Hepatitis B virus genotype-associated variability in antiviral response to adefovir dipivoxil therapy in Chinese Han population

A CRISPR-Cas12b-Based Platform for Ultrasensitive, Rapid, and Highly Specific Detection of Hepatitis B Virus Genotypes B and C in Clinical Application

Hepatitis B virus (HBV) is one of the most dangerous and prevalent agents that causes acute and chronic liver diseases in humans. Genotyping plays an important role in determining clinical outcomes and response to antiviral treatment in HBV-infected patients. Here, we first devised a CRISPR-based testing platform, termed "CRISPR-HBV," for ultrasensitive, highly specific, and rapid detection of two major HBV genotypes (HBV-B and HBV-C) in clinical application. The CRISPR-HBV employed multiple cross displacement amplification (MCDA) for rapid preamplification and then Cas12b-based detection for decoding the targets. Finally, the detection result was read out with real-time fluorescence and a lateral flow biosensor. The sensitivity of CRISPR-HBV was 10 copies per test. The specificity was one hundred percent, and no cross reactions were observed in other HBV genotypes and pathogens. The whole detection process, including DNA template extraction (15 min), preamplification reaction of MCDA (30 min at 65°C), CRISPR-Cas12b-based detection (5 min at 37°C), and results readout (∼2 min), could be completed within 1 h. The feasibility of the CRISPR-HBV assay for genotyping HBV-B and -C as successfully validated with clinical samples. Hence, the CRISPR-HBV assay has remarkable potential to develop a point-of-care testing for identifying and distinguishing HBV genotypes B and C in clinical settings, especially in resource-scarcity countries.

Novel subgenotype D11 of hepatitis B virus in NaPo County, Guangxi, bordering Vietnam

Hepatitis B virus has been classified into 10 genotypes and 48 subgenotypes worldwide. We found previously, through polymerase chain reaction (PCR) amplification of a sample collected in 2011, that an HBsAg carrier was infected with two genotypes (B and D) of HBV. We carried out cloning, sequencing and phylogenetic analysis of the complete genomes and, for confirmation, analysed a sample collected from the same individual in 2018. Fifteen complete sequences were obtained from each sample. The carrier was infected in 2011 by genotypes B and D and by various recombinants, but only genotype D was present in 2018. The major and minor parents of the recombinants are genotypes B and D, respectively, although the recombination breakpoints vary among them. All 23 genotype D isolates form a cluster, branching out from other subgenotype D sequences and supported by a 100 % bootstrap value. Based on complete genome sequences, almost all of the estimated intragroup nucleotide divergence values between our isolates and HBV subgenotypes D1-D10 exceed 4 %. Compared to the other subgenotypes (D1-D10), 35 unique amino acids were present in our isolates. Our data provide evidence for a novel subgenotype, provisionally designated HBV subgenotype D11.

Mutations in the S gene and in the overlapping reverse transcriptase region in chronic hepatitis B Chinese patients with coexistence of HBsAg and anti-HBs

Background

The mechanism underlying the coexistence of hepatitis B surface antigen and antibodies to HBsAg in chronic hepatitis B patients remains unknown.

Aims

This research aimed to determine the clinical and virological features of the rare pattern.

Methods

A total of 32 chronic hepatitis B patients infected by HBV genotype C were included: 15 carrying both HBsAg and anti-HBs (group I) and 17 solely positive for HBsAg (group II). S gene and reverse transcriptase region sequences were amplified, sequenced and compared with the reference sequences.

Results

The amino acid variability within major hydrophilic region, especially the “a” determinant region, and within reverse transcriptase for regions overlapping the major hydrophilic region in group I is significantly higher than those in group II. Mutation sI126S/T within the “a” determinant was the most frequent change, and only patients from group I had the sQ129R, sG130N, sF134I, sG145R amino acid changes, which are known to alter immunogenicity.

Conclusions

In chronic patients, the concurrent HBsAg/anti-HBs serological profile is associated with an increased aa variability in several key areas of HBV genome. Additional research on these genetic mutants are needed to clarify their biological significance for viral persistence.

Effect of hepatitis B virus genotypes on the efficacy of adefovir dipivoxil antiviral therapy

BACKGROUND

Hepatitis B is a common infectious disease in China. Many studies have shown that the genotype of hepatitis B virus (HBV) is probably associated with the efficacy of some antiviral drugs such as interferon α (IFN-α) and Lamivudine (LAM). However, the association between HBV genotype and adefovir dipivoxil (ADV) is controversial. ADV is the most popular antiviral drug in China due to its low price, good antiviral efficacy, few side effects, and convenient of administration.

