title: Toll-like receptor 3 gene polymorphisms are not associated with the risk of hepatitis B and hepatitis C virus infection.
abstract: BACKGROUND
  The present study investigated the prevalence of two single-nucleotide polymorphisms (SNPs) in the Toll-like receptor 3 (TLR3) gene in patients infected with hepatitis B virus (HBV) and hepatitis C virus (HCV).
  
  
  METHODS
  Samples collected from HCV (n = 74) and HBV (n = 35) carriers were subjected to quantitative real-time PCR (qPCR) to detect the presence of the SNPs rs5743305 and rs3775291 in TLR3 and to measure the following biomarkers: alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), and prothrombin time (PT). A healthy control group was investigated and consisted of 299 HCV- and HBV-seronegative individuals.
  
  
  RESULTS
  No significant differences in allele, genotype and haplotype frequencies were observed between the investigated groups, and no association was observed between the polymorphisms and histopathological results. Nevertheless, genotypes TA/AA (rs5743305) and GG (rs3775291) appear to be associated with higher levels of ALT (p<0.01), AST (p<0.05) and PT (p<0.05). In addition, genotypes TT (rs5743305; p<0.05) and GG (rs3775291; p<0.05) were associated with higher GGT levels.
  
  
  CONCLUSIONS
  This genetic analysis revealed the absence of an association between the polymorphisms investigated and susceptibility to HBV and HCV infection; however, these polymorphisms might be associated with a greater degree of biliary damage during the course of HCV infection.
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Keyla Santos Guedes de
authors.initials: KS
authors.lastname: Sá
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Orlando de Souza
authors.initials: Ode S
authors.lastname: Pires-Neto
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Barbara Brasil
authors.initials: BB
authors.lastname: Santana
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Samara Tatielle Monteiro
authors.initials: ST
authors.lastname: Gomes
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Ednelza da Silva Graça
authors.initials: Eda S
authors.lastname: Amoras
authors.affiliation: Instituto de Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Simone Regina da Silva
authors.initials: SR
authors.lastname: Conde
authors.affiliation: Instituto de Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Sâmia
authors.initials: S
authors.lastname: Demachki
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Vânia Nakauth
authors.initials: VN
authors.lastname: Azevedo
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Luiz Fernando Almeida
authors.initials: LF
authors.lastname: Machado
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Rosimar Neris
authors.initials: RN
authors.lastname: Martins-Feitosa
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Marluísa de Oliveira Guimarães
authors.initials: Mde O
authors.lastname: Ishak
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ishak
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Antonio Carlos Rosário
authors.initials: AC
authors.lastname: Vallinoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000410:Alanine Transaminase / Q000097:blood; D000483:Alleles; D001219:Aspartate Aminotransferases / Q000097:blood; D018450:Disease Progression; D005260:Female; D005838:Genotype; D006239:Haplotypes; D019694:Hepatitis B, Chronic / Q000235:genetics*; D019698:Hepatitis C, Chronic / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012307:Risk Factors; D051196:Toll-Like Receptor 3 / Q000235:genetics*; D055815:Young Adult; D005723:gamma-Glutamyltransferase / Q000097:blood
chemical_list: C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3; D005723:gamma-Glutamyltransferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase