Humoral immunity, the underestimated player in hepatitis B

Hepatitis B reactivation in patients with multiple myeloma treated with anti-CD38 monoclonal antibody-based therapies: a pharmacovigilance analysis

BACKGROUND

Daratumumab and isatuximab are anti-CD38 monoclonal antibodies indicated for the treatment of multiple myeloma. These agents can increase the risk of infectious complications, including viral infections. Cases of hepatitis B virus (HBV) reactivation have been reported in the literature in patients receiving anti-CD38 monoclonal antibody-based therapies.

AIM

The objective of this analysis was to determine if the association between anti-CD38 monoclonal antibody exposure and the development of hepatitis B reactivation had a detectable reporting signal in the United States Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS).

METHOD

We conducted a post marketing pharmacovigilance analysis by querying the FAERS for reports of HBV reactivation with daratumumab or isatuximab exposure reported between 2015 and 2022. Disproportionality signal analysis was conducted by calculating reporting odds ratios (RORs).

RESULTS

Sixteen cases of hepatitis B virus reactivation were reported in the FAERS database among patients receiving daratumumab or isatuximab reported between 2015 and 2022. The ROR for HBV reactivation was statistically significant for both daratumumab (ROR 4.76, 95% CI 2.76-8.22) and isatuximab (ROR 9.31, 95% CI 3.00-28.92).

CONCLUSION

Overall, our analysis demonstrates a significant reporting signal for HBV reactivation with daratumumab and isatuximab.

Prevention and management of hepatitis B virus reactivation in patients with hematological malignancies in the targeted therapy era

Hepatitis due to hepatitis B virus (HBV) reactivation can be serious and potentially fatal, but is preventable. HBV reactivation is most commonly reported in patients receiving chemotherapy, especially rituximab-containing therapy for hematological malignancies and those receiving stem cell transplantation. Patients with inactive and even resolved HBV infection still have persistence of HBV genomes in the liver. The expression of these silent genomes is controlled by the immune system. Suppression or ablation of immune cells, most importantly B cells, may lead to reactivation of seemingly resolved HBV infection. Thus, all patients with hematological malignancies receiving anticancer therapy should be screened for active or resolved HBV infection by blood tests for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen. Patients found to be positive for HBsAg should be given prophylactic antiviral therapy. For patients with resolved HBV infection, there are two approaches. The first is pre-emptive therapy guided by serial HBV DNA monitoring, and treatment with antiviral therapy as soon as HBV DNA becomes detectable. The second approach is prophylactic antiviral therapy, particularly for patients receiving high-risk therapy, especially anti-CD20 monoclonal antibody or hematopoietic stem cell transplantation. Entecavir and tenofovir are the preferred antiviral choices. Many new effective therapies for hematological malignancies have been introduced in the past decade, for example, chimeric antigen receptor (CAR)-T cell therapy, novel monoclonal antibodies, bispecific antibody drug conjugates, and small molecule inhibitors, which may be associated with HBV reactivation. Although there is limited evidence to guide the optimal preventive measures, we recommend antiviral prophylaxis in HBsAg-positive patients receiving novel treatments, including Bruton's tyrosine kinase inhibitors, B-cell lymphoma 2 inhibitors, and CAR-T cell therapy. Further studies are needed to determine the risk of HBV reactivation with these agents and the best prophylactic strategy.

Immunoglobulin A and complement C4 are involved in the progression of liver fibrosis in patients with chronic hepatitis B

OBJECTIVE

To explore the relationship between immunoglobulin A (IgA), complement C4, and liver fibrosis (L.F.) progression (LFP) in patients with chronic hepatitis B (CHB).

METHODS

This is a retrospective cohort study of CHB patients who received liver biopsies. Relevant data, including demographics, clinical serum markers, and immunological results obtained during liver biopsies, were collected and analyzed to assess and verify the relationship between IgA, C4, and LFP.

RESULTS

This study included 1,938 CHB patients, of whom 132 received two liver biopsies (group 1). Thirty (22.7%) of these patients were diagnosed with LFP (increase in L.F. stage (Scheuer score F ≥ 1)). IgA (C-IgA) and C4 (C-C4) change values between the first and second biopsies were independent risk factors for LFP. IgA levels increased, and C4 levels decreased during the second liver puncture. The remaining 1,806 patients received one liver puncture (group 2). They were divided into the following subgroups: A (F ≤ 1), B (1 < F ≤ 3), and C (F > 3) to verify whether the same trend was observed by cross-sectional study. IgA levels were highest, and C4 levels were lowest in group C (IgA: C > B > A, p < 0.05; C4: C < B < A, p < 0.05).

CONCLUSIONS

The findings of this study suggest that serum IgA and C4 levels are independent risk factors for LFP that could serve as future targets for L.F. management and treatment.

NAFLD and HBV interplay - related mechanisms underlying liver disease progression

Non-alcoholic fatty liver disease (NAFLD) and Hepatitis B virus infection (HBV) constitute common chronic liver diseases with worldwide distribution. NAFLD burden is expected to grow in the coming decade, especially in western countries, considering the increased incidence of diabetes and obesity. Despite the organized HBV vaccinations and use of anti-viral therapies globally, HBV infection remains endemic and challenging public health issue. As both NAFLD and HBV have been associated with the development of progressive fibrosis, cirrhosis and hepatocellular carcinoma (HCC), the co-occurrence of both diseases has gained great research and clinical interest. The causative relationship between NAFLD and HBV infection has not been elucidated so far. Dysregulated fatty acid metabolism and lipotoxicity in NAFLD disease seems to initiate activation of signaling pathways that enhance pro-inflammatory responses and disrupt hepatocyte cell homeostasis, promoting progression of NAFLD disease to NASH, fibrosis and HCC and can affect HBV replication and immune encountering of HBV virus, which may further have impact on liver disease progression. Chronic HBV infection is suggested to have an influence on metabolic changes, which could lead to NAFLD development and the HBV-induced inflammatory responses and molecular pathways may constitute an aggravating factor in hepatic steatosis development. The observed altered immune homeostasis in both HBV infection and NAFLD could be associated with progression to HCC development. Elucidation of the possible mechanisms beyond HBV chronic infection and NAFLD diseases, which could lead to advanced liver disease or increase the risk for severe complications, in the case of HBV-NAFLD co-existence is of high clinical significance in the context of designing effective therapeutic targets.

Anti-HBc IgG Responses Occurring at the Early Phase of Infection Correlate Negatively with HBV Replication in a Mouse Model

Anti-HBc IgG is usually recognized as a diagnostic marker of hepatitis B, while the functional role anti-HBc IgG in HBV infection has not been fully elucidated. In this study, we firstly investigated the relationship between the anti-HBc IgG responses and the replication of HBV using AAV8-1.3HBV infected C57BL/6N mice. Our data showed that the anti-HBc IgG responses at the early phase of infection correlated negatively with the concentrations of circulating HBsAg and HBV DNA at both the early and chronic phases of infection. This observation was confirmed by an independent experiment using AAV8-1.3HBV infected C57BL/6J mice. Furthermore, to comprehend the potential causal relationship between the anti-HBc IgG responses and HBV infection, mice were treated with an anti-HBc monoclonal antibody at three days post AAV8-1.3HBV infection. Our data showed that the anti-HBc mAb significantly suppressed the fold increase of circulating HBsAg level, and the protective effect was not affected by NK cell depletion. Collectively, our study demonstrated that anti-HBc antibodies occurring at the early phase of HBV infection may contribute to the constraint of the virus replication, which might be developed as an immunotherapy for hepatitis B.

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.

A quantitative systems pharmacology model for acute viral hepatitis B

•

Mechanistic model characterizing acute immune response and HBV system interactions.

•

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

•

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.

Reactivation of Resolved Hepatitis B After Daratumumab for Multiple Myeloma

The risk of reactivation of resolved hepatitis B virus (HBV) in hepatitis B surface antigen (HBsAg)-negative multiple myeloma patients after daratumumab has not been reported. Among 93 patients with daratumumab treatment, reactivation occurred in 6 patients (6.5%) with one hepatic failure. This is the first report demonstrating a considerable risk of reactivation of resolved HBV after daratumumab.

Serum free light chain is associated with histological activity and cirrhosis in patients with chronic hepatitis B

BACKGROUND

The antiviral immune response is the main cause of hepatocyte damage and inflammatory necrosis. The serum free light chain, reflecting the immune function of B-cells, is strongly associated with inflammation and disease activity. We aimed to investigate the association of serum free light chain with the progression of chronic hepatitis B.

