title: Association of haplotypes in the IL8 gene with susceptibility to chronic periodontitis in a Brazilian population.
abstract: BACKGROUND
  Interleukin 8 (IL-8) is a chemokine related to the initiation and amplification of acute and chronic inflammatory processes. Polymorphisms in the IL8 gene have been associated with inflammatory diseases. We investigated whether the -845(T/C) and -738(T/A) single nucleotide polymorphisms (SNPs) in the IL8 gene, as well as the haplotypes they form together with the previously investigated -353(A/T), are associated with susceptibility to chronic periodontitis.
  
  
  METHODS
  DNA was extracted from buccal epithelial cells of 400 Brazilian individuals (control n=182, periodontitis n=218). SNPs were genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Disease associations were analyzed by the chi(2) test, Exact Fisher test and Clump program. Haplotypes were reconstructed using the expectation-maximization algorithm and differences in haplotype distribution between the groups were analyzed to estimate genetic susceptibility for chronic periodontitis development.
  
  
  RESULTS
  When analyzed individually, no SNPs showed different distributions between the control and chronic periodontitis groups. Although, nonsmokers carrying the TTA/CAT (OR=2.35, 95% CI=1.03-5.36) and TAT/CTA (OR=6.05, 95% CI=1.32-27.7) haplotypes were genetically susceptible to chronic periodontitis. The TTT/TAA haplotype was associated with protection against the development of periodontitis (for nonsmokers OR=0.22, 95% CI=0.10-0.46).
  
  
  CONCLUSIONS
  Although none of the investigated SNPs in the IL8 gene was individually associated with periodontitis, some haplotypes showed significant association with susceptibility to, or protection against, chronic periodontitis in a Brazilian population.
authors.affiliation: Departamento de Diagnóstico e Cirurgia, Faculdade de Odontologia de Araraquara, UNESP-UNIV Estadual Paulista, SP, Brazil.
authors.forename: Yeon Jung
authors.initials: YJ
authors.lastname: Kim
authors.forename: Aline Cavalcante
authors.initials: AC
authors.lastname: Viana
authors.forename: Karen Maria C
authors.initials: KM
authors.lastname: Curtis
authors.forename: Silvana Regina Perez
authors.initials: SR
authors.lastname: Orrico
authors.forename: Joni Augusto
authors.initials: JA
authors.lastname: Cirelli
authors.forename: Celso Teixeira
authors.initials: CT
authors.lastname: Mendes-Junior
authors.forename: Raquel Mantuaneli
authors.initials: RM
authors.lastname: Scarel-Caminaga
mesh_terms: D000328:Adult; D001938:Brazil; D002908:Chronic Disease; D005260:Female; D006239:Haplotypes; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide
chemical_list: D016209:Interleukin-8