Unresolved issues of immune tolerance in chronic hepatitis B

Inverse relationship between HBV DNA levels and liver histopathological changes in immune-tolerant CHB patients

Limited data exist regarding the association between hepatitis B virus (HBV) DNA levels and liver histopathological changes in patients with chronic hepatitis B (CHB) during the immune tolerant (IT) phase. In this study, we retrospectively analysed liver biopsy results from 150 adult IT-CHB patients. The liver tissue necroinflammation and fibrosis were evaluated by the Scheuer scoring system. Multivariate logistic regression, smooth curve fitting, and segmented regression models were used to examine the association between HBV DNA levels and liver histopathological changes. A total of 26%, 30.67% and 42% of IT patients had significant necroinflammation (≥G2), significant fibrosis (≥S2) and significant histopathological changes (≥G2 and/or ≥S2), respectively. HBV DNA levels were independently and non-linear inversely associated with significant necroinflammation and histopathological changes in IT-CHB patients. Patients with HBV DNA levels <107 IU/mL had a higher risk of significant histopathological changes compared to those with levels >107 IU/mL. The findings were further confirmed by smooth curve fitting analyses, subgroup and sensitivity analyses. In segmented regression model analyses, the optimal DNA value for the lowest odds ratio of significant histopathological changes was 7.26 log10 IU/mL. A non-linear inverse association between HBV DNA levels and significant histopathological changes in IT-CHB patients. DNA 7.26 log10 IU/mL may serve as a potential cut-off point to define a 'true immune tolerant phase' with minimal liver histopathological changes.

Latest insights into the epidemiology, characteristics, and therapeutic strategies of chronic hepatitis B patients in indeterminate phase

As a hepatotropic virus, hepatitis B virus (HBV) can establish a persistent chronic infection in the liver, termed, chronic hepatitis B (CHB), which causes a series of liver-related complications, including fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). HCC with HBV infection has a significantly increased morbidity and mortality, whereas it could be preventable. The current goal of antiviral therapy for HBV infection is to decrease CHB-related morbidity and mortality, and achieve sustained suppression of virus replication, which is known as a functional or immunological cure. The natural history of chronic HBV infection includes four immune phases: the immune-tolerant phase, immune-active phase, inactive phase, and reactivation phase. However, many CHB patients do not fit into any of these defined phases and are regarded as indeterminate. A large proportion of indeterminate patients are only treated with dynamic monitoring rather than recommended antiviral therapy, mainly due to the lack of definite guidelines. However, many of these patients may gradually have significant liver histopathological changes during disease progression. Recent studies have focused on the prevalence, progression, and carcinogenicity of indeterminate CHB, and more attention has been given to the prevention, detection, and treatment for these patients. Herein, we discuss the latest understanding of the epidemiology, clinical characteristics, and therapeutic strategies of indeterminate CHB, to provide avenues for the management of these patients.

Clinical application value of hepatitis B virus basal core promoter 1762/1764 and GGTII and GGT in patients with HBV-DNA-positive primary liver cancer

BACKGROUND

Hepatitis B virus (HBV) is closely related to the occurrence and development of primary liver cancer (PLC). The early diagnosis of PLC is difficult. The study explored the clinical application value of the HBV gene basal core promoter (BCP) region 1762/1764 combined with gamma-glutamyl transpeptidase (GGT) and its isozyme II (GGTII) in PLC.

METHODS

From June 2017 to June 2021, 145 hepatitis B surface antigen-positive and HBV DNA-positive patients were enrolled in the Third People Hospital of Zigong. Of them, 67 were chronic hepatitis B (CHB) patients, 30 were liver cirrhosis patients, and 48 were patients with hepatitis B-associated PLC. The HBV BCP 1762/1764 mutation was detected through the amplification refractory mutation system fluorescence PCR method, and GGTII was detected using the double-antibody sandwich method.

