Avaliação da presença de mutações de resistência no gene da NS5B e do prognóstico da infecção pelo HCV através da IL-28B em pacientes monoinfectados com HCV no RJ / Evaluation of resistance mutations presence in the NS5B gene and prognosis of HCV infection throught IL-28B in HCV monoinfected patients of RJ

Estima-se que a prevalência global da população mundial com hepatite C é de 3%. Pouco se sabe sobre a resposta ao tratamento com respeito à resistência viral. Algumas mutações no fragmento de 109 aminoácidos da NS5B são associadas com resistência ao interferon (IFN) e ribavirina (RBV). Estudos moleculares e clínicos identificaram fatores associados com o hospedeiro e vírus relacionados associada com a resposta ao tratamento, tal como o gene que codifica a IL-28B. Este estudo foi dividido em duas fases, cujos objetivos foram caracterizar a frequência de mutações que conferem resistência ao HCV e avaliar a relevância das mutações em pacientes Respondedores (R) ou Não Respondedores (NR) ao tratamento e caracterizar geneticamente as populações sobre polimorfismos genéticos nos SNPs da IL-28B em relação ao prognóstico da resposta ao tratamento. As amostras dos pacientes foram submetidas a testes de genotipagem e carga viral. As sequências geradas foram comparadas no BLAST e no banco de dados Los Alamos HCV. Realizamos o alinhamento das sequências homólogas e as mutações identificadas. Com base no genótipo e carga viral determinamos a classificação dos pacientes de acordo com a resposta à terapia. O DNA genômico foi isolado a partir de sangue periférico para a realização da tipagem de SNPs de IL-28B. A metodologia utilizada foi de PCR em tempo real utilizando sondas TaqMan SNP específico. A análise dos dados foi realizada utilizando GraphPad Prism com qui-quadrado, risco relativo (RR), Odds Ratio (OR) e intervalo de confiança de 95%, com um nível de significância de P <0,05. Foi encontrado na primeira fase deste estudo uma taxa significativa mutações associadas ao tratamento nas amostras estudadas. A prevalência de mutações associadas à resistência ao IFN e RBV bem como a novos medicamentos antivirais localizados no fragmento de 109 aminoácidos da NS5B foi examinado em 69 indivíduos infectados naïve no Rio de Janeiro, Brasil. Na segunda fase, as mutações foram ...

It is estimated that the overall prevalence of the average world population with hepatitis C is 3%. Little is known about the treatment response with respect to viral resistance. Some mutations in the 109-aminoacid fragment of NS5B are associated to Interferon (IFN) and Ribavirin (RBV) resistance. Molecular and clinical studies have identified factors associated with the host and related viruses associated with response to treatment, as the gene encoding IL-28B. This study was divided into two phases whose objectives were to characterize the frequency of mutations conferring resistance to HCV viral evaluating the relevance of these in Responders (R) or Non-Responders (NR) patients to treatment and to characterize genetically the populations regarding genetic polymorphisms SNPs IL-28B in relation to prognosis of response to treatment for HCV. Patient samples were subjected to tests for genotyping and viral load. The sequences generated were compared in the BLAST and the Los Alamos database HCV. We conducted the alignment of homologous sequences and mutations identified. Based on virological parameters genotype and viral load determined the classification of patients according to response to therapy. Genomic DNA was isolated from peripheral blood for carrying out the typing of SNPs of IL-28B. The methodology used was real-time PCR using TaqMan probes specific SNPs. Data analysis was performed using GraphPad Prism with chi-square, relative risk (RR), Odds Ratio (OR) and confidence interval of 95% with a significance level of P <0.05. To study these biological parameters we associated the responsive patients, non-responders, the viral load, genotype, and IL-28B polymorphism to treatment outcome. We found in the first phase of this study a significant rate of treatment-associated mutations in the samples studied. The prevalence of mutations associated to resistance to interferon and ribavirin (IFN/RBV) as well new antiviral drugs located in the 109 aminoacid ...

Association of hepatitis C virus NS5B variants with resistance to new antiviral drugs among untreated patients

Mutations located in the 109-amino acid fragment of NS5B are typically associated with resistance to interferon (IFN) and ribavirin (RIB) and to new antiviral drugs. The prevalence of these mutations was examined in 69 drug-naïve individuals with hepatitis C virus (HCV) infections in Rio de Janeiro, Brazil. Mutations related to non-response to IFN/RIB were observed in all subtypes studied (1a, 1b, 2b, 3a and 4). The most common mutation was Q309R, present in all subtypes, except subtype 2b with frequency above 20 percent. D244N was detected only in subtype 3a and A333E was detected only in subtype 2b. We did not detect the S282T, S326G or T329I mutations in any of the samples analysed. Of note, the C316N mutation, previously related to a new non-nucleoside compound (HCV796 and AG-021541), was observed in only eight of 33 (24 percent) samples from subtype 1b. Site 316 was under positive selection in this HCV variant. Our data highlight the presence of previously described resistance mutations in HCV genotypes from drug-naïve patients.