ORIGINAL ARTICLE Salivary interleukin-17 and tumor necrosis factor-α in relation to periodontitis and glycemic status in type 2 diabetes mellitus Ulvi Kahraman GÜRSOY, 1 Sinem YILDIZ ÇI ˙ FTLI ˙ KLI ˙ , 2 Eija KÖNÖNEN, 1 Mervi GÜRSOY 1 and Bas ¸ak DOG ˘ AN 2 1 Institute of Dentistry, University of Turku, Turku, Finland, and 2 Faculty of Dentistry, University of Marmara, Istanbul, Turkey Correspondence Bas ¸ak Dog ˘ an, Marmara University, Faculty of Dentistry, Department of Periodontology, Nis ¸ antası Kampüsü, Büyükçiflik Sok. No:8 34365 Nis ¸ antası-Sis ¸li, Istanbul, Turkey. Tel: +90 212 231 9120 Ext: 502 Fax: +90 212 246 5247 Email: basakdogan@marmara.edu.tr Received 17 May 2014; revised 9 September 2014; accepted 24 September 2014. doi: 10.1111/1753-0407.12228 Abstract 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)-α 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 peri- odontal 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 hemo- globin (HbA1c), were collected. Salivary IL-17 and TNF-α concentrations were analyzed using the Luminex®-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 com- parison 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-α 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 sub- jects 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 peri- odontal disease in T2DM. The association between PPD and IL-17 in saliva, however, is independent from the effect of glycemic status. Keywords: interleukin-17, periodontal disease, saliva, tumor necrosis factor-α, type 2 diabetes mellitus. Significant findings of the study: There is a relation between the severity of periodontal disease and poorly controlled glycemic status. However, glycemic condition does not influence the association between IL-17 in saliva and deepened periodontal pockets. What this study adds: Although IL-17 associates with periodontitis, it does not explain the observed link between periodontitis and diabetes. Journal of Diabetes 7 (2015) 681–688 681 © 2014 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd