The hepatitis B virus persists for decades after patients' recovery from acute viral hepatitis despite active maintenance of a cytotoxic T-lymphocyte response

Novel digital droplet inverse PCR assay shows that natural clearance of hepatitis B infection is associated with fewer viral integrations

Hepatitis B virus (HBV) DNA integration into the host cell genome is reportedly a major cause of liver cancer, and a source of hepatitis B surface antigen (HBsAg). High HBsAg levels can alter immune responses which therefore contributes to the progression of HBV-related disease. However, to what extent integration leads to the persistent circulating HBsAg is unclear. Here, we aimed to determine if the extent of HBV DNA integration is associated with the persistence of circulating HBsAg in people exposed to HBV. We established a digital droplet quantitative inverse PCR (dd-qinvPCR) method to quantify integrated HBV DNA in patients who had been exposed to HBV (anti-HBc positive and HBeAg-negative). Total DNA extracts from both liver resections (n = 32; 14 HBsAg-negative and 18 HBsAg-positive) and fine-needle aspirates (FNA, n = 10; 2 HBsAg-negative and 8 HBsAg-positive) were analysed. Using defined in vitro samples for assay establishment, we showed that dd-qinvPCR could detect integrations within an input of <80 cells. The frequency of integrated HBV DNA in those who had undergone HBsAg loss (n = 14, mean ± SD of 1.514 × 10-3 ± 1.839 × 10-3 integrations per cell) was on average 9-fold lower than those with active HBV infection (n = 18, 1.16 × 10-2 ± 1.76 × 10-2 integrations per cell; p = 0.0179). In conclusion, we have developed and validated a highly precise, sensitive and quantitative PCR-based method for the quantification of HBV integrations in clinical samples. Natural clearance of HBV is associated with fewer viral integrations. Future studies are needed to determine if dynamics of integrated HBV DNA can inform the development of curative therapies.

Hepatitis B virus surface antigen drives T cell immunity through non-canonical antigen presentation in mice

Hepatitis B virus (HBV) exclusively infects hepatocytes and produces large amounts of subviral particles containing its surface antigen (HBsAg). T cell immunity is crucial for controlling and clearing HBV infection. However, the intercellular processes underlying HBsAg presentation to T cells are incompletely understood. Here, using preclinical mouse models, we show that, following HBsAg expression, the intrahepatic Batf3+XCR1+CCR7- conventional dendritic cell subset cDC1 presents HBsAg by MHC-I cross-dressing, driving CD8+ T cell response. Meanwhile, upon HBsAg access to lymphoid tissues, B cells acquire HBsAg directly in the follicles of lymphoid tissues and initiate CD4+ T cell responses sequentially in the follicular and interfollicular regions, guided by chemoattractant receptors CCR5 and EBI2, respectively. Finally, we identify ALCAM, LFA-1, and CD80 as key co-stimulatory signals essential for optimal T cell responses. Thus, these findings reveal the roadmap of non-canonical antigen presentation that drives T cell immunity against HBsAg, advancing novel therapeutic strategies for chronic HBV infection.

First detection of HBV nucleic acid in the lung tissue of a patient with spontaneous recovery from HBV infection by tNGS: a case report

BACKGROUND

After recovery from hepatitis B virus (HBV) infection, the virus is likely to reactivate once the body is in an immunosuppressed state. Currently, routine liver biopsies are difficult to obtain, and there are few reports on HBV nucleic acid detection in biopsies of other human organs and tissues. Targeted Next-Generation Sequencing (tNGS) can precisely focus on specific gene regions. Through high-throughput sequencing techniques, it can efficiently obtain a large amount of target nucleic acid sequence information and is widely applied in fields such as disease gene detection and tumor molecular diagnosis. With the development of tNGS, a new path has been opened for HBV nucleic acid detection in different organs, tissues and body fluids, offering hope to break through the current predicament.

CASE PRESENTATION

This case is about a 78-year-old male patient. He was first hospitalized for pulmonary infection. During this hospitalization, tNGS of the bronchoalveolar lavage fluid sample detected a small amount of hepatitis B virus nucleic acid sequences. Two months later, he was re - hospitalized due to cough and expectoration. TNGS of his transthoracic lung fine needle aspiration sample showed a high number of hepatitis B virus nucleic acid sequences. The serological test results during hospitalization indicated that the patient was in a state of spontaneous recovery from hepatitis B virus infection, with HBsAg negative, Anti - HBs positive, Anti - HBc positive, and HBV nucleic acid negative. Fluorescent quantitative PCR detected HBV nucleic acid in the bronchoalveolar lavage fluid sample and the transthoracic lung fine needle aspiration sample at different times.

CONCLUSION

This case study is the first to use tNGS to precisely analyze the bronchoalveolar lavage fluid sample and the transthoracic lung fine needle aspiration sample from different sampling periods. It accurately identifies HBV nucleic acid replication in the lungs of patients with spontaneous HBV - infection recovery, offering new ideas and evidence for HBV research in extra - hepatic tissues.

Role of liver-resident NK cells in liver immunity

The tolerogenic immune microenvironment of the liver (the immune system avoids attacking harmless antigens, such as antigens derived from food and gut microbiota) has garnered significant attention in recent years. Inherent immune cells in the liver play a unique role in regulating this microenvironment. Liver-resident natural killer (LrNK) cells, also known as liver type 1 innate lymphoid cells (ILC1s), are a recently discovered subset of immune cells that possess properties distinct from those of conventional NK (cNK) cells. Accumulating evidence suggests that there are significant differences between LrNK and cNK cells, with LrNK cells potentially exhibiting immunosuppressive functions in the liver. This review summarizes the latest findings on LrNK cells, focusing on their phenotype, heterogeneity, plasticity, origin, development, and the required transcription factors. In addition, immune functions of LrNK cells in various liver diseases, including liver cancer, viral infections, liver injury, and cirrhosis, were analyzed. By elucidating the role of LrNK cells in liver immunity, this review aims to enhance our understanding of the mechanisms underlying liver immunity and contribute to the improvement of liver disease treatment.

Impact of Hepatitis B Infection on Patient and Graft Survival After Kidney Transplantation

Objectives: Chronic Hepatitis B virus (HBV) infection is a significant global health issue, with dialysis patients at increased risk and reduced response to HBV vaccination. The effects of HBV serological status on kidney transplant outcomes, particularly for patients with resolved or inactive HBV infection, needs more data, especially from current era. This study evaluated the impact of chronic and non-active HBV infection on patient and graft survival after kidney transplantation. Methods: Retrospective analysis was conducted of kidney-only transplant recipients at our center from 1 January 1990 to 31 August 2019 (end of observation). Patients were grouped by their HBV serostatus before transplantation into three categories: HBV negative (HBsAg-/Anti-Hbc-), non-active HBV infection (HbsAg-/Anti-Hbc+) and chronic HBV infection (HbsAg+/Anti-Hbc+). Primary outcomes included patient survival, graft survival, and overall graft and patient survival, analyzed using Kaplan-Meier (KM) curves, log-rank tests, Restricted mean survival times (RMST), and Accelerated failure time (AFT) models. Results: Among 2490 patients, 2197 were HBV negative, 218 had non-active HBV, and 75 had chronic HBV. Over a mean follow-up of 8.1 years, mortality and graft failure rates were highest in chronic HBV patients (49% and 37%), followed by non-active HBV (39% and 29%) and HBV-negative patients (30% and 20%). KM analysis revealed significantly lower overall survival rates for chronic HBV and non-active HBV groups compared to HBV-negative patients (p = 0.006). RMST confirmed significant reductions in survival for the non-active group (12.57 vs. 14.17 years, p = 0.007). Cox regression and AFT models identified older recipient/donor age, Hepatitis-C-virus coinfection, and broad antigen mismatches as negative predictors, while living donors improved outcomes. Conclusions: While unadjusted Kaplan-Meier curves and RMST analysis suggested differences in patient and graft survival, further thorough multivariable AFT analysis did not show a significant association between non-active or chronic HBV infection and patient or graft survival after kidney transplantation.

