ABSTRACT
INTRODUCTION: The identification of genotypes was essential for the prognosis and treatment of hepatitis C virus chronic patients in recent years. The aims of the study were to know the frequency of genotypes diagnosed in the last six years at the laboratory, and reveal the contribution of an in-house assay for molecular characterization of viruses. MATERIAL AND METHODS: The genotyping of hepatitis C virus by LiPA was performed in 923 samples, mostly from male individuals. The subtyping of hepatitis C virus by an in-house assay to target regions in the Core/E1 and/or NS5B was performed in 112 samples. RESULTS: We observed a high prevalence of genotype 1 (56.6%), with a frequency of subtype 1a four times higher compared to 1b. All cases of genotype 3 (27.5%) were subtype 3a. For the cases of genotype 4 (12.9%), it were identified subtypes 4a (65.5%), 4d (31%), 4b (1.7%) and 4c (1.7%). Recombinants intragenotype 2, the RF1_2k/1b, and mixed infections, were also identified. DISCUSSION: The most prevalent subtypes (1a and 3a) obtained are usually described in injecting drug users. Although most of the samples analysed match to inmates (78.4%), we cannot exclude any possible risk behaviors associated with illicit drug use. CONCLUSIONS: The high prevalence of subtype 1a, the frequency and diversity of genotype 4, and the identification of recombined virus suggest modification of the molecular pattern of hepatitis C virus infection described in the past. The in-house assay proved to be useful for the correct classification of hepatitis C virus and improving knowledge about the diversity of virus circulating in the country.
Introdução: A identificação dos genótipos do vírus da hepatite C foi essencial para o prognóstico e tratamento dos doentes crónicos durante os últimos anos. Foram objetivos deste estudo conhecer a frequência de genótipos do vírus da hepatite C nos últimos seis anos, e revelar o contributo de um ensaio in-house para caracterização molecular do vírus. Material e Métodos: A genotipagem do vírus da hepatite C por LiPA foi realizada em 923 amostras, maioritariamente provenientes de indivíduos do sexo masculino. A subtipagem do vírus da hepatite C pelo ensaio in-house com alvo nas regiões Core/E1 e/ou NS5B foi efetuada em 112 amostras. Resultados: Observámos elevada prevalência do genótipo 1 (56,6%), sendo a frequência do subtipo 1a quatro vezes superior ao subtipo 1b. Todos os casos de genótipo 3 (27,5%) foram classificados em subtipo 3a. Nas infeções pelo genótipo 4 (12,9%), identificaram-se os subtipos 4a (65,5%), 4d (31%), 4b (1,7%) e 4c (1,7%). Foram identificadas a RF1_2k/1b, recombinantes intragenótipo 2 e potenciais infeções mistas na população analisada. Discussão: Os subtipos mais prevalentes, 1a e 3a, estão descritos como comuns em utilizadores de drogas injetáveis. Apesar da maioria das amostras analisadas corresponder a reclusos (78,4%), não podemos excluir eventuais comportamentos de risco associados ao consumo de drogas ilícitas. Conclusões: A prevalência elevada do subtipo 1a, a frequência e diversidade do genótipo 4 e a identificação de vírus geneticamente recombinados, sugerem alteração do padrão molecular vírus da hepatite C descrito no passado. O ensaio in-house implementado revelou ser útil para a correta classificação do vírus da hepatite C e melhoria do conhecimento sobre a diversidade do vírus em circulação no país.
Subject(s)
Genotype , Hepacivirus/genetics , Hepatitis C/epidemiology , Adult , Brazil/epidemiology , Drug Users , Female , Hepacivirus/pathogenicity , Humans , Male , Risk-Taking , Viral Nonstructural ProteinsABSTRACT
Hepatitis C virus (HCV) genotype determination is required in clinical practice to establish the dose and duration of antiviral treatment. Although subtype identification does not impact on current therapy this is changing with new specific inhibitors of HCV enzymes and functions which are becoming available worldwide. These new drugs may yield different antiviral responses and resistance profiles. Accurate classification of HCV genotype and subtype is therefore crucial. An "in-house" method was developed for improving HCV subtyping and the results were compared with a second-generation line probe assay (LiPA) used extensively in Portugal. Phylogenetic analysis was undertaken of the C/E1 and NS5B genomic regions of HCV isolated from 72 prisoners with chronic HCV infection and from reference samples. Although LiPA is considered to be a good method for genotyping, HCV was subtyped in only 47.2% of cases compared with 95.8% of cases by the "in-house" method. Molecular data for both C/E1 and NS5B regions were obtained in 88.9% of the samples. Two out of 23 cases of subtype 1a were misclassified as subtype 1b by LiPA. A putative recombinant like RF1_2k/1b, two potential inter-genotypic recombinants 1b/4a and 3a/4a, and also a potential intra-genotypic recombinant 2q/2k in C/E1 and 2k/2a in NS5B were also identified. The "in-house" method enabled HCV to be subtyped accurately with the detection, in some cases, of recombinant viruses or dual HCV infections. Near full-length genomic analysis to characterize these potential recombinant viruses is planned.