RESULTS

The results showed that the serum GGT activity, GGTII level, aspartate aminotransferase (AST) activity, AST/alanine aminotransferase (ALT) ratio, GGT/ALT ratio, and GGT/AST ratio were significantly different between the PLC and CHB groups. Statistically significant differences in serum GGT activity, AST activity, and GGT/ALT ratio were observed between the PLC and LC groups. The BCP 1762/1764 mutation rate between the PLC and CHB groups was statistically significant. The GGTII level in the early PLC (stage I + II) group and the advanced PLC (stage III + IV) group was higher than that in the N-PLC group. Serum GGT activity in the early PLC and advanced PLC groups was higher than that in the N-PLC group. The area under the curve of the receiver operator characteristic curve of GGT and GGTII for diagnosing PLC was 0.775 (95% confidence interval [CI] [0.697, 0.854]) and 0.608 (95% CI [0.512, 0.704]), respectively. The area under curve of GGT and GGTII for diagnosing early PLC was 0.732 (95% CI [0.620, 0.845]) and 0.579 (95% CI [0.452, 0.706]), respectively.

CONCLUSION

HBV gene BCP 1762/1764 mutation, GGT, and GGTII may be related to PLC occurrence. The HBV gene BCP region 1762/1764 combined with GGT has certain clinical diagnostic values for PLC and early PLC. However, GGTII is not a good indicator of early PLC and is more relevant to advanced PLC.

Lowering the threshold of alanine aminotransferase for enhanced identification of significant hepatic injury in chronic hepatitis B patients

BACKGROUND

The clinical and histological features of chronic hepatitis B (CHB) patients who fall into the "grey zone (GZ)" and do not fit into conventional natural phases are unclear.

AIM

To explore the impact of varying the threshold of alanine aminotransferase (ALT) levels in identifying significant liver injury among GZ patients.

METHODS

This retrospective analysis involved a cohort of 1617 adult patients diagnosed with CHB who underwent liver biopsy. The clinical phases of CHB patients were determined based on the European Association for the Study of the Liver 2017 Clinical Practice Guidelines. GZ CHB patients were classified into four groups: GZ-A (HBeAg positive, normal ALT levels, and HBV DNA ≤ 107 IU/mL), GZ-B (HBeAg positive, elevated ALT levels, and HBV DNA < 104 or > 107 IU/mL), GZ-C (HBeAg negative, normal ALT levels, and HBV DNA ≥ 2000 IU/mL), and GZ-D (HBeAg negative, elevated ALT levels, and HBV DNA ≤ 2000 IU/mL). Significant hepatic injury (SHI) was defined as the presence of notable liver inflammation (≥ G2) and/or significant fibrosis (≥ S2).

RESULTS

The results showed that 50.22% of patients were classified as GZ, and 63.7% of GZ patients developed SHI. The study also found that lowering the ALT treatment thresholds to the American Association for the Study of Liver Diseases 2018 treatment criteria (35 U/L for men and 25 U/L for women) can more accurately identify patients with significant liver damage in the GZ phases. In total, the proportion of patients with ALT ≤ 40 U/L who required antiviral therapy was 64.86% [(221 + 294)/794]. When we lowered the ALT treatment threshold to the new criteria (30 U/L for men and 19 U/L for women), the same outcome was revealed, and the proportion of patients with ALT ≤ 40 U/L who required antiviral therapy was 75.44% [(401 + 198)/794]. Additionally, the proportion of SHI was 49.1% in patients under 30 years old and increased to 55.3% in patients over 30 years old (P = 0.136).

CONCLUSION

These findings suggest the importance of redefining the natural phases of CHB and using new ALT treatment thresholds for better diagnosis and management of CHB patients in the GZ phases.

Exploring shark VNAR antibody against infectious diseases using phage display technology

Antibody with high affinity and specificity to antigen has widely used as a tool to combat various diseases. The variable domain of immunoglobulin new antigen receptor (VNAR) naturally found in shark contains autonomous function as single-domain antibody. Due to its excellent characteristics, the small, non-complex, and highly stable have made shark VNAR can acquires the antigen-binding capability that might not be reached by conventional antibody. Phage display technology enables shark VNAR to be presented on the surface of phage, allowing the exploration of shark VNAR as an alternative antibody format to target antigens from various infectious diseases. The application of phage-displayed shark VNAR in antibody library and biopanning eventually leads to the discovery and isolation of antigen-specific VNARs with diagnostic and therapeutic potential towards infectious diseases. This review provides an overview of the shark VNAR antibody, the types of phage display technology with comparison to the other types of display system, as well as the application and case studies of phage-displayed shark VNAR antibodies against infectious diseases.

