Hepatitis B virus genotyping: current methods and clinical implications

ALT to qHBsAg ratio predicts long-term HBsAg seroclearance after entecavir cessation in Chinese patients with chronic hepatitis B

BACKGROUND & AIMS

Factors predicting HBsAg seroclearance after treatment cessation, irrespective of nucleos(t)ide analogue (NA) resumption, have important clinical implications. We evaluated predictors of long-term HBsAg seroclearance after entecavir cessation.

METHODS

This study followed-up Chinese patients with chronic hepatitis B from two previous studies of entecavir cessation. All patients were non-cirrhotic, HBeAg-negative, with undetectable HBV DNA (<20 IU/ml) at end-of-treatment (EOT). They were monitored closely for 48 weeks with regular HBV DNA, quantitative HBsAg (qHBsAg) and alanine aminotransferase (ALT) measurements. Entecavir was resumed at HBV DNA >2,000 IU/ml, irrespective of ALT levels. After the initial 48 weeks, patients were assessed every 6 months, regardless of entecavir resumption, to monitor for HBsAg seroclearance.

RESULTS

A total of 194 patients (63.4% male, mean age 49.9 years, on entecavir for a median of 47.2 months) were recruited; 94 (48.5%) and 158 (81.4%) patients had EOT qHBsAg <100 IU/ml and <1,000 IU/ml, respectively; 151 (77.8%) patients were eventually resumed on entecavir. After follow-up for a median of 70.7 (51.0-118.2) months, 28 (14.4%) patients had HBsAg seroclearance. qHBsAg levels at weeks 36 and 48 after EOT independently predicted HBsAg seroclearance (both p <0.01), whereas qHBsAg from EOT to week 24 only trended towards statistical significance. The ratio of ALT/qHBsAg at all time points from EOT to week 48 independently predicted HBsAg seroclearance (hazard ratios ranging from 1.003-1.028, all p <0.01) with excellent diagnostic performance (area under the receiver-operating characteristic curve 0.799-0.933, negative predictive value >90% at different time points), regardless of whether entecavir was resumed.

CONCLUSIONS

The ALT/qHBsAg ratio after entecavir cessation predicts HBsAg seroclearance, even in patients who were resumed on treatment. Its use may mitigate the risk of severe hepatitis flares in patients managed by observation without treatment resumption.

IMPACT AND IMPLICATIONS

Current predictors of HBsAg seroclearance after finite nucleos(t)ide analogue (NA) therapy have suboptimal predictive value. We demonstrated that the ALT/qHBsAg ratio may be able to reflect the balance between host control and virological activity. The ALT/qHBsAg ratio at different time points from end-of-treatment till week 48 independently and accurately predicted HBsAg seroclearance in patients who have stopped entecavir. The ALT/qHBsAg ratio may be utilized by clinicians for patient selection and retreatment decisions in finite NA therapy.

A hepatitis B virus (HBV) sequence variation graph improves alignment and sample-specific consensus sequence construction

Nearly 300 million individuals live with chronic hepatitis B virus (HBV) infection (CHB), for which no curative therapy is available. As viral diversity is associated with pathogenesis and immunological control of infection, improved methods to characterize this diversity could aid drug development efforts. Conventionally, viral sequencing data are mapped/aligned to a reference genome, and only the aligned sequences are retained for analysis. Thus, reference selection is critical, yet selecting the most representative reference a priori remains difficult. We investigate an alternative pangenome approach which can combine multiple reference sequences into a graph which can be used during alignment. Using simulated short-read sequencing data generated from publicly available HBV genomes and real sequencing data from an individual living with CHB, we demonstrate alignment to a phylogenetically representative 'genome graph' can improve alignment, avoid issues of reference ambiguity, and facilitate the construction of sample-specific consensus sequences more genetically similar to the individual's infection. Graph-based methods can, therefore, improve efforts to characterize the genetics of viral pathogens, including HBV, and have broader implications in host-pathogen research.

A hepatitis B virus (HBV) sequence variation graph improves sequence alignment and sample-specific consensus sequence construction for genetic analysis of HBV

Hepatitis B virus (HBV) remains a global public health concern, with over 250 million individuals living with chronic HBV infection (CHB) and no curative therapy currently available. Viral diversity is associated with CHB pathogenesis and immunological control of infection. Improved methods to characterize the viral genome at both the population and intra-host level could aid drug development efforts. Conventionally, HBV sequencing data are aligned to a linear reference genome and only sequences capable of aligning to the reference are captured for analysis. Reference selection has additional consequences, including sample-specific 'consensus' sequence construction. It remains unclear how to select a reference from available sequences and whether a single reference is sufficient for genetic analyses. Using simulated short-read sequencing data generated from full-length publicly available HBV genome sequences and HBV sequencing data from a longitudinally sampled individual with CHB, we investigate alternative graph-based alignment approaches. We demonstrate that using a phylogenetically representative 'genome graph' for alignment, rather than linear reference sequences, avoids issues of reference ambiguity, improves alignment, and facilitates the construction of sample-specific consensus sequences genetically similar to an individual's infection. Graph-based methods can therefore improve efforts to characterize the genetics of viral pathogens, including HBV, and may have broad implications in host pathogen research.

Genotyping and sero-virological characterization of hepatitis B virus-infected blood donors in Central Eritrea

Aim: To determine the serological markers and genotype profiles of hepatitis B virus (HBV) isolates in Central Eritrea. Materials & methods: A total of 191 hepatitis B surface antigen (HBsAg)-positive sera were randomly selected for the study. ELISA was used to perform HBV seromarker screening, genotypes were determined using multiplex-nested PCR. Results: Of 191, 77.5% (148/191) were positive for HBcAb (total), among which 99.3% (147/148) and 0.7% (1/148) were positive for HBsAg and hepatitis B surface antibody, respectively. Of the 147 positive HBcAb/HBsAg, 16 (10.9%) and 131 (77.9%) were positive for HBeAg and HBeAb, respectively. A total of 73 HBV isolates were successfully genotyped: 39 (53.4%) D; 10 (13.7%) E; 6 (8.2%) A; 6 (8.2%) C/D; 4 (5.5%) C; 3 (4.1%) C/D/E; 2 (2.7%) A/D; 2 (2.7%) D/E; and 1 (1.4%) B/D. Conclusion: HBV genotype D is the predominant genotype among blood donors in Eritrea.

Common hepatitis B virus genotypes among blood donors in Lagos, Nigeria

BACKGROUND

Hepatitis B virus (HBV) infection is one of the public health diseases causing global health problems. It is a leading cause of cirrhosis and hepatocellular carcinoma. Blood transfusion is a major route of its transmission and screening of blood is suboptimal in our environment. Occult HBV infection describes the presence of HBV DNA in blood or liver tissue in patients who are hepatitis B surface antigen (HBsAg) seronegative. This study documented the common genotypes of HBV a blood-borne infection in the population of blood donors in Lagos.

METHODS

This was a cross-sectional study carried out at the blood donor clinics of ten Lagos State Government-owned hospitals in Lagos State. A total of 1400 participants were recruited consecutively from November 2020 to June 2021. All participants' samples were screened using Diaspot Rapid Test Kit (RTK) and Dialabenzyme enzyme-linked immunosorbent assay (ELISA) kit. Furthermore, some of the plasma samples were used for HBV DNA extraction and genotyping using the real time-polymerase chain reaction. Statistical analysis was carried out using the Statistical Package for the Social Sciences (SPSS) software version 26 and P value was considered significant at ≤0.05.

RESULTS

The sero-prevalence of HBsAg using RTK and ELISA was 19.9% and 22.4%, respectively. The prevalence of occult HBV infection was 5.2%. A total of 278 and 313 HBsAg RTK and ELISA positive samples were obtained, respectively. HBV genotype result had A (46.6%) as the most prevalent followed closely by B (44.7%), E (23.8%), D (20.9%) and C (11.2%).

CONCLUSION

HBV infection has a high prevalence among blood donors. ELISA is a more sensitive screening tool and its use should be advocated nationally. HBV genotype A is the most prevalent genotype from our study.

SEB genotyping: SmartAmp-Eprimer binary code genotyping for complex, highly variable targets applied to HBV

Background

SmartAmp-Eprimer Binary code (SEB) Genotyping is a novel isothermal amplification method for rapid genotyping of any variable target of interest.

Methods

After in silico alignment of a large number of sequences and computational analysis to determine the smallest number of regions to be targeted by SEB Genotyping, SmartAmp primer sets were designed to obtain a binary code of On/Off fluorescence signals, each code corresponding to a unique genotype.

Results

Applied to HBV, we selected 4 targets for which fluorescence amplification signals produce a specific binary code unique to each of the 8 main genotypes (A–H) found in patients worldwide.

Conclusions

We present here the proof of concept of a new genotyping method specifically designed for complex and highly variable targets. Applied here to HBV, SEB Genotyping can be adapted to any other pathogen or disease carrying multiple known mutations. Using simple preparation steps, SEB Genotyping provides accurate results quickly and will enable physicians to choose the best adapted treatment for each of their patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07458-4.

Comparison of Two Diagnostic Methods for the Detection of Hepatitis B Virus Genotypes in the Slovak Republic

The hepatitis B virus (HBV), belonging to the Hepadnaviridae family, is responsible for a global health concern still in the 21st century. The virus is divided into 10 genotypes, which differ in geographical distribution and in their effect on disease progression and transmission, susceptibility to mutations, and response to treatment. There are many methods for diagnostics of HBV and differentiating its genotypes. Various commercial kits based on real-time polymerase chain reaction (RT PCR) and hybridization available, as well as whole genome sequencing or the sequencing of only individual parts of the genomes. We compared a commercial kit AmpliSens HBV-genotype-FRT, based on RT PCR, with an adapted method of amplification of the surface genomic region combined with Sanger sequencing. In the examined samples we identified the A, B, C, D, and E genotypes. By PCR with Sanger sequencing, the genotypes were determined in all 103 samples, while by using the commercial kit we successfully genotyped only 95 samples, including combined genotypes, which we could not detect by sequencing.

Early dynamic changes of quasispecies in the reverse transcriptase region of hepatitis B virus in telbivudine treatment

BACKGROUND

Telbivudine (LdT) - a synthetic thymidine β-L-nucleoside analogue (NA) - is an effective inhibitor for hepatitis B virus (HBV) replication. The quasispecies spectra in the reverse transcriptase (RT) region of the HBV genome and their dynamic changes associated with LdT treatment remains largely unknown.

METHODS

We prospectively recruited a total of 21 treatment-naive patients with chronic HBV infection and collected sequential serum samples at five time points (baseline, weeks 1, 3, 12, and 24 after LdT treatment). The HBV RT region was amplified and shotgun-sequenced by the Ion Torrent Personal Genome Machine (PGM)® system. We reconstructed full-length haplotypes of the RT region using an integrated bioinformatics framework, including de novo contig assembly and full-length haplotype reconstruction. In addition, we investigated the quasispecies' dynamic changes and evolution history and characterized potential NAs resistant mutations over the treatment course.

RESULTS

Viral quasispecies differed obviously between patients with complete (n = 8) and incomplete/no response (n = 13) at 12 weeks after LdT treatment. A reduced d_N/d_S ratio in quasispecies demonstrated a selective constraint resulting from antiviral therapy. The temporal clustering of sequential quasispecies showed different patterns along with a 24-week observation, although its statistic did not differ significantly. Several patients harboring pre-existing resistant mutations showed different clinical responses, while NAs resistant mutations were rare within a short-term treatment.

CONCLUSION

A complete profile of quasispecies reconstructed from in-depth shotgun sequencing may has important implications for enhancing clinical decision in adjusting antiviral therapy timely.

E3 ubiquitin ligase TRIM21 restricts hepatitis B virus replication by targeting HBx for proteasomal degradation

As a cytosol ubiquitin ligase and antibody receptor, Tripartite motif-containing 21 (TRIM21) has been reported to mediate the restriction of hepatitis B virus (HBV) through an HBx-antibody-dependent intracellular neutralization (ADIN) mechanism. However, whether TRIM21 limits HBV replication by targeting viral proteins remains unclarified. In this study, we demonstrate that TRIM21 inhibits HBV gene transcription and replication in HBV plasmid transfected and HBV-infected hepatoma cells. RING and PRY-SPRY domains are involved in this activity. TRIM21 interacts with HBx protein and targets HBx for ubiquitination and proteasomal degradation, leading to impaired HBx-mediated degradation of structural maintenance of chromosomes 6 (Smc6) and suppression of HBV replication. TRIM21 fails to restrict the replication of an HBx-deficient HBV. And knock-down of Smc6 largely impairs the anti-HBV activity of TRIM21 in HepG2 cells. In a hydrodynamic injection (HDI)-based HBV mouse model, we confirm an in vivo anti-HBV and anti-HBx therapeutic effect of TRIM21 by over-expression or knocking-out strategy. Our findings reveal a novel mechanism that TRIM21 restricts HBV replication through targeting HBx-Smc5/6 pathway, which may have an implication in the future TRIM21-based therapeutic application.

