The IL-13(-1112) promoter polymorphisms in Taiwanese patients with chronic periodontitis

Objective: Based on the proposed role of IL-13 in the immune response in periodontitis lesions, the previous reported association of IL-13 polymorphisms with systemic diseases and the racial differences in the genetic polymorphisms, the aim of this study was to investigate the IL-13 gene polymorphisms at position -1112 in patients with chronic periodontitis (CP) and periodontitis-free controls (HC). Material and Methods: Forty-five patients with diagnosis of CP and 112 HC participated in the study. Blood samples were collected and DNA isolated. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to determine polymorphisms in the IL-13 gene at -1112 position. The products were investigated by sequence analysis also. Results: All loci were in Hardy-Weinberg equilibrium in the HC. The frequency of T allele in the IL-13 promoter region was 22.22% in the CP and 25.89% in the HC (p >0.05). The homozygous (CC+TT) genotype was 77.77% in CP and 76.79% in HC respectively (p>0.05). The heterozygous CT genotype was 22.22% in CP versus 23.21% in HC (p >0.05). After adjusted for gender, age and smoking status for logistic regression analysis, the genotype frequencies and odds ratios for chronic periodontitis remain not statistically significant. Conclusion: The frequency of T allele was lower and the frequency of CC/CT+TT genotype was higher in CP than in HC. Thus, it does not appear that IL-13 SNP at -1112C>T is associated with the susceptibility of Taiwanese individuals to chronic periodontitis. This study was partially supported by a grant from the Kaohsiung Medical University Hospital, Taiwan.