The role of immune regulation in HBV infection and hepatocellular carcinogenesis

Hepatitis B virus (HBV) infection is a well-documented independent risk factor for developing hepatocellular carcinoma (HCC). Consequently, extensive research has focused on elucidating the mechanisms by which HBV induces hepatocarcinogenesis. The majority of studies are dedicated to understanding how HBV DNA integration into the host genome, viral RNA expression, and the resulting protein transcripts affect cellular processes and promote the malignant transformation of hepatocytes. However, considering that most acute HBV infections are curable, immune suppression potentially contributes to the critical challenges in the treatment of chronic infections. Regulatory T cells (Tregs) are crucial in immune tolerance. Understanding the interplay of Tregs within the liver microenvironment following HBV infection could offer novel therapeutic approaches for treating HBV infections and preventing HBV-related HCC. Two viewpoints to targeting Tregs in the liver microenvironment include means of reducing their inhibitory function and decreasing Treg frequency. As these strategies may disrupt the immune balance and lead to autoimmune responses, careful and comprehensive profiling of the patient's immunological status and genetic factors is required to successfully employ this promising therapeutic approach.

Surveillance Following Hepatitis B Surface Antigen Loss: An Issue Requiring Attention

Due to the lack of agents that directly target covalently closed circular DNA and integrated HBV DNA in hepatocytes, achieving a complete cure for chronic hepatitis B (CHB) remains challenging. The latest guidelines recommend (hepatitis B surface antigen) HBsAg loss as the ideal treatment target for improving liver function, histopathology, and long-term prognosis. However, even after HBsAg loss, hepatitis B virus can persist, with a risk of recurrence, reactivation, cirrhosis, and hepatocellular carcinoma. Therefore, follow-up and surveillance are still necessary. With increasing treatment options available for achieving HBsAg loss in patients with CHB, developing effective surveillance strategies has become crucial. Recent studies on outcomes following HBsAg loss provide new insights for refining current surveillance strategies, though further improvement is needed through long-term observation and follow-up.

Viral Oncogenesis: Synergistic Role of Genome Integration and Persistence

Persistence is a strategy used by many viruses to evade eradication by the immune system, ensuring their permanence and transmission within the host and optimizing viral fitness. During persistence, viruses can trigger various phenomena, including target organ damage, mainly due to an inflammatory state induced by infection, as well as cell proliferation and/or immortalization. In addition to immune evasion and chronic inflammation, factors contributing to viral persistence include low-level viral replication, the accumulation of viral mutants, and, most importantly, maintenance of the viral genome and reliance on viral oncoprotein production. This review focuses on the process of genome integration, which may occur at different stages of infection (e.g., HBV), during the chronic phase of infection (e.g., HPV, EBV), or as an essential part of the viral life cycle, as seen in retroviruses (HIV, HTLV-1). It also explores the close relationship between integration, persistence, and oncogenesis. Several models have been proposed to describe the genome integration process, including non-homologous recombination, looping, and microhomology models. Integration can occur either randomly or at specific genomic sites, often leading to genome destabilization. In some cases, integration results in the loss of genomic regions or impairs the regulation of oncogene and/or oncosuppressor expression, contributing to tumor development.

Hepatitis B Virus DNA and RNA Persist in Liver After Serologic Recovery in Persons With Hepatitis C Virus

After recovery from a hepatitis B virus (HBV) infection, reactivation can occur with immunosuppression; thus, it is assumed that replication competent HBV persists in the liver. We sought to detect persistent HBV from 13 people with spontaneous recovery. We quantified HBV DNA and RNA in core liver biopsy specimens (median, 1.72 × 106 cells) from persons who inject drugs. Of 13 biopsy specimens, 8 (61%) had evidence of HBV DNA or RNA and 5 (38%) had both HBV DNA and RNA. Messenger RNAs were derived from covalently closed circular DNA and integrated HBV DNA. Here, we show prevalent HBV DNA and RNA despite clinical recovery in persons who inject drugs.

Drug-induced hepatitis B virus reactivation: insights from FAERS database analysis

BACKGROUND

Reactivation of the hepatitis B virus (HBV) induced by drugs is a commonly overlooked but clinically significant complication, posing risks of treatment interruptions, hepatitis exacerbation, liver failure, and even mortality.

METHODS

Disproportionality analyses were conducted on the Food and Drug Administration Adverse Event Reporting System (FAERS) database data spanning from January 2017 to December 2023 to detect drugs posing a risk of HBV reactivation (HBV-R). HBV-R cases were identified using the Medical Dictionary for Regulatory Activities (MedDRA), and drug generic names were ascertained from the DrugBank database.

RESULTS

A total of 2596 adverse event reports (AERs) were found to be related to drug-induced HBV-R.According to the disproportionality analysis, the top five drugs with the highest ROR and PRR were daklinza, vocabria, doxorubicin, sovaldi, and ribavirin. The top 40 drugs causing drug-induced HBV-R can be roughly divided into three categories: anti-tumor drugs, immunosuppressive drugs, and antiviral drugs. Among them, 23 drugs do not explicitly mention the risk of HBV-R in their drug instructions.

CONCLUSIONS

It was observed that some pharmaceuticals do not adequately address the risk of HBV-R in their drug documentation. These findings could assist healthcare providers in promptly recognizing drug-induced HBV-R.

The immune response in chronic HBV infection

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

A case report: cccDNA and pgRNA remain positive in liver tissue in a chronic hepatitis B patient with functional cure

Hepatitis B surface antigen (HBsAg) seroclearance is recommended as the ideal endpoint for nucleos(t)ide analog (NA) treatments. Functional cure of chronic hepatitis B (CHB) is defined as having undetectable serum hepatitis B virus (HBV) deoxyribonucleic acid and serum HBsAg. We report a functional cure case of CHB with a family history of hepatocellular carcinoma (HCC) after long-term NA therapy. Despite achieving functional cure for over 7 years, both HBV covalently closed circular deoxyribonucleic acid (cccDNA) and pregenomic ribonucleic acid (pgRNA) remain positive in the liver tissue of the patient, indicating that a sterilizing cure has not been achieved. This case highlights the importance of active surveillance of HBV cccDNA and pgRNA for sterilizing the cure and risk of HCC.

Applications of CRISPR/Cas as a Toolbox for Hepatitis B Virus Detection and Therapeutics

Hepatitis B virus (HBV) infection remains a significant global health challenge, leading to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). Covalently closed circular DNA (cccDNA) and integrated HBV DNA are pivotal in maintaining viral persistence. Recent advances in CRISPR/Cas technology offer innovative strategies to inhibit HBV by directly targeting both cccDNA and integrated HBV DNA or indirectly by degrading HBV RNAs or targeting host proteins. This review provides a comprehensive overview of the latest advancements in using CRISPR/Cas to inhibit HBV, with a special highlight on newer non-double-strand (non-DSB) break approaches. Beyond the canonical use of CRISPR/Cas for target inhibition, we discuss additional applications, including HBV diagnosis and developing models to understand cccDNA biology, highlighting the diverse use of this technology in the HBV field.

Activating adaptive immunity by bispecific, T-cell engager antibodies bridging infected and immune-effector cells is a promising novel therapy for chronic hepatitis B

Bispecific antibodies (bsAbs) are engineered immunoglobulins that combine two different antigen-binding sites in one molecule. BsAbs can be divided into two molecular formats: IgG-like and non-IgG-like antibodies. Structural elements of each format have implications for engaging the immune system. T cell engager antibodies (TCEs) are bsAbs designed to engage T cells with target cells. TCEs can be applied not only in cancer but also in infectious disease therapy to activate T-cell responses. In this review, we focus on current literature on the design and use of bsAbs as an innovative strategy to enhance adaptive antiviral immune responses. We summarized the novel T cell-related immunotherapies with a focus on TCEs, that are developed for the treatment of chronic hepatitis B. Chronic infection with the hepatitis B virus (HBV) had a death toll of 1.1 million humans in 2022, mainly due to liver cirrhosis and hepatocellular carcinoma developing in the more than 250 million humans chronically infected. A curative treatment approach for chronic hepatitis B is lacking. Combining antiviral therapy with immune therapies activating T-cell responses is regarded as the most promising therapeutic approach to curing HBV and preventing the sequelae of chronic infection. Attracting functionally intact T cells that are not HBV-specific and, therefore, have not yet been exposed to regulatory mechanisms and activating those at the target site in the liver is a very interesting therapeutic approach that could be achieved by TCEs. Thus, TCEs redirecting T cells toward HBV-positive cells represent a promising strategy for treating chronic hepatitis B and HBV-associated hepatocellular carcinoma.

Discovery of hepatitis B virus subviral particle biogenesis inhibitors from a bioactive compound library

High levels of hepatitis B virus (HBV) surface antigen (HBsAg) in the blood of chronic HBV carriers are considered to drive the exhaustion of antigen-specific T and B lymphocytes and thus responsible for the persistence of infection. Accordingly, therapeutic elimination of HBsAg may facilitate the activation of adaptive antiviral immune responses against HBV and achieve a functional cure of chronic hepatitis B. We discovered recently that an amphipathic alpha helix spanning W156 to R169 of HBV small envelope (S) protein plays an essential role in the morphogenesis of subviral particles (SVPs) and metabolism of S protein. We thus hypothesized that pharmacological disruption of SVP morphogenesis may induce intracellular degradation of S protein and reduce HBsAg secretion. To identify inhibitors of SVP biogenesis, we screened 4417 bioactive compounds with a HepG2-derived cell line expressing HBV S protein and efficiently secreting small spherical SVPs. The screen identified 24 compounds that reduced intracellular SVPs and secreted HBsAg in a concentration-dependent manner. However, 18 of those compounds inhibited the secretion of HBsAg and HBeAg in HBV replicon transfected HepG2 cells at similar efficiency, suggesting each of those compounds may disrupt a common cellular function required for the synthesis and/or secretion of these viral proteins. Interestingly, lycorine more efficiently inhibited the secretion of HBsAg in HepG2 cells transfected with HBV replicons, HepG2.2.15 cells and HBV infected - HepG2 cells expressing sodium taurocholate cotransporting polypeptide (NTCP). The structure activity relationship and antiviral mechanism of lycorine against HBV have been determined.

Hepatitis B Reactivation and Vaccination Effectiveness after Solid Organ Transplantation: A Matched Case-Control Study

Solid organ transplant (SOT) recipients are at significant risk of hepatitis B (HB) virus (HBV) reactivation (HBVr). Despite the clinical significance of HBVr after solid organ transplantation, data on the risk factors for HBVr and vaccine effectiveness in SOT recipients with resolved HBV infection are limited. This study evaluated the risk factors for HBVr and the seroconversion rates after HBV vaccination in SOT recipients. Patients who had undergone solid organ transplantation and those with a resolved HBV infection were identified. We matched patients who experienced post-transplantation HBVr with those who did not. We also explored the characteristics and seroconversion rates of HBV-vaccinated patients following transplantation. In total, 1299 SOT recipients were identified as having a resolved HBV infection at the time of transplantation. Thirty-nine patients experienced HBVr. Pre-transplant HB surface antibodies (anti-HBs) positivity and allograft rejection within 3 months after transplantation were independently associated with HBVr. Among the 17 HBV-vaccinated patients, 14 (82.4%) received three or fewer vaccine doses, and 13 (76.5%) had seroconversion with positive anti-HBs results. Pre-transplant anti-HBs(-) status and allograft rejection were risk factors for HBVr in SOT recipients with a resolved HBV infection, and HBV vaccination after transplantation resulted in a high rate of anti-HBs seroconversion. HBV vaccination after transplantation should be considered to reduce the HBVr risk.

SARS-CoV-2-associated lymphopenia: possible mechanisms and the role of CD147

T lymphocytes play a primary role in the adaptive antiviral immunity. Both lymphocytosis and lymphopenia were found to be associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While lymphocytosis indicates an active anti-viral response, lymphopenia is a sign of poor prognosis. T-cells, in essence, rarely express ACE2 receptors, making the cause of cell depletion enigmatic. Moreover, emerging strains posed an immunological challenge, potentially alarming for the next pandemic. Herein, we review how possible indirect and direct key mechanisms could contribute to SARS-CoV-2-associated-lymphopenia. The fundamental mechanism is the inflammatory cytokine storm elicited by viral infection, which alters the host cell metabolism into a more acidic state. This "hyperlactic acidemia" together with the cytokine storm suppresses T-cell proliferation and triggers intrinsic/extrinsic apoptosis. SARS-CoV-2 infection also results in a shift from steady-state hematopoiesis to stress hematopoiesis. Even with low ACE2 expression, the presence of cholesterol-rich lipid rafts on activated T-cells may enhance viral entry and syncytia formation. Finally, direct viral infection of lymphocytes may indicate the participation of other receptors or auxiliary proteins on T-cells, that can work alone or in concert with other mechanisms. Therefore, we address the role of CD147-a novel route-for SARS-CoV-2 and its new variants. CD147 is not only expressed on T-cells, but it also interacts with other co-partners to orchestrate various biological processes. Given these features, CD147 is an appealing candidate for viral pathogenicity. Understanding the molecular and cellular mechanisms behind SARS-CoV-2-associated-lymphopenia will aid in the discovery of potential therapeutic targets to improve the resilience of our immune system against this rapidly evolving virus.