Prevalence of hepatitis B virus genotypes among patients with liver disease in Eritrea

Eritrea is an East African multiethnic country with an intermediate endemicity for hepatitis B. Our aim was to establish the most prevalent genotypes of hepatitis B virus (HBV) among patients with liver disease. A total of 293 Eritrean patients with liver disease who were hepatitis B surface antigen (HBsAg) positive were enrolled. All sera were tested for liver transaminases, HBV DNA viral load, and hepatitis B seromarkers including HBsAg, anti-HBcAb (total), HBeAg, and anti-HBeAb. Those reactive for HBsAg and anti-HBc (total) were further tested for HBV genotyping. The median (interquartile range) of HBV DNA viral load and ALT levels were 3.47 (1.66) log IU/mL and 28 (15.3) IU/L, respectively. Using type-specific primer-based genotyping method, 122/293 (41.6%) could be genotyped. Irrespective of mode of occurrence, HBV genotype D (21.3%) was the predominant circulating genotype, followed by genotypes C (17.2%), E (15.6%), C/D (13.1%), and C/E (10.7%). Genotypes C/D/E (7.4%), A/D (4.9%), D/E (4.1%), A (2.5%), and B, A/E, B/E, and A/D/C (0.8%) were also present. HBV in Eritrea is comprised of a mixture of HBV genotypes. This is the first study of HBV genotyping among patients with liver disease in Eritrea.

Next-generation sequencing for the diagnosis of hepatitis B: current status and future prospects

INTRODUCTION

Hepatitis B virus (HBV) causes a complex and persistent infection with a major impact on patients health. Viral-genome sequencing can provide valuable information for characterizing virus genotype, infection dynamics and drug and vaccine resistance.

AREAS COVERED

This article reviews the current literature to describe the next-generation sequencing progress that facilitated a more comprehensive study of HBV quasispecies in diagnosis and clinical monitoring.

EXPERT OPINION

HBV variability plays a key role in liver disease progression and treatment efficacy. Second-generation sequencing improved the sensitivity for detecting and quantifying mutations, mixed genotypes and viral recombination. Third-generation sequencing enables the analysis of the entire HBV genome, although the high error rate limits its use in clinical practice.

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.

Molecular epidemiology of Hepatitis B virus, Hepatitis C virus, and Hepatitis D virus in general population of Afghanistan

BACKGROUND/AIMS

This study gives a clue about genotypes, subgenotypes and subtypes of HBV, HCV and HDV viruses in general population of Afghanistan.

MATERIALS AND METHODS

A total of 234 HBsAg, 44 anti-HCV and 5 Anti-Delta positive patients belong to 25-70 age group were obtained through a rapid screening test among 5898 residents of Afghanistan. After quantifying viral load, genotyping of 61 HBV, 29 HCV and 1 HDV samples were accomplished by sequencing of a segment of the HBV Pre S, HCV NS5B, and HDV Delta antigen regions respectively. Clinically important variants of the HBV polymerase gene, the "a" determinant of HBsAg, HCV NS5B and NS3 regions were assessed.

RESULTS

All HBV isolates were dispersed throughout the genotype D branch and ayw2 was the only subtypes found. The anti-HDV prevalence among HBsAg positive individuals was 2.2% and the single HDV sample, belonged to HDV genotype I. Analysis of HCV isolates revealed subtype HCV-1b in 75.86%, HCV-3a in 20.69% and HCV-3b in 3.44% patients. The observed mutant variants in the MHR of HBsAg were Y100 15%, Q101 5%, G102 15%, T115 45%, P120 5%, T131 5%. Likewise, S213T 10%, Q215P 5% and N248H 100% mutations were detected in the HBV polymerase region. C316N mutation was prevalent in 72.7% of HCV 1b participants.

CONCLUSION

Genotypic variation in Afghan patients is in line with the ones existing in neighboring countries and regions. HBV genotypes D1, subtype ayw2, HDV RNA type I, and HCV RNA genotype 1b are likely to be dominant in Afghan patients.

Prevalence of chronic HBV infection in pregnant woman attending antenatal care in a tertiary hospital in Mwanza, Tanzania: a cross-sectional study

BACKGROUND

Tanzania has a high prevalence (7.17%) of chronic hepatitis B infection. Mother to Child transmission is very common, resulting in high rate of chronic infections. Currently, there is no screening program for HBV in pregnant women. This study investigated the prevalence and risk factors for chronic HBV infection in pregnant women in a tertiary hospital in Mwanza, Tanzania.

METHODS

Seven hundred and forty-three women attending antenatal care and/or delivering at the Bugando Medical Centre were enrolled. All answered a questionnaire on sociodemographic and other risk factors and were tested for HBsAg using a rapid test. In HBsAg positive mothers, maternal blood and umbilical cord blood samples collected after delivery were analyzed for serological (HBsAg, HBeAg and anti-HBe) and virologic (HBV-DNA viral load and genotype) markers. All their babies were vaccinated within 24 h of delivery. The children were followed up at 3 years of age. Data was analyzed using the Mann-Whitney U-test, independent sample T-test and logistic regression.

RESULTS

Of the 743 participants, 22 (3%) were positive for HBsAg, and 2 (9%) had detectable HBe-antigen. Low condom use was the only statistically significant risk factor for chronic HBV infection (OR = 3.514, 95%CI = 1.4-8.0). Of 14 maternal blood samples genotyped, 10 (71%) were genotype A and 4 (29%) were genotype D. HBV-DNA was detected in 21/22 samples, with a median of 241 IU/ml (range: 27.4-25.9 × 107 IU/ml). Five (33%) of 15 available cord blood samples were positive for HBsAg and 10 (67%) were negative. At follow-up, one child showed chronic HBV infection characteristics, one had anti-HBs level of 7 mIU/ml and 5/7(71%) had protective anti-HBs levels (> 10 mIU/ml).

CONCLUSION

This cohort of pregnant women showed a lower-intermediate prevalence of HBV of 3%. In the 3 years follow-up only 1 out of 7 children showed evidence of chronic HBV infection. The child's mother with high viral load (25.9 × 107 IU/ml), was positive for HBeAg with a high degree of sequence similarity suggesting vertical transmission. These results highlight a need for improved diagnosis and treatment of HBV infection in pregnant women in Tanzania, in order to prevent vertical transmission.

