Detection of hepatitis B virus genotypes using oligonucleotide chip among hepatitis B virus carriers in Eastern China

A Recent Prevalence of Hepatitis B Virus (HBV) Genotypes and Subtypes in Asia: A Systematic Review and Meta-Analysis

Background and Aim: Despite introducing the hepatitis B virus (HBV) vaccine, the incidence of the Hepatitis B virus globally is still a major health concern. This systematic review and meta-analysis were conducted to provide detailed information on the prevalence of HBV genotypes and subtypes in circulation in Asia. Methods: A systematic search for articles describing the prevalence of HBV genotypes and subtypes in Asia was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Results: Our search returned 207 eligible articles involving 49,279 genotypes and 7457 subtypes representing 28 Asian countries. A meta-analysis was performed on our eligible studies using the Random effect Model. The pooled prevalence of HBV genotypes showed that genotype C (30.9%) (95% CI, 27.5–34.5%; I2 = 97.57%; p < 0.001) was the most common HBV genotype in Asia, followed by genotype B (17.8%) (95% CI, 15.5–20.4%; I2 = 97.26%; p < 0.001) and genotype D (15.4%) (95% CI, 11.8–19.8%). Vietnam had the highest prevalence of genotype B, Lebanon had the highest prevalence of genotypes C, and Jordan had the highest prevalence of genotype D. There was variation in genotypic prevalence with respect to the target genes for HBV genotyping. Reverse dot blot hybridization had the highest estimate of genotypes B and C. HBV subtype C2 (40.0%) (95% CI, 33.3–47.0) is the most prevalent HBV subtype. Conclusion: Evidence from this study reveals that HBV genotypes C and B are the most dominant HBV genotypes in Asia, and HBV subtype C2 is more endemic in Asia.

Ultrasensitive amplification refractory mutation system real-time PCR (ARMS RT-PCR) assay for detection of minority hepatitis B virus-resistant strains in the era of personalized medicine

Resistance to antiviral treatment for chronic hepatitis B virus (HBV) has been associated with mutations in the HBV polymerase region. This study aimed at developing an ultrasensitive method for quantifying viral populations with all major HBV resistance-associated mutations, combining the amplification refractory mutation system real-time PCR (ARMS RT-PCR) with a molecular beacon using a LightCycler. The discriminatory ability of this method, the ARMS RT-PCR with molecular beacon assay, was 0.01 to 0.25% for the different HBV resistance-associated mutations, as determined by laboratory-synthesized wild-type (WT) and mutant (Mut) target sequences. The assay showed 100% sensitivity for the detection of mutant variants A181V, T184A, and N236T in samples from 41 chronically HBV-infected patients under antiviral therapy who had developed resistance-associated mutations detected by direct PCR Sanger sequencing. The ratio of mutant to wild-type viral populations (the Mut/WT ratio) was >1% in 38 (63.3%) of 60 samples from chronically HBV-infected nucleos(t)ide analogue-naive patients; combinations of mutations were also detected in half of these samples. The ARMS RT-PCR with molecular beacon assay achieved high sensitivity and discriminatory ability compared to the gold standard of direct PCR Sanger sequencing in identifying resistant viral populations in chronically HBV-infected patients receiving antiviral therapy. Apart from the dominant clones, other quasispecies were also quantified. In samples from chronically HBV-infected nucleos(t)ide analogue-naive patients, the assay proved to be a useful tool in detecting minor variant populations before the initiation of the treatment. These observations need further evaluation with prospective studies before they can be implemented in daily practice.

Development of a novel DNA sequencing method not only for hepatitis B virus genotyping but also for drug resistant mutation detection

Background

In HBV-infected patients, different genotypes of the hepatitis B virus influence liver disease progression and response to antiviral therapy. Moreover, long-term antiviral therapy will eventually select for drug-resistant mutants. Detection of mutations associated to antiviral therapy and HBV genotyping are essential for monitoring treatment of chronic hepatitis B patients.