OBJECTIVES

This study focused on the effect of HBV genotypes on antiviral efficacy of ADV in patients with chronic hepatitis B infection (CHB).

PATIENTS AND METHODS

A total of 526 HBeAg-positive patients with CHB were randomly allocated into two groups. One group took ADV and another group took placebo. Nested Polymerase Chain Reaction (PCR) with multiple pairs of genotype-specific primers (nPCR-MPP) was used to analyze genotypes of HBV in these patients. Antiviral efficacy after treatment for three, six, 12 months was compared among the patients with different HBV genotypes.

RESULTS

Genotype B (73.6%) and genotype C (26.4%) were detected in these patients. After treatment for 12 months, the rate of HBV DNA seroclearance, ALT normalization, and HBeAg seroconversion were significantly higher in ADV group than in placebo group (P < 0.05). However, there were no significant differences in these three rates between patients infected with genotype B and C (P > 0.05).

CONCLUSIONS

HBV genotypes B and C have no significant difference in virologic, biochemical, and immunologic response to ADV.

Optimization therapy for the treatment of chronic hepatitis B

Chronic hepatitis B (CHB) is currently medically managed with either interferon-alpha or one of the five nucleos(t)ide analogs. However, there are still a large number of CHB patients whose response to the above therapies remains less than satisfactory, and their incomplete or non-response to antiviral therapies has plagued clinicians worldwide. In recent years, a newly proposed optimization therapy has provided us with a new approach to solve this problem. The key points in this optimization therapy are to initiate antiviral therapy with an appropriate agent at the correct time point, and to adjust treatments in patients with poor early responses by adding a second agent or switching to another more potent agent. In this review, we summarize recent developments in optimization therapy for the treatment of CHB, and provide an outlook for future research in this field.

HBV genotype B/C and response to lamivudine therapy: a systematic review

A number of nucleoside analogues such as lamivudine (LAM), actually used for the treatment of chronic hepatitis B, can suppress HBV DNA replication, improve transaminase level and liver histology, and enhance the rate of hepatitis B e antigen (HBeAg) clearance. The responses to LAM therapy involve HBeAg clearance and HBV DNA conversion of negative. However, the associations between HBV genotype B/C and response to LAM therapy remain ambiguous. The aim of this meta-analysis is to determine more precise estimations of the relationship. All the publications on the associations between HBV genotype B/C and response to LAM (HBeAg clearance and HBV DNA conversion of negative) through June 2013 were collected. Relative risk (RR) with 95% confidence intervals (95% CI) was calculated in fixed or random model, I² was calculated to examine heterogeneity, and funnel plots were plotted to examine small study effects with Stata 11 software. Overall, for HBeAg clearance and genotype B/C, the RR (95% CI) was 1.27 (0.94–1.71), while for HBV DNA conversion of negative and genotype B/C, the RR (95% CI) was 1.07 (0.98–1.17). HBV genotype B/C shows no significance associations with response to lamivudine therapy (HBeAg clearance and HBV DNA conversion of negative).

Binding sensitivity of adefovir to the polymerase from different genotypes of HBV: molecular modeling, docking and dynamics simulation studies

AIM

To investigate the molecular mechanisms underlying the influence of DNA polymerase from different genotypes of hepatitis B virus (HBV) on the binding affinity of adefovir (ADV).

METHODS

Computational approaches, including homology modeling, docking, MD simulation and MM/PBSA free energy analyses were used.

RESULTS

Sequence analyses revealed that residue 238 near the binding pocket was not only a polymorphic site but also a genotype-specific site (His238 in genotype B; Asn238 in genotype C). The calculated binding free-energy supported the hypothesis that the polymerase from HBV genotype C was more sensitive to ADV than that from genotype B. By using MD simulation trajectory analysis, binding free energy decomposition and alanine scanning, some energy variation in the residues around the binding pocket was observed. Both the alanine mutations at residues 236 and 238 led to an increase of the energy difference between genotypes C and B (ΔΔG(C-B)), suggesting that these residues contributed to the genotype-associated antiviral variability with regard to the interaction with ADV.

CONCLUSION

The results support the hypothesis that the HBV genotype C polymerase is more sensitive to ADV than that from genotype B. Moreover, residue N236 and the polymorphic site 238 play important roles in contributing to the higher sensitivity of genotype C over B in the interaction with ADV.

