Prevalence of the −295 T‐to‐C promoter polymorphism of the interleukin (IL)‐16 gene in periodontitis
Interleukin (IL)‐16 is involved in the regulation of the expression of several proinflammatory cytokines, i.e. tumour necrosis factor (TNF)α and interleukin (IL)‐1β. The present study aimed to determine the prevalence of the −295 promoter polymorphism of the interleukin (IL)‐16 gene in periodontal disease. A total of 123 patients with periodontal disease and 122 healthy controls were genotyped for the −295 IL‐16 promoter polymorphism. Genotyping has been performed by PCR and restriction fragment length polymorphism (RFLP) analysis. The frequencies of alleles and genotypes as well of haplotypes within both study groups were compared using the Pearson χ2 test at a level  of  significance  of  5% (P < 0·05).  The  distribution  of  genotypes  for  the −295 IL‐16 gene polymorphism showed no significant difference between periodontitis patients and healthy control subjects (P = 0·886). Also stratification analysis according to the disease severity revealed no significant difference regarding the genotype distribution among both study groups. Herein the IL‐16 −295 gene polymorphism was not associated with chronic periodontitis.