Results

In this study, a simple method of partial-S gene sequencing using a common PCR amplification was established for genotyping clinical HBV isolates sensitively, which could detect the drug-resistant mutations successfully at the same time.

Conclusions

The partial S gene sequencing assay developed in this study has potential for application in HBV genotyping and drug resistant mutation detection. It is simpler and more convenient than traditional S gene sequencing, but has nearly the same sensitivity and specificity when compared to S gene sequencing.

Molecular methods in the diagnosis and management of chronic hepatitis B

Chronic hepatitis B (CHB) infection remains a major global problem but the recent advances in molecular methods have revolutionized the diagnosis and management of CHB. Hepatitis B virus (HBV) DNA quantitation is the most useful molecular marker for the diagnosis and management of CHB. There is increasing evidence that the clinical outcome and efficacy of antiviral therapy for CHB could vary with the infecting HBV genotype, core promoter and precore mutations. Early identification of drug resistance is imperative in the management of CHB. The molecular methods for HBV DNA quantitation, HBV genotyping, the identification of mutants, genotypic and phenotypic methods for monitoring drug resistance and their utility and limitations for use in the diagnosis and monitoring of CHB are discussed in this article.

Robust hepatitis B virus genotyping by mass spectrometry

Genotyping of hepatitis B virus (HBV) is important for tracking HBV infections, prognosticating the development of severe liver disease, and predicting outcomes of therapy. Current genotyping methods can be laborious and costly and rely on subjective data interpretation. To identify less expensive but equally reliable alternatives, we compared "gold standard" sequencing to a novel mass spectrometry approach. Sera from individuals with acute or chronic HBV infection (n = 756), representing all genotypes, were used to PCR amplify the HBV S gene. All amplicons were subjected to base-specific cleavage and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). The resulting mass peak patterns were used to identify HBV genotype by automated comparison to peak patterns simulated from reference sets of HBV sequences of known genotypes. The MALDI-TOF MS data and phylogenetic analysis of HBV sequences produced completely concordant results. Several parameters such as genetic relatedness of tested HBV variants to the reference set, chronic infections, and the quality of PCR products can lower the MS score but never affected the accuracy of the genotype call. This new streamlined MS-based method provides for rapid and accurate HBV genotyping, produces automated data reports, and is therefore suitable for routine use in diagnostic settings.

A sensitive direct sequencing assay based on nested PCR for the detection of HBV polymerase and surface glycoprotein mutations

Drug resistance is a crucial problem emerging frequently during treatment of hepatitis B, resulting in treatment failure and progression of liver damage. A direct sequencing method based on a nested PCR was established to detect mutations in samples with low viral load. Primers were designed to obtain an amplicon encompassing the A, B, C, D and E functional domains of HBV polymerase. Fifty-five samples were tested, containing HBV DNA ranging from 19 to 1700 IU/mL. Sixteen samples were also tested by the commercially available assay INNO-LiPA HBV DR v2. Sequencing was successful for all samples, and mutations were detected in 24/55 (43.6%). When used in parallel with DR v2, concordant results were found in 8/16 samples. In the eight discordant cases, four were resolved by sequencing and not by DR v2, and four had differences in the mutation patterns. Direct sequencing was able to show pol mutations not revealed by DR v2, such as rtV214A, rtQ215H/S, and rtM250V. Genotype and env variations were also established. This highly sensitive sequencing protocol, providing valuable sequencing data from samples with a low viral load, is suitable for detection of mutations at the very early signs of failure of treatment, thereby allowing to maximize the success of early treatment changes.