Nucleos(t)ide analogues treatment outcome in genotype B and C chronic hepatitis B

Background:

Hepatitis B genotypes influence the course and severity of the disease.

Aim:

To compare the treatment outcome of chronic hepatitis B genotype B and C patients after treating with nucleos(t)ide analogues for six months.

Patients and Methods:

Forty chronic hepatitis B patients attending the liver clinic of Hospital for Tropical diseases, Bangkok, were studied in retrospective cohort design. Six genotype B patients (15%) and thirty-four genotype C patients (85%) were treated. Serum hepatitis B viral load, serum alanine amino transferase level, HBeAg status and alpha-feto protein level were measured at the time of starting nucleos(t) analogues therapy, and six months later. Besides, achievement of undetectable viral load was assessed in patients with normal serum alanine amino transferase compared to patients with high serum alanine amino transferase level.

Results:

After six months of nucleos (t) analogues treatment, achievement of undetectable hepatitis B viral load was higher in genotype B patients (66.7%) than in genotype C patients (42.4%) (Relative Risk=1.57, 0.79-3.14). Biochemical remission, HBeAg seroconversion and tumor marker levels between the two groups were not significantly different. Moreover, achievement of undetectable hepatitis B viral load was significantly higher in normal alanine amino transferase level (75%) than in patients with high serum alanine amino transferase level (33.3%) on nucleos(t)ide analogue treatment (Relative Risk=2.25, 1.20- 4.20).

Conclusion:

Chronic hepatitis B treatment outcome between genotype B and C were not significantly different. Patients with normalized serum alanine amino transferase level tend to achieve undetectable viral load after nucleoside analogues treatment.

Factors predicting the efficacy of adefovir dipivoxil on treatment-naïve chronic hepatitis B patients at 48 weeks

Background/Aims

To reveal possible factors predicting the effect of adefovir dipivoxil (ADV) treatment on chronic hepatitis B (CHB) and optimize the utilization of ADV.

Methods

In total, 168 treatment-naïve CHB patients were enrolled, including 117 hepatitis B e antigen (HBeAg)-positive patients and 51 HBeAg-negative patients who met the inclusion criteria. All patients were treated with ADV 10 mg per day for 48 weeks. Multiple logistic regression analyses were used to investigate baseline factors, and responses at weeks 12 and 24 were analyzed as predictive values.

Results

Multiple regression analyses showed that baseline HBeAg status and HBV DNA levels significantly affected the virological response (VR) (p<0.05), baseline ALT levels were an independent predictor of serological response (SR) (p<0.05) and the body mass index (BMI) may affect the biochemical response (BR) (p<0.05). There was a statistically significant difference in the VR and SR between patients with a primary nonresponse (PNR) at week 12 and those with a VR at week 12 (p<0.01). Additionally, the VR was significantly different between patients with HBV DNA lower than 10³ copies/mL at week 24 and those with greater than 10³ copies/mL (p<0.01).

Conclusions

Patients with negative HBeAg, lower HBV DNA levels and higher ALT values at baseline are more suitable for ADV treatment, whereas patients with lower BMIs may be more amenable to ALT normalization. Adjustments for treatment strategy should be considered if PNR at week 12 or HBV DNA ≥10³ copies/mL at week 24 is observed.

Hepatitis B virus genotypes

Hepatitis B virus (HBV) is a member of the hepadnavirus family and can lead to severe liver disease. HBV has a very high genetic variability. Currently, eight genotypes of HBV have been recognized, and most genotypes are now divided into subgenotypes with distinct virological and epidemiological properties. In addition, recombination among HBV genotypes increases the variability of HBV. This review summarizes current knowledge of the epidemiology of genetic variability in hepadnaviruses and, due to rapid progress in the field, updates several recent reviews on HBV genotypes and subgenotypes.

Th1 and Th2 immune response in chronic hepatitis B patients during a long-term treatment with adefovir dipivoxil

Adefovir dipivoxil treatment has significantly improved the outcome of chronic hepatitis B virus (HBV) infection. However, it remains largely unknown how immune system responds to the treatment. Chronic HBV patients were treated with adefovir dipivoxil and examined for serum HBV DNA loads, cytokines, and T helper (Th1) and 2 (Th2) cytokine producing T cells during 104 weeks of the treatment. Th1/Th2 cytokines producing T cells were significantly lower in chronic HBV patients as compared to normal individuals. Adefovir dipivoxil treatment led to the increase of Th1/Th2 cytokines producing T cells and serum cytokine levels in association with the decline of HVB DNA load. In contrast, Th1/Th2 cytokines producing T cells remained lower in one patient detected with adefovir dipivoxil resistant HBV A181T/V mutation. This study has established inverse correlation of the increase of Th1/Th2 immunity and the decline of HBV DNA load in chronic HBV patients during adefovir dipivoxil treatment.