CD8 T cell-mediated depletion of HBV surface-antigen-expressing, bilineal-differentiated liver carcinoma cells generates highly aggressive escape variants

The expression of viral antigens in chronic hepatitis B virus (HBV) infection drives continuous liver inflammation, one of the main risk factors to develop liver cancer. HBV developed immune-suppressive functions to escape from the host immune system, but their link to liver tumor development is not well understood. Here, we analyzed if and how HBV surface antigen (HBs) expression in combined hepatocellular-cholangiocarcinoma (cHCC/iCCA) cells influences their antigenicity for CD8 T cells. We randomly isolated liver tumor tissues from AlfpCre+-Trp53fl/fl/Alb-HBs+ tg mice and established primary carcinoma cell lines (pCCL) that showed a bilineal (CK7+/HNF4α+) cHCC/iCCA phenotype. These pCCL uniformly expressed HBs (HBshi), and low levels of MHC-I (MHC-Ilo), and were transiently convertible to a high antigenicity (MHC-Ihi) phenotype by IFN-γ treatment. HBshi/pCCL induced HBs/(Kb/S190-197)-specific CD8 T cells and developed slow-growing tumors in subcutaneously transplanted C57Bl/6J (B6) mice. Interestingly, pCCL-ex cells, established from HBshi/pCCL-induced and re-explanted tumors in B6 but not those in immune-deficient Rag1-/- mice showed major alterations, like an MHC-Ihi phenotype, a prominent growth-biased gene expression signature, a significantly decreased HBs expression (HBslo) and a switch to fast-growing tumors in re-transplanted B6 or PD-1-/- hosts with an unlocked PD-1/PD-L1 control system. CD8 T cell-mediated elimination of HBshi/pCCL, together with the attenuation of the negative restraints of HBs in the tumor cells, like ER-stress, reveals a novel mechanism to unleash highly aggressive HBslo/pCCL-ex immune-escape variants. Under certain conditions, HBs-specific CD8 T-cell responses thus potentiate tumor growth, an aspect that should be considered for therapeutic vaccination strategies against chronic HBV infection and liver tumors.

A nomogram based on HBeAg, AST, and age to predict non-minimal liver inflammation in CHB patients with ALT <80 U/L

Objective

Precise assessment of liver inflammation in untreated hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B virus (HBV) infection can determine when to initiate antiviral therapy. The aim of this study was to develop and validate a nomogram model for the prediction of non-minimal liver inflammation based on liver pathological injuries combined with age and alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatitis B surface antigen (HBsAg), HBeAg, and HBV DNA quantification.

Methods

We retrospectively included 735 HBeAg-positive chronic hepatitis B (CHB) patients with ALT < 80 U/L as the primary cohort and prospectively enrolled 196 patients as the validation cohort. Multivariate logistic regression analysis identified independent impact factors. A nomogram to predict significant liver inflammation was developed and validated.

Results

Multivariate logistic regression analysis showed that HBeAg, AST, and age were independent risk factors for predicting non-minimal liver inflammation in untreated CHB patients. The final formula for predicting non-minimal liver inflammation was Logit(P) = -1.99 - 0.68 × Log₁₀HBeAg + 0.04 × Age + 0.06 × AST. A nomogram for the prediction of non-minimal liver inflammation was established based on the results from the multivariate analysis. The predicted probability of the model being consistent with the actual probability was validated by the calibration curves, showing the best agreement in both the primary and validation cohorts. The C-index was 0.767 (95%CI = 0.734-0.802) in the primary cohort and 0.749 (95%CI = 0.681-0.817) in the prospective validation cohort.

Conclusions

The nomogram based on HBeAg, AST, and age might help predict non-minimal liver inflammation in HBeAg-positive CHB patients with ALT < 80 U/L, which is practical and easy to use for clinicians.

