBsAg and HBeAg levels in the serum as well as an increased percentage of the HBsAg positive mice, whereas the level of HBV DNA in the serum and the expression of HBcAg in the liver were inhibited at the early stage after HI. Meanwhile, we found that the productions of both HBcAb and HBsAb were suppressed after the application of mIFNγ. In addition, we found that HBV could be effectively inhibited in mice immunized with HBsAg expression plasmid before the application of mIFNγ. Furthermore, mIFNγ showed antiviral effect and promoted the production of HBsAb when the mice subjected to the core-null HBV plasmid. These results indicate that the application of mIFNγ in the HBV HI mouse model, the mice showed defective HBcAg-specific immunity that impeded the production of HBcAb and HBsAb, finally allowing the persistence of the virus. Moreover, IFNγ-induced negative immune regulatory factors also play an important role in virus persistence.

Single-cell RNA-sequencing of virus-specific cellular immune responses in chronic hepatitis B patients

Chronic hepatitis B (CHB) is a major global health challenge. CHB can be controlled by antivirals but a therapeutic cure is lacking. CHB is characterized by limited HBV-specific T cell reactivity and functionality and expression of inhibitory receptors. The mechanisms driving these T cell phenotypes are only partially understood. Here, we created a single-cell RNA-sequencing dataset of HBV immune responses in patients to contribute to a better understanding of the dysregulated immunity. Blood samples of a well-defined cohort of 21 CHB and 10 healthy controls, including a subset of 5 matched liver biopsies, were collected. scRNA-seq data of total immune cells (55,825) plus sorted HBV-specific (1,963), non-naive (32,773) and PD1+ T cells (96,631) was generated using the 10X Genomics platform (186,123 cells) or the full-length Smart-seq2 protocol (1,069 cells). The shared transcript count matrices of single-cells serve as a valuable resource describing transcriptional changes underlying dysfunctional HBV-related T cell responses in blood and liver tissue and offers the opportunity to identify targets or biomarkers for HBV-related immune exhaustion.

Classifying hepatitis B therapies with insights from covalently closed circular DNA dynamics

The achievement of a functional cure for chronic hepatitis B (CHB) remains limited to a minority of patients treated with currently approved drugs. The primary objective in developing new anti-HBV drugs is to enhance the functional cure rates for CHB. A critical prerequisite for the functional cure of CHB is a substantial reduction, or even eradication of covalently closed circular DNA (cccDNA). Within this context, the changes in cccDNA levels during treatment become as a pivotal concern. We have previously analyzed the factors influencing cccDNA dynamics and introduced a preliminary classification of hepatitis B treatment strategies based on these dynamics. In this review, we employ a systems thinking perspective to elucidate the fundamental aspects of the HBV replication cycle and to rationalize the classification of treatment strategies according to their impact on the dynamic equilibrium of cccDNA. Building upon this foundation, we categorize current anti-HBV strategies into two distinct groups and advocate for their combined use to significantly reduce cccDNA levels within a well-defined timeframe.

IFN-γ: A Crucial Player in the Fight Against HBV Infection?

About 0.8 million people die because of hepatitis B virus (HBV) infection each year. In around 5% of infected adults, the immune system is ineffective in countering HBV infection, leading to chronic hepatitis B (CHB). CHB is associated with hepatocellular carcinoma, which can lead to patient death. Unfortunately, although current treatments against CHB allow control of HBV infection, they are unable to achieve complete eradication of the virus. Cytokines of the IFN family represent part of the innate immune system and are key players in virus elimination. IFN secretion induces the expression of interferon stimulated genes, producing proteins that have antiviral properties and that are essential to cell-autonomous immunity. IFN-α is commonly used as a therapeutic approach for CHB. In addition, IFN-γ has been identified as the main IFN family member responsible for HBV eradication during acute infection. In this review, we summarize the key evidence gained from cellular or animal models of HBV replication or infection concerning the potential anti-HBV roles of IFN-γ with a particular focus on some IFN-γ-inducible genes.

Unusual serological profile in hepatitis B virus (HBV) infection associated with a probable clinical case of acute exacerbation of pre-existing chronic HBV infection

BACKGROUND

Acute or chronic HBV infection in an individual can be laboratory characterized according to the serological profile of the viral markers in the bloodstream, and the dynamics monitoring of these markers is necessary to assess the disorder course and the infection outcome. However, under certain circumstances unusual or atypical serological profiles may be observed in both acute and chronic HBV infection. They are considered as such because they do not properly characterize the form or infection clinical phase or because they seem inconsistent, considering the viral markers dynamics in both clinical contexts. This manuscript comprises the analysis of an unusual serological profile in HBV infection.

METHODS AND RESULTS

This clinical-laboratory study, had as reference a patient who presented clinical profile suggestive of acute HBV infection after recent exposure, whose laboratory data were initially compatible with this clinical presentation. However, the serological profile analysis and its monitoring demonstrated unusual pattern of viral markers expression, which has been observed in several clinical contexts, and is often associated a number of agent- or host-related factors.

CONCLUSION

The serological profile analyzed here, associated with the biochemical markers serum levels found, is indicative of active chronic infection, consequence of viral reactivation. This finding suggests that in the event of unusual serological profiles in HBV infection, if the influence of agent- or host-related factors is not properly considered and neither the viral markers dynamics properly analyzed, there may be mistake in the infection clinical diagnosis, especially when the patient's clinical and epidemiological history is unknown.

Mesenchymal stem cells-based therapy in liver diseases

Multiple immune cells and their products in the liver together form a complex and unique immune microenvironment, and preclinical models have demonstrated the importance of imbalances in the hepatic immune microenvironment in liver inflammatory diseases and immunocompromised liver diseases. Various immunotherapies have been attempted to modulate the hepatic immune microenvironment for the purpose of treating liver diseases. Mesenchymal stem cells (MSCs) have a comprehensive and plastic immunomodulatory capacity. On the one hand, they have been tried for the treatment of inflammatory liver diseases because of their excellent immunosuppressive capacity; On the other hand, MSCs have immune-enhancing properties in immunocompromised settings and can be modified into cellular carriers for targeted transport of immune enhancers by genetic modification, physical and chemical loading, and thus they are also used in the treatment of immunocompromised liver diseases such as chronic viral infections and hepatocellular carcinoma. In this review, we discuss the immunological basis and recent strategies of MSCs for the treatment of the aforementioned liver diseases. Specifically, we update the immune microenvironment of the liver and summarize the distinct mechanisms of immune microenvironment imbalance in inflammatory diseases and immunocompromised liver diseases, and how MSCs can fully exploit their immunotherapeutic role in liver diseases with both immune imbalance patterns.

Functional molecular expression of nature killer cells correlated to HBsAg clearance in HBeAg-positive chronic hepatitis B patients during PEG-IFN α-2a therapy

Objective

To explore whether the frequencies and functional molecules expression of Natural Killer cells (NK cells) are related to hepatitis B surface antigen (HBsAg) disappearance in hepatitis B e envelope antigen (HBeAg)-positive patients with chronic hepatitis B (CHB) throughout peginterferon alpha-2a (PEG-IFN α-2a) treatment.

