Remodeling of B-Cell Subsets in Blood during Pegylated IFNα-2a Therapy in Patients with Chronic Hepatitis B Infection

A role for immune modulation in achieving functional cure for chronic hepatitis B among current changes in the landscape of new treatments

INTRODUCTION

Chronic hepatitis B (CHB) is rarely cured using available treatments. Barriers to cure are: 1) persistence of reservoirs of hepatitis B virus (HBV) replication and antigen production (HBV DNA); 2) high burden of viral antigens that promote T cell exhaustion with T cell dysfunction; 3) CHB-induced impairment of immune responses.

AREAS COVERED

We discuss options for new therapies that could address one or more of the barriers to functional cure, with particular emphasis on the potential role of immunotherapy.

EXPERT OPINION/COMMENTARY

Ideally, a sterilizing cure for CHB would translate into finite therapies that result in loss of HBV surface antigen and eradication of HBV DNA. Restoration of a functional adaptive immune response, a key facet of successful CHB treatment, remains elusive. Numerous strategies targeting the high viral DNA and antigen burden and aiming to restore the host immune responses will enter clinical development in coming years. Most patients are likely to require combinations of several drugs, personalized according to virologic and disease characteristics, patient preference, accessibility, and affordability. The management of CHB is a global health priority. Expedited drug development requires collaborations between regulatory agencies, scientists, clinicians, and within the industry to facilitate testing of the best drug combinations.

Hepatitis B functional cure and immune response

Hepatitis B virus (HBV) is a hepatotropic virus, which damage to hepatocytes is not direct, but through the immune system. HBV specific CD4⁺ T cells can induce HBV specific B cells and CD8⁺ T cells. HBV specific B cells produce antibodies to control HBV infection, while HBV specific CD8⁺ T cells destroy infected hepatocytes. One of the reasons for the chronicity of HBV infection is that it cannot effectively activate adoptive immunity and the function of virus specific immune cells is exhausted. Among them, virus antigens (including HBV surface antigen, e antigen, core antigen, etc.) can inhibit the function of immune cells and induce immune tolerance. Long term nucleos(t)ide analogues (NAs) treatment and inactive HBsAg carriers with low HBsAg level may "wake up" immune cells with abnormal function due to the decrease of viral antigen level in blood and liver, and the specific immune function of HBV will recover to a certain extent, thus becoming the "dominant population" for functional cure. In turn, the functional cure will further promote the recovery of HBV specific immune function, which is also the theoretical basis for complete cure of hepatitis B. In the future, the complete cure of chronic HBV infection must be the combination of three drugs: inhibiting virus replication, reducing surface antigen levels and specific immune regulation, among which specific immunotherapy is indispensable. Here we review the relationship, mechanism and clinical significance between the cure of hepatitis B and immune system.

Levels of Antibodies to Hepatitis B Core Antigen Are Associated With Liver Inflammation and Response to Peginterferon in Patients With Chronic Hepatitis B

BACKGROUND

Emerging evidence suggests a pivotal role for B-cell responses in the natural history of chronic hepatitis B. Serum levels of antibodies to hepatitis B core antigen (anti-HBc) vary across infection stages, but their role in predicting response to antiviral therapy is uncertain.

METHODS

Anti-HBc levels were assessed before peginterferon (PEG-IFN) therapy in patients with chronic hepatitis B who either started de novo PEG-IFN (n = 299; 195 hepatitis B e antigen [HBeAg] positive) or started PEG-IFN as add-on to an existing nucleo(s)tide analogue backbone (n = 91; all HBeAg-positive). Associations were explored between anti-HBc and (1) serum biomarkers, (2) liver histological findings, and (3) treatment response.

RESULTS

We studied 390 patients. The hepatitis B virus (HBV) genotype were A, B, C, and D in 24%, 9%, 16%, and 49%, respectively; 72% of patients were Caucasian. Among currently untreated HBeAg-positive patients, anti-HBc was correlated with HBV DNA, hepatitis B core-related antigen (HBcrAg), hepatitis B surface antigen (HBsAg), and HBV RNA, but not with alanine aminotransferase (ALT). Higher anti-HBc was associated with more severe histological inflammatory activity (P < .001), irrespective of HBeAg status. After de novo PEG-IFN, higher anti-HBc levels were associated with HBeAg loss, sustained response, HBsAg decline, and HBsAg clearance (P < .050). Among patients treated with add-on PEG-IFN, higher anti-HBc was associated with HBeAg loss (P = .01).

CONCLUSIONS

Serum anti-HBc levels correlate with histological inflammatory activity. Higher anti-HBc levels were associated with favorable treatment outcomes. These findings suggest that anti-HBc could be used to select patients most likely to respond to immunomodulatory therapy.

CLINICAL TRIALS REGISTRATION

NCT00114361, NCT00146705, NCT00877760, and NCT01532843.

Follow-Up of 108 Patients with Chronic Hepatitis B Virus Infection Treated with Polyethylene Glycol-Conjugated Derivatives of Interferon-Alpha and Monitoring of Off-Treatment Virological Relapse

BACKGROUND This single center study, which enrolled 108 patients with chronic hepatitis B virus infection treated with pegylated interferon-alpha (PEG-IFN-alpha), aimed to follow up and monitor off-treatment responses, including virological relapse, and analyze predictors of long-term efficacy of the PEG-IFN-alpha regimen. MATERIAL AND METHODS In total, 108 hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B who had completed the PEG-IFN-alpha regimen and achieved virological suppression were enrolled. The patients were followed up for 5 years to monitor off-treatment responses. Twenty-eight relevant factors, including the history of antiviral therapy and HBeAg seroconversion, were analyzed using the Cox proportional hazards regression model. RESULTS The cumulative rates of virological suppression were 75.70%, 68.68%, 65.25%, 63.91%, and 63.91% at 1, 2, 3, 4, and 5 years of the follow-up period, respectively. Compared with the rates of virological suppression, the cumulative rates of clinical suppression were 88.41%, 79.83%, 78.59%, 75.65%, and 75.65%, respectively, for the 5 years. Alanine aminotransferase (ALT) normalization at 24 weeks after off-therapy (relative risk [RR]=3.430, P=0.013) was a potential predictor for sustained virological suppression, and the history of anti-viral therapy (RR=0.164, P=0.004), quantitative value of hepatitis B virus surface antigen (HBsAg) at 48 weeks of anti-viral therapy (RR=2.697, P=0.039), and ALT normalization at 24 weeks after off-therapy (RR=5.467, P=0.004) were potential predictors for sustained clinical suppression. CONCLUSIONS Our results suggested that increased HBsAg levels at 48 weeks and normalization of ALT at 24 weeks after off-therapy might be predictive factors for long-term treatment efficacy.[color=red] [/color].

B Cell-mediated Humoral Immunity in Chronic Hepatitis B Infection

B cell-mediated humoral immunity plays a vital role in viral infections, including chronic hepatitis B virus (HBV) infection, which remains a critical global public health issue. Despite hepatitis B surface antigen-specific antibodies are essential to eliminate viral infections, the reduced immune functional capacity of B cells was identified, which was also correlated with chronic hepatitis B (CHB) progression. In addition to B cells, T follicular helper (Tfh) cells, which assist B cells to produce antibodies, might also be involved in the process of anti-HBV-specific antibody production. Here, we provide a comprehensive review of the role of various subsets of B cells and Tfh cells during CHB progression and discuss current novel treatment strategies aimed at restoring humoral immunity. Understanding the mechanism of dysregulated B cells and Tfh cells will facilitate the ultimate functional cure of CHB patients.

Immunomodulation Induced During Interferon-α Therapy Impairs the Anti-HBV Immune Response Through CD24+CD38hi B Cells

Type I interferon is widely used for antiviral therapy, yet has yielded disappointing results toward chronic HBV infection. Here we identify that PEG-IFNα-2b therapy toward persistent infection in humans is a double-edged sword of both immunostimulation and immunomodulation. Our studies of this randomised trial showed persistent PEG-IFNα-2b therapy induced large number of CD24⁺CD38^hi B cells and launched a CD24⁺CD38^hi B cells centered immunosuppressive response, including downregulating functions of T cells and NK cells. Patients with low induced CD24⁺CD38^hi B cells have achieved an improved therapeutic effect. Specifically, using the anti-CD24 antibody to deplete CD24⁺CD38^hi B cells without harming other B cell subsets suggest a promising strategy to improve the therapeutic effects. Our findings show that PEG-IFNα-2b therapy toward persistent infection constitutes an immunomodulation effect, and strategies to identifying the molecular basis for the antiviral versus immunomodulatory effects of PEG-IFNα-2b to selectively manipulate these opposing activities provide an opportunity to ameliorate anti-virus immunity and control viral infection.

Switching renal transplant recipients to belatacept therapy: results of a real-life gradual conversion protocol

Conversion to belatacept immunosuppression is a therapeutic option for renal-transplant recipients with calcineurin inhibitors (CNI) toxicity, but it associates with high risk of acute rejection. Gradual conversion and serial immune monitoring with urinary chemokine CXCL9 may allow increasing safety of this maneuver. We converted kidney transplant recipients with signs of toxicity to CNI or other immunosuppressive drugs to belatacept over a 2-month period. We monitored renal function, metabolic profile, and circulating lymphocyte subsets. We also quantified urinary CXCL9 over a 12-month follow-up period. Between September 2016 and March 2017, 35 patients were successfully switched to belatacept immunosuppression at 3.3 (1.3-7.2) years after transplant. Two patients had a reversible rise in serum creatinine, associated with acute rejection in one case. Urinary CXCL9 increased before serum creatinine. After conversion, blood pressure and HbA1c significantly declined while eGFR and proteinuria remained stable. The percentage of circulating effector T cells and memory B cells significantly declined. Conversion from CNI to belatacept, in this setting, was feasible and safe, provided it was performed over a 2-month time-period. Monitoring urinary CXCL9 may further increase safety through earlier identification of patients at risk for acute rejection. The procedure associates with improved blood pressure, metabolic profile, and reduced circulating effector T and B cells.

Novel Strategy for Phenotypic Characterization of Human B Lymphocytes from Precursors to Effector Cells by Flow Cytometry

A precise identification and phenotypic characterization of human B-cell subsets is of crucial importance in both basic research and medicine. In the literature, flow cytometry studies for the phenotypic characterization of B-lymphocytes are mainly focused on the description of a particular cell stage, or of specific cell stages observed in a single type of sample. In the present work, we propose a backbone of 6 antibodies (CD38, CD27, CD10, CD19, CD5 and CD45) and an efficient gating strategy to identify, in a single analysis tube, a large number of B-cell subsets covering the whole B-cell differentiation from precursors to memory and plasma cells. Furthermore, by adding two antibodies in an 8-color combination, our approach allows the analysis of the modulation of any cell surface marker of interest along B-cell differentiation. We thus developed a panel of seven 8-colour antibody combinations to phenotypically characterize B-cell subpopulations in bone marrow, peripheral blood, lymph node and cord blood samples. Beyond qualitative information provided by biparametric representations, we also quantified antigen expression on each of the identified B-cell subsets and we proposed a series of informative curves showing the modulation of seventeen cell surface markers along B-cell differentiation. Our approach by flow cytometry provides an efficient tool to obtain quantitative data on B-cell surface markers expression with a relative easy-to-handle technique that can be applied in routine explorations.