In Silico Analysis of Hepatitis B Virus Genotype D Subgenotype D1 Circulating in Pakistan, China, and India

The focus of this study was the computational analysis of hepatitis B virus (HBV) genotype D subgenotype D1 in Pakistan, China, and India. In total, 54 complete genome sequences of HBV genotype D subgenotype D1 were downloaded from National Center for Biotechnology Information (NCBI). Of these, 6 complete genome sequences were from Pakistan, 14 were from China, and 34 were from India. Sequence alignment showed less than 4% divergence in these sequences. C and X genes showed divergence of less than 3%. Comparison over the S gene showed more than 97% similarity among the nucleotide sequences of genotype D subgenotype D1. The identity and similarity matrix of 54 nucleotide sequences of HBV genotype D subgenotype D1 from Pakistan, China, and India revealed more than 93% identity and 93% similarity. Phylogenetic analysis highlighted that complete genome isolates of HBV circulating in Pakistan had the closest evolutionary relationship with its neighboring countries China and India. China’s (HQ833466) and Pakistan’s (AB583680.1) isolates shared the same ancestor. Gene structure analysis showed that “P” gene exons were the longest, about three-fourth of the genome size, whereas gene “S” had the second longest coding regions with 2 exons and 1 intron. However, “C” and “X” genes had 1 smallest exon. X proteins had proven role in spreading of the HBV infection diseases. For HBx analysis, 1 X protein sequence of HBV genotype D subgenotype D1 belonging to each country was obtained. Homology models of the 3 X proteins generated using SWISS-MODEL revealed GMQE (Global Model Quality Estimation) = 0.1. Global and local quality estimate scores including Z-scores for Qualitative Model Energy Analysis (QMEAN) C-beta, all-atom, solvation, and torsion energy scores were similar indicating good quality, accuracy, and reliability of the predicted models. Three-dimensional (3D) visualization showed similar structures and Ramachandran plots showed a high percentage of protein residues into the favorable region for X protein models.

Origin and dissemination of hepatitis B virus genotype C in East Asia revealed by phylodynamic analysis and historical correlates

Hepatitis B virus disease progression in East Asia is most frequently associated with genotype C (HBV/C). The increasing availability of HBV/C genetic sequences and detailed annotations provides an opportunity to investigate the epidemiological factors underlying its evolutionary history. In this study, the Bayesian phylogeography framework was used to investigate the origins and patterns in spatial dissemination of HBV/C by analyzing East Asian sequences obtained from 1992 to 2010. The most recent common ancestor of HBV/C was traced back to the early 1900s in China, where it eventually diverged into two major lineages during the 1930s-1960s that gave rise to distinct epidemic waves spreading exponentially to other East Asian countries and the USA. Demographic inference of viral effective population size over time indicated similar dynamics for both lineages, characterized by exponential growth since the early 1980s, followed by a significant bottleneck in 2003 and another increase after 2004. Although additional factors cannot be ruled out, we provide evidence to suggest this bottleneck was the result of limited human movement from/to China during the SARS outbreak in 2003. This is the first extensive evolutionary study of HBV/C in East Asia as well as the first to assess more realistic spatial ecological influences between co-circulating infectious diseases.

Viral Biomarkers in Chronic HBeAg Negative HBV Infection

Viral biomarkers are important tools for monitoring chronic hepatitis B virus (HBV) hepatitis B early antigen (HBeAg) negative infection, both in its natural course as well as during and after treatment. The biomarkers consist of antibodies against viral epitopes, viral proteins, and molecular surrogate markers of the quantity and transcriptional activity of the stable episomal HBV covalently closed circular DNA (cccDNA) which is located in the nuclei of the infected hepatocytes. HBV deoxyribonucleic acid (DNA) or else viral load measurement in plasma or serum is a marker of HBV replication of major clinical importance. HBV DNA is used for staging and treatment monitoring as described in international scientific guidelines. Quantification of HBV antigens, mainly hepatitis B surface antigen (HBsAg) as well as Hepatitis B core related antigen (HBcrAg), play an important yet secondary role, especially in cases of low or undetectable HBV DNA and has been evaluated for the classification of the inactive carrier state, as a predictor of subsequent HBsAg clearance, treatment outcome, and development of hepatocellular carcinoma (HCC). The measurement of the replicative intermediate HBV RNA in serum is currently evaluated and may also prove to be a significant biomarker particularly in patients treated with nucleot(s)ide analogs. This review focuses on the viral biomarkers mentioned above and their role in HBV, HBeAg negative, infection.

F221Y mutation in hepatitis B virus reverse transcriptase is associated with hepatocellular carcinoma prognosis following liver resection

Hepatitis B virus (HBV) reverse transcriptase (RT) is encoded by the polymerase gene in the reverse transcriptase region, which overlaps with the S gene. The association between mutations of HBV RT and the pathobiological features of hepatocellular carcinoma (HCC) remain to be elucidated. The present study aimed to examine mutations in this region of the HBV genome and its clinical significance. Briefly, HBV total DNA was extracted from 84 pairs of HCC tumor tissue and corresponding adjacent non‑tumor tissue samples. The RT/S regions (nt130‑1161) were amplified and sequenced using the Sanger method, and associations between RT mutations and the clinical characteristics of patients with HCC were analyzed. Finally, 27 and 29 mutations with frequencies >5% were identified in the RT and S regions, respectively. The rtF221Y variation and a tumor size >8 cm were found to be independent risk factors for the postoperative recurrence of HCC, with hazard ratios of 2.345 (95% CI, 1.391‑3.953; P=0.001) and 1.838 (95% CI, 1.069‑3.161; P=0.028), respectively. rtF221Y was also an independent risk factor for poor overall survival rates (HR=2.557; 95% CI, 1.344‑4.866; P=0.004). The mutation of R122 K in the HBV S protein was closely associated with tumor recurrence (P<0.001). As a result, rtF221Y was identified as a risk factor for poor prognosis and may be a potential viral marker for predicting prognosis in HCC.

Simultaneous detection of multiple viruses based on chemiluminescence and magnetic separation

In this report, a DNA hybridization based chemiluminescent detection method has been proposed for reliable detection of multiple pathogens. The use of surface modified magnetic nanoparticles can help to integrate this system into an automated platform for high throughput applications.

A Smartphone-Based Genotyping Method for Hepatitis B Virus at Point-of-Care Settings

We reported a rapid, convenient, and easy-to-use genotyping method for hepatitis B virus (HBV) based on the smartphone at point-of-care (POC) settings. To perform HBV genotyping especially for genotypes A, B, C, and D, a smartphone is used to image and analyze a one-step immunoassay lateral flow strip functionalized with genotype-specific monoclonal antibodies (mAbs) on multiple capture lines. A light-emitting diode (LED) positioned on the top of the lateral flow strip is used to shine the multiple capture lines for excitation. Fluorescence detection is obtained with a smartphone whose camera is used to take the fluorescent images. An intelligent algorithm is developed to first identify each capture line from the fluorescent image and then determine the HBV genotype based on a genotyping model. Based on the pattern of the detection signal from different samples, a custom HBV genotyping model is developed. Custom application software running on a smartphone is developed with Java to collect and analyze the fluorescent image, display the genotyping result, and transmit it if necessary. Compared with the existing methods with nucleic acid analysis, more convenient, instant, and efficient HBV genotyping with significantly lower cost and a simpler procedure can be obtained with the developed smartphone POC HBV genotyping method.

MOLECULAR-BIOLOGICAL MARKERS OF HEPATITIS В IN PATIENTS WITH LIVER FIBROSIS/CIRRHOSIS IN UZBEKISTAN

Aim. Evaluate prevalence of genetic variants of hepatitis В viruses in population of various regions of Uzbekistan with hepatitis of various genesis and different severity levels of liver fibrosis and cirrhosis. Materials and methods. Blood plasma and liver biopsy from 39 patients with different severity levels of liver fibrosis and cirrhosis served as study material. Genotyping based on direct sequencing of Pre-Sl/Pre-S2/S HBV DNA region was applied. Results. Hepatitis В virus was detected in 32 samples ofthe 39 provided, frequency of occurrence - 82%, respectively. Phylogenetic analysis has shown, that only genotype D was detected among the examined patients, hepatitis В virus subtype D1 predominated (84.38%) compared with D2 (3.12%) and D3 (12.5%) subtypes. Conclusion. Large-scale sequencing of HBV in Central Asia will allow to evaluate routes of transmission and time of evolutionary separation of virus isolates. Understanding the epidemiology of the infectious process is important for development of programs for prophylaxis and therapy of the infection.

HBV/4DR 9G test and its comparison with INNO-LiPA HBV multi-DR test for the detection of drug-resistant Hepatitis B virus

A significant proportion of patients with chronic Hepatitis B infection require antiviral therapy during their life time. The Antiviral therapy with lamivudine or adefovir or telbivudine has shown to be a major risk factor for selection of resistance. Eighty percent of patients showed a development of lamivudine-resistant strains after five years of treatment with lamivudine alone. Adefovir and telbivudine inhibit HBV with very high efficacy and have moderate incidences of drug resistance. Entecavir and tenofovir have been shown to have a higher barrier to resistance with rates of less than 1.5% after five years of treatment. The rtA181V, rtM204V/I, rtN236T and, rtM250V are high prevalent mutations found in the drug-resistant HBV strains. Therefore, for accurate treatment of HBV-infected patients, it is important to discriminate the drug-resistant HBV strains by using simple and accurate detection method. In this study, we describe the HBV/4DR 9G test and its evaluation by using clinical samples and plasmid DNA standards with a range of HBV mutation sites. In tests with 384 plasmid DNA standards, the HBV/4DR 9G test showed higher than 95% sensitivity and 98% specificity. The HBV/4DR 9G test was compared with the INNO-LiPA HBV Multi DR test for detection of drug-resistant HBV strains only in clinical samples. The plasma samples were collected from patients suspected with HBV drug-resistant strain infection. The results of both tests were cross-checked with the HBV DNA sequence analysis. The HBV/4DR 9G test demonstrated a good agreement with the sequencing results as compared to the INNO-LiPA HBV Multi-DR test. These results indicate that the HBV/4DR 9G test can be a reliable, sensitive, and accurate diagnostic tool for the detection of drug-resistant genotypes of HBV in clinical specimens. HBV/4DR 9G test can genotype 4 drug resistant HBV strains in 1 PCR. The HBV/4DR 9G test will help to minimize the risk of HBV patients from liver cancer.

X region mutations of hepatitis B virus related to clinical severity

Chronic hepatitis B virus (HBV) infection remains a major health problem, with more than 240 million people chronically infected worldwide and potentially 650000 deaths per year due to advanced liver diseases including liver cirrhosis and hepatocellular carcinoma (HCC). HBV-X protein (HBx) contributes to the biology and pathogenesis of HBV via stimulating virus replication or altering host gene expression related to HCC. The HBV X region contains only 465 bp encoding the 16.5 kDa HBx protein, which also contains several critical cis-elements such as enhancer II, the core promoter and the microRNA-binding region. Thus, mutations in this region may affect not only the HBx open reading frame but also the overlapped cis-elements. Recently, several types of HBx mutations significantly associated with clinical severity have been described, although the functional mechanism in most of these cases remains unsolved. This review article will mainly focus on the HBx mutations proven to be significantly related to clinical severity via epidemiological studies.

Precore/core region mutations of hepatitis B virus related to clinical severity

Despite the availability of an effective vaccine, hepatitis B virus (HBV) infection remains a major health problem, with more than 350 million chronically infected people worldwide and over 1 million annual deaths due to cirrhosis and liver cancer. HBV mutations are primarily generated due both to a lack of proofreading capacity by HBV polymerase and to host immune pressure, which is a very important factor for predicting disease progression and therapeutic outcomes. Several types of HBV precore/core (preC/C) mutations have been described to date. The host immune response against T cells drives mutation in the preC/C region. Specifically, preC/C mutations in the MHC class II restricted region are more common than in other regions and are significantly related to hepatocellular carcinoma. Certain mutations, including preC G1896A, are also significantly related to HBeAg-negative chronic infection. This review article mainly focuses on the HBV preC/C mutations that are related to disease severity and on the HBeAg serostatus of chronically infected patients.

The clinical implications of hepatitis B virus genotypes and HBeAg in pediatrics

Although a successful vaccine against HBV has been implemented in 184 countries, eradication of hepatitis B virus (HBV) is still not on the horizon. There are over 240 million chronic carriers of HBV globally. The risk of developing chronic hepatitis ranges from >90% in newborns of hepatitis Be antigen (HBeAg)‐positive mothers, 25%–35% in children under 5 years of age and <5% in adults. HBeAg, a non‐particulate viral protein, is a marker of HBV replication. This is the only HBV antigen to cross the placenta, leading to specific unresponsiveness of helper T cells to the capsid protein and HBeAg in newborns. HBeAg is tolerated in utero and acts as a tolerogen after birth. Perinatal transmission is frequent when mothers are HBeAg‐positive, whereas it occurs less frequently when mothers are HBeAg‐negative. Sequence heterogeneity is a feature of HBV. Based on an intergroup divergence >7.5% across the complete genome, HBV is classified phylogenetically into at least nine genotypes. With between ~4% and 8% intergroup nucleotide divergence, genotypes A–D, F, H and I are classified further into subgenotypes. HBV genotypes/subgenotypes may have distinct geographical distribution and can develop different mutations in the regions of the HBV genome that code for HBeAg. These differences can be related to the role of HBV genotypes to the natural history of infection and mode of transmission. Thus genotypes/subgenotypes of HBV can be responsible for the different natural history of infection and modes of transmission in children, found in various regions of the world, where different genotypes/subgenotypes prevail. Copyright © 2016 John Wiley & Sons, Ltd.