Methods

In this prospective research, HBeAg-positive patients with CHB received PEG-IFN α-2a treatment, completing 4-year follow-up. After PEG-IFN α-2a treatment, undetectable HBV DNA, HBsAg loss, and HBeAg disappearance were defined as functional cure. Proportions of NK, CD56^dim, CD56^bright, NKp46⁺, NKp46^dim, NKp46^high, and interferon alpha receptor 2 (IFNAR2)⁺ NK cells, and the mean fluorescence intensity (MFI) of NK cell surface receptors IFNAR2 and NKp46 were detected.

Results

66 patients were enrolled into the study in which 17 patients obtained functional cure. At baseline, hepatitis B virus desoxyribose nucleic acid (HBV DNA) titer in patients with functional cure was remarkably lower than that in Non-functional cure group. Compared with baseline, HBV DNA levels, HBsAg levels, and HBeAg levels significantly declined at week 12 and 24 of therapy in patients with functional cure. At baseline, the negative correlation between CD56^bright NK% and HBV DNA and the negative correlation between CD56^dim NK% and HBV DNA was showed; CD56^bright NK% and IFNAR2 MFI in patients with functional cure were remarkably higher than those in patients without functional cure. After therapy, CD56^bright NK% and NKp46^high NK% in patients with functional cure were higher than those in patients without functional cure. In Functional cure group, after 24 weeks of treatment NK%, CD56^bright NK%, IFNAR2 MFI weakly increased, and NKp46^high NK% and NKp46 MFI significantly increased, meanwhile, CD56^dim NK% and NKp46^dim NK% decreased. Only NKp46 MFI increased after therapy in patients without functional cure.

Conclusion

The lower HBV DNA load and the higher CD56^bright NK% before therapy, and the higher the post-treatment CD56^bright NK%, IFNAR2 MFI, NKp46^high NK%, the easier to achieve functional cure.

Natural killer cells during acute HIV-1 infection: clues for HIV-1 prevention and therapy

Despite progress in preexposure prophylaxis, the number of newly diagnosed cases with HIV-1 remains high, highlighting the urgent need for preventive and therapeutic strategies to reduce HIV-1 acquisition and limit disease progression. Early immunological events, occurring during acute infection, are key determinants of the outcome and course of disease. Understanding early immune responses occurring before viral set-point is established, is critical to identify potential targets for prophylactic and therapeutic approaches. Natural killer (NK) cells represent a key cellular component of innate immunity and contribute to the early host defence against HIV-1 infection, modulating the pathogenesis of acute HIV-1 infection (AHI). Emerging studies have identified tools for harnessing NK cell responses and expanding specialized NK subpopulations with adaptive/memory features, paving the way for development of novel HIV-1 therapeutics. This review highlights the knowns and unknowns regarding the role of NK cell subsets in the containment of acute HIV-1 infection, and summarizes recent advances in selectively augmenting NK cell functions through prophylactic and therapeutic interventions.

Cytokine profiles and CD8+ T cells in the occurrence of acute and chronic hepatitis B

OBJECTIVE

We explore the expression of functional molecules on CD8+ T lymphocytes, cytokines concentration, and their correlation to occurrence of hepatitis B and hepatitis B virus (HBV) desoxyribose nucleic acid (DNA), hepatitis B surface antigen (HBsAg), hepatitis B envelope antigen (HBeAg), and alanine aminotransferase (ALT) in patients infected with HBV.

METHODS

This is a single center study. 32 patients with acute hepatitis B (AHB), 30 patients with immune tolerant (IT) phase chronic HBV infected, and 50 patients with chronic hepatitis B (CHB) were enrolled. The activation molecules (CD69) and the apoptosis-inducing molecules (CD178) on surface of CD8+ T lymphocytes were tested by the flow cytometry. Fms-like tyrosine kinase 3 ligand (Flt-3L), interleukin 17A (IL-17A), interferon γ (IFN-γ), and Interferon α2 (IFN-α2) were quantitated by Luminex assay. We use linear regression analysis to analyze their correlations to ALT, HBV DNA, HBsAg, and HBeAg.

RESULTS

The frequency of CD69+CD8+ T lymphocytes in CHB and AHB groups were increased significantly compared with IT group (4.19[3.01, 6.18]% and 4.45[2.93, 6.71]% vs. 3.02[2.17, 3.44]%; H=26.207, P=0.001; H=28.585, P=0.002), and the mean fluorescence intensity (MFI) of CD69 in AHB group was significantly higher than IT and CHB groups (27.35[24.88, 32.25] vs. 20.45[19.05, 27.75] and 23.40[16.78, 28.13]; H=25.832, P=0.005 and H=22.056, P=0.008). In IT group, HBsAg levels and HBV DNA loads were negatively correlated with CD69MFI (β=-0.025, t=-2.613, P=0.014; β=-0.021, t=-2.286, P=0.030), meanwhile, HBeAg was negatively related to the frequency of CD69+CD8+ T lymphocytes (β=-61.306, t=-2.116, P=0.043). In AHB group, IFN-α2 was positively related to the frequency of CD8+ T lymphocytes (β=6.798, t=2.629, P=0.016); however, in CHB group, IFN-α2 was negatively associated with frequency of CD8+ T lymphocytes (β=-14.534, t=-2.085, P=0.043). In CHB group, HBeAg was positively associated with frequency of CD69+CD8+ T lymphocytes (β=43.912, t=2.027, P=0.048). In AHB group, ALT was positively related to CD69MFI (β=35.042, t=2.896, P=0.007), but HBsAg was negatively related to CD178MFI (β=-0.137, t=-3.273, P=0.003).

CONCLUSIONS

The activation of CD8+ T lymphocytes was associated with the occurrence of AHB and CHB. However, due to the insufficient expression of functional molecules of CD8+ T lymphocytes and the depletion of CD8+ T lymphocytes, CHB patients were difficult to recover from HBV infection.

Hepatitis B viral infection and role of alcohol

End-stage liver disease is frequently caused by hepatitis B virus (HBV) and alcohol consumption. Notably, the mechanism by which alcohol affects the course of HBV-associated liver disease is unknown, and additional research is needed in this area. A reduced immunological response, oxidative stress, endoplasmic reticulum stress, Golgi apparatus stress, and enhanced HBV replication are a few potential causes.

