Interleukin-10 haplotype frequencies in children with gingivitis

Polymorphisms in the promoter region of the interleukin (IL)-10 gene have been identified at positions -1082 (G-->A), -819 (C-->T), and -592 (C-->A). Linkage disequilibrium between alleles -819*C, and -592*C was observed. A previous study addressed the association between the -1082*A allele and gingivitis in white Caucasian children. The aim of this case-control study was to test whether differences could exist between children with and without gingivitis in the distribution of IL-10 alleles and haplotypes at positions -1082, -819, and -592.

A total of 248 subjects aged 8 to 12 years from the University Dental Hospital of Manchester were enrolled in this study. According to gingival and bleeding on probing indices, 84 children were classified as controls and 164 as children with gingivitis. Amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) was used for genotyping IL-10 polymorphisms. Allele and haplotype frequencies were calculated by direct counting and by a haplotype frequency estimation (EH) program. Differences between subjects with gingivitis and controls in the frequency of haplotypes were determined by a chi2 test of homogeneity.

The GCC/GCC genotype, which has been associated with increased production of IL-10, was significantly more frequent in controls than in children with gingivitis (36% versus 23%) (P=0.036). In addition, there was a marginally significant difference between controls and cases in the frequency of haplotypes (P=0.06). The GCC haplotype was more frequent in controls than in children with gingivitis (60% versus 50%). In contrast, the ACC and ATA haplotypes were more frequent in children with gingivitis (27% and 23% versus 19% and 21% in controls).

These findings suggest that IL-10 gene promoter polymorphisms could have an active role in the pathogenesis of gingivitis in Caucasian children.