Correlation between IL-17A, IL-6, and nitric oxide (NO) in saliva (a) and serum (b). The production of NO correlated with salivary IL-17A and IL-6 levels (r = 0.71, P <0.001, and r = 0.70, P <0.001), serum IL-17A and IL-6 (r = 0.72, P <0.001, and r = 0.67, P <0.01).