Surface gene variants of hepatitis B Virus in Saudi Patients

BACKGROUND/AIMS

Hepatitis B virus (HBV) continues to be one of the most important viral pathogens in humans. Surface (S) protein is the major HBV antigen that mediates virus attachment and entry and determines the virus subtype. Mutations in S gene, particularly in the "a" determinant, can influence virus detection by ELISA and may generate escape mutants. Since no records have documented the S gene mutations in HBV strains circulating in Saudi Arabia, the current study was designed to study sequence variation of S gene in strains circulating in Saudi Arabia and its correlation with clinical and risk factors.

PATIENTS AND METHODS

A total of 123 HBV-infected patients were recruited for this study. Clinical and biochemical parameters, serological markers, and viral load were determined in all patients. The entire S gene sequence of samples with viral load exceeding 2000 IU/mL was retrieved and exploited in sequence and phylogenetic analysis.

RESULTS

A total of 48 mutations (21 unique) were recorded in viral strains in Saudi Arabia, among which 24 (11 unique) changed their respective amino acids. Two amino acid changes were recorded in "a" determinant, including F130L and S135F with no evidence of the vaccine escape mutant G145R in any of the samples. No specific relationship was recognized between the mutation/amino acid change record of HBsAg in strains in Saudi Arabia and clinical or laboratory data. Phylogenetic analysis categorized HBV viral strains in Saudi Arabia as members of subgenotypes D1 and D3.

CONCLUSION

The present report is the first that describes mutation analysis of HBsAg in strains in Saudi Arabia on both nucleotide and amino acid levels. Different substitutions, particularly in major hydrophilic region, may have a potential influence on disease diagnosis, vaccination strategy, and antiviral chemotherapy.

Implementation of Next-Generation Sequencing for Hepatitis B Virus Resistance Testing and Genotyping in a Clinical Microbiology Laboratory

Sanger sequencing or DNA hybridization have been the primary modalities for hepatitis B (HBV) resistance testing and genotyping; however, there are limitations, such as low sensitivity and the inability to detect novel mutations. Next-generation sequencing (NGS) for HBV can overcome these limitations, but there is limited guidance for clinical microbiology laboratories to validate this novel technology. In this study, we describe an approach to implementing deep pyrosequencing for HBV resistance testing and genotyping in a clinical virology laboratory. A nested PCR targeting the pol region of HBV (codons 143 to 281) was developed, and the PCR product was sequenced by the 454 Junior (Roche). Interpretation was performed by ABL TherapyEdge based on European Association for the Study of the Liver (EASL) guidelines. Previously characterized HBV samples by INNO-LiPA (LiPA) were compared to NGS with discordant results arbitrated by Sanger sequencing. Genotyping of 105 distinct samples revealed a concordance of 95.2% (100/105), with Sanger sequencing confirming the NGS result. Resistance testing by NGS was concordant with LiPA in 85% (68/80) of previously characterized samples. Additional mutations were found in 8 samples, which related to the identification of low-level mutant subpopulations present at <10% (6/8). To balance the costs of testing for the validation study, reproducibility of the NGS was investigated through an analysis of sequence variants at loci not associated with resistance in a single patient sample. Our validation approach attempts to balance costs with efficient data acquisition.

Virome analysis of antiretroviral-treated HIV patients shows no correlation between T-cell activation and anelloviruses levels

BACKGROUND

Abnormally high levels of T-cell activation can persist in HIV-infected subjects despite effective anti-retroviral therapy (ART) and has been associated with negative health outcomes. The nature of the antigenic drivers or other causes of this residual T-cell activation remain uncertain. Anelloviruses are universally acquired soon after birth, resulting in persistent viremia, and considered part of the commensal human virome. Reduced immunocompetence results in increased anellovirus levels.

OBJECTIVES

To test whether increased levels of anelloviruses or other viruses in plasma are associated with higher levels of persistent T-cell activation during ART.

STUDY DESIGN

Two amplification methods combined with next generation sequencing were used to detect all viruses and estimate relative anellovirus levels in plasma from 19 adults on effective ART who exhibited a wide range of T-cell activation levels.

RESULTS

Nucleic acids from HBV and HCV were detected in one patient each while pegivirus A (GBV-C) was found in three patients. Anellovirus DNA was detected in all patients with some individuals carrying up to eight different genotypes. Specific anellovirus genotypes or higher level of co-infections were not detected in subjects with higher levels of T-cell activation. No association was detected between relative plasma anellovirus DNA levels and the percentage of activated CD4 or CD8 T cells.

CONCLUSIONS

Human anelloviruses were detected in all HIV suppressed subjects, exhibited a wide range of viremia levels, and were genetically highly diverse. The level of persistent T-cell activation was not correlated with the level of viremia or genotypes present indicating that anellovirus antigens are unlikely to be a dominant source of antigens driving chronic T-cell activation.

Genotypes and viral variants in chronic hepatitis B: A review of epidemiology and clinical relevance

The Hepatitis B Virus (HBV) has a worldwide distribution and is endemic in many populations. It is constantly evolving and 10 genotypic strains have been identified with varying prevalences in different geographic regions. Numerous stable mutations in the core gene and in the surface gene of the HBV have also been identified in untreated HBV populations. The genotypes and viral variants have been associated with certain clinical features of HBV related liver disease and Hepatocellular carcinoma. For example Genotype C is associated with later hepatitis B e antigen (HBeAg) seroconversion, and more advanced liver disease. Genotype A is associated with a greater risk of progression to chronicity in adult acquired HBV infections. Genotype D is particularly associated with the precore mutation and HBeAg negative chronic hepatitis B (CHB). The genotypes prevalent in parts of West Africa, Central and South America, E, F and H respectively, are less well studied. Viral variants especially the Basal Core Promotor mutation is associated with increased risk of fibrosis and cancer of the liver. Although not currently part of routine clinical care, evaluation of genotype and viral variants may provide useful adjunctive information in predicting risk about liver related morbidity in patients with CHB.

Hepatitis B virus Genotyping Among Patients With Cirrhosis

Background:

Hepatitis B virus (HBV) infection is a worldwide public health problem. Nine HBV genotypes (A-I) have been already discovered. HBV genotypes are important both in the clinical manifestation of disease and treatment response. Moreover, HBV DNA without HBs (Hepatitis B surface)-antigenemia was detected in some patients with chronic hepatitis (occult hepatitis). There is little information about HBV genotypes and its relation to occult infection despite the importance of this infection in Khuzestan Province.

Objectives:

This study aimed to determine both occult hepatitis B infection and HBV genotypes among cirrhotic patients.

Patients and Methods:

Thirty-eight patients with liver cirrhosis, including 11 (28.9%) HBsAg-positive patients and 27 (71.1%) patients with cryptogenic cirrhosis participated in this study. The mean age of the patients at the time of cirrhosis diagnosis was 54.85 years (range 26-75 years). All patients were anti-HCV and anti-HIV negative. For all the samples, the serological Enzyme-Linked Immunosorbent Assay (ELISA) was performed for HBV markers including HBsAg, HBcAb, HBeAg, HBeAb tests. The common primer of S region of HBV was used for Nested PCR. The PCR products of the positive individuals were sequenced for genotyping and subtyping of HBV.

Results:

Eleven (40.7%) out of 27 HBV cryptogenic cirrhosis and all 11 HBsAg-positive patients were positive for HBV DNA. The seroprevalences of Hepatitis B virus HBe antigen, anti-HBe and anti-HBc antibodies among the cryptogenic cirrhosis patients were 5 (18.5%), 1 (3.7%), and 5 (20.83), and among HBsAg-positive patients were 6 (54.5%), 5 (45.5%), and 7 (63.6%), respectively.

Conclusions:

In our study, only HBV genotype D was found among all the positive HBsAg and occult HBV infection. Moreover, high prevalence (40.7%) of occult HBV infection was determined among patients suffered from cryptogenic cirrhosis.

Serum hepatitis B virus RNA levels as an early predictor of hepatitis B envelope antigen seroconversion during treatment with polymerase inhibitors

Hepatitis B envelope antigen (HBeAg) seroconversion represents an endpoint of treatment of chronic hepatitis B virus (HBV) infections. We have studied whether levels of serum HBV RNA during polymerase inhibitor treatment might be helpful for predicting HBeAg seroconversion. HBV RNA levels were determined in serial serum samples from 62 patients with chronic HBV infection (50 HBeAg positive). Patients received antiviral treatment for a mean duration of 30 ± 15 (range, 4-64) months. A new rapid amplification of complimentary DNA-ends-based real-time polymerase chain reaction was established for quantitative analysis of polyadenylated full-length (fl) and truncated (tr) HBV RNA. HBV RNA, HBV DNA, and hepatitis B surface antigen (HBsAg) levels as well as presence of HBeAg and hepatitis B envelope antibody were measured at baseline, month 3, month 6, and subsequent time points. Fifteen patients who achieved HBeAg seroconversion after a mean duration of 19 ± 14 (range, 3-56) months of antiviral treatment showed a significantly stronger decline in mean HBV flRNA and trRNA levels from baseline to month 3 of 1.0 ± 1.4 (range, -1.6-3.4) and 2.1 ± 1.4 (range, 0-3.9) and to month 6 of 1.8 ± 1.4 (range, 0-4.6) and 3.1 ± 1.7 (range, 0-5.1) log10 copies/mL, respectively, in comparison to 35 HBeAg-positive patients without HBeAg seroconversion (P < 0.001 for months 3 and 6). A similar decline in HBV RNA levels was observed in HBeAg-negative patients. The decline of HBV RNA levels at months 3 and 6 of treatment was to be the strongest predictor of HBeAg seroconversion, when compared to levels of HBV DNA, HBsAg, alanine aminotransferase, and HBV genotype, age, and sex.

CONCLUSION

Serum HBV RNA levels may serve as a novel tool for prediction of serological response during polymerase inhibitor treatment in HBeAg-positive patients.

Hepatitis B vaccination

Hepatitis B virus is a worldwide leading cause of acute and chronic liver disease including cirrhosis and hepatocellular carcinoma. Effective vaccines have been available since the early '80s and vaccination has proved highly successful in reducing the disease burden, the development of the carrier state and the HB-related morbidity and mortality in the countries where vaccination has been implemented.   Neutralizing (protective) antibodies (anti-HBs) induced by vaccination are targeted largely towards the amino acid hydrophilic region, referred to as the common a determinant which is present on the outer protein coat or surface antigen (HBsAg), spanning amino acids 124-149. This provides protection against all HBV genotypes (from A to H) and is responsible for the broad immunity afforded by hepatitis B vaccination. Thus, alterations of residues within this region of the surface antigen may determine conformational changes that can allow replication of the mutated HBV in vaccinated people. An important mutation in the surface antigen region was identified in Italy some 25 years ago in infants born to HBsAg carrier mothers who developed breakthrough infections despite having received HBIG and vaccine at birth. This virus had a point mutation from guanosine to adenosine at nucleotide position 587, resulting in aa substitution from glycine (G) to arginine (R) at position 145 in the a determinant. Since the G145R substitution alters the projecting loop (aa 139-147) of the a determinant, the neutralizing antibodies induced by vaccination are no longer able to recognize the mutated epitope. Beside G145R, other S-gene mutations potentially able to evade neutralizing anti-HBs and infect vaccinated people have been described worldwide. In addition, the emergence of Pol mutants associated with resistance to treatment with nucleos(t)ide analogues can select viruses with crucial changes in the overlapping S-gene, potentially able to alter the S protein immunoreactivity. Thus such mutants have the potential to infect both naïve and immunized people, negatively affecting the efficacy of both the antiviral treatment and the vaccination programs. Despite concern, at present the overall impact of vaccine escapes mutants seems to be low and they do not pose a public health threat or a need to modify the established hepatitis B vaccination programs. The development of novel NAs with a high barrier to resistance is warranted.