Simultaneous genotyping and quantification of hepatitis B virus for genotypes B and C by real-time PCR assay

Hepatitis B virus (HBV) is an important cause of human chronic liver diseases and is a major public health problem. Viral load and HBV genotype play critical roles in determining clinical outcomes and response to antiviral treatment in hepatitis B patients. Viral genotype detection and quantification assays are currently in use with different levels of effectiveness. In this study, the performance of a real-time genotyping and quantitative PCR (GQ-PCR)-based assay was evaluated. Through the use of genotype-specific primers and probes, this assay provides simultaneous identification and quantification of genotypes B and C in a single reaction. Our GQ-PCR correctly identified all predefined genotypes B and C, and no cross-reaction between genotypes B and C were observed. The GQ-PCR identified more cases of HBV infections with mixed genotypes B and C than direct sequencing did. Samples from 127 HBV-infected Chinese patients were genotyped with GQ-PCR, revealing 56.7% HBV as genotype B, 13.4% as genotype C, and 29.8% as mixed genotypes B and C. This assay provides a reliable, efficient, and cost-effective means for quantification of the B and C genotypes of HBV in single or mixed infections. This assay is suitable for sequential monitoring of viral load levels and for determining the relationship between the genotype viral load and stage of disease in Asians.

Prevalence of hepatitis B virus genotypes and their relationship to clinical laboratory outcomes in Tibetan and Han Chinese

This study was designed to investigate the prevalence of hepatitis B virus (HBV) genotypes in Tibetan and Han nationalities in Sichuan Province, China, and their clinical significance. Sera from 376 patients (286 Han nationals, 90 Tibetan nationals) were genotyped by polymerase chain reaction. Of the 286 Han nationals, 127 were HBV asymptomatic carriers, 90 were symptomatic patients and 69 had hepatocellular carcinoma. The distribution of HBV genotypes was related to geography as well as ethnicity. The HBV genotype frequencies were: B, 57.9%; C, 16.0%; and BC, 26.1%. Association studies between genotypes and clinical laboratory outcomes showed HBV genotype C to be more virulent. There was a higher prevalence of mixed genotype BC in Tibetan nationals compared with Han nationals. There was no synergistic effect in terms of virulence in patients coinfected with genotypes B and C.

Hepatitis B therapy in children

Chronic hepatitis B virus (HBV) infection is a major cause of liver disease throughout the world, leading to cirrhosis and hepatocellular carcinoma in many individuals. Children are more likely to develop chronic HBV infection as they demonstrate greater immunotolerance to the virus, and response to therapy in children remains disappointing. Three therapeutic agents for chronic HBV infection in children have been approved in the USA, including standard IFN-alpha, lamivudine and adefovir. IFN-alpha has been the most effective ( approximately 30% hepatitis B e antigen [HBeAg] seroconversion; 10% hepatitis B surface antigen [HBsAg] seroconversion), although benefits are primarily observed in children with alanine aminotransferase levels over two-times the upper limit of normal and must be weighed against significant side effects. Studies comparing the long-term outcome of chronic hepatitis B in children treated with IFN-alpha and in untreated controls show that the rate of anti-HBeAb seroconversion tends to overlap in treated and untreated patients within a few years of follow-up, suggesting that IFN-alpha simply accelerates a spontaneous event. Lamivudine's virologic response rates mirror those of IFN-alpha (23-31% HBeAg seroconversion) with easier administration and a better safety profile but lower HBsAg seroconversion (2-3%) and high rates of drug resistance. Adefovir data show low rates of resistance and a good safety profile, but virologic response was limited to adolescent patients and was lower than that of lamivudine (16% HBeAg seroconversion; <1% HBsAg seroconversion). Entecavir and tenofovir, both approved therapies for adults with chronic HBV infection, are in trials for use in children. Future therapies will probably include these agents as well as combined therapies. Finally, watchful waiting of children is an option since current therapies are only 30% effective at best, although the long-term impact of therapy in childhood on rates of cirrhosis and hepatocellular carcinoma remains unknown.