Interleukin‐8 Gene Promoter Polymorphism (rs4073) May Contribute to Chronic Periodontitis

Abstract

Background: The proinflammatory chemokine interleukin (IL)‐8 is important in the regulation of the inflammatory response. Analyses of the single nucleotide polymorphism (SNP) reference sequence (rs) 4073 showed that the A allele upregulated IL‐8 levels after stimulation with lipopolysaccharides. We investigated the association of the SNP rs4073 with chronic periodontitis. Methods: Genotyping was performed by a standard polymerase chain reaction–restriction fragment length polymorphism assay in 289 genomic DNA samples of healthy control subjects and patients with chronic periodontitis; analyses were adjusted by multivariate logistic regression modeling. A real‐time polymerase chain reaction performance was used to detect levels of the IL‐8 mRNA. Results: The analysis pointed to a statistically significant association of chronic periodontitis with the heterozygous TA genotype ( P = 0.001); the results showed an increase in the frequency of the A allele in the diseased group (36% in the control group versus 48% in the periodontitis group). The higher levels of the IL‐8 mRNA were found in the periodontitis group, mainly in individuals who presented the TA genotype ( P = 0.03). Conclusion: The SNP rs4073 was associated with chronic periodontitis in non‐smoker Brazilian subjects because the frequency of the A allele was higher in the disease group than in the control group, and the TA genotype was associated with increased levels of IL‐8 mRNA transcripts.