Interleukin-17A Gene Variability in Patients with Type 1 Diabetes Mellitus and Chronic Periodontitis: Its Correlation with IL-17 Levels and the Occurrence of Periodontopathic Bacteria

Abstract EN

Interleukin-17 contributes to the pathogenesis of type 1 diabetes mellitus (T1DM) and chronic periodontitis (CP).

We analyzed IL-17A −197A/G and IL-17F +7488C/T polymorphisms in T1DM and CP and determined their associations with IL-17 production and occurrence of periopathogens.

Totally 154 controls, 125 T1DM, and 244 CP patients were genotyped using 5′ nuclease TaqMan® assays.

Bacterial colonization was investigated by a DNA-microarray kit.

Production of IL-17 after in vitro stimulation of mononuclear cells by mitogens and bacteria was examined by the Luminex system.

Although no differences in the allele/genotype frequencies between patients with CP and T1DM + CP were found, the IL-17A −197 A allele increased the risk of T1DM (P<0.05).

Levels of HbA1c were significantly elevated in carriers of the A allele in T1DM patients (P<0.05).

Production of IL-17 by mononuclear cells of CP patients (unstimulated/stimulated by Porphyromonas gingivalis) was associated with IL-17A A allele (P<0.05).

IL-17A polymorphism increased the number of Tannerella forsythia and Treponema denticola in patients with CP and T1DM + CP, respectively (P<0.05).

IL-17A gene variability may influence control of T1DM and the “red complex” bacteria occurrence in patients with CP and T1DM + CP.

Our findings demonstrated the functional relevance of the IL-17A polymorphism with higher IL-17 secretion in individuals with A allele.