Hepatitis B genotypes and the response to interferon therapy

Incidence and factors associated with hepatitis B surface antigen seroclearance in patients co-infected with HBV/HIV during antiretroviral therapy in Guangdong, China

BACKGROUND

Hepatitis B surface antigen (HBsAg) clearance is vital for a functional cure of hepatitis B virus (HBV) infection. However, the incidence and predictors of HBsAg seroclearance in patients co-infected with HBV and human immunodeficiency virus (HIV) remain largely unknown in Guangdong, China.

METHODS

Between 2009 and 2019, patients co-infected with HBV/HIV undergoing antiretroviral therapy (ART) in Guangzhou Eighth People's Hospital affiliated to Guangzhou Medical University were retrospectively reviewed with the endpoint on December 31, 2020. The incidence and risk factors for HBsAg seroclearance were evaluated using Kaplan-Meier and multivariate Cox regression analyses.

RESULTS

A total of 1550 HBV/HIV co-infected patients were included in the study, with the median age of 42 years and 86.0% (1333/1550) males. Further, 98.3% (1524/1550) received ART containing tenofovir disoproxil fumarate (TDF) plus lamivudine (3TC). HBV DNA was examined in 1283 cases at the last follow-up. Over the median 4.7 years of follow-up, 8.1% (126/1550) patients achieved HBsAg seroclearance, among whom 50.8% (64/126) obtained hepatitis B surface antibody, 28.1% (137/488) acquired hepatitis B e antigen seroconversion, and 95.9% (1231/1283) undetectable HBV DNA. Compared with patients who maintained HBsAg positive, cases achieving HBsAg seroclearance showed no differences in age, gender, CD4 + T cell count, alanine aminotransferase (ALT) level, or fibrosis status; however, they presented lower HBV DNA levels, lower HBsAg levels, and higher rates of HBV genotype B at the baseline. Multivariate analysis showed that baseline HBsAg <1500 cutoff index (COI) (adjusted hazard ratio [aHR], 2.74, 95% confidence interval [95% CI]: 1.48-5.09), ALT elevation >2 × upper limit of normal during the first six months after receiving ART (aHR, 2.96, 95% CI: 1.53-5.77), and HBV genotype B (aHR, 3.73, 95% CI: 1.46-9.59) were independent predictors for HBsAg seroclearance (all P <0.01).

CONCLUSIONS

Long-term TDF-containing ART has high anti-HBV efficacy including relatively high overall HBsAg seroclearance in HBV/HIV co-infected patients. Lower baseline HBsAg levels, HBV genotype B, and elevated ALT levels during the first six months of ART are potential predictors of HBsAg seroclearance.

Antiviral Response across Genotypes after Treatment of Chronic Hepatitis B Patients with the Therapeutic Vaccine NASVAC or Pegylated Interferon

An open-level, randomized and treatment-controlled clinical trial has shown that a therapeutic vaccine containing hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) (NASVAC) is endowed with antiviral and liver protecting capacity and is safer than pegylated interferon (Peg-IFN) in patients with chronic hepatitis B (CHB). The present study provides information about the role of the hepatitis B virus (HBV) genotype in this phase III clinical trial. From a total of 160 patients enrolled in this trial, the HBV genotypes of 133 patients were characterized, and NASVAC induced a stronger antiviral effect (HBV DNA reduction below 250 copies per mL) than Peg-IFN. The antiviral effects and alanine aminotransferase levels were not significantly different among different HBV genotypes in NASVAC-treated patients. However, a significantly higher proportion of genotype-D patients receiving NASVAC showed better therapeutic effects, compared to genotype-D patients receiving Peg-IFN, with a marked difference of 44%. In conclusion, NASVAC seems to be a better alternative to Peg-IFN, especially in patients with HBV genotype-D patients. This reflects the attractiveness of NASVAC in countries where genotype D is highly prevalent. The mechanisms underlying the effect of HBV genotype are being studied in a new clinical trial.

HBsAg Loss as a Treatment Endpoint for Chronic HBV Infection: HBV Cure

Despite the availability of effective vaccines and antiviral therapy over the past two to three decades, chronic hepatitis B virus (HBV) infection remains a major global health threat as a leading cause of cirrhosis and liver cancer. Functional HBV cure defined as hepatitis B surface antigen (HBsAg) loss and undetectable serum HBV DNA is associated with improved clinical outcomes in patients with chronic HBV infection. However, spontaneous loss of HBsAg is rare and occurs in only 1% of all HBsAg-positive individuals annually. Furthermore, the rate of functional cure with currently available antiviral therapy is even lower, <1% patients on treatment per year. Nonetheless, HBsAg loss has become the new target or therapeutic endpoint for antiviral treatment. Recently, there has been much excitement surrounding the development of novel antiviral agents such as small interfering RNA (siRNA), core assembly modulators (CAMs), nucleic acid polymers (NAPs) among others, which may be used in combination with nucleos(t)ide analogs and possibly immunomodulatory therapies to achieve functional cure in a significant proportion of patients with chronic hepatitis B. Novel assays with improved sensitivity for detection of very low levels of HBsAg and to determine the source of HBsAg production will also be required to measure efficacy of newer antiviral treatments for HBV cure. In this narrative review, we will define HBV cure, discuss various sources of HBsAg production, evaluate rates of HBsAg loss with current and future antiviral agents, review clinical factors associated with spontaneous HBsAg loss, and explore clinical implications of functional cure.

Pathogenicity and virulence of Hepatitis B virus

Hepatitis B virus (HBV) is a hepatotropic virus and an important human pathogen. There are an estimated 296 million people in the world that are chronically infected by this virus, and many of them will develop severe liver diseases including hepatitis, cirrhosis and hepatocellular carcinoma (HCC). HBV is a small DNA virus that replicates via the reverse transcription pathway. In this review, we summarize the molecular pathways that govern the replication of HBV and its interactions with host cells. We also discuss viral and non-viral factors that are associated with HBV-induced carcinogenesis and pathogenesis, as well as the role of host immune responses in HBV persistence and liver pathogenesis.

Current laboratory tests for diagnosis of hepatitis B virus infection

BACKGROUND

Hepatitis B virus (HBV) has a long history in human infectious diseases. HBV infection can progress chronically, leading to cancer. After introduction of a vaccine, the overall incidence rate of HBV infection has decreased, although it remains a health problem in many countries.

PURPOSE

The aim of this review was to summarise current diagnostic efforts for HBV infection and future HBV diagnosis perspectives.

METHODS

We reviewed and summarised current laboratory diagnosis related with HBV infection in clinical practice.

RESULTS

There have been various serologic- and molecular-based methods to diagnose acute or chronic HBV infection. Since intrahepatic covalently closed circular DNAs (cccDNAs) function as robust HBV replication templates, cure of chronic HBV infection is limited. Recently, new biomarkers such as hepatitis B virus core-related antigen (HBcrAg) and HBV RNA have emerged that appear to reflect intrahepatic cccDNA status. These new biomarkers should be validated before clinical usage.

CONCLUSION

An effective diagnostic approach and current updated knowledge of treatment response monitoring are important for HBV infection management. Brand new ultrasensitive and accurate immunologic methods may pave the way to manage HBV infection in parallel with immunotherapy era.

Interferon mediated prophylactic protection against respiratory viruses conferred by a prototype live attenuated influenza virus vaccine lacking non-structural protein 1

The influenza A non-structural protein 1 (NS1) is known for its ability to hinder the synthesis of type I interferon (IFN) during viral infection. Influenza viruses lacking NS1 (ΔNS1) are under clinical development as live attenuated human influenza virus vaccines and induce potent influenza virus-specific humoral and cellular adaptive immune responses. Attenuation of ΔNS1 influenza viruses is due to their high IFN inducing properties, that limit their replication in vivo. This study demonstrates that pre-treatment with a ΔNS1 virus results in an antiviral state which prevents subsequent replication of homologous and heterologous viruses, preventing disease from virus respiratory pathogens, including SARS-CoV-2. Our studies suggest that ΔNS1 influenza viruses could be used for the prophylaxis of influenza, SARS-CoV-2 and other human respiratory viral infections, and that an influenza virus vaccine based on ΔNS1 live attenuated viruses would confer broad protection against influenza virus infection from the moment of administration, first by non-specific innate immune induction, followed by specific adaptive immunity.

