Interleukin-10 Genotypes of the −1087 Single Nucleotide Polymorphism Influence Sp1 Expression in Periodontitis Lesions

Background: Interleukin (IL)-10 is an important cytokine in immune regulation, and the −1087 IL-10 single nucleotide polymorphism (SNP) is associated with chronic periodontitis. The binding of the transcription factor Sp1 to the −1087 position in the IL-10 promoter upregulates IL-10 gene expression, especially in patients with the GG genotype. A correlation between the −1087 GG genotype and high IL-10 and Sp1 gene expressions was found.Methods: Twenty-five individuals with severe generalized chronic periodontitis were genotyped for the −1087 IL-10 gene polymorphism. SV40 promoter factor 1/specificity protein 1 (Sp1) and IL-10 mRNA were analyzed using a real-time polymerase chain reaction. The amount of Sp1-positive cells and Sp1-positive B cells, as well as the amount of Sp1 protein, in periodontitis lesions were assessed using immunohistochemistry and an in situ proximity ligation assay.Results: The mRNA expression of Sp1 and IL-10 in patients with the GG genotype was four times higher than that in patie...