Molecular characteristics and stages of chronic hepatitis B virus infection

Correlation between hepatitis B virus genotypes and clinical outcomes

Hepatitis B virus (HBV) has been classified into 10 genotypes (A-J) according to genome sequence divergence. HBV genotypes have a distinct geographical distribution. As chronic HBV infection is endemic in the Asian region, genotypes B and C prevail there, and genotypes A and D are mainly found in the western world and Europe. Genotypes A, B, C, and D have been studied most extensively. In Europe and Asia, most patients with genotypes A and B have acute hepatitis B; however, some mutants may tend to cause fulminant hepatitis B. Many studies have indicated that the severity and outcomes of chronic hepatitis B infections are more serious in patients with genotypes C and D than in those with genotypes A and B. Cirrhosis and hepatocellular carcinoma (HCC) are more frequently diagnosed in carriers of genotypes C and D than in those of genotypes A and B. Accumulating evidence indicated that higher plasma HBV DNA levels, infection with HBV genotype C, as well as mutations at 1653T, 1753V, and A1762T/G1764A are independently associated with the risk of HCC in Asian men. However, the therapeutic responses differ with regard to the different HBV genotypes. For example, the response to interferon-α treatment in patients with genotypes A and B was better than that in patients with genotypes C, D, and mixed genotypes. Some studies have shown seroconversion after treatment, i.e., genotypes A and C may switch to genotypes D and B, respectively. Some reports indicated a correlation between the emergence of the hepatitis B e antigen-negative variant in patients with genotypes C and D and worsening of liver injury without sustained response. In order to provide better treatment options for these poorly responding patients, further studies, e.g, novel immunomodulatory therapies, are required. Many studies have shown that HBV genotypes have remarkable clinical and epidemical differences; however, HBV sub-genotypes, mixed genotype infections, and the effect of different genotypes on the treatment of HBV infections require further studies.

c-Myc-mediated overexpression of miR-17-92 suppresses replication of hepatitis B virus in human hepatoma cells

MicroRNAs (miRNAs) regulate post-transcriptional gene expression in various physiological and pathological processes, including viral infections. The miR-17-92 cluster encodes six miRNAs (miR-17-5p, miR-18a, miR-19a, miR-19b, miR-20a, and miR-92a-1) which are transactivated by c-Myc. Because hepatitis B virus transactivates c-Myc, the interaction between the miR-17-92 cluster and HBV replication was examined in this study. Inducing HBV replication in a human hepatoma cell line increased miR-17-5p, miR-20a and miR-92a-1 expression. HBV-induced overexpression of miR-17-92 was reversed by c-Myc knockdown. Antisense peptide nucleic acids against miR-20a and miR-92a-1 augmented HBV replication. A computational analysis yielded potential binding sites for miR-20a and miR-92a-1 in the HBV genome. The direct interaction between these two miRNAs and target regions in HBV transcripts was confirmed by luciferase reporter analysis. These results demonstrated negative feedback suppression of HBV replication by the miR-17-92 polycistron.

Diagnostic potential of serum direct markers and non-invasive fibrosis models in patients with chronic hepatitis B

AIM

  Liver biopsy is recommended in the majority of patients with chronic viral hepatitis for fibrosis evaluation. Because of the disadvantages of liver biopsy, many studies related to non-invasive biomarkers and scores have been performed. In this study, we aimed to assess the diagnostic value of serum direct markers and non-invasive fibrosis models to predict liver fibrosis in the treatment-naive chronic hepatitis B (CHB) patients and to compare their diagnostic performance.

METHODS

  This study included 58 patients with a diagnosis of CHB virus infection and 30 healthy controls. Hyaluronic acid, tissue inhibitor of matrix metalloproteinase 1 and amino-terminal propeptide of type III procollagen were measured by enzyme-linked immunosorbent assay; and the Original European Liver Fibrosis panel, the Enhanced Liver Fibrosis (ELF) panel, PP score, aspartate aminotransferase to platelet ratio index (APRI) and FIB-4 indexes were calculated using the formulas taken from previous publications. Fibrosis stage was determined using Ishak's scoring system.

RESULTS

  The fibrosis stages identified upon liver biopsy was F0 in 12 patients (20.7%), F1-2 in 36 (62.1%) and F3-5 in 10 (17.2%). The diagnostic value of all the non-invasive indices was low to detect mild fibrosis. We demonstrated that the diagnostic accuracy of HA is the best for predicting fibrosis of F3 or more (area under the receiver-operator curve, 0.902). In our study, the results from a combination of tests showed that ELF and APRI had the highest diagnostic value sensitivity of 90%, specificity of 100%, positive predictive value of 100% and negative predictive value of 96.4% for detection of fibrosis of F3 or more.

CONCLUSION

  In CHB patients, combination of ELF and APRI has a better diagnostic value in predicting fibrosis of F3 or more.

Changes in CD4+ T lymphocyte subsets and clinical outcomes of hepatitis B virus infection

Various clinical manifestations may develop in people infected with hepatitis B virus (HBV), ranging from asymptomatic infection to acute severe hepatitis B. Some infections become self-limiting when the virus is cleared, while approximately 90% of children and 10% of adults become HBV carriers or patients with chronic hepatitis B, who can further develop cirrhosis and hepatocellular carcinoma. CD4⁺ T lymphocytes play a central role in anti-infection immunity and can be divided into different subsets, including Th1, Th2, Treg, Th17, Th22, Th9 and Tfh. These T lymphocyte subsets all come from the same progenitor cells (Th0), although they have particular differentiation pathway and secrete different kinds of cytokines. Furthermore, they are able to interact with each other and change into each other. Particularly, the balances of Th1/Th2 and Th17/Treg play a vital role in determining the clinical outcomes of HBV infection.

The immunopathogenetic role of autoantibodies in canine autoimmune hepatitis: lessons to learn from human autoimmune hepatitis

Autoimmune hepatitis (AIH) is not a disease entity restricted to man, but it can be found in other animals including canines. An increasing number of studies have focused on the immunopathogenesis of human autoimmune hepatitis (hAIH), but little is known of what triggers canine autoimmune hepatitis (cAIH). Several drugs, toxins, microbial and viral agents are able to induce autoantibodies and indeed immune-mediated chronic canine hepatitis with immunological and serological features similar of those seen in the human disease. We discuss the features of cAIH paying attention to the autoantibody profile of the disease in comparison to that seen in hAIH. We also discuss the immunomodulatory role of specific molecular signaling pathways such as those mediated by tumor growth factor and p38 mitogen-activated kinase in the induction of AIH, and the potential of these molecules to act as targets of specialized immunotherapeutic interventions. Review of the literature indicates that we have more to learn for the delineation of autoantibody profile and the antigen-specific immunoregulatory mechanisms involved in the pathogenesis of cAIH from the human disease, rather than the other way around.

Diagnostic significance of hepatitis B viral antigens in patients with glomerulonephritis-associated hepatitis B virus infection

Hepatitis B viral infection can lead to hepatitis B virus-associated glomerulonephritis, a clinically significant subtype of secondary nephritis. In the present study, we examined the presence of PreS1/S2 antigen in renal tissues by use of immunohistochemistry and investigated the use of PreS1/S2 and 2 HBV serum antigens, HBe-Ag and HBs-Ag, in the diagnosis. We assessed the presence of these 3 antigens in patients with confirmed hepatitis B virus-associated glomerulonephritis (n = 22) and patients without this disease (n = 19). Our results indicate that the combined use of PreS1/S2-Ag and serum HBe-Ag in the diagnosis of hepatitis B virus-associated glomerulonephritis had good positive predictive value (0.89), modest negative predictive value (0.77), and substantial agreement based on Cohen's kappa coefficient (κ = 0.660, P < 0.001). We suggest that our results be considered in the development of more definitive diagnostic criteria for hepatitis B virus-associated glomerulonephritis.

The relationship between core promoter mutation of hepatitis B virus, viral load and hepatitis B e antigen status in chronic hepatitis B patients

The aim of this study is to detect the possible association of hepatitis B virus (HBV) core mutation, hepatitis B e antigen (HBeAg) status and the viral load in chronic hepatitis B (CHB) patients. Sixty-six patients with CHB were enrolled. Hepatitis markers and hepatitis C virus antibody (HCV-Ab) were tested using micro particle enzyme immunoassay kits. Viral load was measured by real-time polymerase chain reaction (PCR) and the mutation was analyzed by nested PCR followed by restriction fragment length polymorphism. Most of CHB patients were HBeAg (-ve). The HBeAg status did not have an influence on the presence or absence of T1762/A1764 mutation. HBV-DNA serum level was not significantly different in patients with core mutation and patients without core mutation in HBeAg (-ve) group, while in HBeAg (+ve) group HBV-DNA serum level was significantly higher in patients with core mutation. This study reports the predominance of HBeAg (-ve) and HBV core promoter mutation.