Interpretation of HBV Serologies

Hepatitis B was discovered by researchers who were investigating jaundice associated with blood transfusions as well as parenterally administered medications. Through trial and error, the HBV was identified. There are specific tests that detect HBV infection, whether it is a previous exposure or active infection. The various HBV serologies are reviewed in this work as well. Hepatitis B surface antigen has emerged as a tool in defining treatment endpoint and its significance is reviewed. HBV genotypes are distributed uniquely throughout the world, in particular, genotype C is associated with higher rates of hepatocellular carcinoma. Various HBV genotypes and their impact on the clinical course are discussed. The relationship of HBV serologies and HBV DNA to disease progression is outlined. There are specific recommendations on monitoring those infected with HBV and this is reviewed here. HBV mutations have an impact on the disease course and those of significance are also discussed.

Prophylactic protection against respiratory viruses conferred by a prototype live attenuated influenza virus vaccine

The influenza A non-structural protein 1 (NS1) is known for its ability to hinder the synthesis of type I interferon (IFN) during viral infection. Influenza viruses lacking NS1 (ΔNS1) are under clinical development as live attenuated human influenza virus vaccines and induce potent influenza virus-specific humoral and cellular adaptive immune responses. Attenuation of ΔNS1 influenza viruses is due to their high IFN inducing properties, that limit their replication in vivo. This study demonstrates that pre-treatment with a ΔNS1 virus results in an immediate antiviral state which prevents subsequent replication of homologous and heterologous viruses, preventing disease from virus respiratory pathogens, including SARS-CoV-2. Our studies suggest that ΔNS1 influenza viruses could be used for the prophylaxis of influenza, SARS-CoV-2 and other human respiratory viral infections, and that an influenza virus vaccine based on ΔNS1 live attenuated viruses would confer broad protection against influenza virus infection from the moment of administration, first by non-specific innate immune induction, followed by specific adaptive immunity.

Intracellular interferon signalling pathways as potential regulators of covalently closed circular DNA in the treatment of chronic hepatitis B

Infection with the hepatitis B virus (HBV) is still a major global health threat as 250 million people worldwide continue to be chronically infected with the virus. While patients may be treated with nucleoside/nucleotide analogues, this only suppresses HBV titre to sub-detection levels without eliminating the persistent HBV covalently closed circular DNA (cccDNA) genome. As a result, HBV infection cannot be cured, and the virus reactivates when conditions are favorable. Interferons (IFNs) are cytokines known to induce powerful antiviral mechanisms that clear viruses from infected cells. They have been shown to induce cccDNA clearance, but their use in the treatment of HBV infection is limited as HBV-targeting immune cells are exhausted and HBV has evolved multiple mechanisms to evade and suppress IFN signalling. Thus, to fully utilize IFN-mediated intracellular mechanisms to effectively eliminate HBV, instead of direct IFN administration, novel strategies to sustain IFN-mediated anti-cccDNA and antiviral mechanisms need to be developed. This review will consolidate what is known about how IFNs act to achieve its intracellular antiviral effects and highlight the critical interferon-stimulated gene targets and effector mechanisms with potent anti-cccDNA functions. These include cccDNA degradation by APOBECs and cccDNA silencing and transcription repression by epigenetic modifications. In addition, the mechanisms that HBV employs to disrupt IFN signalling will be discussed. Drugs that have been developed or are in the pipeline for components of the IFN signalling pathway and HBV targets that detract IFN signalling mechanisms will also be identified and discussed for utility in the treatment of HBV infections. Together, these will provide useful insights into design strategies that specifically target cccDNA for the eradication of HBV.

Mechanisms of Hepatitis B Virus-Induced Hepatocarcinogenesis

Hepatitis B virus (HBV) is a major cause of hepatocellular carcinoma (HCC). There are approximately 250 million people in the world that are chronically infected by this virus, resulting in nearly 1 million deaths every year. Many of these patients die from severe liver diseases, including HCC. HBV may induce HCC through the induction of chronic liver inflammation, which can cause oxidative stress and DNA damage. However, many studies also indicated that HBV could induce HCC via the alteration of hepatocellular physiology that may involve genetic and epigenetic changes of the host DNA, the alteration of cellular signaling pathways, and the inhibition of DNA repair mechanisms. This alteration of cellular physiology can lead to the accumulation of DNA damages and the promotion of cell cycles and predispose hepatocytes to oncogenic transformation.

Factors Associated with Hepatitis B Surface Antigen Kinetics and Responses in Pegylated Interferon Alpha-2a Monotherapy for Patients with Chronic Hepatitis B

Objective Pegylated-interferon monotherapy is the standard treatment for patients with chronic hepatitis B; however, the factors associated with its therapeutic effects remain unclear. Methods Patients with chronic hepatitis B were treated with pegylated interferon α-2a for 48 weeks. We evaluated the kinetics of hepatitis B surface antigen (HBsAg) during treatment and follow-up periods and the factors associated with an HBsAg response (defined as a change in HBsAg of ≥-1 log IU/mL from baseline). Results The study population comprised 50 patients. The median baseline levels of hepatitis B virus DNA and HBsAg were 5.00 and 3.40 log IU/mL. The median values of HBsAg reduction from baseline were -0.44 (n=48), -0.41 (n=40), and -0.68 (n=11) log IU/mL at the end of treatment and at 48 and 144 weeks post-treatment, respectively. The rates of HBsAg response were 24.0% and 22.5% at the end of treatment and at 48 weeks post-treatment, respectively. A multivariate analysis identified HBsAg <3.00 log IU/mL as an independent baseline factor contributing to the HBsAg response at the end of treatment and 48 weeks post-treatment (p=1.07×10^-2 and 4.42×10^-2, respectively). There were significant differences in the reduction of the HBsAg levels at 12 weeks of treatment and in the incidence of serum ALT increase during treatment between patients with and without an HBsAg response. Conclusion These findings suggest that the baseline HBsAg level, HBsAg kinetics at 12 weeks of treatment, and ALT increase during treatment are important factors contributing to the HBsAg response in pegylated interferon α-2a monotherapy for patients with chronic hepatitis B.

Developing a sensitive HBV genotyping assay for HBV DNA suppressed patients using both DNA and RNA sequencing

Hepatitis B virus (HBV) genotypes impact treatment outcomes and disease progression. The current genotyping methods have limitations in patients with low HBV viral load. In this study, a more sensitive assay has been developed for determining the HBV genotype in HBV DNA suppressed patients. Fifty-five serum samples from 55 chronic hepatitis B patients (HBeAg-, n = 20; HBeAg+, n = 35) across genotypes A to H with long-term nucleos(t)ide analogs (NAs) treatment were collected. All samples had HBV DNA less than 29 IU/mL. Total nucleic acid (viral DNA and RNA) was extracted and a 341 bp amplicon located at HBV S gene overlapping with reverse transcriptase domain of polymerase (pol/RT) was amplified via real time (RT)-nested polymerase chain reaction (PCR) followed by population sequencing. HBV genotype was determined by phylogenetic analysis. The assay successfully amplified HBV S/RT gene from 53 of 55 (96.4%) patient serum samples. Phylogenetic analysis demonstrated that the genotypes of all the 53 PCR positive samples matched the historical genotypes as determined by INNO-LiPA or RT sequence from the corresponding baseline samples. This assay was able to accurately determine HBV genotype irrespective of baseline genotype, HBeAg status, or duration of viral suppression. The ability to determine genotype in virally suppressed patients may facilitate the evaluation of novel treatment agents for HBV in this patient population.

The evolution and clinical impact of hepatitis B virus genome diversity

The global burden of hepatitis B virus (HBV) is enormous, with 257 million persons chronically infected, resulting in more than 880,000 deaths per year worldwide. HBV exists as nine different genotypes, which differ in disease progression, natural history and response to therapy. HBV is an ancient virus, with the latest reports greatly expanding the host range of the Hepadnaviridae (to include fish and reptiles) and casting new light on the origins and evolution of this viral family. Although there is an effective preventive vaccine, there is no cure for chronic hepatitis B, largely owing to the persistence of a viral minichromosome that is not targeted by current therapies. HBV persistence is also facilitated through aberrant host immune responses, possibly due to the diverse intra-host viral populations that can respond to host-mounted and therapeutic selection pressures. This Review summarizes current knowledge on the influence of HBV diversity on disease progression and treatment response and the potential effect on new HBV therapies in the pipeline. The mechanisms by which HBV diversity can occur both within the individual host and at a population level are also discussed.

