The association of interleukin-4 haplotypes with chronic periodontitis in a Czech population.

BACKGROUND

Cytokine gene polymorphisms are known to influence the susceptibility and disease course of many chronic disorders. Recently, interleukin (IL)-4 gene polymorphisms were associated with aggressive periodontitis. The aim of this study was to test differences in the distribution of the IL-4 alleles, genotypes, and haplotypes between patients with chronic periodontitis (CP) and healthy controls in a Czech population.

METHODS

The association study was conducted using an age- and smoking status-matched case-control design in patients with CP (n = 194) and healthy controls (n = 158) using the polymerase chain reaction-restriction fragment length polymorphism methods for the -590C/T, -33C/T, and intron 3 variable number tandem repeat (VNTR) variants of the IL-4 gene.

RESULTS

No significant differences between patients and controls were found in allele and genotype frequencies of all three polymorphisms. Nevertheless, complex analysis revealed significant differences in haplotype frequencies between the groups (P = 0.005). The haplotype T(-590)/T(-33)/allele 2 VNTR (70 base pairs)(2) of the IL-4 gene was significantly more frequent in patients with CP than in controls (17.0% versus 11.0%; odds ratio = 1.85; 95% confidence interval: 1.19 to 2.87).

CONCLUSION

The three polymorphisms in the IL-4 gene act in a cooperative fashion and suggest that the high-production IL-4 haplotype was associated with an increased risk for CP in the Czech population.