Enduring Challenges despite Progress in Preventing Mother-to-Child Transmission of Hepatitis B Virus in Angola

Sub-Saharan Africa has one of the highest rates of hepatitis B virus (HBV) infection globally, with an incidence of 1.5 million and 0.8 million yearly deaths, which drives synergistic efforts towards its elimination. To assess the risk of mother-to-child transmission of HBV infection, a cross-sectional study was conducted on 1012 pregnant women in Angola to investigate HBV serological and molecular profiles. The prevalence of HBV was 8.7% (n = 88), with hepatitis B core IgM antibody (anti-HBc IgM) positivity identified in 12.8%, hepatitis B "e" antigen (HBeAg) positivity in 30%, and HBV DNA ≥ 200,000 IU/mL in 28.2%. Family tracking studied 44 children, of which 11 (25%) received at least two doses of the hepatitis B vaccine. HBV was detected in 10/44 (22.7%) children, with vaccination reported in one infected child. Further testing identified anti-HBc IgM positivity in 3/10 (30%), HBeAg positivity in 55%, and both seromarkers in 20%. The results revealed the importance of antenatal HBV screening, antiviral prophylaxis for mothers with high viral loads or HBeAg positivity, and timely first-dose hepatitis B vaccines in newborns. Anti-HBc IgM positivity among pregnant women and children highlights prophylactic measures worth considering, including antenatal hepatitis B vaccination and catch-up vaccination to young children.

An age-structured model of hepatitis B viral infection highlights the potential of different therapeutic strategies

Hepatitis B virus (HBV) is a global health threat, and its elimination by 2030 has been prioritised by the World Health Organisation. Here we present an age-structured model for the immune response to an HBV infection, which takes into account contributions from both cell-mediated and humoral immunity. The model has been validated using published patient data recorded during acute infection. It has been adapted to the scenarios of chronic infection, clearance of infection, and flare-ups via variation of the immune response parameters. The impacts of immune response exhaustion and non-infectious subviral particles on the immune response dynamics are analysed. A comparison of different treatment options in the context of this model reveals that drugs targeting aspects of the viral life cycle are more effective than exhaustion therapy, a form of therapy mitigating immune response exhaustion. Our results suggest that antiviral treatment is best started when viral load is declining rather than in a flare-up. The model suggests that a fast antibody production rate always leads to viral clearance, highlighting the promise of antibody therapies currently in clinical trials.

Immunobiology and pathogenesis of hepatitis B virus infection

Hepatitis B virus (HBV) is a non-cytopathic, hepatotropic virus with the potential to cause a persistent infection, ultimately leading to cirrhosis and hepatocellular carcinoma. Over the past four decades, the basic principles of HBV gene expression and replication as well as the viral and host determinants governing infection outcome have been largely uncovered. Whereas HBV appears to induce little or no innate immune activation, the adaptive immune response mediates both viral clearance as well as liver disease. Here, we review our current knowledge on the immunobiology and pathogenesis of HBV infection, focusing in particular on the role of CD8⁺ T cells and on several recent breakthroughs that challenge current dogmas. For example, we now trust that HBV integration into the host genome often serves as a relevant source of hepatitis B surface antigen (HBsAg) expression during chronic infection, possibly triggering dysfunctional T cell responses and favouring detrimental immunopathology. Further, the unique haemodynamics and anatomy of the liver - and the changes they frequently endure during disease progression to liver fibrosis and cirrhosis - profoundly influence T cell priming, differentiation and function. We also discuss why therapeutic approaches that limit the intrahepatic inflammatory processes triggered by HBV-specific T cells might be surprisingly beneficial for patients with chronic infection.

A quantitative systems pharmacology model for acute viral hepatitis B

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Mechanistic model characterizing acute immune response and HBV system interactions.

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Key role of the cellular and regulatory response triggering hepatitis B chronicity.

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Modelling framework to easily incorporate and explore additional biological mechanisms.

Hepatitis B liver infection is caused by hepatitis B virus (HBV) and represents a major global disease problem when it becomes chronic, as is the case for 80–90% of vertical or early life infections. However, in the vast majority (>95%) of adult exposures, the infected individuals are capable of mounting an effective immune response leading to infection resolution. A good understanding of HBV dynamics and the interaction between the virus and immune system during acute infection represents an essential step to characterize and understand the key biological processes involved in disease resolution, which may help to identify potential interventions to prevent chronic hepatitis B.

In this work, a quantitative systems pharmacology model for acute hepatitis B characterizing viral dynamics and the main components of the innate, adaptive, and tolerant immune response has been successfully developed. To do so, information from multiple sources and across different organization levels has been integrated in a common mechanistic framework. The final model adequately describes the chronology and plausibility of an HBV-triggered immune response, as well as clinical data from acute patients reported in the literature. Given the holistic nature of the framework, the model can be used to illustrate the relevance of the different immune pathways and biological processes to ultimate response, observing the negligible contribution of the innate response and the key contribution of the cellular response on viral clearance. More specifically, moderate reductions of the proliferation of activated cytotoxic CD8+ lymphocytes or increased immunoregulatory effects can drive the system towards chronicity.

The Inflammatory Cytokine Profile Associated with Liver Damage is Broader and Stronger in Chronic Hepatitis B Patients Compared to Acute Hepatitis B Patients

Liver damage in hepatitis B is immune driven and correlates with inflammatory markers in patient serum. There is no comparison of these markers to determine if inflammatory profiles are distinct to different types of liver damage across patients at different stages of disease. We measured 25 inflammatory markers in acute hepatitis B, chronic hepatitis B patients with HBeAg seroconversion and chronic patients stopping nucleoside analogue therapy. Myeloid markers dominated the inflammatory profile in all stages of hepatitis B. More inflammatory markers were detectable in chronic patients, including elevated concentrations of cytotoxic effectors Fas ligand, TRAIL and TNF-α.

Serum HBV pregenomic RNA exhibited opposite associations with NKdim and NKbright cell immunity in treatment-naïve chronic hepatitis B patients

Hepatitis B virus (HBV) pregenomic RNA (pgRNA) is a new biomarker that reflects HBV replication, but its relationship with natural killer (NK) cell immunity in chronic hepatitis B (CHB) is unknown. We assessed serum HBV pgRNA levels in 323 CHB patients by reverse transcription-polymerase chain reaction, assessed cytokine production and activation and inhibitory markers of NK cells by flow cytometry, and measured serum cytokines by enzyme-linked immunosorbent assays (ELISAs). Among the different CHB phases, the serum HBV pgRNA level was highest in the immune-tolerant (IT) and immune-active (IA) phases. Regarding NK and NKdim cells, HBV pgRNA was negatively associated with frequencies, but positively associated with NKp44 and NKp46 expression (activation markers). Regarding NKbright cells, serum HBV pgRNA was positively associated with frequency and programmed cell death protein 1 (PD1) expression (inhibitory marker), but negatively associated with NKp44 and NKp46. Serum HBV pgRNA was not associated with NKp30 (activation marker) on NK cells or subsets. Lastly, serum HBV pgRNA was positively correlated with the levels of serum IL-7 and IL-12P40 (NK cell-promoting cytokines) and negatively correlated with serum prostaglandin E2 (PGE2) level (which negatively regulates NK cells). In conclusion, we found varied relationships between serum HBV pgRNA and NK cells and subsets, indicating that HBV pgRNA may play a complicated role in NK cell-related immunity, providing new information on HBV and host immunity.

