The -308 polymorphism in the promoter region of the tumor necrosis factor-alpha (TNF-α) gene and ex vivo lipopolysaccharide-induced TNF-α expression in patients with aggressive periodontitis and/or type 1 diabetes mellitus

Several single-nucleotide polymorphisms (SNPs) have been identified in the TNF-α gene promoter. The transition G→A at position -308 generates the TNF-α1 (G/G) and TNF-α2 (G/A or A/A) alleles, where the polymorphic TNF-α2 allele is associated with a high, in vitro TNF-α expression and an increased susceptibility to diverse illnesses. Here we study the association of the -308 TNF-α SNP with the susceptibility for developing aggressive periodontitis (AP), AP combined with type 1 diabetes mellitus (DM) and DM. We also explore the TNF-α capability expression and the presence of the -308 polymorphism. For this purpose we recruited 27 individuals with AP (AP+ group), 27 individuals with AP combined with DM (AP+/DM+ group), and 27 individuals with DM without signs of periodontitis upon clinical examination (DM+ group). The control group was comprised of 30 subjects. Genotyping for TNF-α promoter was performed by PCR-RFLP analysis. For TNF-α expression we used a blood culture system.