The characteristic of the synonymous codon usage and phylogenetic analysis of hepatitis B virus

Background

Hepatitis B virus (HBV) infection is a crucial medical issue worldwide. The dependence of HBV replication on host cell machineries and their co-evolutionary interactions prompt the codon usage pattern of viral genes to translation selection and mutation pressure.

Objective

The evolutionary characteristics of HBV and the natural selection effects of the human genome on the codon usage characteristics were analyzed to provide a basis for medication development for HBV infection.

Methods

The codon usage pattern of sequences from different HBV genotypes of our isolates and reference HBV genome sequences downloaded from the National Center for Biotechnology Information (NCBI) database were analyzed by computing the relative synonymous codon usage (RSCU), nucleotide content, codon adaptation index (CAI) and the effective number of codons (ENC).

Results

The highest ENC values were observed in the C genotypes, followed by the B genotypes. The ENC values indicated a weak codon usage bias (CUB) in HBV genome. The number of codons differentially used between the three genotypes was markedly higher than that of similarly used codons. High CAI values indicated a good adaptability of HBV to its host. The ENC plot indicated the occurrence of mutational pressure in the three genotypes. The mean Ka/Ks ratios in the three genotypes were lower than 1, which indicated a negative selection pressure. The CAI and GC3% plot indicated the existence of CUB in the HBV genome.

Conclusions

Nucleotide composition, mutation bias, negative selection and mutational pressure are key factors influencing the CUB and phylogenetic diversity in HBV genotypes. The data provided here could be useful for developing drugs for HBV infection.

Electronic supplementary material

The online version of this article (10.1007/s13258-020-00932-w) contains supplementary material, which is available to authorized users.

Molecular epidemiology of hepatitis B virus genotypes in blood donors in Islamabad, Pakistan

BACKGROUND:

Hepatitis B virus (HBV) is a major causative agent of early, severe and prolonged liver infection that subsequently leads to cirrhosis of liver and hepatocellular carcinoma. The aim of this study was to evaluate the molecular epidemiology of hepatitis B virus (HBV) genotypes and comparison of serological assay performance versus polymerase chain reaction (PCR) in HBV screening.

METHODS:

Blood samples of 8517 healthy blood donors were collected during the period of January to June 2017 from Blood Bank of Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad. Samples were screened for HBsAg assay using technique of chemiluminescence immunoassay. PCR of positive samples was carried out using already reported genotype-specific primers by Naito et al. (2001). The results were confirmed by visualizing genotype bands.

RESULTS:

The study confirmed the presence of HBV in 2.5% of blood donors, and PCR confirmed the presence of HBV-DNA in 92 samples. The genotyping was done by PCR using type-specific primer sequences. PCR was dogged to check six genotypes, i.e., A, B, C, D, E, and F. The results of this study show high levels of Genotype D is this region, i.e., 52.17% with less dominating Genotype C, which is 16.30% with decreasing ratio of Genotype E (14.13%), Genotype A and B (9.78%), and mixed D + E (2.17%). The presence of coinfection is found at lowest rate. Due to the high percentage of HBV/D, it is concluded that D genotype is common in our population.

CONCLUSION:

The most prevalent HBV genotype in ICT region was genotype D, which is responsible for liver cirrhosis and hepatocellular carcinoma. Efficacy of drugs varies with variation in genotypes of hepatitis B virus and also with geographical distribution.

Significance of switching of the nucleos(t)ide analog used to treat Japanese patients with chronic hepatitis B virus infection from entecavir to tenofovir alafenamide fumarate

The significance of switching of the nucleos(t)ide analog used to treat patients with hepatitis B virus (HBV) from entecavir (ETV) to tenofovir alafenamide fumarate (TAF) is uncertain. The subjects of this study were 159 patients with HBV who received treatment with ETV followed by TAF. Among these patients, serial changes in the HBV marker levels were monitored in 92 patients in whom the serum HBsAg levels were ≥100 IU/mL during the 48-week period immediately before and after the switching. A questionnaire survey for medication compliance was performed in 127 patients. The serum HBsAg levels (log IU/mL) decreased by 0.041 during the ETV treatment period and by 0.068 during the TAF administration period. The degree of reduction was higher during the TAF administration period than during the ETV administration period in patients without cirrhosis (P = .030), patients with genotype B HBV (P = .014), and patients with undetectable serum HBcrAg (P = .038). Multivariate analysis revealed the HBV genotype (B vs C; odds ratio, 3.400; P = .025) and serum aspartate aminotransferase level (every 1+; 1.111; P = .015) at the time of switching as factors influencing the treatment efficacy. Thirty-six patients (28%) responded that the number of days that they forgot to take the drug decreased after the drug switching, and 77 patients (61%) reported feeling satisfied with the drug switching. Switching of the nucleos(t)ide analog used from ETV to TAF may be useful in the treatment of patients with HBV infection, as it is associated with both a decrease in the serum HBsAg level and improvement of the medication compliance.

The response of hepatitis B virus genotype to interferon is associated with a mutation in the interferon-stimulated response element

Genetic variation and genotype of Hepatitis B virus (HBV) are related to the efficiency of interferon alpha (IFN-α)-based antiviral therapy. However, the correlation of variation in interferon-stimulated response element (ISRE) and HBV genotype response to IFN-α therapy remains elusive.Differences of ISRE between genotype B and C HBV were explored using the HBV sequences retrieved from GenBank, and further investigated by ISRE region cloning and sequencing from 60 clinical samples post-IFN-α therapy. Additionally, ISRE mutants were constructed and their relation to responsiveness of IFN-α was evaluated by real-time PCR and Southern blot analysis.ISRE pattern between genotype B and C were found based on both clinical sample sequencing and full-length sequence alignment. The primary difference is the fourth base within the ISRE region, with T and C for genotype B and C, respectively. HBV with genotype C-type ISRE had a higher replicative capability as compared to HBV with genotype B-type ISRE after IFN-α treatment in huh7 cells. CONCLUSION:: Preference of ISRE between genotype B and C HBV are distinct. Single nucleotide difference (C to T) within the HBV ISRE region may link to the efficacy of IFN-α therapy to genotype B and C HBV. Therefore, this study provides a clue for the determination of IFN-α therapy response to HBV treatment.

Long-term prognosis of liver disease in patients with chronic hepatitis B virus infection receiving nucleos(t)ide analogue therapy: an analysis using a Markov chain model

AIM

Even during nucleos(t)ide analogue therapy, development of hepatocellular carcinoma (HCC) has been observed in patients with chronic hepatitis B virus (HBV) infection. We simulated the long-term prognosis of liver disease in patients with chronic HBV who received nucleos(t)ide analogue therapy.

PATIENTS AND METHODS

A total of 254 patients with chronic HBV receiving nucleos(t)ide analogue therapy were enrolled. Yearly transition probabilities between liver disease states [chronic hepatitis, cirrhosis, HCC, and hepatitis B surface antigen (HBsAg)-negative status] were calculated using a Markov chain model.

RESULTS

In the analysis of 1-year liver disease state transition probabilities, the development of HCC occurred in men with chronic hepatitis in their 50s (1.8%) and at least 70 years (2.8%) and in patients with cirrhosis in all age groups (40-49, 50-59, 60-69, and ≥ 70 years). HBsAg-negative status was present in patients with chronic hepatitis in their 50s (1.8%) and 60s (2.6%), and in patients with cirrhosis in their 60s (0.6%). In female patients, the development of HCC occurred in patients with cirrhosis during their 50s (0.8%), 60s (0.8%), and older (4.5%). HBsAg-negative status was simulated in patients with cirrhosis in their 50s (0.8%) and 60s (0.8%). Assuming a chronic hepatitis state at age 40 as the starting condition for simulation over the next 40 years, the probability of developing HCC increased gradually with age in male patients and in female patients after the age of 70 years.

CONCLUSION

There is a risk of development of HCC in middle-aged men with chronic hepatitis or cirrhosis and older women with cirrhosis even while receiving nucleos(t)ide analogue therapy.

