Haplotype association of Interleukin-8 gene with susceptibility to periodontitis

Objective: The purpose of this study was to investigate whether there is an individual association of the –845(T/C), –738(T/A) and –353(A/T) single nucleotide polymorphisms (SNPs) in the IL8 gene, as well their haplotypes with susceptibility to periodontitis in Brazilian population. Methods: DNA was extracted from buccal epithelial cells from 500 Brazilian individuals (Control group n = 224, Periodontitis group n = 276). The –845 and –738 SNPs were genotyped by PCR-RFLP method (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism). The –353 SNP was investigated using Sequence Specific Primers Polymerase Chain Reaction method (SSP-PCR). Differences of the allelic and genotypic frequencies were assessed by Chi-squared test or by using the CLUMP program for rare alleles. Haplotypes were estimated using the ARLEQUIN program. Differences in the haplotype frequencies between the studied groups were assessed by the CLUMP program. Results: No differences were observed in the allelic and genotypic distribution of all the investigated SNPs between control and periodontitis group when they were analyzed alone. The haplotypes distribution in the periodontitis and controls groups was significantly different considering the total casuistic and in the non-smokers subgroup. Individuals with CTA haplotype seemed to be over twice more likely to develop periodontitis than individuals with other haplotypes (OR=2.14, 95% CI =1.36-3.38). Conclusion: The analysis of haplotypes constructed from –845(T/C), –738(T/A) and –353 (A/T) polymorphisms in the IL8 gene demonstrated association with susceptibility to periodontitis in Brazilian individuals.

This study was supported by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (Fapesp - 05/03231-7)