Highlights from the 2023 International Meeting on the Molecular Biology of Hepatitis B virus

Since its discovery in 1965, our understanding of the hepatitis B virus (HBV) replication cycle and host immune responses has increased markedly. In contrast, our knowledge of the molecular biology of hepatitis delta virus (HDV), which is associated with more severe liver disease, is less well understood. Despite the progress made, critical gaps remain in our knowledge of HBV and HDV replication and the mechanisms underlying viral persistence and evasion of host immunity. The International HBV Meeting is the leading annual scientific meeting for presenting the latest advances in HBV and HDV molecular virology, immunology, and epidemiology. In 2023, the annual scientific meeting was held in Kobe, Japan and this review summarises some of the advances presented at the Meeting and lists gaps in our knowledge that may facilitate the development of new therapies.

Hepatitis B virus reactivation in patients treated with monoclonal antibodies

Hepatitis B virus (HBV) reactivation poses a significant clinical challenge, especially in patients undergoing immunosuppressive therapies, including monoclonal antibody treatments. This manuscript briefly explores the complex relationship between monoclonal antibody therapy and HBV reactivation, drawing upon current literature and clinical case studies. It delves into the mechanisms underlying this phenomenon, highlighting the importance of risk assessment, monitoring, and prophylactic measures for patients at risk. The manuscript aims to enhance the understanding of HBV reactivation in the context of monoclonal antibody therapy, ultimately facilitating informed clinical decision-making and improved patient care. This paper will also briefly review the definition of HBV activation, assess the risks of reactivation, especially in patients treated with monoclonal antibodies, and consider management for patients with regard to screening, prophylaxis, and treatment. A better understanding of patients at risk can help clinicians provide optimum management to ensure successful patient outcomes and prevent morbidity.

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

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

Mechanism of interferon alpha therapy for chronic hepatitis B and potential approaches to improve its therapeutic efficacy

Hepatitis B virus (HBV) chronically infects 296 million people worldwide and causes more than 820,000 deaths annually due to cirrhosis and hepatocellular carcinoma. Current standard-of-care medications for chronic hepatitis B (CHB) include nucleos(t)ide analogue (NA) viral DNA polymerase inhibitors and pegylated interferon alpha (PEG-IFN-α). NAs can efficiently suppress viral replication and improve liver pathology, but not eliminate or inactivate HBV covalently closed circular DNA (cccDNA). CCC DNA is the most stable HBV replication intermediate that exists as a minichromosome in the nucleus of infected hepatocyte to transcribe viral RNA and support viral protein translation and genome replication. Consequentially, a finite duration of NA therapy rarely achieves a sustained off-treatment suppression of viral replication and life-long NA treatment is most likely required. On the contrary, PEG-IFN-α has the benefit of finite treatment duration and achieves HBsAg seroclearance, the indication of durable immune control of HBV replication and functional cure of CHB, in approximately 5% of treated patients. However, the low antiviral efficacy and poor tolerability limit its use. Understanding how IFN-α suppresses HBV replication and regulates antiviral immune responses will help rational optimization of IFN therapy and development of novel immune modulators to improve the rate of functional cure. This review article highlights mechanistic insight on IFN control of HBV infection and recent progress in development of novel IFN regimens, small molecule IFN mimetics and combination therapy of PEG-IFN-α with new direct-acting antivirals and therapeutic vaccines to facilitate the functional cure of CHB.

A Particle Gel Assay for Detection of Intracellular Hepatitis B Virus Subviral Particles in Cultured Cells

Chronic hepatitis B virus (HBV) infection is due to the failure of host immune system to resolve the viral infection. Accordingly, restoration or reconstitution of a functional antiviral immune response to HBV is essential to achieve durable control of HBV replication leading to a functional cure of chronic hepatitis B (CHB). Noninfectious subviral particles (SVPs), comprised of HBV surface antigen (HBsAg), are the predominant viral products secreted by HBV-infected hepatocytes. The high levels of SVPs in the circulation induce immune tolerance and contribute to the establishment of chronic HBV infection. The current standard-of-care medications for CHB efficiently suppress HBV replication but fail to reduce the levels of HBsAg in majority of treated patients. Further understanding the mechanisms underlying SVP morphogenesis, secretion and regulation by viral and host cellular factors are critical for the discovery of therapeutics that can inhibit SVP production and/or induce the degradation of HBV envelope proteins. We describe herein a protocol for intracellular SVP detection by a native agarose gel electrophoresis-based particle gel assy. The method is suitable for quantitative detection of intracellular HBV SVPs and can be applied in dissecting the molecular mechanism of SVP morphogenesis and the discovery of antiviral agents targeting SVP formation in hepatocytes.

One-Step Reverse Transcriptase qPCR Method for Serum Hepatitis B Virus RNA Quantification

In recent years, serum hepatitis B virus (HBV) RNA has been identified as a promising noninvasive surrogate biomarker of intrahepatic covalently closed circular DNA (cccDNA), detection of which requires an invasive liver biopsy in patients with chronic HBV infection. It is impractical to detect intrahepatic cccDNA as a routine diagnosis for chronic hepatitis B (CHB) patients in clinical management. Here, we describe a detailed protocol for serum HBV RNA quantification, which can reflect the activity of intrahepatic cccDNA. The procedure includes three major steps: (1) Simultaneous isolation of HBV DNA and RNA from patients' serum, (2) DNase I digestion for removing HBV DNA contamination, and (3) HBV RNA quantification by one-step reverse transcription qPCR.

Integrated HBV DNA and cccDNA maintain transcriptional activity in intrahepatic HBsAg-positive patients with functional cure following PEG-IFN-based therapy

BACKGROUND

Hepatitis B surface antigen (HBsAg) seroclearance marks regression of hepatitis B virus (HBV) infection. However, more than one-fifth of patients with functional cure following pegylated interferon-based therapy may experience HBsAg seroreversion. The mechanisms causing the HBV relapse remain unclear.

AIM

To investigate the level and origin of HBV transcripts in patients with functional cure and their role in predicting relapse.

METHODS

Liver tissue obtained from patients with functional cure, as well as uncured and treatment-naïve HBeAg-negative patients with chronic hepatitis B (CHB) were analysed for intrahepatic HBV markers. HBV capture and RNA sequencing were used to detect HBV integration and chimeric transcripts.

RESULTS

Covalently closed circular DNA (cccDNA) levels and the proportion of HBsAg-positive hepatocytes in functionally cured patients were significantly lower than those in uncured and treatment-naïve HBeAg-negative patients. Integrated HBV DNA and chimeric transcripts declined in functionally cured patients compared to uncured patients. HBsAg-positive hepatocytes present in 25.5% of functionally cured patients, while intrahepatic HBV RNA remained in 72.2%. The levels of intrahepatic HBV RNA, integrated HBV DNA, and chimeric transcripts were higher in functionally cured patients with intrahepatic HBsAg than in those without. The residual intrahepatic HBsAg in functionally cured patients was mainly derived from transcriptionally active integrated HBV DNA; meanwhile, trace transcriptional activity of cccDNA could also remain. Two out of four functionally cured patients with intrahepatic HBsAg and trace active cccDNA experienced HBV relapse.

CONCLUSION

Integrated HBV DNA and cccDNA maintain transcriptional activity and maybe involved in HBsAg seroreversion in intrahepatic HBsAg-positive patients with functional cure and linked to virological relapse.

What Is the Current Status of Hepatitis B Virus Viro-Immunology?

The natural history of hepatitis B virus (HBV) infection is closely dependent on the dynamic interplay between the host immune response and viral replication. Spontaneous HBV clearance in acute self-limited infection is the result of an adequate and efficient antiviral immune response. Instead, it is widely recognized that in chronic HBV infection, immunologic dysfunction contributes to viral persistence. Long-lasting exposure to high viral antigens, upregulation of multiple co-inhibitory receptors, dysfunctional intracellular signaling pathways and metabolic alterations, and intrahepatic regulatory mechanisms have been described as features ultimately leading to a hierarchical loss of effector functions up to full T-cell exhaustion.

Hepatitis B surface antigen reduction is associated with hepatitis B core-specific CD8+ T cell quality

Despite treatment, hepatitis B surface antigen (HBsAg) persists in patients with chronic hepatitis B (CHB), suggesting the likely presence of the virus in the body. CD8+ T cell responses are essential for managing viral replication, but their effect on HBsAg levels remains unclear. We studied the traits of activated CD8+ T cells and HBV-specific CD8+ T cells in the blood of CHB patients undergoing nucleos(t)ide analog (NUC) therapy. For the transcriptome profiling of activated CD8+ T cells in peripheral blood mononuclear cells (PBMCs), CD69+ CD8+ T cells were sorted from six donors, and single-cell RNA sequencing (scRNA-seq) analysis was performed. To detect HBV-specific CD8+ T cells, we stimulated PBMCs from 26 donors with overlapping peptides covering the HBs, HBcore, and HBpol regions of genotype A/B/C viruses, cultured for 10 days, and analyzed via multicolor flow cytometry. scRNA-seq data revealed that CD8+ T cell clusters harboring the transcripts involved in the cytolytic functions were frequently observed in donors with high HBsAg levels. Polyfunctional analysis of HBV-specific CD8+ T cells utilized by IFN-γ/TNFα/CD107A/CD137 revealed that HBcore-specific cells exhibited greater polyfunctionality, suggesting that the quality of HBV-specific CD8+ T cells varies among antigens. Moreover, a subset of HBcore-specific CD8+ T cells with lower cytolytic potential was inversely correlated with HBsAg level. Our results revealed a stimulant-dependent qualitative difference in HBV-specific CD8+ T cells in patients with CHB undergoing NUC therapy. Hence, the induction of HBcore-specific CD8+ T cells with lower cytolytic potential could be a new target for reducing HBsAg levels.

Hepatitis B Virus Epsilon (ε) RNA Element: Dynamic Regulator of Viral Replication and Attractive Therapeutic Target

Hepatitis B virus (HBV) chronically infects millions of people worldwide, which underscores the importance of discovering and designing novel anti-HBV therapeutics to complement current treatment strategies. An underexploited but attractive therapeutic target is ε, a cis-acting regulatory stem-loop RNA situated within the HBV pregenomic RNA (pgRNA). The binding of ε to the viral polymerase protein (P) is pivotal, as it triggers the packaging of pgRNA and P, as well as the reverse transcription of the viral genome. Consequently, small molecules capable of disrupting this interaction hold the potential to inhibit the early stages of HBV replication. The rational design of such ligands necessitates high-resolution structural information for the ε-P complex or its individual components. While these data are currently unavailable for P, our recent structural elucidation of ε through solution nuclear magnetic resonance spectroscopy marks a significant advancement in this area. In this review, we provide a brief overview of HBV replication and some of the therapeutic strategies to combat chronic HBV infection. These descriptions are intended to contextualize our recent experimental efforts to characterize ε and identify ε-targeting ligands, with the ultimate goal of developing novel anti-HBV therapeutics.

Unraveling the Complexity of Atypical Serological Profiles in Chronic Hepatitis B: Insights Into Disease Dynamics and Clinical Implications

Introduction Chronic hepatitis B (CHB) continues to be a significant global public health problem. Conventional serological markers play a pivotal role in diagnosing and prognosticating CHB, but atypical serological profiles deviating from established norms pose challenges. Methods A cohort of 35 CHB patients who did not receive an antiviral treatment with atypical serological markers was followed for five years (2017-2022). Demographics, serological parameters, and changes were documented. Serological parameters and serum viral loads (hepatitis B virus (HBV)-deoxyribonucleic acid (DNA) levels) were assayed at the central laboratory during their routine follow-ups. Three groups of atypical serological markers are defined: hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs) positivity; hepatitis B e antigen (HBeAg) and anti-hepatitis B e-antigen (anti-HBe) positivity; and isolated core (anti-hepatitis B core (anti-HBc) immunoglobulin G (IgG)) positivity. Patients with concomitant HBsAg and anti-HBs were also stratified into seroreversion groups. Changes in serological markers and HBV-DNA levels across the study period were documented and evaluated at the end of the study period. Statistical analysis was conducted using the Kruskal-Wallis test and IBM SPSS Statistics software for Windows, Version 23.0 (IBM Corp., Armonk, NY, USA). Results In a cohort of 35 patients with atypical hepatitis B serology, demographic analysis revealed that 51.4% (n=18) were female and 48.6% (n=17) were male, with a mean age of 45.7 years. Educational distribution showed that 45.7% (n=16) completed primary education, 22.8% (n=8) had a high school education, and 31.5% (n=11) held university degrees. Among these patients, 10 displayed the concurrent presence of HBsAg and anti-HBs, with 60% (n=6) being female. Serum HBV-DNA was detectable in all cases. After five years, 60% (n=6) exhibited seroconversion from HBsAg to anti-HBs, particularly notable in females (66.7%). These patients showed lower HBsAg titers and serum HBV-DNA levels (p = 0.048, p = 0.036). A subset of 15 patients demonstrated simultaneous HBeAg and anti-HBe positivity. The HBeAg seropositivity waned over time, with 40% (n=6) and 26.7% (n=4) females and males, respectively, retaining positivity by the fifth year. During this period, serum HBV-DNA levels decreased. The remaining five patients sustained HBeAg and anti-HBe positivity. Among 10 patients solely positive for anti-HBc IgG, three had concurrent HBV-DNA positivity. Strikingly, three patients with negative HBV-DNA developed anti-HBs positivity after five years. Conclusion The complexity of CHB infection demands a comprehensive understanding. Atypical serological profiles suggest distinct disease stages, immune response variations, and viral mutations. This study enhances comprehension of viral replication, immune responses, and disease progression, potentially guiding tailored therapeutic strategies.