A systematic genotype and subgenotype re-ranking of hepatitis B virus under a novel classification standard

Background and aim

It is commonly noticed that chaotic and inefficient subgenotyping are universally used academically and clinically, a standardized HBV genotype/subgenotype classification criterion is urgently acquired. Sequence similarity, which was commonly used for the last three decades, should be upgraded by phylogenetic analysis in genotyping of recombinant-free HBV strains.

Methods

In this study, 4,429 HBV whole-genome sequences were employed to reconstruct the phylogeny of HBV using Bayesian inference. After excluding recombinant sequences, calculating partitioned evolutionary models, excluding recombinant sequences, reconstructing phylogenetic trees, and performing a correlation analysis of genetic distances, geographical distribution and serotypes, we systematically redefined the genotypes and subgenotypes of HBV.

Results

Compared to previous taxonomy, fourteen subgenotypes (A5-A7; B5-B9; C2-C4, C7; and D6-D7) were revised in the new standard. Now the HBV is divided into ten genotypes (A-J) and 24 subgenotypes (A1-A3; B1-B5; C1-C6; D1-D6; and F1-F4).

Conclusion

Our robust genotype/subgenotype new taxonomy has objectively re-molded the current shape of HBV classification. We believe that all future hepatitis B related researches or diagnosis will be benefited under the new HBV genotyping/subgenotyping standards.

HBV mutations in EnhII/BCP/PC region contribute to the prognosis of hepatocellular carcinoma

Background

Accompanied by HBV infection, HBV mutations gradually occur because HBV polymerase appears proofread deficiencies. In our previous study, we have identified that EnhII/BCP/PC mutations and genotype C of HBV DNA were associated with hepatocellular carcinoma (HCC) risk. In this study, we extend our research to explore HCC prognosis associated genotype and mutations in EnhII/BCP/PC regions.

Methods

We designed a case‐cohort study of 331 HCC patients to evaluate the effects of the HBV genotypes and mutations on HCC survival. Log‐rank test and Cox proportional hazard models were used for the analyses.

Results

Results showed that genotype C, which was more frequent in HBV‐related HCC (77.4%), presented a negative signal with HCC survival. Interestingly, we detected a significant association between EnhII/BCP/PC mutation nt1753 and HCC prognosis (Log‐rank P = 0.034). Subgroup analysis revealed that this risk effect was more pronounced in non‐B genotype (P = 0.090 for heterogeneity test). We also detected a borderline multiplicative interaction between genotypes of nt1753 and HBV genotype on HCC survival (P for interaction = 0.069).

Conclusions

These findings indicated that, in Chinese population, nt1753 in EnhII/BCP/PC region might be a novel marker for HCC prognosis.

A novel hepatitis B virus recombinant genotype D4/E identified in a South African population

Background

Genetic diversity is a characteristic trait of the hepatitis B virus (HBV) and has been associated with different clinical outcomes. In South Africa, HBV infection is a major public health concern. Most HBV infections are caused by genotype A strains. However rare cases of infection with HBV genotype D have been reported. The purpose of this study was to investigate the molecular characteristics of a rare HBV subgenotype D4 isolate.

Methods

The full-length genome of isolate ZADGM6964 was amplified in a one-step polymerase chain reaction. The amplified product was purified and cloned into a pGEM®-T Easy Vector System to investigate the genetic diversity of the viral quasi-populations. The primary isolate and clones were then directly sequenced and analysed using an array of bioinformatics software.

Results

Phylogenetic analysis showed that the primary isolate and cloned sequences formed a monophyletic cluster away from subgenotype D4 reference strains. Further recombination analysis revealed that isolate ZADGM6964 was in fact a D4/E recombinant strain with breakpoints identified within the X and overlapping pre-Core/Core open reading frames with a >70% bootstrap confidence level. The recombinant genotype D4/E was found to be unique from other D/E strains archived in the genetic database, GenBank.

Conclusion

This study represents the first ever report on the isolation and molecular characterization of an HBV D4/E recombinant strain in South Africa. The findings provide evidence of further HBV genetic diversity in South Africa than has been previously reported.

Prognosis, Prevention and Research Prospects of Progression to Severe Hepatitis B (Liver Failure)

This chapter describes the factors involved in the disease prognosis, parameters of outcome evaluations, principles and techniques for progression prevention. In last section, the future perspectives in both basic and clinical investigations towards unmet medical needs in AECHB and HBV ACLF are discussed.

Factors affecting the prognosis of patients with severe hepatitis B include those related to the virus (including viral load, HBeAg expression, and gene mutation), patient age, co-morbidity, TBil, INR, serum Cr, and the host genetic background. Indicators associated with patient prognosis include TBil, total cholesterol, albumin and prealbumin, hepatic encephalopathy, kidney damage, alpha-fetoprotein and vitamin D binding protein, blood sodium level, virus HBeAg expression and genotype, and blood glucose.

In addition to TBil, INR, hepatic encephalopathy, Cr level and AFP as indicators for prognosis of severe hepatitis, some other parameters such as clinical signs, symptoms, serum levels of total cholesterol and albumin and natrium, and coagulation factors are all valuable in assessment. The roles of cell apoptosis, liver regeneration and immunological parameters in assessing patient prognosis are under study. Prognostic evaluating systems include MELD score, MELD-Na score, iMELD score, KCI and CTP score.

Prevention of severe hepatitis B should be started in asymptomatic patients. Close observation, sufficient rest, adequate nutrition, meticulous nursing and psychological care, preventing and removing exacerbating factors, treating concomitant diseases, reasonable antiviral and comprehensive therapies are helpful to prevent CHB patients from developing to severe hepatitis. For patients who already have severe hepatitis B, the prevention and management of complications is important for lowering mortality rate.

New research directions in acute-on-chronic liver failure include: (1) Additional well controlled studies using present or new liver systems are warranted. Other approaches include the use of granulocyte colony stimulating factor to treat infections as well as the potential of use of stem cells to restore immune integrity and enhance liver regeneration. (2) Using new cell lines and animal models to understand the molecular biology of HBV, the immune response and to develop novel therapies. (3) Development of new anti-HBV strategies, e.g. silencing or remove cccDNA, enhancing immunologic clearance of HBV infection, inhibiting virus entry or HBc expression and using CRISP to disrupt cccDNA.

Taiwan consensus statement on the management of chronic hepatitis B

The experts of Taiwan Association for the Study of Liver (TASL) have actively participated and led the guidelines on hepatitis B virus (HBV) management by Asian Pacific Association for the Study of Liver (APASL) which is the first international association for the study of liver to publish the statement on HBV management before. However, there are more and more new data on the natural history and treatment of HBV infection in the past decade. These include new application of an old biomarker (quantitative HBsAg), clinical significance of HBV genotype and naturally occurring mutations, the role of non-invasive examination in evaluating severity of hepatic fibrosis, clinical significance of outcome calculators, new drug or new combination strategies towards more effective therapy and organ transplantation including liver and non-liver transplantation. It is time to publish the guidelines on HBV management of Taiwan. Hence, TASL have conducted an expert meeting to review, to discuss and to debate the relevant literatures, followed by draft the manuscript of HBV management guidelines and recommendations. The guidelines include general management, indications for fibrosis assessment, time to start or stop drug therapy, choice of drug to initiate therapy, when and how to monitor the patients during and after stopping drug therapy. Recommendations on the therapy of patients in special circumstances, including women in childbearing age, patients with antiviral drug resistance, concurrent viral infection, hepatic decompensation, patient receiving immune suppression or chemotherapy and patients in the setting of liver transplantation and hepatocellular carcinoma, are also included.

Hepatitis B virus genotype G and liver fibrosis progression in chronic hepatitis B and human immunodeficiency virus coinfection

INTRODUCTION

Infection with hepatitis B virus (HBV) genotype G has been associated with increased liver fibrosis levels compared with other genotypes in cross-sectional studies, yet its role in fibrosis evolution remains to be established.

METHODS

In this prospective cohort study, 158 human immunodeficiency virus (HIV)-HBV coinfected patients had available HBV genotyping at baseline. Liver fibrosis was assessed at baseline and every 6 to 12 months by the FibroTest (BioPredictive, Paris, France). Risk factors for fibrosis regression (F3-F4 to F0-F1-F2) and progression (F0-F1-F2 to F3-F4) between baseline and end of follow-up were evaluated.

RESULTS

Most patients were male (88.6%) with a median age of 39 years. HBV genotype A was more prevalent compared with other HBV genotypes (62.7% vs D = 10.8%, E = 10.8%, and G = 15.8%). Patients were followed up for a median of 83 months (IQR = 37-97). In the 43 (27.2%) patients with F3-F4 baseline liver fibrosis, 7 (16.2%) regressed to F0-F1-F2 fibrosis at the last follow-up visit. In the 115 (72.8%) with F0-F1-F2 fibrosis at baseline, 19 (16.5%) progressed to F3-F4 fibrosis at last visit. In multivariable analysis, fibrosis progression was independently associated with older age (P <0.005), baseline CD4+ cell count less than 350/mm ³ ( P <0.01), longer antiretroviral therapy duration ( P <0.03), and HBV genotype G infection (vs non-G, P <0.01). When examining averages over time, the rate of FibroTest increase was faster in genotype G vs non-G-infected patients with baseline F0-F1-F2 fibrosis ( P for interaction = 0.002).

CONCLUSION

In HIV-HBV coinfected patients, HBV genotype G is an independent risk factor for liver fibrosis progression as determined by noninvasive markers. HBV genotype G-infected patients with low initial liver fibrosis levels may require more careful monitoring.

Genetic diversity of hepatitis B co-infection with hepatitis C, D and E viruses among Malaysian chronic hepatitis B patients

BACKGROUND

Hepatitis B virus co-infection with other strains of viral hepatitis is associated with increased risk of liver cirrhosis and hepatic decompensation.

OBJECTIVES

This is a prevalence study that assessed the genetic diversity of chronic hepatitis B patients and coinfection.

METHODS

Chronic hepatitis B patients enrolled in this study were tested for antibodies of other hepatitis viruses using ELISA kits. Patient clinical profiles were collected and partial genes of HBV, HCV, and HEV were amplified, sequenced, and analyzed using phylogenetic analysis. The associations between variables were determined using the chi-squared test.

RESULTS

Of the 82 patients recruited for this study, 53.7% were non-cirrhotic, 22.0% cirrhotic, 20.7% acute flare and 3.7% hepatocellular carcinoma. Majority (58%) of patients had a high level of ALT (≥34 U/L). Sequence analysis showed HBV (63.9%) belonged to genotype B, HEV belonged to genotype 4 while HCV belonged to genotype 3a and the genotypes were found to be significantly associated with the clinical stage of the patients (χ2=56.632; p<0.01). Similarly, Hepatitis B e antigen was also found to be significantly associated with the clinical stage of infection (χ2=51.952; p<0.01).

CONCLUSION

This study revealed that genetic diversity was found to have a significant impact on the severity of infection.

Genotype Matters in Patients with Acute-on-chronic Liver Failure Due to Reactivation of Chronic Hepatitis B

Background

Acute-on-chronic liver failure (ACLF) can be caused by reactivation of chronic hepatitis B virus (HBV) infection (HBV-ACLF). It’s unclear whether HBV genotypes affect the clinical and therapeutical outcomes of patients with HBV-ACLF. This study was to investigate the short-term antiviral response and overall survival in HBV-ACLF patients treated by tenofovir or entecavir.

Methods

Seventy-three consecutive patients with HBV-ACLF were stratified into genotype B group (n = 33) and C group (n = 40). They were prospectively followed-up.

Results

At 2 weeks, the genotype B group had significantly lower HBV-DNA load (P = 0.005), greater HBV-DNA decline (P = 0.026), higher proportion of patients with HBV-DNA < 500 IU/ml (P = 0.007), improved Child-Turcotte-Pugh (CTP; P = 0.032) and model for end-stage liver disease (MELD; P = 0.039) scores compared to the genotype C group. At three months, survivors in both groups had undetectable HBV-DNA loads, comparable CTP (P = 0.850) and MELD (P = 0.861) scores; the genotype C group had markedly lower overall survival rate than the B group (P = 0.013). The genotype (hazard ratio [HR]: 2.138; 95% confidence interval [CI]: 1.034–4.143; P = 0.041), MELD score (HR:1.664, 95%CI: 1.077–2.571; P = 0.022) and HBV-DNA decline (HR: 0.225, 95% CI: 0.067–0.758; P = 0.016) at 2 weeks were significantly associated with mortality at 3 months. No severe adverse event was noted.

Conclusions

Genotype B was associated with better short-term antiviral response and clinical outcome compared to genotype C in patients with HBV-ACLF.

Long-term natural history of liver disease in patients with chronic hepatitis B virus infection: an analysis using the Markov chain model

BACKGROUND

The relationship between the hepatitis B e antigen (HBeAg) seroconversion and the long-term natural history of liver disease has not been sufficiently investigated.

METHODS

A total of 408 [4352 person-year (PY) units] patients with chronic hepatitis B virus (HBV) without antiviral therapy were enrolled. The study patients were divided into three groups, as follows: Group A (2666 PY units), seroconverted of HBeAg at age < 40; Group B (413 PY units), seroconverted of HBeAg at age ≥ 40; Group C (1273 PY units), persistently HBeAg positive. Yearly transition probabilities from each liver state [chronic HBV infection, chronic hepatitis B, cirrhosis, hepatocellular carcinoma (HCC), and hepatitis B surface antigen (HBsAg) negativity] were calculated using the Markov chain model.

RESULTS

In the analysis of 1 year liver disease state transition probabilities, the liver states remained almost the same in Group A. In Groups B and C, each liver state tended to progress to a worse state. Assuming a chronic hepatitis B state at age 40 as the starting condition for simulation over the next 40 years, the chronic hepatitis B state accounted for approximately 60% of males aged ≥ 50 and approximately 40% of females aged ≥ 60 in Group A, and the HBsAg-negative state accounted for approximately 30-40% of males and females aged ≥ 60. In Groups B and C, the probabilities of patients with cirrhosis and HCC gradually increased with age.

CONCLUSIONS

Not only patients with persistent HBeAg positive, but also patients with delayed HBeAg seroconversion showed poor prognosis of liver-related natural history.

Chinese Herbal Medicine Combined with Entecavir for HBeAg Positive Chronic Hepatitis B: Study Protocol for a Multi-Center, Double-Blind Randomized-Controlled Trial

BACKGROUND

The domestic prevalence of chronic hepatitis B (CHB) in China is 7.18% in 2006, imposing great societal healthcare burdens. Nucleot(s)ide analogues (NUCs) anti-hepatitis B virus (HBV) therapies are widely applied despite the relatively low rate of seroconversion and high risk of drug-resistant mutation. More effective treatments for CHB deserve further explorations. Combined therapy of NUCs plus Chinese herbal medicine (CHM) is widely accepted in China, which is recognized as a prospective alternative approach. The study was primarily designed to confirm the hypothesis that Tiaogan-Yipi Granule (, TGYP) or Tiaogan-Jianpi-Jiedu Granule (, TGJPJD) plus entecavir tablet (ETV) was superior over ETV monotherapy in enhancing HBeAg loss rate.

METHODS

The study was a nationwide, large-scale, multi-center, double-blind, randomized, placebo-controlled trial with a designed duration of 108 weeks. A total of 16 hospitals and 596 eligible Chinese HBeAg positive CHB patients were enrolled from November 2012 to September 2013 and randomly allocated into 2 groups in 1:1 ratio via central randomization system: experimental group (EG) and control group (CG). Subjects in EG received CM formulae (TGYP or TGJPJD, 50 g per dose, twice daily) plus ETV tablet (or ETV placebo) 0.5 mg per day in the first 24 weeks (stage 1), and CHM granule plus ETV tablet (0.5 mg per day) from week 25 to 108 (stage 2). Subjects in CG received CHM Granule placebo plus ETV tablet (0.5 mg per day) for 108 weeks throughout the trial. The assessments of primary outcomes (HBV serum markers and HBV-DNA) were conducted by a third-party College of American Pathologists (CAP) qualified laboratory. Adverse effects were observed in the hospitals of recruitment.

DISCUSSION

The study was designed to compare the curative effect of CM plus ETV and ETV monotherapy in respect of HBeAg loss, which is recognized by the European Association for the Study of the Liver as "a valuable endpoint". We believe this trial could provide a reliable status for patients' "journey" towards durable responses after treatment discontinuation. The trial was registered before recruitment on Chinese Clinical trial registry (No. ChiCTR-TRC-12002784, Version 1.0, 2015/12/23).

Pegylated interferon-based sequential therapy for treatment of HBeAg reactive pediatric chronic hepatitis B-First study in children

BACKGROUND

Our aim was to evaluate the efficacy and safety of sequential therapy using pegylated interferon (Peg-IFN) and nucleos(t)ide analogue (NA) for treatment of children in immunoactive (IA) and immunotolerant (IT) phases of chronic hepatitis B.

METHODS

It was a prospective observational study where those willing for sequential therapy were allocated to group 1 (sequential therapy) and others to group 2 (standard therapy). Sequential therapy included 8 weeks of NA followed by 44 weeks of combination of NA and Peg-IFN. In group 2, IA children received NA monotherapy, and IT children received no therapy. HBe seroconversion, HBs seroconversion, and loss of HBV DNA were the major outcome measures.

RESULTS

A total of 61 children (36 IA and 25 IT) were included in the analysis. Among the IA children, 17 received sequential therapy and 19 received standard therapy; whereas, among the IT children, 12 received sequential therapy and 13 did not receive any therapy. In IA phase, sequential therapy led to higher HBe seroconversion (64.7% vs. 21.05%, p = 0.017) and higher virological clearance (94.12% vs. 52.63%, p = 0.008). In IT children, there was no benefit of treatment with sequential therapy over observation alone. Baseline ALT > 100 IU/L predicted response to therapy with 100% sensitivity, 89.5% specificity, and LR⁺ of 9.52.

CONCLUSION

Sequential therapy leads to higher HBe seroconversion and virological response in children in IA phase. Children with baseline ALT > 100 IU/mL are more likely to respond to sequential therapy. There appears to be no role of sequential therapy in children in IT phase.

Hepatitis B virus core-related antigen levels predict progression to liver cirrhosis in hepatitis B carriers

BACKGROUND AND AIM

Several hepatitis B virus (HBV) markers have been identified as risk factors for progression to liver cirrhosis in patients with chronic HBV infection. The predictive impact of HBV markers on progression to cirrhosis in HBV carriers was clarified.

METHODS

A total of 529 hepatitis B e antigen seroconverters with fibrosis-4 (FIB-4) index ≤ 3.6 not on nucleos(t)ide analogue therapy were included. Univariate and multivariate analyses of associations between HBV markers and progression to cirrhosis were performed. In addition, the hazard ratio (HR) spline curves for continuous HBV markers were compared.

RESULTS

Eighty-four patients progressed to cirrhosis (FIB-4 index > 3.6) during the follow-up period. Hepatitis B surface antigen (HBsAg), HBV DNA, HBV core-related antigen (HBcrAg), and basal core promoter status, but not genotype and precore status, were significantly associated with progression to cirrhosis in univariate Cox proportional hazards models. Multivariate Cox proportional hazards models adjusted for HBV genotype, HBsAg, HBV DNA, HBcrAg, precore status, and basal core promoter status indicated that HBsAg ≥ 3.0 log IU/mL (HR, 0.53; 95% confidence interval [CI], 0.30-0.94) and HBcrAg ≥ 3.7 log U/mL (HR, 3.28; 95% CI, 1.60-6.75) are independently associated with progression to cirrhosis. In the HR spline curve analysis, HR and 95% CI gradually increased as HBcrAg levels increased. Conversely, HRs and 95% CIs for HBsAg and HBV DNA did not show this tendency as their levels increased.

CONCLUSIONS

Elevated HBcrAg levels in HBV carriers increases the risk for progression to cirrhosis. HBcrAg is an excellent predictor of the development of cirrhosis.

Hepatitis B virus sensitivity to interferon-α in hepatocytes is more associated with cellular interferon response than with viral genotype

Interferon-α (IFN-α) is used to treat chronic hepatitis B virus (HBV) infection, but only 20%-40% of patients respond well. Clinical observations have suggested that HBV genotype is associated with the response to IFN therapy; however, its role in viral responsiveness to IFN in HBV-infected hepatocytes remains unclear. Here, we produced infectious virions of HBV genotypes A to D to infect three well-recognized cell-culture-based HBV infection systems, including primary human hepatocytes (PHH), differentiated HepaRG (dHepaRG), and HepG2-NTCP cells to quantitatively compare the antiviral effect of IFN-α on HBV across genotypes and cell models. The efficacy of IFN-α against HBV in hepatocytes was generally similar across genotypes A2, B5, C2, and D3; however, it was significantly different among the infection models given that the half maximal inhibitory concentration value of IFN-α for inhibition of viral DNA replication in PHH (<20 U/mL) and dHepaRG cells were much lower than that in HepG2-NTCP cells (>500 U/mL). Notably, even in PHH, IFN-α did not reduce HBV covalently closed circular DNA at the concentrations for which viral antigens and DNA replication intermediates were strongly reduced. The three cell-culture models exhibited differential cellular response to IFN-α. The genes reported to be associated with responsiveness to IFN-α in patients were robustly induced in PHH while weakly induced in HepG2-NTCP cells upon IFN-α treatment. Reduction or promotion of IFN response in PHH or HepG2-NTCP cells significantly attenuated or improved the inhibitory capacity of IFN-α on HBV replication, respectively.

CONCLUSION

In the cell-culture-based HBV infection models, the sensitivity of HBV to IFN-α in hepatocytes is determined more by the cell-intrinsic IFN response than by viral genotype, and improvement of the IFN response in HepG2-NTCP cells promotes the efficacy of IFN-α against HBV. (Hepatology 2018;67:1237-1252).

Effect of hepatitis B virus subgenotype on antiviral response in nucleoside-treated hepatitis B envelope antigen-positive patients

AIM

Previous studies have reported that hepatitis B virus (HBV) genotype is not a predictor of treatment response with nucleos(t)ide analog therapy. However, the impact of subgenotype on treatment response is unknown. The aim of this study is to identify the effect of HBV subgenotype on treatment response.

METHODS

In this retrospective study, the derivation dataset comprised patients from the EFFORT study (NCT00962533) telbivudine monotherapy group; patients infected with genotypes B or C from the GLOBE (NCT00057265) and 015 (NCT00131742) studies formed the validation dataset. The HBV subgenotypes were determined using phylogenetic analysis based on the surface or overlapping polymerase gene. Molecular modeling was used to investigate relationships between positions of the substitutions within reverse transcriptase and genotypic resistance.

RESULTS

Of the patients in the derivation dataset, 110, 24, 162, and 1 patients were classified as having HBV subgenotypes B2, C1, C2, or other, respectively, compared to 222, 146, 282, and 51 in the validation dataset, respectively. Patients infected with subgenotype C1 showed a higher virologic response rate and hepatitis B envelope antigen seroconversion rate, and lower genotypic resistance rate than those infected with subgenotypes B2 and C2. Patients with genotypic resistance to telbivudine with subgenotype C1 showed fewer secondary mutations. The crystal structure model of reverse transcriptase showed that these secondary mutations were located around the YMDD motif, which possibly influenced the chance of mutations at rtM204.

CONCLUSION

Hepatitis B virus subgenotype C1 is associated with better antiviral response to nucleoside analogs in hepatitis B envelope antigen-positive patients than B2 and C2 subgenotypes. The exact mechanism needs to be explored further.