Quantitative dynamics of hepatitis B basal core promoter and precore mutants before and after HBeAg seroconversion

BACKGROUND & AIMS

Hepatitis B e antigen (HBeAg) seroconversion is an important clinical and virological "landmark" during chronic hepatitis B virus (HBV) infection. Mutant viruses carrying the precore G1896A and/or the basal core promoter (BCP) A1762T/G1764A mutations are associated with HBeAg seroconversion. However, the exact role of these mutants in HBeAg seroconversion remains unclear, partly because the evolution of these mutant viruses before and after seroconversion has not been well studied.

METHODS

Using our novel mutant quantification methods, the percentage of the mutant viruses was analyzed both cross-sectionally and longitudinally, before and after seroconversion.

RESULTS

Cross-sectional analysis showed that the percentage of both precore and BCP mutants gradually increased with age in the HBeAg-positive population. Follow-up of 18 HBeAg-positive patients revealed that the mutant percentage may stay low and stable for many years, followed by a steady increase in the percentage of G1896A and/or A1762T/G1764A mutants, from <10% to 50-100%, within about 3 years prior to seroconversion. In all cases, increase of mutant percentage was preceded or accompanied by elevated serum alanine aminotransferase. After the seroconversion, the mutant percentage could remain high or decrease significantly, sometimes to below 20%.

CONCLUSIONS

Levels of G1896A and A1762T/G1764A mutants (of genotypes B and C) in the HBeAg-positive patients may predict the time of HBeAg seroconversion. The dominance of these mutants in the HBeAg-positive phase is more likely the result of immune selection rather than the enhanced replication capability of the mutants. However, anti-HBe antibody may not be a major selection force for these mutants.

T cell responses and viral variability in blood donation candidates with occult hepatitis B infection

BACKGROUND & AIMS

Occult HBV infection (OBI) is defined by the presence of HBV DNA in the liver and/or serum and negative HBsAg testing. Since the implementation of highly sensitive HBV DNA screening, OBI is also detected in healthy blood donors. The aims of this study were to investigate HBV-specific immune responses and genetic variability in donors with OBI, established by HBV DNA in serum.

METHODS

HBV-specific T-cell responses to HBV antigens were tested in 34 OBI donors by IFN-γ ELISpot, cytometric bead array, and intracellular cytokine staining. As comparison populations, 36 inactive HBV carriers, 22 donors with spontaneously resolved HBV infection, 24 vaccinated donors, and 25 seronegative donors were also included. Surface, pre-S, and pre-c/core genes from 44 genotype D isolates (24 OBI and 20 HBsAg-positive) were sequenced.

RESULTS

The immune response of OBI donors to the 3 HBV antigens was 29-41%, similar to the response in subjects with resolved HBV infection and higher than that in HBsAg-positive subjects. On sequence analysis, OBI donors presented a higher HBsAg mutation rate than HBsAg-positive subjects. Mutations were clustered in the major hydrophilic region of HBsAg, and no stop codons or relevant mutations that could affect antigen formation or detection were observed.

CONCLUSIONS

Our results suggest that immune response can suppress viral replication to low levels and HBsAg expression to undetectable levels in OBI blood donors. Relevant mutations were not found in the genomic HBsAg coding region. Hence, the fact that HBsAg was not detected in OBI is likely due to low HBsAg production, rather than to a failure of laboratory reagents.

Evaluation of Chronic Hepatitis B Infection in Patients with Seronegative HbsAg

BACKGROUND

It is estimated that about 370 million people are chronic carriers of HBV worldwide. Apparently 3% of Iranian populations are chronic carriers of this virus. We aimed to evaluate the viral DNA in biological fluids of chronic hepatitis patients compared to a control group.

METHODS

The current case-control study was designed to evaluate the viral DNA in biological fluids of 70 chronic hepatitis patients compared to a control group using ELISA, PCR and Real Time.