Perspectives on current controversial issues in the management of chronic HBV infection

Clinical and basic research in the past decades has achieved consensus in the understanding of chronic hepatitis B virus (HBV) infection and the management of chronic hepatitis B and HBV-cirrhosis. However, debatable challenges to the existing consensus in the concept and/or definitions have emerged. These include (1). alanine aminotransferase upper limit of normal: traditional laboratory-defined vs fixed; (2). nomenclature for phases of chronic HBV infection: classical vs EASL proposal; (3). indication of antiviral therapy: to treat patients vs to treat HBV; (4). finite vs indefinite long-term antiviral therapy: A. finite therapy in HBV-cirrhosis; B. retreatment decision: biochemical markers vs HBsAg/ALT kinetics. The pros and cons of these controversial issues were reviewed, assessed, and discussed in depth based on relevant lines of scientific evidence, intended to clarify or solve these controversial issues.

Role of Innate Immune Regulatory Genes, FOXP3 and FOS in Chronic Hepatitis B Infection

Persistence of hepatitis B virus (HBV) infection leading to chronic infection and its sequalae is responsible for over half a million deaths worldwide. The reason for persistence of chronic hepatitis B (CHB) infection is still not clearly understood. An attempt was made to understand the role of immune regulatory genes in CHB in comparison to spontaneously cleared HBV infection. Relative gene expression of 26 genes involved in innate immunity were studied using Real-Time Polymerase Chain Reaction Array. A total of 679 subjects from three different geographical regions of Northeast India (Assam, Arunachal Pradesh, and Tripura) were included in this case-control study. The cases were subdivided into CHB cases with HBeAg(+)(72), CHB with HBeAg(-)(278), spontaneously cleared controls (88), and healthy controls (228). Overall, 28.3% of the subjects had previous exposure with HBV, while 28.6% had protective antibodies IgG/IgM against HBV. There was a statistically higher number of CHB in men (66.4%) compared to women (33.6%) (p = 0.0001). Proto-oncogene FOS has been found to be moderately upregulated in CHB with HBeAg +ve (2.3-fold) and significantly upregulated (4.1-fold upregulation) in hepatocellular carcinoma. Further, FOXP3 was found to be significantly upregulated (3.0-fold, p = 0.01) in CHB with HBeAg (+) compared to spontaneously cleared HBV infection. In conclusion, CHB with HBeAg positivity was found to have disrupted immune response with upregulation of FOS and FOXP3. Thus, early induction of HBeAg seroconversion with interferon-based therapy or oral nucleos(t)ide analogs along with FOS inhibitors can have important clinical implications in the management of CHB and preventing cirrhosis and HCC.

Quantitative HBsAg versus HBV DNA in Predicting Significant Hepatitis Activity of HBeAg-Positive Chronic HBV Infection

(1) Background: As specialparameters in predicting significant hepatitis activity of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B virus (HBV) infection, the quantitative standard of HBV DNA has not been agreed and that of hepatitis B surface antigen(HBsAg) has not been formed. Our objective is to evaluate the validity of HBsAg and HBV DNA in predicting the significant hepatitis activity of HBeAg-positive patients. (2) Methods: A population of 516 patients with HBeAg-positive chronic HBV infection was enrolled. Serum ALT was measured using an Abbott Architect c16000 autoanalyzer; diagnoses of liver pathological grade and stage referred to the Scheuer standard. Three levels of significant hepatitis activity were preset, which were successively “ALT ≥ 20 IU/L or Grade > G1 or Stage > S1”, “ALT ≥ 30 IU/L or Grade > G1 or Stage > S1” and “ALT ≥ 40 IU/L or Grade > G1 or Stage > S1”. (3) Results: A subpopulation of 288 patients with possible high HBV replication was selected based on locally weighted scatterplot smoothing regression curves between ALT and HBsAg, HBeAg and HBV DNA. In the subpopulation with possible high HBV replication, areas under receiver operating characteristic curves of HBsAg for predicting the three levels of significant hepatitis activity were successively 0.868, 0.839 and 0.789, which were all significantly greater than those of HBV DNA, as those were successively 0.553, 0.550 and 0.574 (p = 0.0002, p < 0.0001 and p < 0.0001). With the standard of HBsAg ≤ 4.699 log₁₀ IU/mL, the sensitivity and specificity of HBsAg for predicting the three levels of significant hepatitis activity were successively 75.81% and 81.82%, 79.23% and 78.57% and 80.82% and 67.44%. (4) Conclusion: Quantitative HBsAg instead of HBV DNA is valuable in predicting significant hepatitis activity of HBeAg-positive chronic HBV infection.