Two Novel Adenovirus Vectors Mediated Differential Antibody Responses via Interferon-α and Natural Killer Cells

Recombinant adenovirus vectors have been widely used in vaccine development. To overcome the preexisting immunity of human adenovirus type 5 (Ad5) in populations, a range of chimpanzee or rare human adenovirus vectors have been generated. However, these novel adenovirus vectors mediate the diverse immune responses in the hosts. In this study, we explored the immune mechanism of differential antibody responses to SARS-CoV-2 S protein in mice immunized by our previously developed two novel simian adenovirus type 23 (Sad23L) and human adenovirus type 49 (Ad49L), and Ad5 vectored COVID-19 vaccines. Sad23L-nCoV-S and Ad5-nCoV-S vaccines induced the low level of interferon-α (IFN-α) and the high level of antigen-specific antibody responses in wild-type and IFN-α/β receptor defective (IFNAR-/-) C57 mice, while Ad49L-nCoV-S vaccine induced the high IFN-α and low antibody responses in C57 mice but the high antibody response in IFNAR-/- mice. In addition, the high antibody response was detected in natural killer (NK) cells-blocked but the low in follicular helper T (TFH) cells -blocked C57 mice immunized with Ad49L-nCoV-S vaccine. These results showed that Ad49L vectored vaccine stimulated IFN-α secretion to activate NK cells, and then reduced the number of TFH cells, generation center (GC) B cells and plasma cells, and subsequently reduced antigen-specific antibody production. The different novel adenovirus vectors could be selected for vaccine development according to the need for either humoral or cellular or both immune protections against a particular disease. IMPORTANCE Novel adenovirus vectors are an important antigen delivery platform for vaccine development. Understanding the immune diversity between different adenoviral vectors is critical to design the proper vaccine against an aim disease. In this study, we described the immune mechanism of Sad23L and Ad49L vectored vaccines for raising the equally high specific T cell response but the different level of specific antibody responses in mice. We found that Ad49L-vectored vaccine initiated the high IFN-α and activated NK cells to inhibit antibody response via downregulating the number of CD4+ TFH cells leading to the decline of GC B cells and plasma cells.

Efficacy of Antiviral Prophylaxis up to 6 or 12 Months From Completion of Rituximab in Resolved Hepatitis B Patients: A Multicenter, Randomized Study

BACKGROUND

Rituximab occasionally induces reactivation of hepatitis B virus (HBV) in patients with resolved HBV, at times with fatal consequences. The optimal duration of prophylactic antiviral therapy in this situation is unclear. We aimed to investigate the difference in HBV reactivation according to the duration of prophylactic tenofovir disoproxil fumarate (TDF) in patients with resolved HBV and receiving rituximab.

METHODS

A multicenter, randomized, open-label, prospective study was conducted in hepatitis B surface antigen-negative and anti-HBc-positive non-Hodgkin's lymphoma patients treated with rituximab-based chemotherapy. A total of 90 patients were randomized and received prophylactic TDF from the initiation of rituximab until 6 months (the 6-month group) or 12 months (the 12-month group) after the completion of rituximab. The primary outcome was the difference in HBV reactivation and the secondary outcomes were the difference in hepatitis flare and adverse events between the two groups.

RESULTS

In an intention to treat (ITT) analysis, HBV reactivation occurred in 1 of 43 patients (2.3%; 95% confidence interval [CI], 0.41-12%) at a median of 13.3 months in the 6-month group and 2 of 41 patients (4.9%; 95% CI, 1.4-16%) at a median of 13.7 months in the 12-month group. In a per protocol (PP) analysis, HBV reactivation occurred in 1 of 18 patients (5.6%; 95% CI, 0.99-26%) at 13.3 months in the 6-month group and 1 of 13 patients (7.7%; 95% CI, 1.4-33%) at 9.7 months in the 12-month group. The cumulative incidence of HBV reactivation was not significantly different between the two groups in ITT and PP analyses (P = 0.502 and 0.795, respectively). The occurrence of adverse events was not significantly different between the two groups in ITT (9.3% in the 6-month group, 22.0% in the 12-month group, P = 0.193) and PP analyses (5.6% in the 6-month group, 7.7% in the 12-month group, P > 0.999).

CONCLUSION

Prophylactic TDF up to 6 months after completion of rituximab-based chemotherapy is sufficient in terms of the efficacy and safety of reducing HBV reactivation in patients with resolved HBV.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02585947.

Global burden of hepatitis B virus: current status, missed opportunities and a call for action

Chronic hepatitis B virus (HBV) infection affects about 296 million people worldwide and is the leading aetiology of cirrhosis and liver cancer globally. Major medical complications also include acute flares and extrahepatic manifestations. In addition, people living with HBV infection also experience stigma. HBV-related cirrhosis resulted in an estimated 331,000 deaths in 2019, and it is estimated that the number of deaths from HBV-related liver cancer in 2019 was 192,000, an increase from 156,000 in 2010. Meanwhile, HBV remains severely underdiagnosed and effective measures that can prevent infection and disease progression are underutilized. Birth dose coverage for HBV vaccines remains low, particularly in low-income countries or regions where HBV burden is high. Patients with HBV infection are inadequately evaluated and linked to care and are undertreated worldwide, even in high-income countries or regions. Despite the goal of the World Health Organization to eliminate viral hepatitis as a public health problem by 2030, the annual global deaths from HBV are projected to increase by 39% from 2015 to 2030 if the status quo remains. In this Review, we discuss the current status and future projections of the global burden of HBV infection. We also discuss gaps in the current care cascade and propose future directions.

Incidence and Risk Factors of Infections Among Diffuse Large B-cell Lymphoma and Classical Hodgkin's Lymphoma Patients in a Tertiary Care Center in Saudi Arabia: A Retrospective Cohort Study

INTRODUCTION

 Non-Hodgkin's lymphoma (NHL) ranked fourth among all cancer types in Saudi Arabia, as reported by the Saudi Health Council in 2015. Diffuse large B-cell lymphoma (DLBCL) is the most common histological type of NHL. On the other hand, classical Hodgkin's lymphoma (cHL) ranked sixth and had a modest tendency to affect young men more frequently. Over recent decades, DLBCL patients were treated with cyclophosphamide, doxorubicin hydrochloride, oncovin, and prednisolone (CHOP) alone. Adding rituximab (R) to the standard regimen (CHOP) shows significant improvement in overall survival. However, it also has a considerable effect on the immune system, impacting complement-mediated and antibody-dependent cellular cytotoxicity and causing an immunosuppressive state through modulating T-cell immunity via neutropenia, which can let the infection spread.

AIMS AND OBJECTIVES

 This study aims to evaluate the incidence and risk factors associated with infections in DLBCL patients in comparison to patients with cHL treated with doxorubicin hydrochloride (Adriamycin), bleomycin sulfate, vinblastine sulfate, and dacarbazine (ABVD).

MATERIALS AND METHODS

 This study is a retrospective case-control study that included 201 patients acquired between January 1st, 2010, and January 1st, 2020. Sixty-seven patients had a diagnosis of cHL and had received ABVD, and 134 had DLBCL and had received rituximab. Clinical data were obtained from the medical records.

