Enhanced B-cell differentiation and reduced proliferative capacity in chronic hepatitis C and chronic hepatitis B virus infections

Hepatitis C Virus and the Host: A Mutual Endurance Leaving Indelible Scars in the Host's Immunity

Hepatitis C virus (HCV) has spread worldwide, and it is responsible for potentially severe chronic liver disease and primary liver cancer. Chronic infection remains for life if not spontaneously eliminated and viral persistence profoundly impairs the efficiency of the host's immunity. Attempts have been made to develop an effective vaccine, but efficacy trials have met with failure. The availability of highly efficacious direct-acting antivirals (DAA) has created hope for the progressive elimination of chronic HCV infections; however, this approach requires a monumental global effort. HCV elicits a prompt innate immune response in the host, characterized by a robust production of interferon-α (IFN-α), although interference in IFN-α signaling by HCV proteins may curb this effect. The late appearance of largely ineffective neutralizing antibodies and the progressive exhaustion of T cells, particularly CD8 T cells, result in the inability to eradicate the virus in most infected patients. Moreover, an HCV cure resulting from DAA treatment does not completely restore the normal immunologic homeostasis. Here, we discuss the main immunological features of immune responses to HCV and the epigenetic scars that chronic viral persistence leaves behind.

Clinical study of hepatitis B vaccine in achieving hepatitis B surface antibody seroconversion in patients with functional cure

Hepatitis B Surface Antigen (HBsAg) seroclearance is the highest treatment goal recommended by the current guidelines for hepatitis B. Levels of antibodies to HBsAg (anti-HBs) are strongly associated with HBsAg recurrence, but hepatitis B vaccination may increase the anti-HBs seroconversion rate and reduce recurrence. We conducted a retrospective clinical study to ascertain the effect of this vaccination on the seroconversion rate and levels of protective anti-HBs after HBsAg. In this retrospective study, we distributed a questionnaire through an online survey platform to collect information related to hepatitis B vaccination in patients with functional cure of hepatitis B with Interferon-α (IFNα) therapy. We enrolled 320 patients who achieved functional cure from IFNα therapy. Of these, 219 patients had received hepatitis B vaccination according to their personal preference and drug accessibility after HBsAg seroclearance, whereas the remaining 101 patients did not receive hepatitis B vaccination. The anti-HBs seroconversion rate of 78.1% in the vaccinated group was significantly greater than that in the unvaccinated group (41.6%) (p < 0.001). Stratified comparisons with anti-HBs of ≥ 100 IU/L and ≥ 300 IU/L showed that both proportions in the vaccinated group were greater than those in the unvaccinated group (71.2% vs. 32.7% and 56.2% vs. 17.8%, respectively, all p-values < 0.001). Logistic regression analysis showed that the odds ratio of vaccination was 4.427, which was the strongest influencing factor for anti-HBs, reaching 100 IU/L or higher. Hepatitis B vaccination in patients after HBsAg seroclearance not only increased the anti-HBs seroconversion rate but also significantly increased antibody levels, with good safety, indicating the clinical value of vaccine therapy for patients with functional cure.

IP10 and Anti-HBc can Predict Virological Relapse and HBsAg Loss in Chronic Hepatitis B Patients after Nucleos(t)ide Analog Discontinuation

INTRODUCTION

To assess predictive ability of serum interferon-inducible protein 10 (IP10) and hepatitis B core antibody (anti-HBc) levels for virological relapse (VR) and hepatitis B surface antigen (HBsAg) loss after nucleos(t)ide analog (NA) discontinuation.

METHODS

In this multicenter prospective study, overall 139 patients were followed up for 24 months after NA discontinuation.

RESULTS

End of treatment (EOT) IP10 and anti-HBc were 29.2 (5.1-66.4) pg/mL and 193.6 (136.9-221.4) IU/mL. EOT IP10 and anti-HBc were independent predictors for VR and HBsAg loss in Cox regression analysis. Cumulative rates of VR in patients with EOT IP10 > 26.99 pg/mL was 31.9% (vs. 70.1%, hazard ratio [HR] 2.998, p < 0.001). Cumulative incidences of VR in patients with EOT anti-HBc ≤141.35 IU/mL was 49.1% (vs. 60.6%, HR 2.99, p < 0.001). Cumulative probabilities of VR was 16.7% in patients with EOT IP10 > 26.99 pg/mL plus anti-HBc ≤141.35 IU/mL (vs. 73.6%, HR 6.464, p < 0.001). Cumulative probabilities of HBsAg loss in patients with EOT IP10 > 93.5 pg/mL was 46.2% (vs. 4.7%, HR 10.94, p < 0.001). Cumulative probabilities of HBsAg loss in patients with EOT anti-HBc ≤78.42 IU/mL were 47.1% (vs. 5%, HR 12.27, p < 0.001). Patients with EOT IP10 > 93.5 pg/mL plus anti-HBc ≤78.42 IU/mL had the highest 24-month cumulative HBsAg loss rate (53.8% vs. 4%, HR 16.83, p < 0.001).

CONCLUSION

High EOT IP10 and low EOT anti-HBc levels were related to both lower risk of VR and higher probability of HBsAg loss.

Recent Insights into the Role of B Cells in Chronic Hepatitis B and C Infections

Chronic viral hepatitis infections, caused by the hepatitis B or C virus, are a major global health problem causing an estimated one million deaths each year. Immunological studies have classically focused on T cells, while B cells have largely been neglected. Emerging evidence, however, highlights a role for B cells in the immunopathogenesis of chronic hepatitis B and C infections. B cell responses appear to be altered across different clinical phases of chronic HBV infection and across stages of disease in chronic HCV infection. These B cell responses show signs of a more activated state with a simultaneous enrichment of phenotypically exhausted atypical memory B cells. Despite the fact that studies show an activating B cell signature in chronic viral hepatitis infection, antibody responses to HBsAg remain impaired in chronic HBV infection, and glycoprotein E2-specific neutralizing antibody responses remain delayed in the acute phase of HCV infection. At the same time, studies have reported that a subset of HBV- and HCV-specific B cells exhibit an exhausted phenotype. This may, at least in part, explain why antibody responses in chronic HBV and HCV patients are suboptimal. Here, we summarize recent findings and discuss upcoming research questions while looking forward to how new single-cell technologies could provide novel insights into the role of B cells in chronic viral hepatitis infections.

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.

Serum IL-5 levels predict HBsAg seroclearance in patients treated with Nucleos(t)ide analogues combined with pegylated interferon

Background

Knowing about cytokine profile contributes to clarify the underling immune mechanism of HBsAg seroclearance rate increase. This study aims to investigate cytokine changes during nucleos(t)ide analogues (NAs) and peginterferon-α (Peg-IFNα) therapy and their impact on the HBsAg serologic response.

Methods

A total of 78 HBV DNA-negative chronic Hepatitis B (CHB) patients were studied after a lead-in phase of NAs with complete serum cytokines. Serum cytokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-17 and TNF-α) were quantified by flow cytometry (FCM) every 24 weeks, before, during and at the end of NAs and Peg-IFNα treatment. Clinical and laboratory data were also taken at the same time. Analysis was performed between cured and uncured groups characterized by HBsAg seroclearance. PBMCs samples from five patients (two in cured group and three in uncured group) were analyzed by FCM.

Results

HBsAg seroclearance was achieved in 30 (38,5%) patients defined as the cured group. In comparison to uncured individuals, cured patients showed similar expressions of serum IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-17 and TNF-α during the treatment of NAs and Peg-IFNα. Compared with the uncured groups, IL-5 was remarkably increased in cured patients. IL-5 at weeks 24 and 48 were associated with HBsAg seroconversion (p=0.033 and 0.027, respectively). PBMCs sample analysis confirmed the predicted value of IL-5 in response to NAs and Peg-IFNα treatment.

Conclusions

IL-5 at weeks 24 and 48 might be used as a biomarker for HBsAg seroclearance in NAs-experienced CHB patients treated with NAs combined with Peg-IFNα. More importantly, exploiting the expression of this cytokine may help to develop a better understanding of the immune pathogenesis of chronic HBV infection.

Corticosteroid treatment in severe patients with SARS-CoV-2 and chronic HBV co-infection: a retrospective multicenter study

Background

The impact of corticosteroids on patients with severe coronavirus disease 2019 (COVID-19)/chronic hepatitis B virus (HBV) co-infection is currently unknown. We aimed to investigate the association of corticosteroids on these patients.

Methods

This retrospective multicenter study screened 5447 confirmed COVID-19 patients hospitalized between Jan 1, 2020 to Apr 18, 2020 in seven centers in China, where the prevalence of chronic HBV infection is moderate to high. Severe patients who had chronic HBV and acute SARS-cov-2 infection were potentially eligible. The diagnosis of chronic HBV infection was based on positive testing for hepatitis B surface antigen (HBsAg) or HBV DNA during hospitalization and a medical history of chronic HBV infection. Severe patients (meeting one of following criteria: respiratory rate > 30 breaths/min; severe respiratory distress; or SpO2 ≤ 93% on room air; or oxygen index < 300 mmHg) with COVID-19/HBV co-infection were identified. The bias of confounding variables on corticosteroids effects was minimized using multivariable logistic regression model and inverse probability of treatment weighting (IPTW) based on propensity score.

Results

The prevalence of HBV co-infection in COVID-19 patients was 4.1%. There were 105 patients with severe COVID-19/HBV co-infections (median age 62 years, 57.1% male). Fifty-five patients received corticosteroid treatment and 50 patients did not. In the multivariable analysis, corticosteroid therapy (OR, 6.32, 95% CI 1.17–34.24, P = 0.033) was identified as an independent risk factor for 28-day mortality. With IPTW analysis, corticosteroid treatment was associated with delayed SARS-CoV-2 viral RNA clearance (OR, 2.95, 95% CI 1.63–5.32, P < 0.001), increased risk of 28-day and in-hospital mortality (OR, 4.90, 95% CI 1.68–14.28, P = 0.004; OR, 5.64, 95% CI 1.95–16.30, P = 0.001, respectively), and acute liver injury (OR, 4.50, 95% CI 2.57–7.85, P < 0.001). Methylprednisolone dose per day and cumulative dose in non-survivors were significantly higher than in survivors.

Conclusions

In patients with severe COVID-19/HBV co-infection, corticosteroid treatment may be associated with increased risk of 28-day and in-hospital mortality.

B10 Cells Are Associated With Clinical Prognosis During Adult Symptomatic Acute HBV Infection

There are few reports about the role of B10 cells in acute hepatitis B (AHB) infection. In this study, based on 48 acute hepatitis B infected patients, we analysis the correlation of B10 cells with HBV clinical prognosis. The results showed that B10 was positively correlated with HBsAg and HBeAg and inversely correlated with anti-HBs. The level of B10 in one week before HBsAg clearance was significantly lower than 2 weeks prior to HBsAg clearance and after 1-2 weeks of HBsAg clearance. B10 cell frequency displayed no correlation with HBV DNA; however, it showed significant temporal synchronization with hepatic inflammatory markers such as ALT. B10 level also associated with hospitalization time. These results indicated that B10 is closely related to the clinical prognosis of acute HBV infection.

Natural antibody IgG levels are associated with HBeAg-positivity and seroconversion in chronic hepatitis B patients treated with entecavir

B1 cell-derived natural antibodies are non-specific polyreactive antibodies and can activate the complement pathway leading to lysis of enveloped virus particles before activation of the adaptive immune response. We investigated the relationship between natural antibody levels and treatment outcomes of 126 treatment-naïve chronic hepatitis B (CHB) patients, who underwent entecavir (ETV) treatment. Serum IgG1-3 and complement C3 levels were significantly higher in HBeAg-positive patients. In pre-treatment, IgG1 (odd ratios [OR] 2.3, p < 0.0001), IgG2 (OR 9.8, p < 0.0001), IgG3 (OR 7.4, p < 0.0001), and C3 (OR 7.2, p < 0.0001) were associated with HBeAg-positive patients. At baseline, IgG2 (OR 10.2, p = 0.025), IgG4, (OR 3.4, p = 0.026), and complement C1q (OR 5.0, p = 0.0068) were associated with seroconverters. Post-treatment levels of IgG1-4 and C3/C1q were also associated with HBeAg-positive patients and seroconverters. High levels of IgG2-4 and C1q were observed in seroconverters but not in virological responders. Thus, high pretreatment and post-treatment levels of natural antibody IgG1-4, complement C3, and/or C1q were significantly associated with HBeAg-positivity and HBeAg seroconverters in CHB patients with ETV treatment. These results suggest that the presence of preexisting host immunity against chronic hepatitis B is closely related to outcome of ETV treatment.

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.

A Role for B Cells to Transmit Hepatitis C Virus Infection

Hepatitis C virus (HCV) is highly variable and transmits through infected blood to establish a chronic liver infection in the majority of patients. Our knowledge on the infectivity of clinical HCV strains is hampered by the lack of in vitro cell culture systems that support efficient viral replication. We and others have reported that HCV can associate with and infect immune cells and may thereby evade host immune surveillance and elimination. To evaluate whether B cells play a role in HCV transmission, we assessed the ability of B cells and sera from recent (<2 years) or chronic (≥ 2 years) HCV patients to infect humanized liver chimeric mice. HCV was transmitted by B cells from chronic infected patients whereas the sera were non-infectious. In contrast, B cells from recently infected patients failed to transmit HCV to the mice, whereas all serum samples were infectious. We observed an association between circulating anti-glycoprotein E1E2 antibodies and B cell HCV transmission. Taken together, our studies provide evidence for HCV transmission by B cells, findings that have clinical implications for prophylactic and therapeutic antibody-based vaccine design.

Vaccine-elicited CD4 T cells prevent the deletion of antiviral B cells in chronic infection

Chronic viral infections subvert protective B cell immunity. An early type I interferon (IFN-I)-driven bias to short-lived plasmablast differentiation leads to clonal deletion, so-called "decimation," of antiviral memory B cells. Therefore, prophylactic countermeasures against decimation remain an unmet need. We show that vaccination-induced CD4 T cells prevented the decimation of naïve and memory B cells in chronically lymphocytic choriomeningitis virus (LCMV)-infected mice. Although these B cell responses were largely T independent when IFN-I was blocked, preexisting T help assured their sustainability under conditions of IFN-I-driven inflammation by instructing a germinal center B cell transcriptional program. Prevention of decimation depended on T cell-intrinsic Bcl6 and Tfh progeny formation. Antigen presentation by B cells, interactions with antigen-specific T helper cells, and costimulation by CD40 and ICOS were also required. Importantly, B cell-mediated virus control averted Th1-driven immunopathology in LCMV-challenged animals with preexisting CD4 T cell immunity. Our findings show that vaccination-induced Tfh cells represent a cornerstone of effective B cell immunity to chronic virus challenge, pointing the way toward more effective B cell-based vaccination against persistent viral diseases.

Th1-Biased Hepatitis C Virus-Specific Follicular T Helper-Like Cells Effectively Support B Cells After Antiviral Therapy

Circulating Th1-biased follicular T helper (cTfh1) cells have been associated with antibody responses to viral infection and after vaccination but their B cell helper functionality is less understood. After viral elimination, Tfh1 cells are the dominant subset within circulating Hepatitis C Virus (HCV)-specific CD4 T cells, but their functional capacity is currently unknown. To address this important point, we established a clone-based system to evaluate CD4 T cell functionality in vitro to overcome experimental limitations associated with their low frequencies. Specifically, we analyzed the transcription factor expression, cytokine secretion and B cell help in co-culture assays of HCV- (n = 18) and influenza-specific CD4 T cell clones (n = 5) in comparison to Tfh (n = 26) and Th1 clones (n = 15) with unknown antigen-specificity derived from healthy donors (n = 4) or direct-acting antiviral (DAA)-treated patients (n = 5). The transcription factor expression and cytokine secretion patterns of HCV-specific CD4 T cell clones indicated a Tfh1 phenotype, with expression of T-bet and Bcl6 and production of IFN-γ and IL-21. Their B helper capacity was superior compared to influenza-specific or Tfh and Th1 clones. Moreover, since Tfh cells are enriched in the IFN-rich milieu of the HCV-infected liver, we investigated the impact of IFN exposure on Tfh phenotype and function. Type I IFN exposure was able to introduce similar phenotypic and functional characteristics in the Tfh cell population within PBMCs or Tfh clones in vitro in line with our finding that Tfh cells are elevated in HCV-infected patients shortly after initiation of IFN-α therapy. Collectively, we were able to functionally characterize HCV-specific CD4 T cells in vitro and not only confirmed a Tfh1 phenotype but observed superior Tfh functionality despite their Th1 bias. Furthermore, our results suggest that chronic type I IFN exposure supports the enrichment of highly functional HCV-specific Tfh-like cells during HCV infection. Thus, HCV-specific Tfh-like cells after DAA therapy may be a promising target for future vaccination design aiming to introduce a neutralizing antibody response.

Association of anti-HBc and liver inflammation in HBeAg-negative chronic hepatitis B virus-infected patients with normal ALT and detectable HBV DNA

Serum hepatitis B core antibody (anti-HBc) is associated with liver inflammation in chronic hepatitis B patients. This study aimed to investigate whether anti-HBc could serve as a predictor of significant liver inflammation in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B virus (HBV) infected patients with normal alanine aminotransferase (ALT) and detectable HBV DNA. Treatment-naïve HBeAg-negative chronic HBV infected patients with normal ALT and detectable HBV DNA who underwent liver biopsy were retrospectively included from two medical centers. Liver inflammation grade was evaluated using the Scheuer scoring system and significant liver inflammation was defined as ≥G2. Serum anti-HBc levels were measured by commercial immunoassays (Abbott GmbH & Co. KG). A total of 117 patients were included and 50 (42.7%) patients showed significant liver inflammation. Serum anti-HBc levels in patients with significant liver inflammation were significantly higher than patients with no or mild liver inflammation (<G2) (p < 0.001). High serum anti-HBc (odds ratio 1.562, 95% confidential interval 1.157-2.110, p = 0.004) was an independent risk factor of significant liver inflammation. The area under the receiver operating characteristic curve of serum anti-HBc in predicting significant liver inflammation was 0.769 and the optimal cut-off value was 10.87 S/CO, with a sensitivity of 59.2% and a specificity of 87.9%. Our data revealed that a substantial of HBeAg-negative chronic infection patients with normal ALT and detectable HBV DNA showed significant liver inflammation. Serum anti-HBc can predict significant liver inflammation in these patients.

Higher risk of mortality in HIV-HBV co-infected patients from sub-Saharan Africa is observed at lower CD4+ cell counts

Background

Hepatitis B virus (HBV) co-infection in human immunodeficiency virus (HIV)-positive individuals increases the risk of overall mortality, especially when HBV DNA levels are high. The role of CD4+ cell counts in this association is poorly defined. We aimed to determine whether HIV–HBV co-infection influences changes in CD4+ cell count before and during antiretroviral therapy and whether it affects mortality risk at levels of CD4+.

Methods

2052 HIV-positive participants from Côte d’Ivoire in a randomized-control trial assessing early or deferred ART were included. HBV-status was determined by hepatitis B surface antigen (HBsAg). Changes in CD4+ cell levels were estimated using a mixed-effect linear model. The incidence rates of all-cause mortality were estimated at CD4+ counts ≤350, 351–500, >500/mm3 and were compared between HBV-status groups as incidence rate ratios (IRR).

Results

At baseline, 190 (9%) were HBsAg-positive [135 (71%) with HBV DNA <2000 IU/mL, 55 (29%) ≥2000 IU/mL]. Follow-up was a median 58 months (IQR = 40–69). Between co-infection groups, there were no differences in CD4+ decline before ART initiation and no differences in CD4+ increase after ART initiation. After adjusting for sex, age, baseline HIV RNA level, and early/deferred ART arm, mortality rates were not significantly different between HBsAg-positive versus HBsAg-negative participants across strata of CD4+ levels. However, HBsAg-positive individuals with HBV-DNA ≥2000 IU/mL versus HBsAg-negative individuals had increased mortality rates at ≤350/mm3 (adjusted-IRR = 3.82, 95% CI = 1.11–9.70) and 351–500/mm3 (adjusted-IRR = 4.37, 95% CI = 0.98–13.02), but not >500/mm3 (adjusted-IRR = 1.07, 95% CI = 0.01–4.91).

Conclusion

Despite no effect of HBV-infection on CD4+ levels, HIV-HBV co-infected individuals with high HBV replication are at higher risk of mortality when CD4+ is <500/mm3.

Baseline quantitative HBcAb strongly predicts undetectable HBV DNA and RNA in chronic hepatitis B patients treated with entecavir for 10 years

The predictive effect of quantitative anti-hepatitis B core on double-negative HBV DNA and RNA remains unstudied. We observed dynamic changes in this measure in chronic hepatitis B patients receiving entecavir for 10 years, evaluating its predictive value for double-negative HBV DNA and RNA. Twenty-seven chronic hepatitis B patients treated with entecavir for 10 years were enrolled in this study. Liver function, quantitative anti-hepatitis B core, hepatitis B surface and e antigens, HBV DNA and RNA were measured at baseline and each follow-up. Virological response was defined as double-negative HBV DNA and RNA; serological response was defined as hepatitis B e antigen seroconversion. After antiviral therapy, quantitative anti-hepatitis B core showed an overall downward trend. Patients with virological response had significantly higher quantitative anti-hepatitis B core levels than those without virological response at baseline. Patients with serological response also had higher quantitative anti-hepatitis B core levels than those without serological response at baseline and week 24. Baseline quantitative anti-hepatitis B core level was the only independent predictor for virological and serological responses. Baseline quantitative anti-hepatitis B core level was powerfully predictive of double-negative HBV DNA and RNA in chronic hepatitis B patients receiving long-term entecavir therapy.

Reduced Energy Metabolism Impairs T Cell-Dependent B Cell Responses in Patients With Advanced HBV-Related Cirrhosis

Background and Aims

Patients with decompensated HBV-related liver cirrhosis (HBV D-LC) showed compromised immune responses, which manifested as a proneness to develop infections and hyporesponsiveness to vaccines, resulting in accelerated disease progression. The alterations in T cell-dependent B cell responses in this pathophysiological process were not well understood. This study aimed to investigate T cell-dependent B cell responses in this process and discuss the mechanism from the perspective of metabolism.

Methods

Changes in phenotypes and subsets of peripheral B cells between HBV D-LC patients and healthy controls (HCs) were compared by flow cytometry. Isolated B cells were activated by coculture with circulating T follicular (cTfh) cells. After coculture, the frequencies of plasmablasts and plasma cells and immunoglobin levels were analyzed. Oxidative phosphorylation (OXPHOS) and glycolysis were analyzed by a Seahorse analyzer. Mitochondrial function and the AKT/mTOR pathway were analyzed by flow cytometry.

Results

The proliferation and differentiation capacities of B cells after T cell stimulation were impaired in D-LC. Furthermore, we found that B cells from D-LC patients showed reductions in OXPHOS and glycolysis after activation, which may result from reduced glucose uptake, mitochondrial dysfunction and attenuated activation of the AKT/mTOR pathway.

Conclusions

B cells from HBV D-LC patients showed dysfunctional energy metabolism after T cell-dependent activation. Understanding the regulations of B cell metabolic pathway and their changes may provide a new direction to rescue B cell hyporesponsiveness in patients with HBV D-LC, preventing these patients be infected and improving sensitivity to vaccines.

Clinical Non-invasive Model to Predict Liver Inflammation in Chronic Hepatitis B With Alanine Aminotransferase ≤ 2 Upper Limit of Normal

Background and Aim: Liver biopsy remains the gold standard for evaluating liver histology. However, it has certain limitations, and many patients refuse it. Non-invasive methods of liver evaluation are thus attracting considerable interest. In this study, we sought predictors of liver inflammation in chronic hepatitis B (CHB) patients with alanine aminotransferase (ALT) levels ≤ 2-fold the upper limit of normal (ULN); these may guide decisions on whether to commence antiviral therapy.

Methods: We retrospectively analyzed 720 patients with CHB who underwent liver biopsy and whose ALT levels were ≤2 ULN. The patients were randomly divided into a training and validation set. We used univariate and multivariate regression analyses of data from the training set to construct a model that predicted significant (grade ≥2) liver inflammation, and validated the model employing the validation set.

Results: Aspartate aminotransferase (AST) level, prothrombin time (PT), glutamyl transpeptidase (GGT) level, and anti-hepatitis B virus core antibody (anti-HBC) level were independent predictors of significant liver inflammation in CHB patients with ALT levels ≤ 2 ULN. A model featuring these four parameters afforded areas under the ROC curve of 0.767 and 0.714 for the training and validation sets. The model was more predictive than were the individual factors.

Conclusion: AST, GGT, anti-HBC, and PT reflect significant liver inflammation among CHB patients with ALT levels ≤ 2 ULN. Their combination indicates whether antiviral therapy is required.

Efficacy of Antiviral Treatment in Liver Biopsy-Proven Immune-Tolerant Chronic Hepatitis B Patients: A Retrospective Cohort Study

The optimal timing of initiating antiviral treatment for immune-tolerant (IT) patients remains unknown. We conducted this study in liver biopsy-proven IT patients to compare the long-term outcomes of untreated and treated patients suffering non-cirrhotic chronic hepatitis B (CHB). This retrospective cohort study recruited 171 consecutive treatment-naïve CHB patients who completed liver biopsy test. Patients were stratified into IT (n = 60), mildly-active (MA; n = 31), immune-active (IA; n = 80), according to alanine aminotransferase (ALT) and liver biopsy data. One hundred and nine patients receiving antiviral treatment constituted the treated set, and 62 patients under close follow-up comprised the untreated set. Primary outcomes were virological response, HBeAg seroconversion, HBsAg loss, ALT normalization, and liver stiffness measurement normalization (NCT03740789). The study population was predominantly male (62.6%) with a mean age of 31 years. The proportion of virological response in treated patients in the MA phase was 57.1%, and the proportion of HBeAg seroconversion was 28.6%, which showed no difference with the 43.8% virological response and 31.5% HBeAg seroconversion in IA patients. The proportions of virological response and seroconversion were 18.2 and 9.1%, respectively, in the IT phase, which were lower than the rates in the MA and IA phases. However, 95.5% of IT patients persisted normal ALT, and 100% of IT patients persisted normal liver stiffness measurement in the treated group. Therefore, antiviral treatment should be considered for CHB patients with high viral load regardless of phase to minimize further damage to hepatocytes.

Sorted B cell transcriptomes point towards actively regulated B cell responses during ongoing chronic hepatitis B infections

The natural course of chronic hepatitis B virus (HBV) infections follows distinct clinical disease phases, characterized by fluctuating levels of serum HBV DNA and ALT. The immune cells and their features that govern these clinical disease transitions remain unknown. In the current study, we performed RNA sequencing on purified B cells from blood (n = 42) and liver (n = 10) of healthy controls and chronic HBV patients. We found distinct gene expression profiles between healthy controls and chronic HBV patients, as evidenced by 190 differentially expressed genes (DEG), but also between the clinical phenotypes of a chronic HBV infection (17-110 DEG between each phase). Numerous immune pathways, including the B cell receptor pathway were upregulated in liver B cells when compared to peripheral B cells. Further investigation of the detected DEG suggested an activation of B cells during HBeAg seroconversion and an active regulation of B cell signalling in the liver.

Human antiviral B cell responses: Emerging lessons from hepatitis B and COVID-19

Humoral immunity is a critical component of the coordinated response required to resolve viral infections and mediate protection following pathogen clearance or vaccination. A better understanding of factors shaping the memory B cell response will allow tailored development of efficient preventative vaccines against emerging acute viral infections, therapeutic vaccines, and immunotherapies for chronic viral infections. Here, we use recent data obtained by profiling antigen-specific B cell responses in hepatitis B as a framework to explore lessons that can be learnt from different viral infections about the diverse influences on humoral immunity. Hepatitis B provides a paradigm where successful B cell responses in resolved or vaccinated individuals can be contrasted to the failed response in chronic infection, while also exemplifying the degree to which B cell responses within infected individuals can differ to two antigens from the same virus. Drawing on studies in other human and murine infections, including emerging data from COVID-19, we consider the influence of antigen quantity and structure on the quality of the B cell response, the role of differential CD4 help, the importance of germinal center vs extrafollicular responses and the emerging concept that responses residing in non-lymphoid organs can participate in B cell memory.

B cells were related to HBsAg seroconversion in inactive HBsAg carriers following peginterferon therapy

Our recent study showed high rate of HBsAg seroconversion achieved in inactive HBsAg carriers (IHCs) treated with peginterferon (PEG-IFN). To better understand the immune-mediated component to the HBsAg seroconversion, we investigated the role of B cells in this study. A total of 44 IHCs were given 48 weeks of PEG-IFN. Fifteen cases achieve HBsAg seroconversion (R group), whereas 29 failed (NR group). The proportion of total B cells and plasma B cells were measured before and during treatment. We found that the proportion of total B cells and plasma B cells was no significant between R group and NR group at baseline, but significantly higher in R group than NR group during PEG-IFN treatment, even when the exact age-, sex-, and treatment period-match was made. In conclusion, we demonstrated the increase of total B cell and plasma B cells during PEG-IFN treatment favored HBsAg seroconversion for IHC, and B cells may play a role in HBV seroconversion.

Reconstitution of T follicular helper-humoral immune axis with elimination of hepatitis C virus

Exhaustion of Hepatitis C Virus (HCV)-specific T cells and abnormal B cell function is a hallmark of chronic HCV infection. Direct-acting antiviral (DAA) therapies are effective in achieving sustained virologic response (SVR), however, whether successful DAA treatment reconstitute T follicular helper (T_FH)-B cell axis in HCV patients is unclear. Here, we aimed to evaluate the immunological changes in global and HCV-specific CD4 + CXCR5 + T_FH, CD4 + CXCR5-T and B cells in 20 HCV patients who achieved SVR with Sofosbuvir and Ledipasvir for 12 weeks and compared with 15 healthy controls (HC). Global and HCV-specific CD4 + CXCR5 + T_FH, CD4 + CXCR5-T and CD19 + B cells had significant phenotypic and functional reconstitution post DAA therapy. Reconstitution of effector, central and terminally differentiated memory cell population and increased ICOS and BCL6 expression was seen in HCV patients at SVR12. HCV-specific cytokines were also improved post DAA. Exhausted and regulatory B cells were declined whereas memory B cells were expanded post DAA therapy. Importantly, frequencies of T_FH cells were significantly associated with HCV RNA reduction, expansion of memory B and plasmablasts, while negatively associated with exhausted/regulatory B cells. Our results demonstrate that SVR with DAA therapy is effective in the reconstitution of phenotypic and functional abnormalities of T_FH-B cell axis.

Quantitative and Qualitative Analysis of Humoral Immunity Reveals Continued and Personalized Evolution in Chronic Viral Infection

Control of established chronic lymphocytic choriomeningitis virus (LCMV) infection requires the production of neutralizing antibodies, but it remains unknown how the ensemble of antibodies evolves during ongoing infection. Here, we analyze the evolution of antibody responses during acute or chronic LCMV infection, combining quantitative functional assays and time-resolved antibody repertoire sequencing. We establish that antibody responses initially converge in both infection types on a functional and repertoire level, but diverge later during chronic infection, showing increased clonal diversity, the appearance of mouse-specific persistent clones, and distinct phylogenetic signatures. Chronic infection is characterized by a longer-lasting germinal center reaction and a continuous differentiation of plasma cells, resulting in the emergence of higher-affinity plasma cells exhibiting increased antibody secretion rates. Taken together, our findings reveal the emergence of a personalized antibody response in chronic infection and support the concept that maintaining B cell diversity throughout chronic LCMV infection correlates with the development of infection-resolving antibodies.

Skewed CD39/CD73/adenosine pathway contributes to B-cell hyperactivation and disease progression in patients with chronic hepatitis B

Background

The mechanisms underlying B-cell hyperactivation in patients with chronic hepatitis B virus (HBV) infection remain largely undefined. The present study assessed the clinical characteristics of the CD39/CD73/adenosine pathway in patients with chronic hepatitis B (CHB).

Methods

We examined CD39 and CD73 expression and adenosine production by B-cells from 202 HBV-infected patients. B-cell-activation phenotypes were assessed by flow cytometry after CpG+CD40 ligand stimulation with or without blockade and activation of the adenosine pathway.

Results

CD39 and CD73 expression on circulating B-cells was decreased in CHB patients with high HBV DNA, HBeAg positivity, high HBsAg levels, and active liver inflammation, and was hierarchically restored in complete responders according to HBeAg seroconversion or HBsAg reduction. However, CD39 and CD73 expression on activated memory and tissue-like memory B-cell subsets in complete responders was not increased despite effective antiviral treatments. Furthermore, CD39 and CD73 expression on intra-hepatic B-cells was decreased in inflammatory livers. In vitro, B-cells from CHB patients showed a markedly reduced capacity to generate CD39/CD73-dependent extracellular adenosine and expressed increased levels of activation markers after adenosine-production blockade. Contrastingly, metformin significantly reduced activation-marker expression via regulating AMP-activated protein kinase.

Conclusions

The skewed CD39 and CD73 expression on B-cells was associated with a high viral burden, liver inflammation, and antiviral efficacy in CHB patients, and the skewed CD39/CD73/adenosine pathway contributed to B-cell hyperactivation. Regulation of the CD39/CD73/adenosine pathway using metformin may represent a therapeutic option to reverse HBV-induced immune pathogenesis.

Hepatitis B virus activity in untreated hepatitis B e antigen-negative human immunodeficiency virus-hepatitis B virus co-infected patients from sub-Saharan Africa

BACKGROUND

In human immunodeficiency virus (HIV) and hepatitis B virus (HBV) co-infected patients from sub-Saharan Africa with hepatitis B e antigen (HBeAg)-negative status, data are limited on the evolution of HBV activity when antiretroviral treatment (ART) is absent.

METHODS

A total of 43 HBeAg-negative co-infected patients not indicated for ART (per concomitant World Health Organization recommendations) were followed during participation in a randomized controlled trial in Côte d'Ivoire. Chronic HBeAg-negative phases were classified at yearly visits and defined as 'infection' (HBV DNA ≤10 000 copies/mL and normal alanine aminotransferase [ALT]) or 'hepatitis' (HBV DNA >10 000 copies/mL and/or above normal ALT). Dispersion in HBV DNA and ALT levels during follow-up was assessed using interquartile range (IQR) regression.

RESULTS

During a median 25 months (IQR 19-31), 17 (40%) patients consistently had 'infection', 5 (12%) consistently had 'hepatitis' and 21 (48%) fluctuated between phases. Wider dispersion in HBV DNA over time was associated with higher baseline HIV RNA (p=0.02) and higher baseline HBV DNA levels (p=0.008), while wider dispersion in ALT was associated with higher baseline HIV RNA (p<0.001), higher baseline ALT levels (p=0.02) and baseline hepatitis surface antigen >4.0 log10 IU/mL (p=0.02).

CONCLUSIONS

HBV activity is common with HBeAg-negative status, whose variation is partly linked to HIV replication. Fluctuations in disease phase make it difficult to assess the risk of morbidity and mortality after ART initiation.

Hepatitis B surface antigen seroclearance: Immune mechanisms, clinical impact, importance for drug development

HBsAg seroclearance occurs rarely in the natural history of chronic hepatitis B (CHB) infection and is associated with improved clinical outcomes. Many factors are associated with HBsAg seroconversion, including immune and viral factors. However, the immune mechanisms associated with HBsAg seroclearance are still difficult to elucidate. HBsAg seroclearance is the ideal aim of HBV treatment. Unfortunately, this goal is rarely achieved with current treatments. Understanding the mechanisms of HBsAg loss appears to be important for the development of curative HBV treatments. While studies from animal models give insights into the potential immune mechanisms and interactions occurring between the immune system and HBsAg, they do not recapitulate all features of CHB in humans and are subject to variability due to their complexity. In this article, we review recent studies on these immune factors, focusing on their influence on CHB progression and HBsAg seroconversion. These data provide new insights for the development of therapeutic approaches to partially restore the anti-HBV immune response. Targeting HBsAg will ideally relieve the immunosuppressive effects on the immune system and help to restore anti-HBV immune responses.

Hepatitis B core-specific memory B cell responses associate with clinical parameters in patients with chronic HBV

BACKGROUND & AIMS

Little is known about the frequency, phenotype and function of HBV-specific B cells during chronic infection. Here we study HBcAg and HBsAg-specific B cells in different clinical phases of a chronic HBV infection.

METHODS

We included 118 treatment naïve and 34 nucleos(t)ide analogue-treated patients with chronic HBV and 23 healthy HBsAg-vaccinated controls. Global and HBV-specific B lymphocytes were examined by FACS using fluorescently labeled HBsAg and HBcAg as baits. Functional HBV-specific B cell responses were quantified in B cell ELISPOT assays. Anti-HBs and anti-HBc antibodies were measured in serum and in ELISPOT supernatant by ELISA.

RESULTS

Higher HBcAg-directed B cell responses were found in HBV clinical phases with elevated vs. low serum alanine aminotransferase (ALT) levels, irrespective of the HBeAg-status. In contrast, HBsAg-directed responses were lower and did not significantly fluctuate. In individual patients a mean 17.8-fold more circulating B cells target HBcAg than HBsAg baits. These HBcAg-specific B cells present a classical memory B cell profile and have slightly higher CD69 expression levels compared to global memory B cells. Viral suppression and ALT normalization upon treatment led to a numeric and functional reduction of HBcAg-specific B cell responses, accompanied by progressive decreases in serum anti-HBc antibodies.

CONCLUSION

HBcAg-specific memory B cells present a classical memory B cell phenotype, vary in number and function throughout HBV's natural history and are significantly reduced during antiviral treatment.

LAY SUMMARY

In recent years, studies examining the role of B cells during chronic hepatitis B virus infection have regained interest. We show that circulating B cells more often target the hepatitis B core antigen than the hepatitis surface antigen. Moreover, these hepatitis B core-specific B cells associate with the natural history of chronic HBV, and their responses decline during effective antiviral treatment.

Hepatitis B virus-induced hyperactivation of B cells in chronic hepatitis B patients via TLR4

B cell hyperactivation and functional impairment were identified from patients with chronic hepatitis B virus (CHB) infection; however, the underlying mechanism remains unknown. Here, we aim to elucidate the mechanisms responsible for B cell hyperactivation during HBV infection. Peripheral CD19⁺ B cells isolated from 4 CHB patients and 4 healthy volunteers were analysed by RNA sequencing. A total of 1401 differentially expressed genes were identified from B cell transcriptome of CHB patients vs healthy volunteers. We found that B cells from CHB patients were functional impaired, with increased TLR4 expression, activated NF‐κB pathway and altered mitochondrial function. The expression of B cell activation‐related genes, including TLR4, was further validated using additional clinical samples. To further verify the role of TLR4 in B cell activation during CHB, B cell phenotypes were determined in wild‐type (WT) and TLR4^−/− HBV‐carrier mice. Hyperactivated B cell and TLR4 signalling pathway were observed in WT HBV‐carrier mice, while TLR4 ablation failed to induce B cell hyperactivation, and downstream MyD88 and NF‐κB were also not altered. Taken together, TLR4 pathway plays a pivotal role in B cell hyperactivation during CHB, which might serve as a promising target for B cell function restoration.

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.

Impact of HCV eradication with direct-acting antiviral agents on serum gamma globulin levels in HCV and HCV/HIV coinfected patients

BACKGROUND

chronic viral infections by both HCV and HIV may lead to polyclonal activation of B cells resulting in hypergammaglobulinemia. This study retrospectively analyzed the effect of HCV eradication with interferon-free direct-acting antiviral agents (DAAs) on the gamma globulin levels in HCV-infected patients with or without HIV coinfection to identify factors potentially associated with gamma globulins decrease.

METHODS

The charts of patients treated with DAAs for HCV chronic infection between January 2015-June 2019 were retrospectively reviewed. Gamma globulin levels before treatment and 12 weeks after the end of anti-HCV therapy were evaluated along with liver tests, liver fibrosis stage by elastography, SVR achievement, HIV-coinfection. Multivariate analyses were carried out to assess the factors and the potential confounders related to the changes in gamma globulin levels.

RESULTS

A significant decrease of gamma globulin concentration was found in both cirrhotic and non-cirrhotic HCV-infected patients after treatment (from mean ± SD of 1.5 ± 0.44 g/dL to 1.31 ± 0.37 g/dL; p = 0.0001). Adjusted linear regression analyses of serum gamma globulin changes from baseline to SVR12 showed a positive significant association with pre-treatment gamma-globulin levels (β-coefficient -0.23; p = 0.0001), Metavir fibrosis score (β-coefficient -0.74; p = 0.008), ALT values and baseline HCV-RNA levels > 800,000. No difference was found between HIV-infected and HIV-uninfected patients.

CONCLUSIONS

Our study confirms previous preliminary observation of the decrease of serum gamma globulins after HCV eradication either achieved with interferon-based therapy or with DAAs, suggesting a leading role of the virus on the activation of B cell compartment and gamma globulins production.

The Study of Correlation Between Serum Vitamin D3 Concentrations and HBV DNA Levels and Immune Response in Chronic Hepatitis Patients

Chronic hepatitis B (CHB) is a common chronic disease. Previous studies have shown a link between 25-hydroxyvitamin D₃ (vitamin D₃) concentration and liver disease. Hepatitis B virus (HBV) infection has been attributed to the inappropriate functioning of cell-mediated immunity. However, the effects of vitamin D₃, immune cell, and HBeAg status on HBV viral load in CHB patients are still unclear. We investigated the relationship between the serum concentration of vitamin D₃, percentage of immune cells in peripheral blood, and the HBV viral load of CHB patients. Sixty CHB patients were recruited, and their blood samples were collected and analyzed. Vitamin D level was measured using a chemiluminescence assay. A level of 30 ng/mL or above was defined as a vitamin D₃ sufficiency. We assigned vitamin D₃ status as either normal (≥30 ng/mL), insufficient (20-30 ng/mL), or deficient (<20 ng/mL). T-lymphocyte and B-lymphocyte surface markers in peripheral blood were detected using flow cytometry. The factors associated with HBV viral load were analyzed using univariate and multivariate-adjusted models. The mean serum vitamin D₃ concentration in the subjects was 20.9±5.6 ng/mL. Up to 88.3% of the patients were either deficient in or had insufficient vitamin D₃. The gender, BMI, hepatitis B surface antigen levels, and ALT levels were significantly related to serum vitamin D₃ levels. Serum vitamin D₃ concentration, HBe status, HBs levels, ALT, and AST levels showed a statistically significant correlation with the HBV DNA levels. Serum vitamin D₃ concentrations and hepatitis B surface antigen levels were strongly correlated with HBV DNA levels. Vitamin D₃ levels were significantly associated with CD19 numbers (β:-6.2, 95% CI: -10.5). In multivariate analysis, vitamin D₃ levels in the deficient and insufficient groups, and the CD8, HBeAg, and WBC counts were significantly associated with HBV DNA levels. In the immune tolerance phase of HBeAg-negative chronic HBV infection, vitamin D₃ may be a modulator of immune function via CD8, CD19, and HBV DNA.

Comparative characterization of B cells specific for HBV nucleocapsid and envelope proteins in patients with chronic hepatitis B

BACKGROUND & AIMS

Knowledge about the regulation of anti-HBV humoral immunity during natural HBV infection is limited. We recently utilized dual fluorochrome-conjugated HBsAg to demonstrate, in patients with chronic HBV (CHB) infection, the functional impairment of their HBsAg-specific B cells. However, the features of their HBcAg-specific B cells are unknown. Here we developed a method to directly visualize, select and characterize HBcAg-specific B cells in parallel with HBsAg-specific B cells.

METHODS

Fluorochrome-conjugated HBcAg reagents were synthesized and utilized to directly detect ex vivo HBcAg-specific B cells in 36 patients with CHB. The frequency, phenotype, functional maturation and transcriptomic profile of HBcAg-specific B cells was studied by flow cytometry, in vitro maturation assays and NanoString-based detection of expression of immune genes, which we compared with HBsAg-specific B cells and total B cells.

RESULTS

HBcAg-specific B cells are present at a higher frequency than HBsAg-specific B cells in patients with CHB and, unlike HBsAg-specific B cells, they mature efficiently into antibody-secreting cells in vitro. Their phenotypic and transcriptomic profiles show that HBcAg-specific B cells are preferentially IgG+ memory B cells. However, despite their phenotypic and functional differences, HBcAg- and HBsAg-specific B cells from patients with CHB share an mRNA expression pattern that differs from global memory B cells and is characterized by high expression of genes indicative of cross-presentation and innate immune activity.

CONCLUSIONS

During chronic HBV infection, a direct relation exists between serological detection of anti-HBs and anti-HBc antibodies, and the quantity and function of their respective specific B cells. However, the transcriptomic analysis performed in HBsAg- and HBcAg-specific B cells suggests additional roles of HBV-specific B cells beyond the production of antibodies.

LAY SUMMARY

Protection of viral infection necessitates the production of antibodies that are generated by specialized cells of the immune system called B cells. During chronic HBV infection, antibodies against the internal part of the virus (core or HBcAg) are detectable while the antibodies directed against the virus envelope (surface or HBsAg) are not present. Here we developed a method that allows us to directly visualize ex vivo the B cells specific for these 2 viral components, highlighting their differences and similarities, and showing how 2 components of the same virus can have different impacts on the function of antiviral B cells.

Genetic association of polymorphisms at the intergenic region between PRDM1 and ATG5 with hepatitis B virus infection in Han Chinese patients

Chronic hepatitis B virus (HBV) infection is related to chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC), and the interplay between the virus and host immune response leads to different outcomes of the infection. PR domain zinc finger protein 1 (PRDM1) and autophagy-related protein 5 (ATG5) are involved in immune response and HBV infection. An intergenic region between PRDM1 and ATG5 (PRDM1-ATG5 region) has been identified, and single-nucleotide polymorphisms (SNPs) in this region were shown to be involved in immune regulation. This study investigated the functionally relevant rs548234, rs6937876, and rs6568431 polymorphisms at the PRDM1-ATG5 region in a Han Chinese population (403 patients with chronic HBV infection [171 chronic hepatitis, 119 cirrhosis, and 113 HCC], 70 infection resolvers, and 196 healthy controls). The frequencies of the rs6568431 allele A in HBV patients (P = .005) and genotype CA in infection resolvers (P = .005) were significantly higher than in healthy controls. In the dominant model, HCC patients had significantly higher frequencies of rs548234 genotypes CC + TC than cirrhosis patients (P = .009). Rs548234 was an independent factor for HCC in comparison with either cirrhosis (P = .005) or all chronic HBV infection without HCC (P = .018). Functional annotation showed evidence of the role of the SNPs in gene regulation. In conclusion, through this study it is revealed for the first time that rs6568431 may be associated with susceptibility to HBV infection and that rs548234 may be associated with HCC risk in chronic HBV infection, supporting the presence of HBV-related disease-causing regulatory polymorphisms in the PRDM1-ATG5 intergenic region.

Human Monoclonal Antibodies as Adjuvant Treatment of Chronic Hepatitis B Virus Infection

Despite the availability of an effective prophylactic vaccine leading to sterilizing immunity, hepatitis B virus (HBV) is responsible for chronic liver disease in more than 250 million individuals, potentially leading to cirrhosis and hepatocellular carcinoma. Antiviral drugs able to completely suppress virus replication are indeed available but they are, by and large, unable to eradicate the virus. Several alternative new treatment approaches are currently being developed but none have so far captured the interest of clinicians for possible clinical development. A constant feature of chronic HBV infection is T-cell exhaustion resulting from persistent exposure to high antigen concentrations as shown by the high expression of programmed cell death protein 1 (PD-1) by HBV-specific CD8 T cells. One way of tackling this problem is to develop HBV-specific neutralizing antibodies that would clear excess envelope proteins from the circulation, allowing for nucleos(t)ide analogs or other antiviral drugs now in preclinical and early clinical development to take advantage of a reconstituted adaptive immunity. Several fully human monoclonal antibodies (mAb) have been developed from HBV-vaccinated and subjects convalescent from acute hepatitis B that show different properties and specificities. It is envisaged that such neutralizing mAb may be used as adjuvant treatment to reduce viral protein load, thus rescuing adaptive immunity in an effort to optimize the effect of antiviral drugs.

Toward a Functional Cure for Hepatitis B: The Rationale and Challenges for Therapeutic Targeting of the B Cell Immune Response

The central role of the cellular immune response in the control and clearance of the hepatitis B virus (HBV) infection has been well-established. The contribution of humoral immunity, including B cell and antibody responses against HBV, has been investigated for a long time but has attracted increasing attention again in recent years. The anti-HBs antibody was first recognized as a marker of protective immunity after the acute resolution of the HBV infection (or vaccination) and is now defined as a biomarker for the functional cure of chronic hepatitis B (CHB). In this way, therapies targeting HBV-specific B cells and the induction of an anti-HBs antibody response are essential elements of a rational strategy to terminate chronic HBV infection. However, a high load of HBsAg in the blood, which has been proposed to induce antigen-specific immune tolerance, represents a major obstacle to curing CHB. Long-term antiviral treatment by nucleoside analogs, by targeting viral translation by siRNA, by inhibiting HBsAg release via nucleic acid polymers, or by neutralizing HBsAg via specific antibodies could potentially reduce the HBsAg load in CHB patients. A combined strategy including a reduction of the HBsAg load via the above treatments and the therapeutic targeting of B cells by vaccination may induce the appearance of anti-HBs antibodies and lead to a functional cure of CHB.

Chronic Hepatitis C: Conspectus of immunological events in the course of fibrosis evolution

In chronically infected HCV patients emergence and evolution of fibrosis, as a consequence of virus persistence, can be considered as an indicator of disease advancement. Therefore the aim of this study was to correlate alterations of immune response in chronic HCV patients with liver histopathology. Sera cytokine levels and frequency of circulating and liver infiltrating cells were evaluated using 13plex Kit Flow Cytomix, flow cytometry and immunohistochemistry. We found that the number of circulating T lymphocytes (including CD4+, CD8+ and Treg) and B lymphocytes, as well as DCs, was higher in patients with no fibrosis than in healthy subjects. In patients with fibrosis frequency of these cells decreased, and contrarily, in the liver, number of T and B lymphocytes gradually increased with fibrosis. Importantly, in patients with advanced fibrosis, liver infiltrating regulatory T cells and DC-SIGN+ mononuclear cells with immunosuppressive and wound-healing effector functions were abundantly present. Cytokine profiling showed predominance of proinflammatory cytokines in patients with no fibrosis and a tendency of decline in level of all cytokines with severity of liver injury. Lower but sustained IL-4 production refers to Th2 predominance in higher stages of fibrosis. Altogether, our results reveal graduall alterations of immunological parameters during fibrosis evolution and illustrate the course of immunological events through disease progression.

PRDM1 levels are associated with clinical diseases in chronic HBV infection and survival of patients with HBV-related hepatocellular carcinoma

PR domain zinc finger protein 1 (PRDM1)/B lymphocyte-induced maturation protein 1 (BLIMP1) is a transcriptional repressor involved in B and T cell responses which are implicated in chronic hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC). This study investigated the association of PRDM1 with clinical diseases of chronic HBV infection and prognosis of HBV -related HCC patients. Serum PRDM1 levels were determined in 403 patients with chronic HBV infection (171 chronic hepatitis, 119 cirrhosis and 113 HCC), 70 HBV infection resolvers and 96 healthy control individuals. The PRDM1 levels were analyzed with regard to clinical diseases and overall survival of HCC patients. Serum PRDM1 concentrations in patients with chronic HBV infection were significantly elevated compared with infection resolvers and healthy controls. HBV-related HCC patients had the most significantly elevated PRDM1 levels. PRDM1 levels could considerably differentiate HCC from chronic hepatitis [area under receiver operating characteristic curve (AUC) 0.889, p < 0.001] or cirrhosis (AUC 0.910, p < 0.001). HCC patients with high PRDM1 levels had a poor prognosis (>300 pg/mL vs. ≤300 pg/mL, p = 0.001). High PRDM1 levels were independently associated with increased mortality in HCC patients (hazard ratio 2.997, 95% confidence interval 1.103-4.722, p = 0.003). Overall, this study demonstrated that PRDM1 levels are associated with the clinical diseases of chronic HBV infection. Highly elevated PRDM1 levels are discriminative of HCC from other clinical diseases and indicative of a poor prognosis of HCC patients. The potential association of PRDM1 levels with disease progression and treatment response warrants further investigation.

Maternal Immunity Influences Vertical Transmission of Hepatitis B to Newborns

Vertical transmission of hepatitis B virus (HBV) from the mother to the newborn often results in viral persistence. To understand mechanisms of maternofetal HBV transmission, we studied maternal immunity and peripheral blood mononuclear cell (PBMC) transcriptome in mothers and newborns. We included 50 mothers and babies who were hepatitis B surface antigen (HBsAg) positive: 22 HBV transmitting mothers (group [Gr.] I) and 28 HBV nontransmitting mothers (Gr. II) to newborns and 10 healthy mother-baby pairs (Gr. III). PBMCs were analyzed for HBV-specific dendritic cells (DCs), T cells, T follicular helper (TFh) cells, B cells, functional immune responses, and cytokine levels as well as transcriptome signatures to identify immune gene expression correlates for protective immunity. Group II mothers had lower HBsAg levels (3.82 × 10³ versus 1.493 × 10⁴; P < 0.0001) with greater HBV-specific responses of DCs, T cells, TFh cells, and B cells than Gr. I mothers. Frequencies of TFh cells were lower in Gr. I mothers, with reduced interleukin-21 (IL-21) levels, and these inversely correlated with HBV DNA levels. Cut-off levels of 9.5% and 8.93% from the receiver operating curve predicted the involvement of TFh cells and B cells in HBV transmission. Transcriptome signatures revealed that maternal gene imprints were reflected in the newborns. Genes related to DCs, TFh cells, and B cells were increased in Gr. II, and Gr. II newborns showed a boost in cellular and humoral responses after vaccination. Conclusion: In mothers infected with HBV, low serum IL-21 levels and decreased TFh-cell and plasma B-cell frequencies are associated with vertical transmission of HBV to newborns. These features are indicative of low protective maternal immunity.

Immunotherapy for Chronic Hepatitis B Virus Infection

While new therapies for chronic hepatitis C virus infection have delivered remarkable cure rates, curative therapies for chronic hepatitis B virus (HBV) infection remain a distant goal. Although current direct antiviral therapies are very efficient in controlling viral replication and limiting the progression to cirrhosis, these treatments require lifelong administration due to the frequent viral rebound upon treatment cessation, and immune modulation with interferon is only effective in a subgroup of patients. Specific immunotherapies can offer the possibility of eliminating or at least stably maintaining low levels of HBV replication under the control of a functional host antiviral response. Here, we review the development of immune cell therapy for HBV, highlighting the potential antiviral efficiency and potential toxicities in different groups of chronically infected HBV patients. We also discuss the chronic hepatitis B patient populations that best benefit from therapeutic immune interventions.

HBV induces inhibitory FcRL receptor on B cells and dysregulates B cell-T follicular helper cell axis

Spontaneous or treatment induced seroconversion in chronic HBV infection is rare and generation of anti-HBs antibodies is the current goal of HBV therapeutics. Here we investigated B and follicular T helper (Tfh) cell defects that persist in HBV infection despite long-term nucleos(t)ide analog (NUC) treatment and possible mechanisms behind them. RNA sequencing revealed that patient B cells have upregulated expression of multiple inhibitory receptors including members of FcRL family and downregulation of genes involved in antigen presentation. An expansion of atypical memory CD19⁺CD10⁻CD27⁻CD21⁻ subset of B cells, that express high levels of FcRL5, is persistently present in patients. HBs antigen specific IgG response is concentrated in classical memory and not in atypical memory subset, confirming dysfunction of this subset. Activated Tfh, which expressed excessive CD40L upon polyclonal stimulation, were present in patients. Incubation of B cells from healthy individuals with HBV core (HBc) or CD40L resulted in induction of inhibitory receptors FcRL4, FcRL5 and PD-1 on CD19+ cells and resulted in altered B cell phenotypes. Mechanistically, HBc binds B cells and causes proliferation specifically of FcRL5+ B cell subset. Our results provide evidence that HBV directly causes upregulation of inhibitory pathways in B cells resulting in an accumulation of atypical B cells that lack anti-HBs function.

PD-1 blockade partially recovers dysfunctional virus-specific B cells in chronic hepatitis B infection

Chronic HBV (CHB) infection suppresses virus-specific T cells, but its impact on humoral immunity has been poorly analyzed. Here, we developed a dual-staining method that utilizes hepatitis B virus (HBV) surface antigens (HBsAg) labeled with fluorochromes as "baits" for specific ex vivo detection of HBsAg-specific B cells and analysis of their quantity, function, and phenotype. We studied healthy vaccinated subjects (n = 18) and patients with resolved (n = 21), acute (n = 11), or chronic (n = 96) HBV infection and observed that frequencies of circulating HBsAg-specific B cells were independent of HBV infection status. In contrast, the presence of serum HBsAg affected function and phenotype of HBsAg-specific B cells that were unable to mature in vitro into Ab-secreting cells and displayed an increased expression of markers linked to hyperactivation (CD21lo) and exhaustion (PD-1). Importantly, B cell alterations were not limited to HBsAg-specific B cells, but affected the global B cell population. HBsAg-specific B cell maturation could be partially restored by a method involving the combination of the cytokines IL-2 and IL-21 and CD40L-expressing feeder cells and was further boosted by the addition of anti-PD-1 Abs. In conclusion, HBV infection has a marked impact on global and HBV-specific humoral immunity, yet HBsAg-specific B cells are amenable to a partial rescue by B cell-maturing cytokines and PD-1 blockade.

Circulating and intrahepatic antiviral B cells are defective in hepatitis B

B cells are increasingly recognized as playing an important role in the ongoing control of hepatitis B virus (HBV). The development of antibodies against the viral surface antigen (HBV surface antigen [HBsAgs]) constitutes the hallmark of resolution of acute infection and is a therapeutic goal for functional cure of chronic HBV (CHB). We characterized B cells directly ex vivo from the blood and liver of patients with CHB to investigate constraints on their antiviral potential. Unexpectedly, we found that HBsAg-specific B cells persisted in the blood and liver of many patients with CHB and were enriched for T-bet, a signature of antiviral potential in B cells. However, purified, differentiated HBsAg-specific B cells from patients with CHB had defective antibody production, consistent with undetectable anti-HBs antibodies in vivo. HBsAg-specific and global B cells had an accumulation of CD21-CD27- atypical memory B cells (atMBC) with high expression of inhibitory receptors, including PD-1. These atMBC demonstrated altered signaling, homing, differentiation into antibody-producing cells, survival, and antiviral/proinflammatory cytokine production that could be partially rescued by PD-1 blockade. Analysis of B cells within healthy and HBV-infected livers implicated the combination of this tolerogenic niche and HBV infection in driving PD-1hiatMBC and impairing B cell immunity.

Aberrant DNA methylation profile of hepatitis B virus infection

We aimed to study the aberrant DNA methylation profile associated with hepatitis B virus (HBV) infection and, to identify key genes and pathways associated with the HBV infection stage. A total of 54 antiviral treatment-naïve HBV-infected patients and six healthy controls were included. Genome-wide methylated DNA immunoprecipitation analysis was performed, as previously described, after which the chip data were preprocessed. Subsequently, Cytoscape software was used for the construction of a protein-protein interaction network, and a database for annotation, visualization, and integrated discovery software was used to conduct functional enrichment analysis. A total of 711 794 CpGs were obtained after data quality control, among which 152 780, 113 814, 90 747, and 175 868 CpGs showed differential methylation in acute hepatitis B (AHB) vs control, total-C vs control, CH1 vs CA1, and AHB vs total-C, respectively. Furthermore, RIPK3, PRDM10, JUN, and SNAI1 were at the center of the four associated networks, respectively. Differential methylated genes differentially methylated in these four comparisons were significantly enriched with olfactory transduction; positive regulation of transport; negative regulation of protein amino acid phosphorylation (eg, JUN), phosphorylation, phosphorus metabolic process, and phosphate metabolic process; and programmed cell death, respectively. RIPK3, PRDM10, JUN, and SNAI1 as well as olfactory transduction, positive regulation of transport, negative regulation of phosphorylation, and programmed cell death are important for the transformation associated with HBV infection stage. Moreover, JUN may be involved in HBV infection, mainly via the negative regulation of amino acid phosphorylation.

Entering the spotlight: hepatitis B surface antigen-specific B cells

Hepatitis B virus-specific (HBV-specific) T cells have been identified as main effector cells in HBV clearance. In contrast, B cells producing neutralizing antibodies against the HBV surface antigen (HBsAg) have been studied in little detail, mainly due to methodical limitations. In this issue of the JCI, two reports use a new technique to specifically detect and characterize HBsAg-specific B cells ex vivo. Indeed, these cells are present, but show phenotypic alterations and impaired function during acute and chronic HBV infection. Thus, HBsAg-specific B cells are a novel attractive target for antiviral strategies toward functional cure of chronic HBV infection.