METHODS

A total of 208 eligible chronic hepatitis B patients who had undergone a liver biopsy were studied. Serum free light chains of all patients were measured by turbidimetry using an immunoassay. Liver histology was assessed according to the METAVIR scoring system (which grades the stage of fibrosis on a five-point scale, F0 = no fibrosis to F4 = cirrhosis, and histological activity on a four-point scale, A0 = no activity to A3 = severe activity). The association of serum free light chains with histological activity and fibrosis progression was evaluated.

RESULTS

The concentration of serum free light chains in CHB patients increased gradually with histological activity and fibrosis progression. The intensity of histological activity was significantly correlated with the serum free kappa chain (r = 0.658, P < 0.001) and the serum free lambda chain (0.675, P < 0.001). The stages of fibrosis were correlated with the serum free kappa chain (r = 0.683, P < 0.001) and serum free lambda chain (0.664, P < 0.001). After adjusting for age, sex and other synergic factors, the serum free kappa chain remained a potential risk factor, but the serum free lambda chain was no longer associated with liver cirrhosis. Similar to FIB-4 and RPR, the serum free kappa chain exhibited excellent performance in the prediction of liver cirrhosis. The AUCs of serum free Kappa chain, FIB-4 and RPR were 0.873, 0.880 and 0.895, respectively, which were significantly higher than those of the AAR and APRI (0.718 and 0.746).

CONCLUSION

Our work revealed that serum free light chains were associated with histological activity and cirrhosis in chronic hepatitis B, which could play a crucial role in the immunopathogenesis of HBV-associated cirrhosis. In addition, free kappa light chain could be a useful predictor of liver cirrhosis.

Immunological Analysis of the Hepatitis B Virus "a" Determinant Displayed on Chimeric Virus-Like Particles of Macrobrachium rosenbergii Nodavirus Capsid Protein Produced in Sf9 Cells

Chimeric virus-like particles (VLPs) have been widely exploited for various purposes including their use as vaccine candidates, particularly due to their ability to induce stronger immune responses than VLPs consisting of single viral proteins. In the present study, VLPs of the Macrobrachium rosenbergii nodavirus (MrNV) capsid protein (Nc) displaying the hepatitis B virus “a” determinant (aD) were produced in Spodoptera frugiperda (Sf9) insect cells. BALB/c mice immunised with the purified chimeric Nc-aD VLPs elicited a sustained titre of anti-aD antibody, which was significantly higher than that elicited by a commercially available hepatitis B vaccine and Escherichia coli-produced Nc-aD VLPs. Immunophenotyping showed that the Sf9-produced Nc-aD VLPs induced proliferation of cytotoxic T-lymphocytes and NK1.1 natural killer cells. Furthermore, enzyme-linked immunospot (ELISPOT)analysis showed the presence of antibody-secreting memory B cells in the mice splenocytes stimulated with the synthetic aD peptide. The significant humoral, natural killer cell and memory B cell immune responses induced by the Sf9-produced Nc-aD VLPs suggest that they present good prospects for use as a hepatitis B vaccine candidate.

Hepatitis B virus reactivation in a myeloma patient with resolved infection who received daratumumab-containing salvage chemotherapy

A 72-year-old female complaining of back pain was diagnosed with IgG-κ multiple myeloma. After osteosynthesis for fracture of the left femoral shaft due to myeloma, she received bortezomib, melphalan, and prednisolone as an initial regimen for multiple myeloma, but discontinued it after three courses due to progressive disease. The patient subsequently received lenalidomide and dexamethasone as a second-line regimen for 2.5 years, and pomalidomide and dexamethasone as a third-line regimen for only 2 months. An anti-CD38 monoclonal antibody, daratumumab (DARA), and bortezomib and dexamethasone (DVd) as a fourth-line regimen were administered for refractory myeloma. However, hepatitis B virus (HBV) reactivation occurred on day 15 of the third course of DVd. The HBV DNA level in peripheral blood suddenly increased to 2.2 log IU/mL. An anti-HBV nucleotide analog, entecavir, was subsequently administered when the HBV DNA level increased to 2.6 log IU/mL. No HBV-related hepatitis was observed during follow-up. DARA can improve the prognosis of patients with multiple myeloma, but also potentially increase the risk of HBV reactivation. Host and viral risk factors need to be identified in such patients in order to implement a more cost-effective strategy against HBV reactivation.