RESULTS

 During the study period, we enrolled 201 patients, of whom 67 had cHL, and 134 had DLBCL. DLBCL patients had a higher serum lactate dehydrogenase upon diagnosis than cHL (p = 0.005). Both groups have similar response rates with complete remission/partial remission. Compared to cHL, patients with DLBCL were more likely to have advanced disease when they first presented (stage III/IV, DLBCL: 67.3 vs. cHL: 56.5; p = 0.005). DLBCL patients had an increased risk of infection as compared to cHL patients (DLBCL: 32.1 % vs. 16.4%; p = 0.02). However, patients with a poor response to treatment had an increased risk of infection compared to patients with a favorable response regardless of the type of disease (odds ratio: 4.6; p = <0.001). When using multivariate analysis, it is revealed that unfavorable therapeutic response continues to be the only predictor raising the probability of infection in the population (odds ratio: 4.2; p = 0.003).

CONCLUSIONS

 Our study explored all potential risk factors for the occurrence of infection in DLBCL patients who received R-CHOP versus cHL. The most reliable predictor of an increased risk of infection during the follow-up period was having an unfavorable response to medication. To assess these results, additional prospective research is required.

Current Best Practice in Hepatitis B Management and Understanding Long-term Prospects for Cure

The hepatitis B virus (HBV) is a major cause of cirrhosis and hepatocellular carcinoma worldwide. Despite an effective vaccine, the prevalence of chronic infection remains high. Current therapy is effective at achieving on-treatment, but not off-treatment, viral suppression. Loss of hepatitis B surface antigen, the best surrogate marker of off-treatment viral suppression, is associated with improved clinical outcomes. Unfortunately, this end point is rarely achieved with current therapy because of their lack of effect on covalently closed circular DNA, the template of viral transcription and genome replication. Major advancements in our understanding of HBV virology along with better understanding of immunopathogenesis have led to the development of a multitude of novel therapeutic approaches with the prospect of achieving functional cure (hepatitis B surface antigen loss) and perhaps complete cure (clearance of covalently closed circular DNA and integrated HBV DNA). This review will cover current best practice for managing chronic HBV infection and emerging novel therapies for HBV infection and their prospect for cure.

Reactivation of occult hepatitis B virus infection in a renal transplant recipient

We report a case of hepatitis B virus (HBV) reactivation in a renal transplant recipient. Reactivation manifested as an occult infection with detectable HBV-DNA and negativity for hepatitis B surface antigen (HBsAg). The anti-HBs antibody titre was above the protective threshold and continued to rise, to 951.36 mIU/ml, after HBV reactivation. Sequencing revealed multiple vaccine- and diagnostic-escape mutations in the major hydrophilic region of HBsAg. This case demonstrates both reactivation of an HBV escape mutant in a vaccinated patient and host immunity after virus mutation.

Identification of antibodies cross-reactive with woodchuck immune cells and activation of virus-specific and global cytotoxic T cell responses by anti-PD-1 and anti-PD-L1 in experimental chronic hepatitis B and persistent occult hepadnaviral infection

Woodchuck (Marmota monax) infected with woodchuck hepatitis virus (WHV) is the most pathogenically compatible naturally occurring model of human hepatitis B virus (HBV) infection, chronic hepatitis B, and HBV-induced hepatocellular carcinoma. This system plays a crucial role in discovery and preclinical evaluation of anti-HBV therapies. Its utilization remains tempered by the relatively narrow range of validated immunologic and molecular tools. We evaluated commercial antibodies against immune cell phenotypic markers and T cell molecules for cross-reactivity with woodchuck antigenic equivalents. The confirmed antibodies against programed cell death protein-1 (PD-1) and its ligand (PD-L1) were examined for ex vivo ability to activate WHV-specific, global and bystander cytotoxic T cells (CTLs) in chronic hepatitis and asymptomatic infection persisting after self-resolved acute hepatitis. Examination of 65 antibodies led to identification or confirmation of 23 recognizing woodchuck T, regulatory T, B and natural killer cells, T cell-associated PD-1, PD-L1, CTLA-4 and TIM-3 molecules, CD25 and CD69 markers of T cell activation, and interferon gamma (IFNγ). Antibodies against woodchuck PD-1 and PD-L1 triggered in vitro highly individualized WHV-specific and global activation of CTLs in both chronic hepatitis and persistent occult infection. WHV-specific CTLs were more robustly augmented by anti-PD-1 than by anti-PD-L1 in chronic hepatitis, while global IFNγ-positive CTL response was significantly suppressed in chronic hepatitis compared to persistent occult infection. Anti-PD-1 and anti-PD-L1 also occasionally activated CTLs to specificities other than those tested suggesting their potency to trigger side effects. This was particularly apparent when T cells from chronic hepatitis were treated with anti-PD-L1. The current findings indicate that inhibition of the PD-1/PD-L1 pathway could reactivate virus-specific and global T cell responses in both chronic hepatitis and asymptomatic persistent infection. They suggest a mechanism of potential reactivation of clinically silent infection during anti-PD-1/PD-L1 treatment and indicate that this therapy may also subdue occult HBV infection.

Hepatitis B x (HBx) as a Component of a Functional Cure for Chronic Hepatitis B

Patients who are carriers of the hepatitis B virus (HBV) are at high risk of chronic liver disease (CLD) which proceeds from hepatitis, to fibrosis, cirrhosis and to hepatocellular carcinoma (HCC). The hepatitis B-encoded X antigen, HBx, promotes virus gene expression and replication, protects infected hepatocytes from immunological destruction, and promotes the development of CLD and HCC. For virus replication, HBx regulates covalently closed circular (ccc) HBV DNA transcription, while for CLD, HBx triggers cellular oxidative stress, in part, by triggering mitochondrial damage that stimulates innate immunity. Constitutive activation of NF-κB by HBx transcriptionally activates pro-inflammatory genes, resulting in hepatocellular destruction, regeneration, and increased integration of the HBx gene into the host genome. NF-κB is also hepatoprotective, which sustains the survival of infected cells. Multiple therapeutic approaches include direct-acting anti-viral compounds and immune-stimulating drugs, but functional cures were not achieved, in part, because none were yet devised to target HBx. In addition, many patients with cirrhosis or HCC have little or no virus replication, but continue to express HBx from integrated templates, suggesting that HBx contributes to the pathogenesis of CLD. Blocking HBx activity will, therefore, impact multiple aspects of the host–virus relationship that are relevant to achieving a functional cure.

Management of hepatitis B virus (HBV) reactivation in patients with resolved HBV infection based on a highly sensitive HB core-related antigen assay

AIMS

To prevent hepatitis B virus (HBV) reactivation-related hepatitis, we examined the clinical usefulness of a highly sensitive HB core-related antigen (iTACT-HBcrAg) assay in patients with resolved HBV infection after nucleos(t)ide analog (NA) treatment for HBV reactivation.

METHODS

We retrospectively analyzed 27 patients with resolved HBV infection who experienced HBV reactivation (defined as HBV DNA levels of 1.3 log IU/ml or more), and who received systemic chemotherapies for hematological malignancies between 2008 and 2020. iTACT-HBcrAg, HBsAg-HQ, and antibodies against hepatitis B surface antigen (anti-HBs) were measured using samples stored after HBV reactivation. The lower limit of quantification for iTACT-HBcrAg was 2.0 log U/ml.