Use of massively parallel ultradeep pyrosequencing to characterize the genetic diversity of hepatitis B virus in drug-resistant and drug-naive patients and to detect minor variants in reverse transcriptase and hepatitis B S antigen

Direct population sequencing and reverse hybridization (line probe assay [LiPA])-based methods are the most common methods for detecting hepatitis B virus (HBV) drug resistance mutations, although only mutations present in viral quasispecies with a prevalence of > or =20% can be detected by sequencing, and only known mutations are detected by LiPA. Massively parallel ultradeep pyrosequencing (UDPS; GS FLX platform) was used to analyze HBV quasispecies in reverse transcriptase (RT) and hepatitis B S antigen (HBsAg) from five drug-naive patients and eight drug-resistant patients. Eight primer pairs were used to obtain partially overlapping amplicons, covering the RT gene from codons 1 to 288 and the complete overlapping HBsAg sequence. A 1% mutation frequency was selected as the cutoff based on an error rate estimated on plasmid DNA. This technology enabled simultaneous analysis of between 2,852 and 18,016 clonally amplified fragments from each patient. The results indicate that UDPS has a relative sensitivity much higher than both direct sequencing and LiPA. In addition, the UDPS results are quantitative, allowing establishment of the relative frequency of both known mutations and novel substitutions. Some of the detected RT substitutions led to changes also in HBsAg. On the whole, genotype D presented a higher heterogeneity than genotype A. Considering the high quantity of information that can be provided by a single test from one patient, the short turnaround time, the information on substitution frequency, and the detection of rare variants, there are strong advantages conferred by UDPS, and the new method could play a relevant role in the clinical management of HBV infection and therapy.

Comparison of reverse hybridization, microarray, and sequence analysis for genotyping hepatitis B virus

Hepatitis B virus (HBV) genotyping has become important in epidemiological and clinical diagnoses, given the relationship between the viral genotype and the progression of disease or the appearance of antiviral resistance. Since genotyping by sequence and phylogenetic analyses is not convenient in the clinical setting, we evaluated InnoLipa HBV genotyping (Innogenetics, Belgium) and an HBV DNA-Chip (bioMerieux, France) prototype assay and compared their sequencing of the gold standard S gene, using a cohort of 275 individual patient samples. All but two samples, belonging to distant and individual subgroups within a single genotype, were detected by InnoLipa HBV assay. Four samples with dual infections belonging to genotypes A and G were identified only by InnoLipa HBV assay. Using an HBV DNA-Chip assay, one sample could not be amplified due to a low viral load. Four samples were identified as genotype C and two as genotype D by sequencing but were classified as genotype A (two samples) and D (two samples) and as A (one sample) and G (one sample) by the DNA-Chip assay. In conclusion, the InnoLipa HBV genotyping strip assay detected dual infections and was an easy and quick tool for genotyping, with a sensitivity of 99.3% and a specificity of 100% compared to sequence analysis. HBV DNA-Chip assay showed a sensitivity and specificity of 97.5 and 97.8%, respectively.

Oligonucleotide chip, real-time PCR and sequencing for genotyping of hepatitis B virus

AIM: To compare the oligonucleotide chip, real-time PCR and sequencing for genotyping of hepatitis B virus in Chinese patients with chronic hepatitis B.

METHODS: Mixture of samples with different genotypes and clinical serum samples from 126 chronic hepatitis B patients was tested for hepatitis B virus genotypes by oligonucleotide chip, real-time PCR and sequencing of PCR products, respectively. Clinical performances, time required and costs of the three assays were evaluated.

RESULTS: Oligonucleotide chips and real-time PCR detected 1% and 0.1% genotypes, respectively, in mixed samples. Of the 126 clinical samples from patients with chronic hepatitis B, genotype B was detected in 41 (33%), 41 (33%) and 45 (36%) samples, and genotype C in 76 (60%), 76 (60%) and 81 (64%) samples, by oligonucleotide chip, real-time PCR and sequencing, respectively. Oligonucleotide chip and real-time PCR detected mixed genotypes B and C in 9 samples. Real-time PCR was the rapidest and cheapest among the three assays.

CONCLUSION: Oligonucleotide chip and real-time PCR are able to detect mixed genotypes, while sequencing only detects the dominant genotype in clinical samples.