Novel HBV recombinants between genotypes B and C in 3'-terminal reverse transcriptase (RT) sequences are associated with enhanced viral DNA load, higher RT point mutation rates and place of birth among Chinese patients

As one of the major global public health concerns, hepatitis B virus (HBV) can be divided into at least eight genotypes, which may be related to disease severity and treatment response. We previously demonstrated that genotypes B and C HBV, with distinct geographical distribution in China, had divergent genotype-dependent amino acid polymorphisms and variations in reverse transcriptase (RT) gene region, a target of antiviral therapy using nucleos(t)ide analogues. Recently recombination between HBV genotypes B and C was reported to occur in the RT region. However, their frequency and clinical significance is poorly understood. Here full-length HBV RT sequences from 201 Chinese chronic hepatitis B (CHB) patients were amplified and sequenced, among which 31.34% (63/201) were genotype B whereas 68.66% (138/201) genotype C. Although no intergenotypic recombination was detected among C-genotype HBV, 38.10% (24/63) of B-genotype HBV had recombination with genotype C in the 3'-terminal RT sequences. The patients with B/C intergenotypic recombinants had significantly (P<0.05) higher serum HBV DNA level than the "pure" B-genotype cohort did. Moreover, the B/C intergenotypic recombinants were prone to more substitutions at several specific residues in the RT region than genotype B or C. Besides, unlike their parental genotypes, the recombinant HBV appeared to display an altered geographic distribution feature in China. Our findings provide novel insight into the virological, clinical and epidemiological features of new HBV B/C intergenotypic recombinants at the 3' end of RT sequences among Chinese CHB patients. The highly complex genetic background of the novel recombinant HBV carrying new mutations affecting RT protein may contribute to an enhanced heterogeneity in treatment response or prognosis among CHB patients.

Efficacy and safety of entecavir versus lamivudine over 5 years of treatment: A randomized controlled trial in Korean patients with hepatitis B e antigen-negative chronic hepatitis B

BACKGROUND/AIMS

Long-term data on antiviral therapy in Korean patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) are limited. This study evaluated the efficacy and safety of entecavir (ETV) and lamivudine (LAM) over 240 weeks.

METHODS

Treatment-naive patients with HBeAg-negative CHB were randomized to receive ETV 0.5 mg/day or LAM 100 mg/day during the 96 week double-blind phase, followed by open-label treatment through week 240. The primary endpoint was the proportion of patients with virologic response (VR; hepatitis B virus [HBV] DNA<300 copies/mL) at week 24. Secondary objectives included alanine aminotransferase (ALT) normalization and emergence of ETV resistance (week 96), VR and log reduction in HBV DNA levels (week 240), and safety evaluation.

RESULTS

In total, 120 patients (>16 years old) were included (ETV, n=56; LAM, n=64). Baseline characteristics were comparable between the two groups. A significantly higher proportion of ETV-treated patients achieved VR compared to LAM at week 24 (92.9% vs. 67.2%, P=0.0006), week 96 (94.6% vs. 48.4%, P<0.0001), and week 240 (95.0% vs. 47.6%, P<0.0001). At week 96, ALT normalization was observed in 87.5% and 51.6% of ETV and LAM patients, respectively (P<0.0001). Virologic breakthrough occurred in one patient (1.8%) receiving ETV and 26 patients (42.6%) receiving LAM (P<0.0001) up to week 96. Emergence of resistance to ETV was not detected. The incidence of serious adverse events was low and unrelated to the study medications.

CONCLUSIONS

Long-term ETV treatment was superior to LAM, with a significantly higher proportion of patients achieving VR. Both treatments were well tolerated.

The virological aspects of hepatitis B

Human hepatitis B virus (HBV) is a hepatotropic virus that is responsible for a significant burden of disease, causing liver disease and hepatocellular carcinoma. It is a small DNA virus with a replication strategy that is similar to that of a retrovirus. HBV is prone to mutagenesis and under the influence of diverse selection pressures, has evolved into a pool of quasispecies, genotypes and mutants, which confers a significant survival advantage. The genome is small, circular, and compact but has a complex replication strategy. The viral life cycle involves the formation of a covalently closed circular DNA (cccDNA), which is organized into a minichromosome that is the template for the synthesis of viral mRNA. HBV DNA (double-stranded linear form) can also integrate into the host genome, ensuring lifelong persistence of the virus. To date, despite great advances in therapeutics, once HBV is chronically established, it is incurable. This is by virtue of many aspects of its virological structure and viral life cycle. In this review, we aim to discuss important aspects of the virology of HBV with a focus on clinical implications.

Impact of FIB-4 index on hepatocellular carcinoma incidence during nucleos(t)ide analogue therapy in patients with chronic hepatitis B: An analysis using time-dependent receiver operating characteristic

BACKGROUND AND AIM

Nucleos(t)ide analogue (NA) therapy has been reported to reduce the risk of hepatocellular carcinoma (HCC) development in patients with chronic hepatitis B (CHB). However, even during NA therapy, development of HCC has been observed in patients with CHB. Therefore, we clarified the predictive power of clinical factors for HCC incidence using receiver operating characteristic (ROC) analysis that takes time dependence into account.

METHODS

A total of 539 patients with CHB treated with NAs were enrolled. Univariate, multivariate, and time-dependent ROC curves for clinical factors associated with the development of HCC were analyzed.

RESULTS

Eighty-one patients developed HCC during the follow-up period (median duration, 5.9 years). α-fetoprotein (AFP) and FIB-4 index at 24 weeks from the initiation of treatment and sex were significantly associated with HCC incidence according to the log-rank test. Cox proportional hazards models including the covariates of sex, hepatitis B genotype, basal core promoter mutations, AFP at 24 weeks, and FIB-4 index at 24 weeks showed that FIB-4 index >2.65 (HR, 5.03; 95% CI, 3.06-8.26; P < 0.001) and male sex were independently associated with HCC incidence. In addition, time-dependent ROC analysis showed that compared with AFP at 24 weeks, FIB-4 index at 24 weeks had higher predictive power for HCC incidence throughout the follow-up period.

CONCLUSIONS

Elevated FIB-4 index at 24 weeks in patients with CHB receiving NA therapy is a risk factor for developing HCC. The FIB-4 index is an excellent predictor of HCC development.

Treatment outcomes and validation of the stopping rule for response to peginterferon in chronic hepatitis B: A Thai nationwide cohort study

BACKGROUND AND AIMS

Peginterferon has demonstrated effectiveness in clinical trials in patients with chronic hepatitis B (CHB). However, its efficacy in real-life settings remains unclear. We investigated the efficacy of peginterferon for CHB and validated the performance of previously identified response predictors in clinical practice.

METHODS

We analyzed prospectively collected data from a Thai nationwide cohort of CHB patients treated with peginterferon alfa-2a (180 µg/week, 48 weeks).

RESULTS

Among a total of 233 patients, mostly with genotype B or C, sustained response was observed in 23% of 135 hepatitis B e antigen (HBeAg)-positive patients (HBeAg seroconversion with hepatitis B virus [HBV] DNA < 2000 IU/mL) and 42% of 98 HBeAg-negative patients (HBV DNA < 2000 IU/mL with aminotransferase normalization) at 24 weeks after treatment. Age, sex, presence of cirrhosis, genotype, and pretreatment levels of aminotransferase, HBV DNA, and hepatitis B surface antigen (HBsAg) were not identified as significant predictors of sustained response. In HBeAg-positive patients, HBsAg > 20 000 IU/mL at week 12 provided a good stopping rule, with a negative predictive value of 96%. In HBeAg-negative patients, the performance of 12-week stopping rules of no decline in HBsAg with a < 2log₁₀ decline in HBV DNA and a < 10% log₁₀ decline in HBsAg showed modest negative predictive values of 80% and 66%, respectively, for achieving sustained response.

CONCLUSION

Outcomes in CHB patients treated with peginterferon in a clinical setting are similar to those demonstrated in clinical trials. Application of the early stopping rule based on HBsAg quantification may allow individualization of therapy, particularly in HBeAg-positive patients.

Current role of transient elastography in the management of chronic hepatitis B patients

Liver fibrosis is an important prognostic factor for chronic hepatitis B (CHB), and accurate evaluation of the stage of liver fibrosis is crucial in establishing management strategies. While liver biopsy is still considered the gold standard for staging liver fibrosis or cirrhosis, transient elastography (TE), a noninvasive means of assessing liver fibrosis, has come to play an increasing role in this process. After extensive validation, TE is now regarded as a reliable surrogate maker for grading the severity of liver fibrosis in CHB patients. It can detect the extent of fibrosis in a patient and can also be used to evaluate longitudinal changes in liver fibrosis over time with or without interventional management, such as antiviral therapy. However, several confounders hinder the effective assessment of liver fibrosis using TE, such as extensive liver necroinflammation, hepatic congestion, and cholestasis. TE has limited use in obese patients or patients with ascites. Although TE has several limitations, due to its accessibility and safety, it is a valuable tool for the initial evaluation and follow-up in patients with CHB.

Diagnosis of hepatitis B

Hepatitis B virus (HBV) infection is a major global health problems leading to severe liver disease such as cirrhosis and hepatocellular carcinoma (HCC). HBV is a circular, partly double-stranded DNA virus with various serological markers: hepatitis B surface antigen (HBsAg) and anti-HBs, anti-HBc IgM and IgG, and hepatitis B e antigen (HBeAg) and anti-HBe. It is transmitted by sexual, parenteral and vertical route. One significant method to diminish the burden of this disease is timely diagnosis of acute, chronic and occult cases of HBV. First step of HBV diagnosis is achieved by using serological markers for detecting antigens and antibodies. In order to verify first step of diagnosis, to quantify viral load and to identify genotypes, quantitative or qualitative molecular tests are used. In this article, the serological and molecular tests for diagnosis of HBV infection will be reviewed.

Treatment strategies according to genotype for chronic hepatitis B in children

This review article was requested by editor-in-chief of this journal as 'pediatric CHB treatment' for the upcoming special issue. The main objective of chronic hepatitis B (CHB) treatment is diminishing the risk of complications related to chronic liver disease. In Asia, there are already some reports about hepatocellular carcinoma (HCC) in hepatitis B virus (HBV) infected children. The key points of treatment in children with CHB infections are selection of which patients to treat and conformation of the optimal therapy time that would reduce viral resistance. The choice of therapy is determined by the district (Western/Eastern), HBV genotype, medical accessibility, and economic state of the country. Newly developed nucleos(t)ide analogues (NAs) are potent in children with CHB. However, to improve therapeutic efficacy, physicians are recommended to follow treatment guidelines and determine the specific genotype in the CHB patient. In this article, the treatment of pediatric CHB is reviewed according to differences in genotype.

Molecular dissection of HBV evasion from restriction factor tetherin: A new perspective for antiviral cell therapy

Viruses have evolved various strategies to escape from the innate cellular mechanisms inhibiting viral replication and spread. Extensive evidence has highlighted the ineffectiveness of interferon (IFN) therapy against chronic hepatitis B virus (HBV) infection, implying the existence of mechanisms by which HBV evades IFN-induced antiviral responses. In our current study, we demonstrate that HBV surface protein (HBs) plays a crucial role in counteracting the IFN-induced antiviral response mediated by tetherin (also known as BST-2). The type I IFN treatment of HBV-producing cells marginally but significantly inhibited the release of HBsAg and viral DNA, but this release was recovered by the knockdown of tetherin. HBs can interact with tetherin via its fourth transmembrane domain thereby inhibiting its dimerization and antiviral activity. The expression of a tetherin mutant devoid of the HBs-binding domain promoted a prominent restriction of HBV particle production that eventually resulted in the alleviation of caspase-1-mediated cytotoxicity and interleukin-1β secretion in induced pluripotent stem cell (iPSC)-derived hepatocytes. Our current results thus reveal a previously undescribed molecular link between HBV and tetherin during the course of an IFN-induced antiviral response. In addition, strategies to augment the antiviral activity of tetherin by impeding tetherin-HBs interactions may be viable as a therapeutic intervention against HBV.

Stronger enhancer II/core promoter activities of hepatitis B virus isolates of B2 subgenotype than those of C2 subgenotype

Hepatitis B virus (HBV) genotype C causes prolonged chronic infection and increased risk for liver cancer than genotype B. Our previous work revealed lower replication capacity of wild-type genotype C2 than B2 isolates. HBV DNA replication is driven by pregenomic RNA, which is controlled by core promoter (CP) and further augmented by enhancer I (ENI) and enhancer II (ENII). DNA fragments covering these regulatory elements were amplified from B2 and C2 isolates to generate luciferase reporter constructs. As ENII is fully embedded in CP, we inserted HBV DNA fragments in the sense orientation to determine their combined activities, and in the antisense orientation to measure enhancer activities alone. Genotype B2 isolates displayed higher ENI+ENII+CP, ENII+CP, and ENII activities, but not ENI or ENI+ENII activity, than C2 isolates. The higher ENII+CP activity was partly attributable to 4 positions displaying genotype-specific variability. Exchanging CP region was sufficient to revert the replication phenotypes of several B2 and C2 clones tested. These results suggest that a weaker ENII and/or CP at least partly accounts for the lower replication capacities of wild-type C2 isolates, which could drive the subsequent acquisition of CP mutations. Such mutations increase genome replication and are implicated in liver cancer development.

HBcrAg predicts hepatocellular carcinoma development: An analysis using time-dependent receiver operating characteristics

BACKGROUND & AIMS

Several hepatitis B virus (HBV) markers have been identified as factors associated with the development of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). We clarified the predictive power of HBV markers for the development of HCC using receiver operating characteristic (ROC) analysis with a consideration of time dependence.

METHODS

A total of 1031 CHB patients who were not treated with nucleos(t)ide analogue therapy were enrolled. Univariate, multivariate, and time-dependent ROC curves for HBV markers associated with the development of HCC were analyzed.

RESULTS

Seventy-eight patients developed HCC during the follow-up period (median duration 10.7years). Different levels or statuses of several HBV markers (HBV genotype, HBV DNA, HBV core-related antigen (HBcrAg), hepatitis B e antigen (HBeAg), and basal core promoter (BCP)), but not hepatitis B surface antigen, were significantly associated with the incidence of HCC by univariate analysis using the log-rank test. Cox proportional hazards models using the covariates of HBV genotype status, HBV DNA levels, HBcrAg levels, HBeAg status, and BCP status indicated that HBcrAg >2.9logU/ml (hazard ratio (HR), 5.05; 95% confidence interval (CI), 2.40-10.63) and BCP mutation (HR, 28.85; 95% CI, 4.00-208.20) were independently associated with the incidence of HCC. Additionally, time-dependent ROC analysis showed that HBcrAg was superior to HBV DNA in terms of predictive power for HCC development throughout the follow-up period.

CONCLUSIONS

Elevation of HBcrAg levels in CHB patients is associated with the development of HCC. HBcrAg is an excellent predictor of HCC development.

LAY SUMMARY

Hepatitis B virus (HBV) core-related antigen (HBcrAg) is an excellent predictor of hepatocellular carcinoma (HCC) development in chronic hepatitis B patients without nucleos(t)ide analogue therapy. HBcrAg was superior to HBV DNA in terms of predictive power for HCC development by time-dependent receiver operating characteristic analysis.

Cell Culture, Technology: Enhancing the Culture of Diagnosing Human Diseases

Cell culture involves a complex of processes of cell isolation from their natural environment (in vivo) and subsequent growth in a controlled environmental artificial condition (in vitro). Cells from specific tissues or organs are cultured as short term or established cell lines which are widely used for research and diagnosis, most specially in the aspect of viral infection, because pathogenic viral isolation depends on the availability of permissible cell cultures. Cell culture provides the required setting for the detection and identification of numerous pathogens of humans, which is achieved via virus isolation in the cell culture as the "gold standard" for virus discovery. In this review, we summarized the views of researchers on the current role of cell culture technology in the diagnosis of human diseases. The technological advancement of recent years, starting with monoclonal antibody development to molecular techniques, provides an important approach for detecting presence of viral infection. They are also used as a baseline for establishing rapid tests for newly discovered pathogens. A combination of virus isolation in cell culture and molecular methods is still critical in identifying viruses that were previously unrecognized. Therefore, cell culture should be considered as a fundamental procedure in identifying suspected infectious viral agent.

Virological and serological tools to optimize the management of patients with chronic hepatitis B

Molecular biology techniques are routinely used to diagnose and monitor treatment in patients with chronic hepatitis B (CHB). These tools can detect and quantify viral genomes and analyse their sequences to determine genotype. The increasing use of these tools to monitor patients has greatly improved the management of CHB infection by maximizing the potential for individualized treatment. HBV genotyping has become increasingly important and provides additional information to predict a response to therapy. More sensitive methods to determine HBV DNA levels are now available and the units of measurements have been standardized. HBsAg levels in serum have been shown to reflect active intrahepatic covalently closed circular DNA (cccDNA) and to have additional value in treatment decisions, especially as an on-treatment marker.