title: Interaction of IL1B and IL1RN polymorphisms, smoking habit, gender, and ethnicity with aggressive and chronic periodontitis susceptibility.
abstract: BACKGROUND
  Although the interleukin-1 (IL-1) plays a critical role in the pathogenesis of periodontitis, associations between IL1 gene cluster polymorphisms and the disease remains unclear.
  
  
  OBJECTIVE
  To investigate the importance of IL1B-511C>T (rs16944), IL1B +3954C>T (rs1143634), and IL1RN intron 2 variable number tandem repeat (VNTR) (rs2234663) polymorphisms, individually or in combination, as the risk factors of periodontitis in a Southeastern Brazilian population with a high degree of miscegenation.
  
  
  METHODS
  A total of 145 individuals, with aggressive (aggressive periodontitis [AgP], n = 43) and chronic (chronic periodontitis [CP], n = 52) periodontitis, and controls (n = 50) were genotyped by polymerase chain reaction (PCR) (IL1RN intron 2 VNTR) or PCR-restriction fragment length polymorphism (PCR-RFLP) (IL1B-511 C>T and IL1B + 3954C>T) techniques.
  
  
  METHODS
  The independent t-test, Chi-square, and Fisher's exact tests were used. The SNPStats program was used for haplotype estimation and multiplicative interaction analyses.
  
  
  RESULTS
  The IL1B +3954T allele represented risk for CP (odds ratio [OR] = 2.84), particularly in smokers (OR = 4.43) and females (OR = 6.00). The minor alleles IL1RN*2 and *3 increased the risk of AgP (OR = 2.18), especially the IL1RN*2*2 genotype among  white Brazilians (OR = 7.80). Individuals with the combinations of the IL1B + 3954T and IL1RN*2 or *3-containing genotypes were at increased risk of developing CP (OR = 4.50). Considering the three polymorphisms (rs16944, rs1143634, and rs2234663), the haplotypes TC2 and CT1 represented risk for AgP (OR = 3.41) and CP (OR = 6.39), respectively.
  
  
  CONCLUSIONS
  Our data suggest that the IL1B +3954C>T and IL1RN intron 2 VNTR polymorphisms are potential candidates for genetic biomarkers of periodontitis, particularly in specific groups of individuals.
authors.affiliation: Department of Periodontology, Rio de Janeiro State University (UERJ), Rio de Janeiro, Brazil.
authors.forename: Magali Silveira Monteiro
authors.initials: MS
authors.lastname: Ribeiro
authors.affiliation: Department of Periodontology, Rio de Janeiro State University (UERJ), Rio de Janeiro, Brazil.
authors.forename: Renata Botelho Antunes
authors.initials: RB
authors.lastname: Pacheco
authors.affiliation: Department of Periodontology, Rio de Janeiro State University (UERJ), Rio de Janeiro, Brazil.
authors.forename: Ricardo Guimarães
authors.initials: RG
authors.lastname: Fischer
authors.affiliation: Department of Biochemistry, Rio de Janeiro State University (UERJ), Rio de Janeiro, Brazil.
authors.forename: Jacyara Maria Brito
authors.initials: JM
authors.lastname: Macedo
keywords: Biomarkers; genotype combinations; haplotypes; interleukin-1; periodontitis; polymorphisms