Effect of type 2 diabetes mellitus and periodontitis on the Th1/Th2 and Th17/Treg paradigm.

PURPOSE: To investigate the effect of type 2 diabetes mellitus (T2DM) and periodontitis on the Th1/Th2/Th17/Treg paradigm.

METHODS

A total of 107 volunteers (aged 18-78 years) were recruited. Peripheral blood samples from patients with periodontitis and T2DM (n= 43), patients with periodontitis only (n= 20), patients with T2DM only (n= 23), and healthy controls (n= 21) were collected. Blood pressure, glycated hemoglobin, fasting plasma glucose, probing depth, gingival index, and clinical attachment loss were measured. The circulating proportions of Th1, Th2, Th17, and Treg cells were estimated by flow cytometry. The data were analyzed by a 2x2 factorial ANOVA.

RESULTS

We observed higher ratios of Th1/Th2 and Th17/Treg cells among patients with T2DM (P< 0.05) than among healthy controls. The proportion of Th17 cells in patients with periodontitis and T2DM was higher than that in other groups (P< 0.05). T2DM exhibited a predominant effect on the proportion of Th1 cells (F= 18.127, P= 0.000) and the Th17/Treg ratio (F= 45.384, P= 0.000). A significant "T2DM x periodontitis" interaction effect on the proportion of Th2, Th17, Treg cells, and the Th1/Th2 ratio (P< 0.05) was also noticed. The area under curve of Th17 was 0.711 (95% CI= 0.584 to 0.803, P< 0.01) in the receiver operating characteristic curve analysis.

CLINICAL SIGNIFICANCE: The results suggest that the proportion of Th2, Th17, Treg cells and the Th1/Th2 ratio is indicative of immune activation and inflammation, which are evident in patients with type 2 diabetes mellitus (T2DM) and periodontitis. The data indicate that the high expression of Th17 cells may be a relevant biological factor that can be associated with an increased risk of developing chronic periodontitis in patients with T2DM.