Lucie Klapušová

Association of interleukin-6 (IL-6) haplotypes with plaque-induced gingivitis in children.

Objectives. The proinflammatory cytokine interleukin-6 (IL-6) is a key regulator of the host response to microbial infection and major modulator of extracellular matrix catabolism and bone resorption. The aim of this case-control study was to test differences between children with and without gingivitis in the distribution of IL-6 alleles at positions −174, −572, and −597 and their haplotypes. Material and methods. A total of 455 Caucasian children, aged 11 to 13 years, were enrolled in this study. According to gingival bleeding on probing indices, 183 were classified as healthy subjects and 272 as children with plaque-induced gingivitis. DNA for genetic analysis was obtained from buccal epithelial cells and PCR-RFLP methods were used for genotyping three selected IL-6 promoter polymorphisms. Results. Complex analysis revealed significant differences in haplotype frequencies between patients and healthy subjects (p<0.01). The CGA haplotype was significantly more frequent in children with gingivitis than in healthy subjects (41.5% versus 34.1%). In subanalyses, we found that IL-6 −174C allele was more frequent in patients (44.3%) than in healthy children (36.1%, p=0.016, Pcorr<0.05). Multivariate logistic regression analysis showed that allele C remained a risk factor for gingivitis in children (p=0.03) regardless of plaque or gender. However, the proportions of the IL-6 −597 and −572 genotypes were comparable between the two groups. Conclusions. Our results indicate that the three promoter polymorphisms in the IL-6 gene act in a cooperative fashion and suggest that IL-6 haplotypes could play a role in the pathogenesis of gingivitis in Caucasian children.

The association of MMP-9 and IL-18 gene promoter polymorphisms with gingivitis in adolescents.

OBJECTIVE Interleukin 18 (IL-18) is shown to be a proinflammatory cytokine that regulates the expression of matrix metalloproteinase 9 (MMP-9). The aim of this study was to test for differences between Czech adolescents with and without gingivitis in relation to MMP-9 and IL-18 polymorphisms. DESIGN A total of 298 Caucasian children, aged 11-13 years, were examined to assess gingival health. DNA for genetic analysis was obtained from buccal epithelial cells, and the MMP-9 -1562C/T and IL-18 -607A/C variants were identified with PCR-RFLP. RESULTS Gingivitis was present in 49.3% of the adolescents examined, the rest of the group was considered healthy. The IL-18 -607C and MMP-9 -1562T alleles were found in 58.9% and 8.3% of the healthy subjects, and in 62.2% and 15.0% of the patients with gingivitis, respectively. Although differences in allele frequencies were not significant for IL-18 variant, they were significant for MMP-9 polymorphism (p=0.01, p(corr) < 0.05). Furthermore, a highly significant association of the composite genotype (formed by the variants of the both genes) with gingivitis was found (p=0.004, p(corr) < 0.05). CONCLUSIONS The -1562 T allele of MMP-9 gene could have a role in gingivitis in adolescents. In addition, interaction of the MMP-9 and IL-18 genes could be considered a risk factor for the development of gingivitis in children.