Molecular Mechanisms during Hepatitis B Infection and the Effects of the Virus Variability

The immunopathogenesis and molecular mechanisms involved during a hepatitis B virus (HBV) infection have made the approaches for research complex, especially concerning the patients’ responses in the course of the early acute stage. The study of molecular bases involved in the viral clearance or persistence of the infection is complicated due to the difficulty to detect patients at the most adequate points of the disease, especially in the time lapse between the onset of the infection and the viral emergence. Despite this, there is valuable data obtained from animal and in vitro models, which have helped to clarify some aspects of the early immune response against HBV infection. The diversity of the HBV (genotypes and variants) has been proven to be associated not only with the development and outcome of the disease but also with the response to treatments. That is why factors involved in the virus evolution need to be considered while studying hepatitis B infection. This review brings together some of the published data to try to explain the immunological and molecular mechanisms involved in the different stages of the infection, clinical outcomes, viral persistence, and the impact of the variants of HBV in these processes.

Modeling reveals no direct role of the extent of HBV DNA integrations on the outcome of infection

Hepatitis B virus (HBV) with its high prevalence and death toll is one of the most important infectious diseases to study. Yet, there is very little progress in the development of within-host models for HBV, which has subsequently hindered our understanding of this virus. The uncertainty around the proliferation of infected hepatocytes has been studied but never in association with other important biological continuous events such as integrations and superinfections. This is despite the fact that these processes affect the diversity and composition of infected cell population in the liver and an improved understanding of the cellular composition will undoubtedly assist in strategizing against this viral infection. Here, we developed novel mathematical models that incorporate these key biological processes and analyzed them both analytically and numerically. Unaffected by the extent of integrated DNA (IDNA), the outcome of HBV infection was primarily dictated by the balance between processes generating and killing infected hepatocytes containing covalent closed circular DNA (cccDNA). The superinfection was found to be a key process in the spread of HBV infection as its exclusion could not reproduce experimentally observed composition of infected hepatocytes at peak of acute HBV infection, a stage where our model predicts that infected hepatocytes most likely carry both cccDNA and IDNA. Our analysis further suggested the existence of some form of selective advantage of infected hepatocytes containing only IDNA to explain the viral dynamics observed during antiviral treatment and the transition from peak to acute infection. Finally, the fine line between liver destruction and resolution of acute HBV infection was found to be highly influenced by the fate of cccDNA during cellular proliferation.

CD4+ T Cells in Chronic Hepatitis B and T Cell-Directed Immunotherapy

The impaired T cell responses observed in chronic hepatitis B (HBV) patients are considered to contribute to the chronicity of the infection. Research on this impairment has been focused on CD8⁺ T cells because of their cytotoxic effector function; however, CD4⁺ T cells are crucial in the proper development of these long-lasting effector CD8⁺ T cells. In this review, we summarize what is known about CD4⁺ T cells in chronic HBV infection and discuss the importance and opportunities of including CD4⁺ T cells in T cell-directed immunotherapeutic strategies to cure chronic HBV.

A systematic study of Tupaia as a model for human acute hepatitis B infection

The molecular features of hepatitis B virus (HBV) infection, eradication, and pathogenesis are poorly understood, partly due to the lack of an adequate animal model that faithfully reproduces the course of infection. Although Tupaia belangeri were previously recognized as HBV-susceptible animals, the course of infection in adult tupaias remains obscure. Herein, we performed a longitudinal study and demonstrated that adult tupaias were efficiently infected (90% infection rate) with 10⁸ copies of the HBV genome. HBV replicated vigorously, produced high levels of covalently closed circular DNA (cccDNA) in hepatocytes, and released hepatitis B surface antigen (HBsAg), hepatitis Be antigen (HBeAg), and HBV DNA into the serum at day 9 post-inoculation (p.i.), which then decreased on day 15 p.i. The kinetics were consistent with the expression of liver HBsAg and HBeAg, as determined with immunohistochemistry. The viral products in serum at day 9 and 15 p.i. represented de novo synthesized viral products, as treatment with a viral entry inhibitor completely abolished these products from the serum. Viral clearance and serological conversion occurred at day 21 p.i. and were accompanied by elevated alanine transaminase (ALT) levels and liver pathology, such as inflammatory infiltration and hepatocyte ballooning degeneration. Although ALT levels eventually returned to normal levels by day 42 p.i., the liver pathology persisted until at least day 120 p.i. The HBV infection process in tupaia, therefore, exhibits features similar to that of human acute HBV infection, including viral replication, viral eradication, ALT elevation, and liver pathology. Thus, adopting the tupaia model to study host-HBV interactions presents an important advance which could facilitate further investigation and understanding of human HBV infection, especially for features like cccDNA that current small-animal models cannot effectively model.

Genetic variants of programmed cell death 1 are associated with HBV infection and liver disease progression

The inhibitory effects of programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) modulates T-cell depletion. T-cell depletion is one of the key mechanisms of hepatitis B virus (HBV) persistence, in particular liver disease progression and the development of hepatocellular carcinoma (HCC). This case–control study aimed to understand the significance of PD-1 polymorphisms (PD-1.5 and PD-1.9) association with HBV infection risk and HBV-induced liver disease progression. Genotyping of PD-1.5 and PD-1.9 variants was performed by direct Sanger sequencing in 682 HBV-infected patients including chronic hepatitis (CHB, n = 193), liver cirrhosis (LC, n = 183), hepatocellular carcinoma (HCC, n = 306) and 283 healthy controls (HC). To analyze the association of PD-1 variants with liver disease progression, a binary logistic regression, adjusted for age and gender, was performed using different genetic models. The PD-1.9 T allele and PD-1.9 TT genotype are significantly associated with increased risk of LC, HCC, and LC + HCC. The frequencies of PD-1.5 TT genotype and PD-1.5 T allele are significantly higher in HCC compared to LC patients. The haplotype CT (PD-1.5 C and PD-1.9 T) was significantly associated with increased risk of LC, HCC, and LC + HCC. In addition, the TC (PD-1.5 T and PD-1.9 C) haplotype was associated with the risk of HCC compared to non-HCC. The PD-1.5 CC, PD-1.9 TT, genotype, and the CC (PD-1.5 C and PD-1.9) haplotype are associated with unfavorable laboratory parameters in chronic hepatitis B patients. PD-1.5 and PD1.9 are useful prognostic predictors for HBV infection risk and liver disease progression.

Identification of a prognostic and therapeutic immune signature associated with hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most prevalent and inflammation-associated cancers. The tumor microenvironment (TME) plays an essential role in HCC development and metastasis, leading to poor prognosis. The overall TME immune cells infiltration characterizations mediated by immune-related genes (IRGs) remain unclear. In this study, we aimed to investigate whether immune-related genes could be indicators for the prognosis of HCC patients and TME cell infiltration characterization as well as responses to immunotherapy.

Methods

We obtained differentially expressed immune-related genes (DE IRGs) between normal liver tissues and liver cancer tissues from The Cancer Genome Atlas (TCGA) database. To identify the prognostic genes and establish an immune risk signature, we performed univariable Cox regression survival analysis and the Least Absolute Shrinkage and Selector Operation (LASSO) regression based on the DE IRGs by robust rank aggregation method. Cox regression analysis was used to identify independent prognostic factors in HCC. We estimated the immune cell infiltration in TME via CIBERSORT and immunotherapy response through TIDE algorithm.