Exploring evidence-based innovative therapy for the treatment of chronic HBV infection: experimental and clinical

With the advent of various vaccines and antimicrobial agents during the 20th century, the control and containment of infectious diseases appeared to be a matter of time. However, studies unveiled the diverse natures of microbes, their lifestyle, and pathogenetic potentials. Since the ground-breaking discovery of the hepatitis B virus (HBV) by Baruch Blumberg and the subsequent development of a vaccine in the early 1980s, the main task of the scientific community has been to develop a proper management strategy for HBV-induced chronic liver diseases. In the early 1980’s, standard interferon (IFN) induced a reduction of HBV DNA levels, followed by the normalization of serum transaminases (alanine aminotransferase, ALT), in some chronic hepatitis B (CHB) patients. However, in the course of time, the limitations of standard IFN became evident, and the search for an alternative began. In the late 1980’s, nucleoside analogs entered the arena of CHB treatment as oral drugs with potent antiviral capacities. At the beginning of the 21st century, insights were developed into the scope and limitations of standard IFN, pegylated-IFN as well as nucleoside analogs for treating CHB. Considering the non-cytopathic nature of the HBV, the presence of covalently closed circular DNA (cccDNA) in the nucleus of the infected hepatocytes and HBV-induced immune-mediated liver damages, a new field of CHB management was initiated by modulating the hosts’ immune system through immune therapy. This review will discuss the nature and design of innovative immune therapy for CHB.

High-frequency and activation of CD4+CD25+ T cells maintain persistent immunotolerance induced by congenital ALV-J infection

Congenital avian leukosis virus subgroup J (ALV-J) infection can induce persistent immunotolerance in chicken, however, the underlying mechanism remains unclear. Here, we demonstrate that congenital ALV-J infection induces the production of high-frequency and activated CD4⁺CD25⁺ Tregs that maintain persistent immunotolerance. A model of congenital infection by ALV-J was established in fertilized eggs, and hatched chicks showed persistent immunotolerance characterized by persistent viremia, immune organ dysplasia, severe imbalance of the ratio of CD4⁺/CD8⁺ T cells in blood and immune organs, and significant decrease in CD3⁺ T cells and Bu-1⁺ B cells in the spleen. Concurrently, the mRNA levels of IL-2, IL-10, and IFN-γ showed significant fluctuations in immune organs. Moreover, the frequency of CD4⁺CD25⁺ Tregs in blood and immune organs significantly increased, and the frequency of CD4⁺CD25⁺ Tregs was positively correlated with changes in ALV-J load in immune organs. Interestingly, CD4⁺CD25⁺ Tregs increased in the marginal zone of splenic nodules in ALV-J-infected chickens and dispersed to the germinal center. In addition, the proliferation and activation of B cells in splenic nodules was inhibited, and the number of IgM⁺ and IgG⁺ cells in the marginal zone significantly decreased. We further found that the mRNA levels of TGF- β and CTLA-4 in CD4⁺CD25⁺ Tregs of ALV-J-infected chickens significantly increased. Together, high-frequency and activated CD4⁺CD25⁺ Tregs inhibited B cells functions by expressing the inhibitory cytokine TGF-β and inhibitory surface receptor CTLA-4, thereby maintaining persistent immunotolerance in congenital ALV-J-infected chickens.