RESULTS

HBV reactivation was diagnosed at a median HBV DNA level of 1.8 log IU/ml, and then all patients received NA treatment. No patient had HBV-related hepatitis with a median maximum HBV DNA level of 2.0 log IU/ml. The positivities of iTACT-HBcrAg and HBsAg-HQ were 96% and 52% after HBV reactivation, respectively. Of 25 patients with detectable iTACT-HBcrAg at the initiation of NA treatment, 17 (68%) achieved iTACT-HBcrAg loss. Median durations from NA treatment to HBV DNA loss and iTACT-HBcrAg loss or the last follow-up were 35 and 175 days, respectively. Recurrence of HBV reactivation after NA cessation was not observed in seven of eight patients who achieved iTACT-HBcrAg loss or seropositive for anti-HBs during follow-up, except for one without anti-HBs after allogeneic transplantation.

CONCLUSIONS

iTACT-HBcrAg could be a potential surrogate marker for diagnosing early-stage HBV reactivation as well as safe cessation of NA treatment in patients with resolved HBV infection after HBV reactivation.

Current challenges in the functional cure of HBe-Antigen-negative chronic hepatitis B

This editorial discusses current challenges in treatment stop in e-antigen-negative chronic hepatitis B, with attention to immunologic and virologic markers associated with functional cure, new therapeutic options for those cases unsuitable for treatment discontinuation, and safety after treatment withdrawal.

Surrogate Markers for Hepatitis B Virus Covalently Closed Circular DNA

Chronic infection with the hepatitis B virus (HBV) is one of the most common causes of liver disease worldwide. Chronic HBV infection is currently incurable because of the persistence of the viral template for the viral transcripts, covalently closed circular deoxyribonucleic acid (cccDNA). Detecting changes in cccDNA transcriptional activity is key to understanding fundamental virology, determining the efficacy of new therapies, and deciding the optimal clinical management of HBV patients. In this review, we summarize surrogate circulating biomarkers that have been used to infer cccDNA levels and activity in people with chronic hepatitis B. Moreover, we outline the current shortcomings of the current biomarkers and highlight the clinical importance in improving them and expanding their use.

HBV cccDNA-A Culprit and Stumbling Block for the Hepatitis B Virus Infection: Its Presence in Hepatocytes Perplexed the Possible Mission for a Functional Cure

Hepatitis B virus infection (HBV) is still a big health problem across the globe. It has been linked to the development of liver cirrhosis and hepatocellular carcinoma and can trigger different types of liver damage. Existing medicines are unable to disable covalently closed circular DNA (cccDNA), which may result in HBV persistence and recurrence. The current therapeutic goal is to achieve a functional cure, which means HBV-DNA no longer exists when treatment stops and the absence of HBsAg seroclearance. However, due to the presence of integrated HBV DNA and cccDNA functional treatment is now regarded to be difficult. In order to uncover pathways for potential therapeutic targets and identify medicines that could result in large rates of functional cure, a thorough understanding of the virus' biology is required. The proteins of the virus and episomal cccDNA are thought to be critical for the management and support of the HBV replication cycle as they interact directly with the host proteome to establish the best atmosphere for the virus while evading immune detection. The breakthroughs of host dependence factors, cccDNA transcription, epigenetic regulation, and immune-mediated breakdown have all produced significant progress in our understanding of cccDNA biology during the past decade. There are some strategies where cccDNA can be targeted either in a direct or indirect way and are presently at the point of discovery or preclinical or early clinical advancement. Editing of genomes, techniques targeting host dependence factors or epigenetic gene maintenance, nucleocapsid modulators, miRNA, siRNA, virion secretory inhibitors, and immune-mediated degradation are only a few examples. Though cccDNA approaches for direct targeting are still in the early stages of development, the assembly of capsid modulators and immune-reliant treatments have made it to the clinic. Clinical trials are currently being conducted to determine their efficiency and safety in patients, as well as their effect on viral cccDNA. The influence of recent breakthroughs in the development of new treatment techniques on cccDNA biology is also summarized in this review.

Occult Hepatitis B Virus Infection: An Update

Occult hepatitis B virus (HBV) infection (OBI) refers to a condition in which replication-competent viral DNA is present in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing negative for the HBV surface antigen (HBsAg). In this peculiar phase of HBV infection, the covalently closed circular DNA (cccDNA) is in a low state of replication. Many advances have been made in clarifying the mechanisms involved in such a suppression of viral activity, which seems to be mainly related to the host's immune control and epigenetic factors. OBI is diffused worldwide, but its prevalence is highly variable among patient populations. This depends on different geographic areas, risk factors for parenteral infections, and assays used for HBsAg and HBV DNA detection. OBI has an impact in several clinical contexts: (a) it can be transmitted, causing a classic form of hepatitis B, through blood transfusion or liver transplantation; (b) it may reactivate in the case of immunosuppression, leading to the possible development of even fulminant hepatitis; (c) it may accelerate the progression of chronic liver disease due to different causes toward cirrhosis; (d) it maintains the pro-oncogenic properties of the "overt" infection, favoring the development of hepatocellular carcinoma.

Occult hepatitis B - the result of the host immune response interaction with different genomic expressions of the virus

With over 40 years of history, occult hepatitis B infection (OBI) continues to remain an important and challenging public health problem. Defined as the presence of replication-competent hepatitis B virus (HBV) DNA (i.e., episomal HBV covalently closed circular DNA) in the liver and/or HBV DNA in the blood of people who test negative for hepatitis B surface antigen (HBsAg) in currently available assays, OBI is currently diagnosed using polymerase chain reaction (PCR) and real-time PCR assays. However, all efforts should be made to exclude a false negative HBsAg in order to completely follow the definition of OBI. In recent years, significant advances have been made in understanding the HBV lifecycle and the molecular mechanisms that lead to the persistence of the virus in the occult form. These factors are mainly related to the host immune system and, to a smaller proportion, to the virus. Both innate and adaptive immune responses are important in HBV infection management, and epigenetic changes driven by host mechanisms (acetylation, methylation, and microRNA implication) are added to such actions. Although greater genetic variability in the S gene of HBV isolated from OBIs was found compared with overt infection, the mechanisms of OBI are not mainly viral mutations.

DNA Repair Factor Poly(ADP-Ribose) Polymerase 1 Is a Proviral Factor in Hepatitis B Virus Covalently Closed Circular DNA Formation

The biogenesis and eradication of HBV cccDNA have been a research priority in recent years. In this study, we identified the DNA repair factor PARP1 as a host factor required for the HBV de novo cccDNA formation.

Assessing immunological and virological responses in the liver: Implications for the cure of chronic hepatitis B virus infection

Cure from chronic HBV infection is rare with current therapies. Basic research has helped to fundamentally improve our knowledge of the viral life cycle and virus-host interactions, and provided the basis for several novel drug classes that are currently being developed or are being tested in clinical trials. While these novel compounds targeting the viral life cycle or antiviral immune responses hold great promise, we are still lacking a comprehensive understanding of the immunological and virological processes that occur at the site of infection, the liver. At the International Liver Congress 2021 (ILC 2021), a research think tank on chronic HBV infection focused on mechanisms within the liver that facilitate persistent infection and looked at the research questions that need to be addressed to fill knowledge gaps and identify novel therapeutic strategies. Herein, we summarise the discussion by the think tank and identify the key basic research questions that must be addressed in order to develop more effective strategies for the functional cure of HBV infection.