Molecular epidemiology of chronic hepatitis B virus infection in northern Poland.
ABSTRACT Hepatitis B virus (HBV) infection is a global health problem, with more than 350 million people chronically infected worldwide. The chronic HBV infection in Poland is also an essential medical and social problem. Starting from 1993, a steady decline of the incidence of HBV has been observed, reaching the estimated rate of 4.5 per 100 000 in 2004. Nothing is known about the genetic variability of HBV in Poland, the occurrence and spreading of genetic variants and mutants of hepatitis B virus in the population of Polish patients during the course of the disease and in relation to antiviral treatment. It is very interesting to study the molecular epidemiology of the Polish population regarding hepatitis B virus infection as Poland is still ethnically a uniform country, with no more than 3-4% of ethnic minorities. The first results regarding distribution of HBV genotypes and serotypes in northern Poland have been published by our group in 2003 and 2004. This work was part of a scientific project supported by the Fifth Framework Programme initiative of the European Union, entitled "Emerging variants of hepatitis B virus: new tools for epidemiological survey, diagnosis of infection, and monitoring of drug resistance". In the course of the project more than 200 hepatitis B infected patients from the northern part of Poland have been enrolled, diagnosed and - if the viral load of HBV was suitable for analysis - genotyped by sequencing of the HBV pol/S gene fragment. This review presents the main characteristics and some interesting aspects of the studied cohort of chronically infected patients from northern Poland as well as the molecular epidemiology.
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ABSTRACT: The early detection of hepatitis B virus (HBV) mutants in clinical samples is important when monitoring chronic HBV patients with lamivudine-resistant mutations during lamivudine therapy. The AllGlo™ probes were designed to distinguish between wild-type (YMDD) and mutant (YVDD and YIDD) strains of HBV. The sensitivity and specificity of the assay were evaluated using a series of diluted mixtures of wild-type and mutant plasmids. This assay was compared with direct sequencing and the mutation-specific primer assay. Each YMDD, YVDD, and YIDD probe only detected its corresponding plasmid. Moreover, the assay correctly identified negative samples from 40 non-HBV infected patients and 100 healthy controls. The detection limit of this assay was 50 copies/ml for YVDD and YIDD. The assay could detect the mutant strains when they were present at ≥10% within a mixed virus population. The assay was fully concordant with direct sequencing in 34 samples (56.7%) and partially concordant in 26 samples (43.3%), and detected more types of the HBV motif than direct sequencing. AllGlo™ probe assay is a novel, sensitive and specific assay to detect lamivudine-related HBV mutants, therefore, may be useful for monitoring chronic HBV patients treated with lamivudine.Clinica chimica acta; international journal of clinical chemistry 02/2011; 412(11-12):1018-21. · 2.54 Impact Factor
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ABSTRACT: Long-term antiviral therapy of chronic hepatitis B virus (HBV) infection can lead to the selection of drug resistant HBV variants and treatment failure. Moreover, these HBV strains are possibly present in treatment-naïve patients. Currently available HBV drug resistance detection assays can identify mutants that constitute ≥5% of viral population. Furthermore, drug resistant HBV variants can be detected when a viral load is higher than 10(4) copies/mL (1718 IU/mL). The aim of this study was to compare matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) and multitemperature single-strand conformation polymorphism (MSSCP) with commercially available assays in detection of HBV drug resistant strains. HBV DNA was extracted from 87 serum samples acquired from 45 chronic hepatitis B (CHB) patients. The 37 selected HBV variants were analyzed in 4 separate primer extension reactions on the MALDI-TOF MS. Moreover, MSSCP for identifying drug resistant HBV YMDD variants was developed and turned out to be more sensitive than INNOLipa HBV DR and direct sequencing. MALDI-TOF MS had the capability to detect mutant strains within a mixed viral population occurring with an allelic frequency of approx. 1% (≥10(2) copies/mL, ≥17.18 IU/mL). In our study MSSCP detected 98% of HBV YMDD variants among strains detected by MALDI-TOF MS assay. The routine tests revealed respectively 40% and 11% for INNOLipa and direct sequencing. The commonly available HBV tests are less sensitive than MALDI-TOF MS in the detection of HBV resistant variants, including quasispecies.Journal of clinical microbiology 09/2013; · 4.16 Impact Factor
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ABSTRACT: Background Success in treating hepatitis B virus (HBV) infection with nucleoside analogues drugs is limited by the emergence of drug-resistant viral strains upon prolonged therapy. In addition to mutation patterns in the viral polymerase gene, host factors are assumed to contribute to failure of treatment in chronic HBV infections. The aim of this study was to analyze the correlation between efficacy of antiviral therapy and the prevalence of HBV pretreatment drug-resistant variants. We also analyzed the role of heterogeneity in the promoter region of the IL-10 on the HBV pol/s gene polymorphisms and efficacy of analogues-driven therapy. Material and Methods HBV DNA was extracted from 54 serum samples from chronic hepatitis B (CHB) patients. Drug-resistance mutations were analyzed using MALDI-TOF mass spectrometry technology (MALDI-TOF MS) and Multi-temperature single-strand conformation polymorphism (MSSCP). IL-10 gene promoter region polymorphisms at positions -1082, -819, and -592 were determined in allele-specific PCR reactions (AS-PCR). Results Drug-resistance mutations were detected in 74% of naïve and 93% of experienced patients, but the effect of pre-existence of drug-resistant HBV variants on antiviral therapy was not statistically significant (p=0.86). The role of polymorphisms at positions -1082 (p=0.88), -819 (p=0.26), and -592 (p=0.26) of IL-10 promoter region polymorphisms was excluded from the response-predicting factors. The main host factors predicting successful response to antiviral therapy were female sex (p=0.007) and young age (p=0.013). Conclusions The presence of drug-resistant HBV variants in baseline is not a viral predictor of good response to nucleoside/nucleotide analogues therapy. Only low HBV viral load predicted positive response to antiviral therapy. The ideal candidate for antiviral therapy is an immunocompetent, young female with low HBV viral load and elevated ALT activity.Medical science monitor: international medical journal of experimental and clinical research 01/2014; 20:321-8. · 1.22 Impact Factor