Hepatitis B Core-Related Antigen: From Virology to Clinical Application

Hepatitis B core-related antigen (HBcrAg) is a composite measure of the serum levels of hepatitis B e antigen, hepatitis B core antigen, and a 22-kDa precore protein. It has been shown to reflect the level and transcriptional activity of covalently closed circular DNA in the liver. Longitudinal cohort studies have improved our understanding of the role of this novel viral marker in the natural history of chronic hepatitis B. HBcrAg kinetics reflect the response to peginterferon, and its role in defining guidelines for stopping peginterferon therapy has been evaluated. HBcrAg is a marker of intrahepatic viral activity, which may influence the risk of hepatocellular carcinoma. In this article, we review the virology and role of HBcrAg in defining phases of chronic hepatitis B. Furthermore, the function of HBcrAg in predicting treatment outcomes and its role in monitoring response to novel antiviral agents will be discussed.

Treatment of hepatitis B virus infection in chronic infection with HBeAg-positive adult patients (immunotolerant patients): a systematic review

Recently, a controversial approach suggesting the early treatment of chronic infection with hepatitis B "e" antigen-positive patients with hepatitis B virus (HBV) infection, has been proposed. The objective of this study is to systematically review medical literature regarding treatment of HBV infection in adult chronic infection with HBeAg-positive patients. A systematic review was performed according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Original studies that evaluated the effect of antivirals in adult chronic infection with HBeAg-positive patients were included. The outcomes of interest were viral load suppression, the loss/seroconversion of HBeAg, the loss/seroconversion of hepatitis B surface antigen, and the development of cirrhosis or hepatocellular carcinoma. The search for eligible studies was performed in Excerpta Medica dataBASE, PubMed and Cochrane databases until January 2020, without language or date restriction. The risk of bias was evaluated using the Newcastle-Ottawa Scale for observational studies and the Revised Cochrane Risk-of-Bias Tool for randomized controlled trials. Two hundred ninety-six articles were retrieved. After analyzing titles and abstracts, 287 articles were excluded and nine were considered potentially eligible. From these, five were excluded after full-text analysis. Finally, four articles were included. Only two were randomized controlled trials. All studies were carried out in Asian patients. Results were variable with regard to viral load, negativation/seroconversion of HBeAg and HBsAg. One study demonstrated that treated patients developed cirrhosis or hepatocellular carcinoma less frequently than untreated individuals. Overall, the studies were of poor quality. In conclusion, the present systematic review demonstrated that, at present, there is not enough evidence to recommend treating this population of patients.

Negligible HCC risk during stringently defined untreated immune-tolerant phase of chronic hepatitis B

BACKGROUND & AIMS

Whether chronic hepatitis B (CHB) patients during immune-tolerant (IT) phase are at low risk of hepatocellular carcinoma (HCC) is still controversial. We performed a multicenter study to determine their long-term prognosis.

METHODS

Untreated IT group included patients < 40 years of age, with persistently hepatitis B e antigen [HBeAg] positivity, serum HBV-DNA>6 log₁₀IU/mL, and ALT level < 40 U/L, using age and HBV-DNA criteria by the American Association for the Study of Liver Diseases (AASLD) guideline. Cumulative HCC risk of untreated IT group (n=194) was compared to HBeAg-positive patients undergoing antiviral therapy according to the practice and reimbursement guidelines (treated HBeAg[+] group, n=454). Patients with history of cirrhosis or HCC at baseline were excluded.

RESULTS

During follow-up (median 62.1 months), HCC did not develop in any patient among untreated IT group, whereas the cumulative probability of HCC at 3, 5, and 9 years in the treated HBeAg(+) group was 0.5%, 0.7%, and 1.3%, respectively (p=0.203). Ninety-seven patients among untreated IT group entered immune-active phase, of whom 86 (88.7%) started antiviral treatment. A high normal ALT level (20-39 U/L) was associated with an increased risk of a phase change, compared to ALT < 20 U/L. After censoring at the time of phase change, the cumulative HCC risk was also not significantly different between two groups (p=0.258).

CONCLUSIONS

No actual HCC risk during untreated IT phase defined by age and HBV-DNA criteria of the AASLD guideline exists, supporting their diagnostic validity from the perspective of long-term prognosis. Further validation studies are required.