Association Of Interleukin-10 Promoter Polymorphisms With The Susceptibility To Severe Chronic Periodontitis In Chinese Han Nationality

Genetic factors have been shown to play an important role in the pathogenesis of periodontitis. Several cytokine genotypes have been described to be associated with periodontal disease. The susceptibility-associated candidate genes include IL-1A-889, IL-1B+3953, TNF-A -308, and FcγRIIA and ⅢB, etc. Three single nucleotide polymorphisms (SNPs) within the IL-10 gene promoter have been identified and appear to influence regulation of its expression. In this study, PCR-RFLP and PCR-SSP were employed to investigate the corresponding relationship between interleukin-10 (IL-10) promorter polymorphisms and susceptibility to severe chronic periodontitis (CP) in Chinese Han nationality.Based on clinical parameters and radiographs, 142 patients with severe CP were included in the study. Additionally, 81 age-matched healthy subjects served as a control group. All of the subjects are non-smokers and free of systematic diseases. As the buccal swab has been proved a convenient and reliable source of DNA for genotyping, genomic DNA was isolated from the buccal swab samples and the IL-10 promoter sequences from positions -592 to -819 and -1082 were amplified by polymerase chain reaction (PCR). Polymorphisms atthe -1082 and -819 positions were detected by sequence specific primers and polymorphism at the -592 position was detected by restriction-enzyme cleavage. Fisher's exact test / Chi-Square tests was used for the statistical analysis. We found that no significant differences were observed in the genotype distribution of IL-10-819T/C and -592A/C between severe CP patients and controls (p = 0.101 ). The *A and *C alleles at the -592 position were linked to the *T and *C alleles at the -819 position, respectively. Although the frequency of IL-10-1082A allele was increased in patients (0.961) compared to control subjects (0.926), there is no significant differences between two groups (Pearson Chi-Square tesf.x2 = 2.634,P=0.105 > 0.05,OR = 1.985, 95% Confidence Interval:0.855-4.608). However, the significant differences were detected in genotype distribution of -1082AA between patients and controls (the Fisher exact test: p=0.0340.05). No significant differences were observed in the haplotype distribution of three SNPs between two groups, except genotype ACC/ACC (Chi-Square tests: % =4.296, P=0.038<0.05) when three SNP polymorphisms were analyzed in combination..In conclusion, most of the past studies suggested -1082AA as a risk factor for many diseases, including periodontitis. Our present study demonstrated for the first time that specific gene markers, that had been associated with decreased IL-10 production, -1082AA and ACC/ACC genotype, may be associated with susceptibility to severe chronic periodontitis. Further studies are undertaken to explore the possible relationship between them.