Results

We constructed an immune signature and validated its predictive capability. The immune signature included 7 differentially expressed IRGs: BIRC5, CACYBP, NR0B1, RAET1E, S100A8, SPINK5, and SPP1. The univariate and multivariate cox analysis showed that the 7-IRGs signature was a robust independent prognostic factor in the overall survival of HCC patients. The 7-IRG signature was associated with some clinical features, including gender, vascular invasion, histological grade, clinical stage, T stage. We also found that the 7-IRG signature could reflect the infiltration characterization of different immunocytes in the tumor microenvironment (TME) and had a good correlation with immune checkpoint molecules, revealing that the poor prognosis might be partly due to immunosuppressive TME. The Tumour Immune Dysfunction and Exclusion (TIDE) analysis data showed that the 7-IRG signature had great potential for indicating the immunotherapy response in HCC patients. The mutation analysis demonstrated a significant difference in the tumor mutation burden (TMB) between the high- and low-risk groups, partially explaining this signature's predictive value.

Conclusion

In a word, we constructed and validated a novel, immune-related prognostic signature for HCC patients. This signature could effectively indicate HCC patients' survival and immunotherapy response. And it might act as potential immunotherapeutic targets for HCC patients.

Highly activated TRAIL+ CD56bright NK cells are associated with the liver damage in HBV-LC patients

BACKGROUND

Chronic hepatitis B-related liver cirrhosis(HBV-LC)is the most common cirrhosis in China, which is characterized as liver damage and high mortality. We aim to investigate the characteristics of TRAIL⁺NK cells in patients with HBV-LC and their relationship with liver damage in patients with HBV-LC.

METHODS

Thirty cases each of chronic hepatitis B (CHB), HBV-related compensated liver cirrhosis (HBV-CLC) and HBV-related decompensated liver cirrhosis (HBV-DLC) patients were recruited in this study. Thirty age-and sex-matched healthy individuals were recruited as healthy controls (HCs). NK cell phenotypes were determined using flow cytometry. Serum chemokine concentrations were ascertained using the CBA Flex set. Cell apoptosis was analyzed using the Annexin V-PE/7-AAD apoptosis Kit.

RESULTS

CD56^bright NK cells increased, but CD56^dim NK cells reduced in HBV-LC patients. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was mainly expressed on CD56^bright NK cells. As the degree of liver damage increased, the frequency and activation of total TRAIL⁺NK cells and TRAIL⁺NK cell subsets continued to increase, especially in the HBV-LC patients. Furthermore, the difference in frequency and activation of total TRAIL⁺NK cells between the HBV-CLC and HBV-DLC groups was mainly due to the highly activation and increase of TRAIL⁺CD56^bright NK cells. With the increasing degree of liver damage, CXCR3-associated chemokines (including CXCL9, CXCL10 and CXCL11) were constantly increased, particularly in the HBV-DLC group. The expression of CXCR3 on CD56^bright NK cells was almost 100 % in all enrolled cohorts. CXCR3-associated chemokines were negatively correlated with liver function and positively correlated with fibrosis degree. TRAIL⁺CD56^bright NK cells were negatively correlated with liver function, and positively correlated with fibrosis degree and CXCR3-associated chemokines. The apoptosis of K562 cells and hepatocytes was suppressed partially by the TRAIL-neutralizing antibodies.

CONCLUSIONS

The increase of CXCR3-related chemokines (including CXCL9, CXCL10 and CXCL11) might be related to the migration of TRAIL⁺ CD56^bright NK cells to the liver. Highly activated TRAIL⁺ CD56^bright NK cells were associated with the liver damage in HBV-LC patients. These findings may provide new perspectives and theoretical basis for future immunotherapy of HBV-LC patients.

Case Report: Application of hepatitis B virus (HBV) deep sequencing to distinguish between acute and chronic infection

Deep sequencing of the full-length hepatitis B virus (HBV) genome provides the opportunity to determine the extent to which viral diversity, genotype, polymorphisms, insertions and deletions may influence presentation and outcomes of disease. Increasing experience with analysis of HBV genomic data opens up the potential for using these data to inform insights into pathophysiology of infection and to underpin decision making in clinical practice. We here set out to undertake whole genome HBV sequencing from an adult who presented acutely unwell with a new diagnosis of HBV infection, and tested positive for both HBV anti-core IgM and IgG, possibly representing either acute hepatitis B infection (AHB) or chronic hepatitis B with an acute reactivation (CHB-AR). The distinction between these two scenarios may be important in predicting prognosis and underpinning treatment decisions, but can be challenging based on routine laboratory tests. Through application of deep whole-genome sequencing we typed the isolate as genotype-D1, and identified several minority variants including G1764A and G1986A substitutions in the pre-core promoter and pre-core regions, which support CHB-AR rather than AHB. In the longer term, enhanced deep sequencing data for HBV may provide improved evidence to distinguish between acute and chronic infection, to predict outcomes and to stratify treatment.

Development and Validation of a Novel Risk Prediction Model Using Recursive Feature Elimination Algorithm for Acute-on-Chronic Liver Failure in Chronic Hepatitis B Patients With Severe Acute Exacerbation

Background: Patients with chronic hepatitis B (CHB) with severe acute exacerbation (SAE) are at a progression stage of acute-on-chronic liver failure (ACLF) but uniform models for predicting ACLF occurrence are lacking. We aimed to present a risk prediction model to early identify the patients at a high risk of ACLF and predict the survival of the patient. Methods: We selected the best variable combination using a novel recursive feature elimination algorithm to develop and validate a classification regression model and also an online application on a cloud server from the training cohort with a total of 342 patients with CHB with SAE and two external cohorts with a sample size of 96 and 65 patients, respectively. Findings: An excellent prediction model called the PATA model including four predictors, prothrombin time (PT), age, total bilirubin (Tbil), and alanine aminotransferase (ALT) could achieve an area under the receiver operating characteristic curve (AUC) of 0.959 (95% CI 0.941-0.977) in the development set, and AUC of 0.932 (95% CI 0.876-0.987) and 0.905 (95% CI 0.826-0.984) in the two external validation cohorts, respectively. The calibration curve for risk prediction probability of ACLF showed optimal agreement between prediction by PATA model and actual observation. After predictive stratification into different risk groups, the C-index of predictive 90-days mortality was 0.720 (0.675-0.765) for the PATA model, 0.549 (0.506-0.592) for the end-stage liver disease score model, and 0.648 (0.581-0.715) for Child-Turcotte-Pugh scoring system. Interpretation: The highlypredictive risk model and easy-to-use online application can accurately predict the risk of ACLF with a poor prognosis. They may facilitate risk communication and guidetherapeutic options.

Macrophage Phenotypes and Hepatitis B Virus Infection

Globally, hepatitis B virus (HBV) infection and its related liver diseases account for 780,000 deaths every year. Outcomes of HBV infection depend on the interaction between the virus and host immune system. It is becoming increasingly apparent that Kupffer cells (KCs), the largest population of resident and monocyte-derived macrophages in the liver, contribute to HBV infection in various aspects. These cells play an important role not only in the anti-HBV immunity including virus recognition, cytokine production to directly inhibit viral replication and recruitment and activation of other immune cells involved in virus clearance but also in HBV outcome and progression, such as persistent infection and development of end-stage liver diseases. Since liver macrophages play multiple roles in HBV infection, they are directly targeted by HBV to benefit its life cycle. In the present review, we briefly outline the current advances of research of macrophages, especially the studies of their phenotypes, in chronic HBV infection.

Dynamic profile of the HBeAg-anti-HBe system in acute and chronic hepatitis B virus infection: A clinical-laboratory approach

Wild-type HBV infection is followed by the blood expression of its widely known serological markers of infection, and designated as, hepatitis B virus surface antigen (HBsAg) and its antibody (anti-HBs), anti-HBc antibodies (IgM/IgG), and hepatitis B virus 'e' antigen (HBeAg) and its antibody (anti-HBe). These markers are detected as the infection develops and its kinetic behavior serves as a basis for monitoring the disorder and for diagnosing the clinical form or infection phase. Among these, the HBeAg-anti-HBe system markers demonstrate a dynamic profile whose interpretation, both in the acute or chronic HBV infection context, can offer greater difficulty to the health professionals, due to its particularities. This review offers a revisit to the markers dynamics of this system in the acute and chronic HBV infection and to the clinical and laboratory significance of its expression in these two clinical contexts.

Case Report: Application of hepatitis B virus (HBV) deep sequencing to distinguish between acute and chronic infection

Deep sequencing of the full-length hepatitis B virus (HBV) genome provides the opportunity to determine the extent to which viral diversity, genotype, polymorphisms, insertions and deletions may influence presentation and outcomes of disease. Increasing experience with analysis of HBV genomic data opens up the potential for using these data to inform insights into pathophysiology of infection and to underpin decision making in clinical practice. We here set out to undertake whole genome HBV sequencing from an adult who presented acutely unwell with a new diagnosis of HBV infection, and tested positive for both HBV anti-core IgM and IgG, possibly representing either acute hepatitis B infection (AHB) or chronic hepatitis B with an acute reactivation (CHB-AR). The distinction between these two scenarios may be important in predicting prognosis and underpinning treatment decisions, but can be challenging based on routine laboratory tests. Through application of deep whole-genome sequencing we typed the isolate as genotype-D1, and identified several minority variants including G1764A and G1986A substitutions in the pre-core promoter and pre-core regions, which support CHB-AR rather than AHB. In the longer term, enhanced deep sequencing data for HBV may provide improved evidence to distinguish between acute and chronic infection, to predict outcomes and to stratify treatment.

Hepatitis B virus persistence and reactivation

Hepatitis B virus (HBV) infection causes chronic hepatitis and has long term complications. Individuals ever infected with HBV are at risk of viral reactivation under certain circumstances. This review summarizes studies on HBV persistence and reactivation with a focus on the definitions and mechanisms. Emphasis is placed on the interplay between HBV replication and host immunity as this interplay determines the patterns of persistence following viral acquisition. Chronic infections exhibit as overt persistence when a defective immune response fails to control the viral replication. The HBV genome persists despite an immune response in the form of covalently closed circular DNA (cccDNA) and integrated DNA, rendering an occult state of viral persistence in individuals whose infection appears to have been resolved. We have described HBV reactivation that occurs because of changes in the virus or the immune system. This review aims to raise the awareness of HBV reactivation and to understand how HBV persists, and discusses the risks of HBV reactivation in a variety of clinical settings.

HBVsvp-Pulsed Dendritic Cell Immunotherapy Induces Th1 Polarization and Hepatitis B Virus-Specific Cytotoxic T Lymphocytes Production

Background

In chronic hepatitis B virus (CHB) patients, both dendritic cells (DCs) and T cells are functionally impaired and consequently the HBV-specific cellular immune responses are downregulated. The present study aims to investigate whether monocyte-derived DC (MoDCs)-pulsed-HBV subviral particles (HBVsvp) can polarize Th1 cells to induce HBV-specific cytotoxic T-lymphocytes (CTL) responses in CHB patients.

Methods and Materials

To this end, the human hepatoma HepG2.2.15 cell line was used to produce HBVsvp as a culturing system, and HBVsvp were concentrated for highly virus titer using the polyethylene glycol protocol. Peripheral blood mononuclear cells (PBMCs), collected from CHB patients and healthy donors, were differentiated into MoDCs and T cells. PBMCs-derived MoDCs were first pulsed with HBVsvp and then cultured with PBMCs-derived T cells. MoDCs and/or T subsets cells were identified for phenotypic activation by FACS analysis. The cytokine secretion of IL-4, IL-12, and IFN-γ in the culture supernatants was detected.

Results

The MoDCs were restored for their activation upon pulsing with HBVsvp in vitro, as identified by significantly overexpression of both CD86 and HLA-DR, and overproduction of IL-4 and IL-12. Furthermore, MoDCs-pulsed-HBVsvp induced Th1 frequencies and activated HBV-specific CTL to produce significantly highest amount of IFN-γ. Enhanced HBV-specific CTL led to strong cytolytic capacity against HepG2.2.15.

Conclusion

Overall, our data suggest that in vitro activation of MoDCs with HBVsvp overcomes the functionally impaired DCs and T cells in CHB patients offering a promising tool for therapeutic or vaccine-based approaches against HBV.

Identification of the association between HBcAg-specific T cell and viral control in chronic HBV infection using a cultured ELISPOT assay

Hepatitis B virus (HBV)-specific T cells play a critical role in determining the outcome of HBV infection. However, T cell response induced by predominant Ag in chronic infection is hardly detectable owing to the lack of a suitable assay. We herein established an optimized method to enumerate HBV-specific T cells and assessed the association between HBV surface Ag (HBsAg) and HBV DNA. Sixty chronic HBV infection patients were enrolled. HBV-specific T cells were expanded by using overlapping peptide pools covering the entire sequence of HBV genotypes B and C. IFN-γ-producing HBV-specific T cells were detected by a cultured enzyme-linked immunospot (ELISPOT) assay, ex vivo ELISPOT assay, or flow cytometry staining. The association between HBV-specific T cells and serum levels of HBsAg and HBV DNA were analyzed. Cultured ELISPOT assay had a higher sensitivity than ex vivo ELISPOT in the detection of HBV-specific T cells. Moreover, consistent results were acquired by flow cytometry analysis and cultured ELISPOT assay, but the latter required only a limited number of cells for detection. Interestingly, HBV core peptide pool induced a robust HBV-specific T cell response in patients with lower levels of HBV DNA and HBsAg. Specifically, the frequency of HBV core Ag-specific IFN-γ⁺ spot-forming cells was inversely correlated with serum levels of HBV DNA and HBsAg. An optimized cultured ELISPOT assay reveals the association between HBV core Ag-induced T cell response and HBV control; this method may favor the investigation of HBV-specific T cell in chronic HBV infection.

Modeling the role of macrophages in HIV persistence during antiretroviral therapy

HIV preferentially infects activated CD4+ T cells. Current antiretroviral therapy cannot eradicate the virus. Viral infection of other cells such as macrophages may contribute to viral persistence during antiretroviral therapy. In addition to cell-free virus infection, macrophages can also get infected when engulfing infected CD4+ T cells as innate immune sentinels. How macrophages affect the dynamics of HIV infection remains unclear. In this paper, we develop an HIV model that includes the infection of CD4+ T cells and macrophages via cell-free virus infection and cell-to-cell viral transmission. We derive the basic reproduction number and obtain the local and global stability of the steady states. Sensitivity and viral dynamics simulations show that even when the infection of CD4+ T cells is completely blocked by therapy, virus can still persist and the steady-state viral load is not sensitive to the change of treatment efficacy. Analysis of the relative contributions to viral replication shows that cell-free virus infection leads to the majority of macrophage infection. Viral transmission from infected CD4+ T cells to macrophages during engulfment accounts for a small fraction of the macrophage infection and has a negligible effect on the total viral production. These results suggest that macrophage infection can be a source contributing to HIV persistence during suppressive therapy. Improving drug efficacies in heterogeneous target cells is crucial for achieving HIV eradication in infected individuals.

Identification of immunological subtypes of hepatocellular carcinoma with expression profiling of immune-modulating genes

Recent studies demonstrate that immune checkpoint inhibitor (ICI) therapy has achieved success in many types of advanced cancers including advanced hepatocellular carcinoma (HCC). However, ICI therapy is beneficial in only some HCC patients, suggesting that immune-responses are highly variable in HCCs. Therefore, understanding the immune status in HCC microenvironment will facilitate ICI immunotherapy and guide patient selection for the therapy. In this study, we first analyzed the expression profile of immune-modulating genes and their relationship with survival of HCC patients using the data downloaded from The Cancer Genome Atlas - Liver Hepatocellular Carcinoma (TCGA-LIHC) database, and found that the higher expressions of CD276 (B7-H3) and CD47 were significantly associated with poor survival. Then we identified 4 immune subtypes of HCCs with different survivals by using the combination expression of B7-H3 (or CD47) and CD8. Patients with B7-H3^low/CD8^high or CD47^low/CD8^high have the best survival while ones with B7-H3^high/CD8^low or CD47^high/CD8^low have the worst survival. The 4 immune subtypes were validated in another 72 HCC patients obtained from South China. In conclusion, our findings suggest that HCC patient prognosis is associated with immunophenotypes by T cell infiltration (CD8 expression) and the expression of the adaptive immune resistance gene (B7-H3 or CD47), and this immune classification system will facilitate HCC patient selection for ICI immunotherapy.

The role of hepatitis B surface antibodies in HBV infection, disease and clearance

The clinical sequelae associated with chronic HBV infection is generally regarded as a consequence of an inadequate and inappropriate immune response to active viral replication, predominantly at the T-cell level. However, recent studies on hepatitis B surface antigen (HBsAg)-specific B cells and hepatitis B surface antibody (anti-HB) responses have identified their previously unrecognized role in the pathogenesis of chronic hepatitis B (CHB). These studies have also uncovered novel therapeutic approaches to more effectively target HBsAg loss and seroconversion, an important end point and regarded as a functional cure. Anti-HBs IgG has also been shown to have multiple direct acting antiviral roles with the Fab component directly blocking viral entry, and release while the Fc component has been linked to antibody dependent cellular cytotoxicity. Likewise, the HBsAg-specific B-cell dysfunctionality can be reversed providing new therapeutic opportunities to achieve functional cure in CHB.

HBV as a target for CAR or TCR-T cell therapy

Engineering HBV-specific T cells utilizing a chimeric antigen receptor (CAR) or a classical T cell receptor (TCR) provides a well characterized, sizeable and functionally intact population of HBV-specific T cells with identical in vitro functionality to the T cells isolated in patients who resolved acute HBV infection. In this review we present evidences of the virological and immunological features of chronic HBV infection, alone or in combination with Hepatitis Delta that might make it amenable for CAR/TCR-T cells therapy.

Hepatitis B infection outcome is associated with novel human leukocyte antigen variants in Ghanaian cohort

IMPACT STATEMENT

Genetic association studies can determine the effect size of gene loci on disease outcomes. In the arena of HBV infections, HLA alleles that associate with HBV outcomes can be used in clinical management decisions. This potential translational utility can shape the future management of HBV infections by identifying at-risk individuals and tailoring medical interventions accordingly. This precision medicine motif is currently only a nascent idea. However, it has stakes that may well override the current "wait and see" approach of clinical management of HBV infections. Here, we have identified HLA alleles associated with HBV outcome in a Ghanaian cohort. Our findings support the motif that HLA alleles associate with HBV outcome along geo-ethnic lines. This buttresses the need for further population pivoted studies. In the long term, our findings add to efforts towards the development of an HLA molecular-based algorithm for predicting HBV infection outcomes.

Role of alcohol in pathogenesis of hepatitis B virus infection

Hepatitis B virus (HBV) and alcohol abuse often contribute to the development of end-stage liver disease. Alcohol abuse not only causes rapid progression of liver disease in HBV infected patients but also allows HBV to persist chronically. Importantly, the mechanism by which alcohol promotes the progression of HBV-associated liver disease are not completely understood. Potential mechanisms include a suppressed immune response, oxidative stress, endoplasmic reticulum and Golgi apparatus stresses, and increased HBV replication. Certainly, more research is necessary to gain a better understanding of these mechanisms such that treatment(s) to prevent rapid liver disease progression in alcohol-abusing HBV patients could be developed. In this review, we discuss the aforementioned factors for the higher risk of liver diseases in alcohol-induced HBV pathogenies and suggest the areas for future studies in this field.

Checkpoint Inhibitors and Therapeutic Vaccines for the Treatment of Chronic HBV Infection

Treatment of chronic hepatitis B virus (HBV) infection is highly effective in suppressing viral replication, but complete cure is rarely achieved. In recent years, substantial progress has been made in the development of immunotherapy to treat cancer. Applying these therapies to improve the management of chronic HBV infection is now being attempted, and has become an area of active research. Immunotherapy with vaccines and checkpoint inhibitors can boost T cell functions in vitro, and therefore may be used to reinvigorate the impaired HBV-specific T cell response. However, whether these approaches will suffice and restore antiviral T cell immunity to induce long-term HBV control remains an open question. Recent efforts have begun to describe the phenotype and function of HBV-specific T cells on the single epitope level. An improved understanding of differing T cell specificities and their contribution to HBV control will be instrumental for advancement of the field. In this review, we outline correlates of successful versus inadequate T cell responses to HBV, and discuss the rationale behind therapeutic vaccines and checkpoint inhibitors for the treatment of chronic HBV infection.

The effects of nucleoside/nucleotide analogues on host immune cells: the baseline for future immune therapy for HBV?

HBV is a non-cytopathic virus and the progression of liver fibrosis is attributed to the host immune response. Complete suppression of viral replication using nucleotide or nucleoside analogues (NUCs) can prevent most complications related to chronic HBV infection. Unfortunately, antiviral treatment has to be administered lifelong to the majority of patients as HBV persists in the hepatocytes. However, although NUCs are very frequently administered in clinical practice, their effects on vital parts of the host immune response to HBV are not well established. In this review we summarize the currently available data gathered from longitudinal studies that investigated treatment-associated alterations of HBV-specific CD4⁺ and CD8⁺ T-cells, regulatory T-cells and natural killer (NK) cells. These observations are important, as they can guide the design of studies that investigate the efficacy of new immune therapeutic agents. Novel experimental compounds will likely be added to ongoing NUC treatment, which leads to a functional cure in only a small minority of patients.

Safety and efficacy of immune checkpoint inhibitors in patients with HBV/HCV infection and advanced-stage cancer: A systematic review

BACKGROUND

Cancer patients with hepatitis B or C virus (HBV/HCV) infection are commonly seen in clinical practice, however, the data of safety and efficacy of immune checkpoint inhibitors (ICIs) among them are sparse, because active HBV/HCV infected patients were generally excluded by clinical trials and the correlation between previous infection and treatment-related adverse events was rarely reported. This review is the first to summarize the results on the safety and efficacy of immune checkpoint inhibitors (ICIs) in HBV/HCV infected cancer patients.

METHOD

We searched literature and conference abstracts in PubMed and Embase followed the PRISMA guideline, using the keywords hepatitis B, hepatitis C, immune checkpoint inhibitor, ipilimumab, nivolumab, pembrolizumab, atezolizumab, durvalumab, avelumab, tremelimumab. Studies described patients with HBV/HCV infection treated with ICIs for advanced stage cancer were included.

FINDINGS

One hundred eighty six patients were identified from 14 articles (8 case reports, 4 case series, 2 trials). Eighty nine patients had HBV infection and 98 had HCV infection (1 both had HBV and HCV). The majority of patients were treated with PD-1 inhibitor monotherapy (140 of 186, 75.3%) and anti-CTLA-4 monotherapy (36 of 186, 19.4%). No treatment-related death was reported. The incidence of grade 3 or 4 hepatic transaminase elevating (HTE) in HBV and HCV infected patients were 3.4% (3/89) and 17.3% (17/98), respectively. 2.8% patients without antivirus therapy experienced virus load increasing, and 1.9% presented virus-related hepatitis. In terms of efficacy, 22 of 118 (18.6%) patients with liver cancer, 11 of 34 (32.4%) with melanoma, 1 of 6 (16.7%) with NSCLC showed objective responses (CR and PR) to ICIs in spite of lines of therapies.

CONCLUSION

ICIs is considered to be safe and effective in advanced cancer patients with hepatitis B or C infection, but still has possibilities to reactive hepatitis virus due to uncertain mechanisms. We recommend that those with viral hepatitis be monitored closely and treated with antiviral therapy if indicated before or during ICIs treatment.

Hepatitis B virus seromarkers among HIV infected adults on ART: An unmet need for HBV screening in eastern Ethiopia

Progression of chronic HBV to cirrhosis, end-stage liver disease (ESLD), and hepatocellular carcinoma (HCC) is more rapid in HIV positive individuals than those with HBV alone; however, the distribution of HBV seromarkers in HIV infected individuals on antiretroviral therapy (ART) is not well described. To address this problem, we assessed the distribution of hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc) and hepatitis B surface antibody (anti-HBs) among HIV infected adults on ART in Eastern Ethiopia. A cross-sectional study was conducted from September 2017 to February 2018. Socio-demographic, behavioral and health related factors, and clinical data were collected using questionnaire and checklist. Plasma samples were tested for HBsAg, anti-HBc and anti-HBs seromarkers using ELISA. Data were double entered into EpiData 3.1, cleaned, exported to and analyzed using STATA 13. Descriptive and logistic regression analysis were conducted and statistical significance was decided at p≤0.05. A total of 901 participants were included and the prevalence of HBsAg was found to be 11.7% [95%CI (10, 14)]. Among the co-infected, 47.6% were also positive for anti-HBc, of which 58% were on an ART containing tenofovir (TDF). Among those screened for the three seromarkers, 38.1% were negative for all and 21% were positive only for anti-HBc (IAHBc). Being single, history of genital discharge and taking ART with TDF combination were significantly associated with HBV co-infection (p≤0.05). There is high burden HBV co-infection among individuals on ART. The unmet need of HBV screening prior to ART initiation leaves many co-infected individuals without appropriate management including therapy, close monitoring or vaccination when indicated, impacting disease prevention.

Innate and adaptive immunity associated with resolution of acute woodchuck hepatitis virus infection in adult woodchucks

Viral and/or host factors that are directly responsible for the acute versus chronic outcome of hepatitis B virus (HBV) infection have not been identified yet. Information on immune response during the early stages of HBV infection in humans is mainly derived from blood samples of patients with acute hepatitis B (AHB), which are usually obtained after the onset of clinical symptoms. Features of intrahepatic immune response in these patients are less studied due to the difficulty of obtaining multiple liver biopsies. Woodchuck hepatitis virus (WHV) infection in woodchucks is a model for HBV infection in humans. In the present study, five adult woodchucks were experimentally infected with WHV and then followed for 18 weeks. Blood and liver tissues were frequently collected for assaying markers of WHV replication and innate and adaptive immune responses. Liver tissues were further analyzed for pathological changes and stained for important immune cell subsets and cytokines. The increase and subsequent decline of viral replication markers in serum and liver, the elicitation of antibodies against viral proteins, and the induction of virus-specific T-cell responses indicated eventual resolution of acute WHV infection in all animals. Intrahepatic innate immune makers stayed unchanged immediately after the infection, but increased markedly during resolution, as determined by changes in transcript levels. The presence of interferon-gamma and expression of natural killer (NK) cell markers suggested that a non-cytolytic response mechanism is involved in the initial viral control in liver. This was followed by the expression of T-cell markers and cytolytic effector molecules, indicating the induction of a cytolytic response mechanism. Parallel increases in regulatory T-cell markers suggested that this cell subset participates in the overall immune cell infiltration in liver and/or has a role in regulating AHB induced by the cytolytic response mechanism. Since the transcript levels of immune cell markers in blood, when detectable, were lower than in liver, and the kinetics, except for NK-cells and interferon-gamma, did not correlate well with their intrahepatic expression, this further indicated enrichment of immune cells within liver. Conclusion: The coordinated interplay of innate and adaptive immunity mediates viral clearance in the woodchuck animal model of HBV infection. The initial presence of NK-cell associated interferon-gamma response points to an important role of this cytokine in HBV resolution.