RESULTS

All individuals (100%) in case group were HBsAg positive while in control group only 2 individuals (2.8%) were HBsAg positive. Three individuals, in control group were positive using PCR and Real Time PCR indicating that about 7% of those in control group were chronic carriers of HBV. The interesting point was the copy of viral DNA; (5.49 ×10(4), 2.162×10(3) and 7.26×10(6)) for 3 chronic carriers using sera while it was about (5.71×10(3), 1.45×10(2) and 2.56×10(5)) using ear cerumen confirming the necessity of investigating for the carriers of HBV in different biological fluid and by different methods.

CONCLUSION

It can be concluded chronic carriers of hepatitis B are much more than what is diagnosed by routine diagnostic tests. On the other hand ELISA alone can not be relied on as a complete test for screening of chronic carriers in hepatitis B. PCR and Real Time PCR are more reliable tests for this purpose.

HBcAg induces PD-1 upregulation on CD4+T cells through activation of JNK, ERK and PI3K/AKT pathways in chronic hepatitis-B-infected patients

Hyper-expression of programmed death-1 (PD-1) is a hallmark of exhausted T cells. In chronic hepatitis-B virus (HBV)-infected patients, PD-1 upregulation on T cells was often observed. The mechanism of it has not been fully understood. In this study, we examined the dynamic changes of PD-1 expression on T cells during the natural history of chronic HBV infection and explored the signaling pathway of PD-1 upregulation by the hepatitis-B core antigen (HBcAg). Sixty-seven chronic HBV-infected patients were categorized into an immune tolerance group, an immune clearance group and an inactive virus carrier group, and 20 healthy volunteers were chosen as normal control group. Peripheral blood mononuclear cells from patients and healthy volunteers, and T lymphocytes from healthy volunteers were separated. Results showed that the PD-1 expression level on CD4(+)T cells in every phase of chronic HBV infection was significantly higher than that in healthy volunteers, whereas such effects were not observed on CD8(+)T cells. In the immune clearance phase, a positive correlation was found between serum HBV DNA level and the PD-1 expression level on CD4(+)T cells. In all phases, no correlation was shown between serum alanine amino transferase (ALT) level and PD-1 expression level. Phosphorylation of JNK, ERK and AKT was induced by HBcAg, and inhibitors of JNK, ERK and PI3K/AKT significantly decreased the HBcAg-induced PD-1 upregulation on CD4(+)T cells. In conclusion, the PD-1 expression level on CD4(+)T cells was upregulated in every phase of chronic HBV infection, which was induced by HBcAg through JNK, ERK and PI3K/AKT signaling pathways.

Kinetics of immune responses to hepatitis B virus infection

The pathogenesis of hepatitis B is mainly triggered by the host's cellular immune responses to hepatitis B virus (HBV) infection, and the immune responses against the virus depends on the interaction of various immune cells. Current research of immunity to hepatitis B infection mainly focuses on understanding the differences between patients who can control HBV infection and those with persistent infection. In this paper, we analyze how immunological events influence the development of innate and adaptive immunity needed to control HBV infection and explore the mechanisms by which high levels of viral antigens, CD4⁺ T cells, programmed death 1 (PD-1), the presence of regulatory T cells, and impaired dendritic cell functions maintain the HBV-specific immunological failure.

An overview of occult hepatitis B virus infection

Occult hepatitis B virus (HBV) infection (OBI), alternatively defined as occult hepatitis B (OHB), is a challenging clinical entity. It is recognized by two main characteristics: absence of HBsAg, and low viral replication. The previous two decades have witnessed a remarkable progress in our understanding of OBI and its clinical implications. Appropriate diagnostic techniques must be adopted. Sensitive HBV DNA amplification assay is the gold standard assay for detection of OBI. Viral as well as host factors are implicated in the pathogenesis of OBI. However, published data reporting the infectivity of OBI by transfusion are limited. Several aspects including OBI transmission, infectivity and its relation to the development of chronic liver diseases and hepatocellular carcinoma have to be resolved. The aim of the present review is to highlight recent data on OBI with a focus on its virological diagnosis and clinical outcome.

