Comparison of Salivary and Serum Levels of Soluble Toll-Like Receptor 3 (TLR3) in Patients with Sj?gren's Syndrome (SS) Compared to Age- and Sex-Matched Controls

This cross-sectional study examined potential differences in concentration of Toll-like receptor 3 (TLR3) in serum and citric acid-stimulated saliva from patients with Sj?gren?s Syndrome (SS) and healthy age-, sex-, and periodontal disease- matched control patients. Salivation was stimulated with 5 ml of 2% citric acid, and whole saliva samples were collected. Full-mouth clinical periodontal measurements were recorded from 21 SS patients and 22 unaffected control patients. Saliva and plasma TLR3 concentrations were determined by enzyme-linked immunosorbentassays (ELISA). Data were tested statistically as appropriate to the data distribution.

No significant difference in clinical periodontal measurements, or serum or salivary TLR3 concentrations was evident between groups. Salivary flow rates were significantly lower (p<0.001) whereas plaque % were significantly higher (p=0.048) in SS patients. SS patients expressed on average 0.183 and 0.219 ng/ml TLR in saliva and serum, respectively, while healthy control patients expressed on average 0.299 and 0.188 ng/ml TLR in saliva and serum, respectively. These differences were not significantly different (p<0.05). This is the first detection of TLR3 in human serum or saliva as quantified or qualified by ELISA.

The present findings do not support a hypothesis that a hyperinflammatory systemic state, as seen in SS patients, can independently raise serum or saliva TLR3 concentration in the absence of periodontal disease in treated SS patients.