title: Toll-like receptor (TLR2, TLR4 and TLR5) gene polymorphisms and Helicobacter pylori infection in children with and without duodenal ulcer.
abstract: Helicobacter pylori infection is mainly acquired in childhood, and polymorphisms in the host genes coding for Toll-like receptors (TLRs) may influence the innate and adaptive immune response to the infection, affecting the susceptibility to H. pylori or the disease outcomes. Our aim was to investigate whether TLR4, TLR2, and TLR5 polymorphisms were associated with H. pylori susceptibility and risk for duodenal ulcer in children. Gastric biopsy specimens were obtained at endoscopy for evaluation of H. pylori status, TLR4, TLR2 and TLR5 polymorphisms from 486 children (254 H. pylori-negative and 232 H. pylori-positive: 72 with and 160 without duodenal ulcer). cagA status of H. pylori infection was investigated by PCR. The levels of gastric cytokines were detected by ELISA. H. pylori-positivity or duodenal ulcer were not associated with TLR2, TLR4 or TLR5 polymorphisms. Otherwise, the presence of TLR4 polymorphic allele was associated with infection by cagA-positive strains and with increased gastric levels of interleukin-8 and interleukin-10. TLR4 polymorphism might ultimately contribute to more severe consequences of the infection in adulthood since it was associated with susceptibility to cagA-positive H. pylori infection early in life.
authors.affiliation: Laboratory of Research in Bacteriology, Faculdade de Medicina, UFMG, Av. Alfredo Balena 190/4026, 30130-100 Belo Horizonte, Brazil.
authors.forename: Sílvia Beleza
authors.initials: SB
authors.lastname: Moura
authors.forename: Luciana Ramos
authors.initials: LR
authors.lastname: Almeida
authors.forename: Juliana Becattini
authors.initials: JB
authors.lastname: Guerra
authors.forename: Gifone Aguiar
authors.initials: GA
authors.lastname: Rocha
authors.forename: Andreia Maria
authors.initials: AM
authors.lastname: Camargos Rocha
authors.forename: Fabrício Freire
authors.initials: FF
authors.lastname: Melo
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Corrêa-Oliveira
authors.forename: Paulo
authors.initials: P
authors.lastname: Bittencourt
authors.forename: Simone Diniz
authors.initials: SD
authors.lastname: Carvalho
authors.forename: Dulciene Maria
authors.initials: DM
authors.lastname: Magalhães Queiroz
mesh_terms: D000293:Adolescent; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000032:analysis; D004198:Disease Susceptibility; D004381:Duodenal Ulcer / Q000235:genetics* / Q000276:immunology / Q000382:microbiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005753:Gastric Mucosa / Q000737:chemistry / Q000276:immunology; D016481:Helicobacter Infections / Q000150:complications* / Q000235:genetics* / Q000276:immunology; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007223:Infant; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012307:Risk Factors; D051193:Toll-Like Receptors / Q000235:genetics*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D016207:Cytokines; D051193:Toll-Like Receptors; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori