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HBV Strains (hbv + strain)
Selected AbstractsCharacterization of hepatitis B virus reverse transcriptase sequences in Chinese treatment naive patientsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 8 2009Yue Han Abstract Background and Aims:, The hepatitis B virus (HBV) reverse transcriptase (RT) plays an important role in viral replication. The aim of the present study was to characterize profiles of the RT region and to construct a database for further studies. Methods:, Serum samples were obtained from 328 treatment naive patients chronically infected with HBV in five Chinese cities. Mutation status, genotypes and deep sequence analysis were carried out by amplifying and sequencing the RT region. Results:, The base usage in the RT region differed at the mono- and dinucleotide level and thymidine dominated. The higher the variability of the strain was, the more it replicated. No significant clustering was found between our HBV RT sequences and those isolated 10 years ago (achieved from genebank). Nucleotide analogue resistance related mutants exist. The M204V/I mutation was found in 1.8% of the strains, 1.2% had L180M+ M204V/I, 0.6% had A181T/V, and only one had all three mutations. Minor strain mutants were found in 9.3% of the samples studied. The genotype B patients made up 36.6% (88.7% B2) and were mostly found in southern China, 63.4% (92.2% C2) were genotype C, and only one was genotype D. The average age of HBeAg positive genotype B patients was 29.5 ± 10.4 years, for genotype C it was 36.1 ± 10.9 (P < 0.001). Conclusion:, Primarily antiviral resistance related mutant strains do exist in treatment naïve patients. Without antiviral pressure, HBV strains evolved at a normal speed. In depth sequence analysis implied that viral replication might be correlated with its variability, which needs to be further investigated. [source] Prediction of response to treatment of chronic hepatitis B with pegylated interferon in the PhilippinesJOURNAL OF MEDICAL VIROLOGY, Issue 2 2010Dorothy M. Agdamag Abstract The response marker for interferon has not been investigated fully for hepatitis B viruses (HBVs) in the Philippines where novel subtypes B5 and C5 were recognized recently. The prediction parameters for interferon treatment were assessed, with emphasis on the mutation patterns in the basal core promoter and precore regions in patients with chronic hepatitis B. Seventeen HBeAg-positive patients were stratified according to response to treatment with pegylated interferon based on HBe seroconversion and HBV load. Intra-patient distributions of wild-type strains (A1762, G1764) and variants (T1762, A1764) were analyzed using HBV-DNA amplification and subsequent molecular cloning. The rate of variants (T1762, A1764) harbored by a patient was higher among responders (41.2% and 31% per person on average) than among non-responders (2.4% and 2.4%) to treatment with pegylated interferon at the baseline, respectively (P,<,0.05). The rate of variants (T1762, A1764) harbored by responders (41.2% and 31%) decreased to 1.7% and 1.7%, and wild-type strains (A1762, G1764) conversely became majority (98.3% and 98.3%) after treatment with pegylated interferon, respectively. HBV strains harbored by two of six responders and a patient with lower baseline load (1.0,×,104,copies/ml) showed genotype shift from A to other genotypes, where genotype A disappeared preferentially after the loss of HBeAg and genotypes B and C formed a major population. These results suggest that the HBV variants (T1762, A1764) and HBV genotype A in the Philippines have an advantage in the response to pegylated interferon. These results warrant a large-scale examination for further precise prediction of the response to treatment with interferon. J. Med. Virol. 82:213,219, 2010. © 2009 Wiley-Liss, Inc. [source] Dynamics of lamivudine-resistant hepatitis B virus during adefovir monotherapy versus lamivudine plus adefovir combination therapyJOURNAL OF MEDICAL VIROLOGY, Issue 7 2008Samreen Ijaz Abstract Adefovir dipivoxil has been used alone or together with lamivudine to suppress lamivudine-resistant hepatitis B virus (HBV). However, the dynamics of HBV populations under different selection pressures and their impact on treatment outcome are poorly understood. Pyrosequencing® was applied to quantify longitudinally the evolution of wild type and lamivudine/ adefovir-resistant HBV. Eight patients, with lamivudine-resistant HBV, were randomized to receive adefovir monotherapy or adefovir/lamivudine combination therapy for a median of 79 and 71 weeks, respectively. Pyrosequencing® proved highly sensitive with a lower limit of quantitation of minor HBV populations of 2% irrespective of viraemia levels. Adefovir/lamivudine treatment resulted in greater viraemia reduction than adefovir monotherapy. During combination therapy, lamivudine-resistant HBV populations (codons 180 and 204) remained dominant (>90%) and no adefovir-resistance developed. During adefovir monotherapy, reversion to wild-type HBV was detected in two patients with one patient accumulating rapidly adefovir-resistant HBV along with increased viraemia. In conclusion, the dynamics of drug-resistant HBV strains vary under different selection pressures which have a significant impact on the success of rescue therapy, as well as for the selection of new mutations. The use of techniques such as Pyrosequencing provides an evidence-based approach for successful management of drug-resistant HBV. J. Med. Virol. 80: 1160,1170, 2008. © 2008 Wiley-Liss, Inc. [source] Lamivudine prevents reactivation of hepatitis B and reduces mortality in immunosuppressed patients: systematic review and meta-analysisJOURNAL OF VIRAL HEPATITIS, Issue 2 2008L. H. Katz Summary., To assess the effects of prophylactic lamivudine on reactivation and mortality following immunosuppressive therapy in hepatitis B surface antigen (HBsAg)-positive patients, we performed a meta-analysis. Systematic review and meta-analysis of randomized and nonrandomized prospective controlled trials and retrospective comparative case series were identified through The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and LILACS. The primary outcomes were virological reactivation, clinical reactivation and mortality. Secondary outcomes included hepatitis B virus (HBV)-related mortality, liver histology, discontinuation or disruption of immunosuppressive therapy, lamivudine-resistant HBV strains and adverse events. A total of 21 studies were included, two of which were randomized controlled trials. Clinical and virological reactivation were significantly reduced in the lamivudine group [odds ratio (OR) 0.09; 95% confidence interval (CI) 0.05,0.15 and OR 0.04; 95% CI 0.01,0.14 respectively]. All-cause mortality was significantly reduced in the lamivudine group (OR 0.36; 95% CI 0.23,0.56) which translates to only 11 patients who need to be treated to prevent one death. Lamivudine significantly reduced HBV-related mortality, and discontinuations or disruptions of the immunosuppressive treatment. No adverse effects of lamivudine were recorded, and resistance to lamivudine occurred in low rates. We demonstrated a clear benefit of lamivudine in terms of clinical and virological HBV reactivation, overall mortality, HBV-related mortality and interruptions or discontinuations in the immunosuppressive treatment. Lamivudine should be administered prophylactically to HBsAg-positive patients who are about to receive immunosuppressive therapy. [source] | ||||||||||