Salivary interleukin-17 and tumor necrosis factor-alpha in relation to periodontitis and glycemic status in type 2 diabetes mellitus.

BACKGROUND: Poorly-controlled glycemic status in type 2 diabetes mellitus (T2DM) is suggested to play a role in the periodontal inflammatory process by aggregating the local cytokine response. Our objectives were to profile salivary interleukin (IL)-17 and tumor necrosis factor (TNF)-alpha levels in subjects with T2DM and to examine their relevance for the periodontal health status and glycemic control levels. METHODS: Unstimulated whole saliva samples, together with full-mouth periodontal recordings (plaque index [PI], bleeding on probing [BOP %], gingival index [GI], probing pocket depth [PPD], and clinical attachment level [CAL]), were collected from 123 subjects with T2DM. Additionally, demographic and general health parameters, including fasting blood glucose, glycated hemoglobin (HbA1c), were collected. Salivary IL-17 and TNF-alpha concentrations were analyzed using the Luminex(R)-xMAP technique. RESULTS: Subjects with poorly-controlled T2DM (HbA1c >/= 7) had elevated serum triglyceride (P < 0.001) concentration as well as elevated scores of BOP % (P = 0.014), PI (P = 0.048), GI (P = 0.033), and CAL (P = 0.003) in comparison to those of well-controlled T2DM (HbA1c < 7). When the subjects with detectable salivary IL-17 were categorized in tertiles, the scores of PPD and BOP%, and salivary TNF-alpha concentrations were significantly elevated in the highest (P = 0.007, P = 0.002 and P < 0.001, respectively) and middle (P = 0.052, P = 0.022, and P = 0.003, respectively) tertiles compared to subjects with non-detectable salivary IL-17. The adjusted association between PPD measurements and salivary IL-17 concentrations was significant (P = 0.008). CONCLUSIONS: Poorly-controlled glycemic status relates to the severity of periodontal disease in T2DM. The association between PPD and IL-17 in saliva, however, is independent from the effect of glycemic status.