Dataset Information

A meta-analysis on genetic variability of RT/HBsAg overlapping region of hepatitis B virus (HBV) isolates of Bangladesh.

ABSTRACT: Background and aim:Hepatitis B caused by HBV is a serious public health hazard prevalent worldwide including Bangladesh. Few scattered molecular studies of HBV have been reported in Bangladesh. This study aimed to analyze the genetic variability of RT/HBsAg overlapping region of HBV isolates of Bangladesh and determination of correlation among the genotype/serotype and HBsAg escape and/or drug-resistant mutations. Methods:A total of 97 complete HBsAg sequences of Bangladeshi HBV isolates from 2005 to 2017 from NCBI GenBank were extracted and analyzed using several HBV bioinformatics tools such as Geno2pheno-HBV, HBV Serotyper, HIV-Grade:HBV-Tool, and CLC sequence viewer. Results:The prevalence of genotypes A, C, and D are 18, 46 and 35% which correspond to serotype adw, adr, and ayw, respectively. The prevalence of HBsAg escape mutations is 51% and most of which (62%) are found in the genotype D followed by 32% in genotype C and 6% in genotype A. Interestingly most (24/36) of the sequences of HBsAg escape mutations contained 128?V mutant which all belongs to only serotype ayw3 (Genotype D). Prevalence of drug-resistant mutations is ~?11%, most of which are from genotype C (63.64%) and D (36.36%). Lamivudine resistant mutations were found in ~?11% of sequences followed by Telbivudine 10% and Adefovir 3% where Tenofovir showed susceptibility to all 97 sequences. Moreover, 7 among of 97 sequences showed both HBsAg and drugs resistant mutations and none of them are found due to the same nucleotide substitutions. Conclusion:There is a strong correlation among the genotype/serotype and HBsAg escape and/or drug-resistant mutations. This meta-analytical review will be helpful for genotype-serotype prediction by PCR-based diagnosis and development of vaccine and/or diagnostic kits, and the treatment against HBV infection in the future.

SUBMITTER: Hossain MG

PROVIDER: S-EPMC6836373 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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A meta-analysis on genetic variability of RT/HBsAg overlapping region of hepatitis B virus (HBV) isolates of Bangladesh.

Hossain Md Golzar MG Ueda Keiji K

Infectious agents and cancer 20191107

<h4>Background and aim</h4>Hepatitis B caused by HBV is a serious public health hazard prevalent worldwide including Bangladesh. Few scattered molecular studies of HBV have been reported in Bangladesh. This study aimed to analyze the genetic variability of RT/HBsAg overlapping region of HBV isolates of Bangladesh and determination of correlation among the genotype/serotype and HBsAg escape and/or drug-resistant mutations.<h4>Methods</h4>A total of 97 complete HBsAg sequences of Bangladeshi HBV i ...[more]

PMID: 31709005

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Project description:Background and objectivesThis study was conducted by the International Consortium for Blood Safety (ICBS) to identify high-quality test kits for detection of hepatitis B virus (HBV) surface antigen (HBsAg) for the benefit of developing countries.Materials and methodsThe 70 HBsAg test kits from around the world were evaluated comparatively for their clinical sensitivity, analytical sensitivity, sensitivity to HBV genotypes and HBsAg subtypes, and specificity using 394 (146 clinical, 48 analytical and 200 negative) ICBS Master Panel members of diverse geographical origin comprising the major HBV genotypes A-F and the HBsAg subtypes adw2,4, adr and ayw1-4.ResultsSeventeen HBsAg enzyme immunoassay (EIA) kits had high analytical sensitivity <0.13 IU/ml, showed 100% diagnostic sensitivity, and were even sensitive for the various HBV variants tested. An additional six test kits had high sensitivity (<0.13 IU/ml) but missed HBsAg mutants and/or showed reduced sensitivity to certain HBV genotypes. Twenty HBsAg EIA kits were in the sensitivity range of 0.13-1 IU/ml. The other eight EIAs and the 19 rapid assays had analytical sensitivities of 1 to >4 IU/ml. These assays were falsely negative for 1-4 clinical samples and 17 of these test kits showed genotype dependent sensitivity reduction. Analytical sensitivities for HBsAg of >1 IU/ml significantly reduce the length of the HBsAg positive period which renders them less reliable for detecting HBsAg in asymptomatic HBV infections. Reduced sensitivity for HBsAg with genetic diversity of HBV occurred with genotypes/subtypes D/ayw3, E/ayw4, F/adw4 and by S gene mutants. Specificity of the HBsAg assays was >or=99.5% in 57 test kits and 96.4-99.0% in the remaining test kits.ConclusionDiagnostic efficacy of the evaluated HBsAg test kits differed substantially. Laboratories should therefore be aware of the analytical sensitivity for HBsAg and check for the relevant HBV variants circulating in the relevant population.

Project description:As alternative indexes of hepatitis B virus (HBV), covalently closed circular DNA (cccDNA) transcriptional activity, hepatitis B surface antigen (HBsAg), hepatitis B core-related antigen (HBcrAg), and peripheral blood RNA known as pgRNA, have been advocated as novel serum markers for prediction of prognosis and treatment response in chronic hepatitis B (CHB). Since the availability of commercial quantitative assays of HBsAg in 2011, HBsAg has been widely used for predicting treatment response of patients with CHB. Patients who received interferon therapy have shown a sharper reduction of HBsAg level than those who received nucleoside drug (NAs) therapy. Upon peginterferon treatment, sustained responders have presented a larger reduction of HBsAg level than the non-responders. An absence of HBsAg decline, together with < 2log reduction in HBV DNA at week 12, can serve as a stopping rule in HBsAg-negative patients infected with genotype D HBV. A sharp reduction of HBsAg titer in the NAs therapy is a predictor of HBsAg clearance in long-term treatment. HBcrAg, which consists of three species of related proteins sharing an identical 149 amino acid sequence, including HbcAg, hepatitis B e antigen (HBeAg), and a truncated 22-kDa precore protein, is still detectable in situations where serum HBV DNA levels become undetectable or HBsAg loss is achieved. Therefore, HBcrAg remains a measurable serum marker to correlate with cccDNA in this situation. The decline in HBcrAg has been observed with NAs therapy and the pattern of decline might provide prognostic information on the risk of HBV post-treatment reactivation. Peripheral blood RNA, which is known as pgRNA, directly derives from cccDNA and reflects intrahepatic cccDNA level. Quantitative pgRNA has been suggested to be helpful in CHB management. However, commercial quantitative assays are lacking. Additionally, the use of simultaneous and continuous clearance of HBV RNA and HBV DNA in serum has been suggested to be a safe stopping rule of NAs therapy for patients with CHB. However, clinical studies of large sample sizes are needed to prove the feasibility and significance of using serum HBV RNA as the assessment standard of antiviral therapy in CHB and the safety of the stopping rule in clinics.

Project description:BackgroundClinically, some patients whose HBsAg becomes negative owing to antiviral therapy or spontaneously still show a low level of HBV DNA persistence in serum. T-lymphocyte subsets, cytokine levels and HBV S gene sequences were analyzed in this study.MethodsA total of 52 HBsAg-negative and HBV DNA-positive patients(HBsAg-/HBV DNA+ patients), 52 persistently HBsAg-positive patients(HBsAg+/HBV DNA+ patients) and 16 healthy people were evaluated. T-lymphocyte subsets of these patients were detected by flow cytometry, serum cytokines and chemokines were detected by the Luminex technique, and the HBV S region was evaluated by Sanger sequencing. T%, T-lymphocyte, CD8+ and CD4+T lymphocyte were lower in the HBsAg-negative group than in the HC group. Compared with the HBsAg-positive group, the HBsAg-negative group had lower levels in T lymphocyte %, CD8+T lymphocyte %, CD8+T lymphocyte and CD4/CD8. These difference were statistically significant (P<0.05). Serum IFN-γ, IFN-α and FLT-3L levels were significantly higher in the HBsAg-negative group than in the HBsAg-positive group (P<0.05). However, levels of many cytokines related to inflammation (i.e., IL-6, IL-8, IL10, IL-12, IL-17A) were lower in the HBsAg-negative group. Fifty-two HBsAg-negative samples were sequenced, revealing high-frequency amino acid substitution sites in the HBV S protein, including immune escape mutations (i.e., Y100C, S114T, C124Y, P127L, G130R, T131N, M133T, C137S, G145A) and TMD region substitutions (i.e., E2K/R/D, G7D/R, G10D, A17R, F20L/S, L21V, L22V).ConclusionsAccording to the results of T-lymphocyte subsets and serum cytokines, it can be deduced that the cellular immune function of HBsAg-negative patients is superior to that of HBsAg-positive patients, with attenuation of liver inflammation. HBsAg-negative patients may show a variety of mutations and amino acid replacement sites at high frequency in the HBV S region, and these mutations may lead to undetectable HBsAg, HBsAg antigenic changes or secretion inhibition.

Dataset Information

A meta-analysis on genetic variability of RT/HBsAg overlapping region of hepatitis B virus (HBV) isolates of Bangladesh.

Publications

A meta-analysis on genetic variability of RT/HBsAg overlapping region of hepatitis B virus (HBV) isolates of Bangladesh.

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