Recent advances in molecular diagnostics of hepatitis B virus

Hepatitis B virus (HBV) is one of the important global health problems today. Infection with HBV can lead to a variety of clinical manifestations including severe hepatic complications like liver cirrhosis and hepatocellular carcinoma. Presently, routine HBV screening and diagnosis is primarily based on the immuno-detection of HBV surface antigen (HBsAg). However, identification of HBV DNA positive cases, who do not have detectable HBsAg has greatly encouraged the use of nucleic acid amplification based assays, that are highly sensitive, specific and are to some extent tolerant to sequence variation. In the last few years, the field of HBV molecular diagnostics has evolved rapidly with advancements in the molecular biology tools, such as polymerase chain reaction (PCR) and real-time PCR. Recently, apart of PCR based amplification methods, a number of isothermal amplification assays, such as loop mediated isothermal amplification, transcription mediated amplification, ligase chain reaction, and rolling circle amplification have been utilized for HBV diagnosis. These assays also offer options for real time detection and integration into biosensing devices. In this manuscript, we review the molecular technologies that are presently available for HBV diagnostics, with special emphasis on isothermal amplification based technologies. We have also included the recent trends in the development of biosensors and use of next generation sequencing technologies for HBV.

Molecular identification of hepatitis B virus genotypes/subgenotypes: revised classification hurdles and updated resolutions

The clinical course of infections with the hepatitis B virus (HBV) substantially varies between individuals, as a consequence of a complex interplay between viral, host, environmental and other factors. Due to the high genetic variability of HBV, the virus can be categorized into different HBV genotypes and subgenotypes, which considerably differ with respect to geographical distribution, transmission routes, disease progression, responses to antiviral therapy or vaccination, and clinical outcome measures such as cirrhosis or hepatocellular carcinoma. However, HBV (sub)genotyping has caused some controversies in the past due to misclassifications and incorrect interpretations of different genotyping methods. Thus, an accurate, holistic and dynamic classification system is essential. In this review article, we aimed at highlighting potential pitfalls in genetic and phylogenetic analyses of HBV and suggest novel terms for HBV classification. Analyzing full-length genome sequences when classifying genotypes and subgenotypes is the foremost prerequisite of this classification system. Careful attention must be paid to all aspects of phylogenetic analysis, such as bootstrapping values and meeting the necessary thresholds for (sub)genotyping. Quasi-subgenotype refers to subgenotypes that were incorrectly suggested to be novel. As many of these strains were misclassified due to genetic differences resulting from recombination, we propose the term "recombino-subgenotype". Moreover, immigration is an important confounding facet of global HBV distribution and substantially changes the geographic pattern of HBV (sub)genotypes. We therefore suggest the term "immigro-subgenotype" to distinguish exotic (sub)genotypes from native ones. We are strongly convinced that applying these two proposed terms in HBV classification will help harmonize this rapidly progressing field and allow for improved prophylaxis, diagnosis and treatment.

A novel HBV genotypes detecting system combined with microfluidic chip, loop-mediated isothermal amplification and GMR sensors

Genotyping of hepatitis B virus (HBV) can be used for clinical effective therapeutic drug-selection. A novel microfluidic biochip for HBV genotyping has been fabricated, for the first time, integrating loop-mediated isothermal amplification (LAMP), line probes assay (LiPA) and giant magnetoresistive (GMR) sensors. Coupling LAMP with LiPA in microfluidic chip shortened reaction time substantially, and combining LAMP with GMR sensor enabled limit of detection to attain 10 copies mL(-1) target HBV DNA molecules in 1 h. Furthermore, the independent designed GMR sensors and microfluidic chip can decrease manufacturing cost and patient's test-cost, and facilitate GMR detector repeating use for signal detection. In addition, the detection system has a lower background signal owing to application of superparamagnetic nanoclusters. And it can be expected to use for multiple target molecules synchronous detection in microfluidic chip based on a characteristic of stationary reaction temperature of LAMP. In conclusion, the neoteric detecting system is well suitable for quick genotyping diagnosis of clinical HBV and other homothetic biomolecule detection in biological and medical fields.

A recombinant multiepitope protein for hepatitis B diagnosis

Hepatitis B is a liver inflammation caused by hepatitis B virus (HBV) and can be diagnosed in clinical stage by hepatitis B core antibody from IgM class (anti-HBcIgM). Hepatitis B core antibody from IgG class (Anti-HBcIgG) appears quickly after IgM, reaching high titers in chronic hepatitis, and remains even after cure. Since hepatitis B core antibody (anti-HBc) is the first antibody identified and sometimes the only marker detected during the course of infection, it can be used both to indicate HBV acute infection (anti-HBc-IgM) and to identify individuals who have come into contact with the virus (anti-HBc-IgG). In this work we propose a recombinant hepatitis B core multiepitope antigen (rMEHB) to be used for diagnosis of hepatitis B. For this purpose, a synthetic gene coding for rMEHB was designed and cloned into vector pET21a with a 6xHis tag at the C-terminal. Time course induction in E. coli showed an induced protein with an apparent molecular mass of ~21 kDa. Protein purification was performed by a single step with affinity chromatography Ni-NTA. Circular dichroism spectroscopy indicated rMEHB as a thermal stable protein at pH 7.0 and 8.0. In these conditions rMEHB was successfully used to perform an enzyme linked immuno sorbent assay (ELISA) with positive and negative sera.

Evaluation of PCR-RFLP in the Pre-S Region as Molecular Method for Hepatitis B Virus Genotyping

BACKGROUND

Hepatitis B virus (HBV) infection is a public health problem in developing countries. HBV genotypes play major role in the evolution of infection since they were involved in different clinical presentations and response to treatment.

OBJECTIVES

This study was conducted to evaluate the efficiency of restriction fragment length polymorphism (RFLP) analysis for HBV genotyping.

PATIENTS AND METHODS

We investigated 98 samples collected from patients chronically infected with HBV. HBV genotypes were determined by analysis of patterns obtained after amplification in Pre-S region and digestion of the amplicon by two endonucleases AvaII and DpnII. Obtained results were confirmed by partial sequencing in the same region.

RESULTS

Two different HBV genotypes were detected in this study, Genotype D (in 95. 9%) and Genotype A (in 4.1%). Seventy-four samples (75.5%) were successfully genotyped with RFLP analysis and all classified as genotype D. The remaining 24 samples (24.5%) which were un-genotyped by RFLP analysis, were classified by partial sequencing of the pre-S region as HBV genotype D (20 samples, 20.4%) and genotype A (4 samples, 4.1%). Atypical profiles were significantly associated with advanced liver disease (P = 0.001) as well as older age (P < 0.05).

CONCLUSIONS

Several previous studies used PCR-RFLP to genotype HBV; however, we showed the high risk to obtain atypical profiles, especially in advanced stages of chronic infection, with as results difficulties to genotype the virus. These profiles resulted from the accumulation of mutations during natural course of infection resulting in a modification in restriction sites for enzymes. So, we recommended completing the investigation by partial sequencing to confirm obtained results.