Prevalência, caracterização e distribuição dos genótipos, e perfil de mutações do pré-core do vírus da hepatite B em doadores de sangue do Rio de Janeiro

• Autor(a) principal: Correia Júnior, António Ludgero
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/7791
• topic: Blood donors; Hepatitis B Virus; HBV genotype; Phylogenetic analysis; Precore mutation; Doadores de sangue; Vírus da Hepatite B; Genótipo de HBV; Análise filogenética; Mutação do pré-core; Hepatite B; Hepatite B Prevenção e controle; Doadores de sangue; Vírus da Hepatite B Genética; CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA MOLECULAR E DE MICROORGANISMOS

Hepatitis B virus (HBV) infection remains to be a serious global health problem, affecting around two billion people. HBV is classified into 10 genotypes (A to J) and has diverse geographical distribution. Some genotypes are related to the evolution of infection, disease severity, and the onset of mutations that can affect the immune system and therapeutic responsiveness. The most commonly reported precore mutation is the G1986A which leads to a premature introduction of a stop codon in the precore region preventing the production of hepatitis B e antigen (HBeAg). Donors represent a healthy population and are ideal for studying viral infectivity, as it avoids the bias of selecting individuals using antiviral drugs. The objective of this study was to determine the prevalence and temporal trend of HBV infection among blood donors from 2001 to 2011 in the city of Rio de Janeiro, to characterize the diversity and evolution of HBV genotypes in this period and to analyze the mutation profile of HBV precore.The first part of the study was conducted on serum from 109 blood donors carrying HBV markers in Rio de Janeiro from 2001-2011. The serology results were confirmed by immunoassay, and the molecular characterization was performed by real-time PCR and direct sequencing followed by phylogenetic analysis. Among 109 donors 81% were male, and the age average was 35 years. The most affected age group was older than 30 years. Four genotypes were observed among the 99 subjects whose samples were successfully genotyped: A (73.7%), D (16.2%), F (8.1%), and E (2.0%). The frequency of donors infected with genotype A decreased by almost the same rate as the frequency of donors positive for HBsAg and anti-HBc. In addition to the decrease of HBV infection, we found two individuals carrying HBV genotype E. To perform the analysis of precore mutation samples from 23 indiduals were used.The analysis of precore mutation revealled that 26.1% of individuals (6/23) were infected with strains presenting the G1896A mutation, of which four were genotype D. The presence of HBV genotype E, unusual in Brazil, and HBV strains carrying precore mutations reinforces the importance of blood bank as sentinel to identify new genotypes circulating into the country and its prompt notification, and thus help to improve the planning of public health policies that promotes prevention, treatment and the monitoring of infection.