The impact of biologic response modifiers on hepatitis B virus infection

INTRODUCTION

The biologic response modifiers are a diverse group of medications that have emerged over the last decade. They target pro-inflammatory cytokines or cell surface molecules that drive illnesses such as rheumatoid arthritis. Despite the greater control afforded they have also ushered in a new spectrum of side effects. As the same immunologic machinery that helps control infections such as HBV contributes to the pathogenesis of rheumatologic diseases, persistence or reactivation of the virus remains an evolving concern.

AREAS COVERED

A systemic literature review was performed using the PubMed and Medline databases (1996 to January 2010) searching for the index term 'Hepatitis B' combined with the terms 'tumor necrosis factor', 'B cell', 'rituximab', 'IL-1', 'anakinra', 'IL-6', 'tocilizumab', 'CTLA-4', and 'abatacept'. All relevant articles in English were reviewed and secondary references of interest were also retrieved. This paper addresses the role of the various cytokines and cluster of differentiation molecules in controlling HBVinfection and the currently known effect that the biologic response modifiers have on viral control by the host immune response.

EXPERT OPINION

The risk of HBV reactivation is greatest in HBsAg positive patients. These patients should start antiviral therapy one week before receiving a biologic response modifier. The risk of HBV reactivation in HBsAg negative patients appears very low but when HBsAb titers are low use of rituximab or TNF-α antagonists may increase the risk of reactivation.

Relationship between IL-10 gene promoter polymorphisms and outcome of hepatitis B virus infection

AIM: To investigate the relationship between interleukin-10 (IL-10) gene promoter polymorphisms at positions -1082 and -819 and the outcome of hepatitis B virus (HBV) infection.

METHODS: TaqMan SNP genotyping and sequencing assays were employed to determine the distribution of genotypes and alleles of the IL-10 gene at positions -1082 and -819 in 187 healthy control subjects, 94 self-limited HBV patients, 130 patients with chronic hepatitis B, 119 patients with HBV-induced liver cirrhosis and 170 patients with HBV-related hepatocellular carcinoma (HCC).

RESULTS: Of the 700 subjects, 82.29% had the AA genotype, 16.00% had the AG genotype, and 1.71% had the GG genotype in the IL-10 gene promoter at position -1082. The frequencies of A and T alleles were 90.29% and 9.71%, respectively. The TT, TC and CC genotypes in the IL-10 gene promoter at position -819 accounted for 41.43%, 48.14%, and 10.43%, respectively. The frequencies of T and C alleles were 65.64% and 34.36%, respectively. There were no significant differences in genotype or allele distribution at the two positions among different groups. IL-10-1082 AG genotype and G allele decreased the risk of chronic hepatitis B and cirrhosis. IL-10-819 TC genotype was associated with a decreased risk of HCC. IL-10-819 CC genotype and C allele decreased the risk of chronic hepatitis B, cirrhosis and HCC. AC haplotype decreased the risk of cirrhosis and HCC, while GC haplotype decreased the risk of chronic hepatitis B and cirrhosis. The frequency of IL-10-819 C was significantly higher in patients with HBV DNA levels < 103 copies/mL than those with HBV DNA levels ≥ 10³ copies/mL (P = 0.025). No significant differences were noted in genotypes or allele frequencies among HCC or cirrhosis subjects with different grades of Child-Pugh classification, different levels of alpha-fetoprotein or different HBsAg status.

CONCLUSION: IL-10-1082 AG genotype and G allele, IL-10-819 TC and CC genotype and C allele, as well as IL-10-1082/-819 AC and GC haplotypes may play a protective role in the disease progression after HBV infection. IL-10-819 C allele may contribute to virus elimination in HBV-infected patients.

Relationship between the MTHFR C677T polymorphism and the outcome of hepatitis B virus infection

AIM: To investigate the relationship between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the outcome of hepatitis B virus (HBV) infection.

METHODS: TaqMan SNP genotyping and sequencing assays were employed to determine the genotypes of MTHFR C677T and the distribution of alleles at this locus in 152 healthy control subjects, 161 self-limited HBV patients, 173 patients with chronic hepatitis B, 138 patients with HBV-induced liver cirrhosis and 181 cases with HBV-related HCC.