HBV-Induced Immune Imbalance in the Development of HCC

Chronic hepatitis B virus (HBV) infection is one of the high-risk factors for human HCC. Despite the integration of virus DNA and the oncoprotein HBx, chronic necroinflammation and hepatocellular regeneration account for hepatocarcinogenesis. As a non-cytopathic virus, HBV is extensively recognized to mediate chronic liver damage through abnormal immune attack. However, the mechanisms driving HBV infection to HCC are poorly understood. During chronic HBV infection in humans, the adaptive immunity changes from immune tolerance to progressive immune activation, inactivation, reactivation and exhaustion, all of which may be the immune pathogenic factors for the development of HCC. Recently, the immunopathogenic mechanisms were described in mouse HBV-induced HCC models, which is absolutely dependent on the presence of HBV-specific T cell response and NK cell-derived IFN-γ, findings which are consistent with the observations from CHB and HCC patients. In this review, we summarize recent research progression on the HBV-specific CD8⁺ T cells, and also CD4⁺ T cells, B cells and non-specific immune cells and molecules underlying chronic HBV infection and eventual HCC development to demonstrate the pathogenesis of HBV-induced immune imbalance. Based on the progression, we discussed the potential of immune-based therapies and their challenges in the treatment of HBV-related HCC, including the checkpoint inhibition, genetically modified T cell transfer, therapeutic vaccines and metabolic modulation.

Immune network for viral hepatitis B: Topological representation

The liver is a well-known immunotolerogenic environment, which provides the adequate setting for liver infectious pathogens persistence such as the hepatitis B virus (HBV). Consequently, HBV infection can derive in the development of chronic disease in a proportion of the patients. If this situation persists in time, chronic hepatitis B (CHB) would end in cirrhosis, hepatocellular carcinoma and eventually, the death of the patient. It is thought that this immunotolerogenic environment is the result of complex interactions between different elements of the immune system and the viral biology. Therefore, the purpose of this work is to unravel the mechanisms implied in the development of CHB and to design a tool able to help in the study of adequate therapies. Firstly, a conceptual framework with the main components of the immune system and viral dynamics was constructed providing an overall insight on the pathways and interactions implied in this disease. Secondly, a review of the literature was performed in a modular fashion: (i) viral dynamics, (ii) innate immune response, (iii) humoral and (iv) cellular adaptive immune responses and (v) tolerogenic aspects. Finally, the information collected was integrated into a single topological representation that could serve as the plan for the systems pharmacology model architecture. This representation can be considered as the previous unavoidable step to the construction of a quantitative model that could assist in biomarker and target identification, drug design and development, dosing optimization and disease progression analysis.

CD4+ T Cells Play a Critical Role in Microbiota-Maintained Anti-HBV Immunity in a Mouse Model

The ability of the host to clear hepatitis B virus (HBV) is closely correlated to the establishment of commensal microbiota. However, how microbiota affects anti-HBV immunity is still unclear. Using a well-known hydrodynamical HBV transfection mouse model and treatment with antibiotics (Atb), we explored the change in adaptive immunity (CD4⁺ cells, germinal center B cells and anti-HBs Ab). In our setting, normal mice exhibited complete clearance of HBV within 6 weeks post-hydrodynamic injection (HDI) of HBV-containing plasmid, whereas Atb-treated mice lost this capacity, showing high serum level of hepatitis B surface antigen (HBsAg) without hepatitis B surface antibodies (anti-HBs), similar as what happened in Rag1^−/− mice or CD4^−/− mice, suggesting that microbiota may influence the function of CD4⁺ T cells. Furthermore, the numbers of splenic and hepatic effector CD4⁺ T cells (CD44^hiCD62L⁻CD4⁺ T cells) both decreased with impaired function (IFN-γ synthesis), resulting in lower frequency of germinal center B cells and CD4⁺ follicular helper T cells, and impaired anti-HBs production. We further tried to find the bacterial species responsible for maintaining anti-HBV immunity, and found that each antibiotic alone could not significantly influence HBV clearance compared to antibiotic combination, suggesting that global commensal microbial load is critical for promoting HBV clearance. We also confirmed that TLRs (e.g., TLR2, 4, 9) are not major players in immune clearance of HBV using their agonists and knock-out mice. These results suggest that commensal microbiota play an important role in maintaining CD4⁺ T cell immunity against HBV infection.