RESULTS: Of the 805 subjects, 47.09% had the CT genotype, 30.43% had the TT genotype, and 22.48% had the CC genotype. The frequencies of C and T allele were 46.02% and 53.98%, respectively, which are significantly different from those reported previously. Males with the TT genotype had a reduced risk of liver diseases. The odds ratio (OR) of TT and CT was lowest in the liver cirrhosis group versus the self-limited group (0.675, 95%CI: 0.308-1.479; 0.510, 95%CI: 0.248-1.050). In contrast, females with the TT and CT genotypes had an increased risk of self-limited HBV infection, chronic hepatitis and liver cirrhosis. The liver cirrhosis group had the highest OR value versus the self-limited group (3.542, 95%CI: 0.885-14.171; 3.167, 95% CI: 0.821-12.211; P = 0.022). Females with the TT and CT genotypes had a reduced risk of HCC (OR = 0.638, 95% CI: 0.213-1.904; OR = 0.500, 95%CI: 0.175-1.432).

CONCLUSION: A relatively high frequency of the TT genotype is noted in a Chinese Han population in Tianjin. The MTHFR C677T polymorphism may play a role in influencing disease progression in patients with HBV infection.

Natural course of chronic hepatitis B is characterized by changing patterns of programmed death type-1 of CD8-positive T cells

AIM: To investigate if and how programmed death type-1 (PD-1) expression affects the natural course of hepatitis B virus (HBV) infection.

METHODS: Sixty-four patients in different natural stages of chronic HBV infection were enrolled in this study. PD-1 expression in total T cells was detected by flow cytometry. Levels of total CD8+ T cell responses and proliferation in relation to PD-1 expression levels were analyzed with intracellular staining and PD-1/PD-L1 blockage.

RESULTS: The PD-1 expression in T cells was dynamically changed during the natural course of chronic HBV infection, did not significantly increase in the immune tolerance phase, and returned to normal in the inactive virus carrier stage. Blockage of the PD-1/PD-L1 pathway could not affect the T-cell response in the immune tolerance and inactive virus carrier stages of chronic HBV infection. However, it could significantly restore the T-cell response in the immune clearance stage of chronic HBV infection. Furthermore, the PD-1 expression level in T cells was associated with the alanine aminotransferase level during the immune clearance stage of chronic HBV infection.

CONCLUSION: The PD-l/PD-L1 pathway plays a different role in T-cell response during the natural course of chronic HBV infection.

Hepatitis B virus overexpresses suppressor of cytokine signaling-3 (SOCS3) thereby contributing to severity of inflammation in the liver

The mechanism by which hepatitis B virus (HBV) infection causes severe inflammatory liver diseases is multifactorial and related to interactions with cell signaling pathways and the ensuing inflammatory response. Activation of JAK/STAT/SOCS signaling is essential for the induction of cellular antiviral responses, contributes to apoptosis and is negatively regulated by SOCS proteins. Recent reports have shown that SOCS3 activation interferes with viral protein expression and treatment response and thereby plays a major role in hepatitis virus infections. We analyzed the expression of SOCS3 in liver specimens from HBV-infected patients using immunohistochemistry (IHC) and determined the effect of HBV on STAT/SOCS signaling in functional cell culture experiments (HuH-7) using HBV-expressing adenoviral constructs (AdHBV). Increased expression of SOCS3 protein was identified in liver specimens from patients with chronic HBV-infection and this correlated with the severity of liver inflammation. In accordance with the IHC-findings, in vitro analyses demonstrated that HBV infection of HuH7 cells was associated with increased expression of SOCS3 protein. In spite of the over expression of its negative regulator SOCS3 we observed a constitutive activation of STAT3. SOCS1 levels were not increased while pSTAT1 was suppressed in HBV-infected HuH7 cells. Our results demonstrate that STAT/SOCS-signaling is dysregulated in HBV-infected hepatocytes both in vivo and in vitro and this correlated with the severity of liver inflammatory changes. This interference of STAT/SOCS signaling by HBV may result in an ineffective immune response against HBV and potentially contributes to viral pathogenesis, malignant transformation and may represent an important mechanism of viral persistence.

Controversies about occult hepatitis B virus infection

We read with great interest the paper written by Shi et al, reviewing the molecular characteristics and stages of chronic hepatitis B virus (HBV) infection. We think that some points in the definition of occult HBV infection (OBI) and their conclusion about the management of OBI may need further considerations.