SALIVARY AND SERUM INTERLEUKIN-6 IN PRIMARY SJOGRENS-SYNDROME

Objective, To measure interleukin 6 (IL-6) salivary and serum concentr ations in primary Sjogren's syndrome (SS), to correlate these data wit h the clinical presentation in patients, and to determine if salivary lL-6 is reflective of local exocrine involvement or of the underlying autoimmune disorder. Methods. Thirty-one patients with primary SS, 15 with primary biliary cirrhosis (PBC), and 14 healthy controls were stu died. Parotid secretion was stimulated with 2% citric acid and collect ed using a Carlson-Crittenden collector. Concentrations of salivary an d serum IL-6 were determined using a high sensitivity ELISA. Serologic autoimmune disease markers and salivary functional and histopathologi c disease markers in the patients with SS were correlated with salivar y and serum IL-6 levels. Results, Mean serum IL-6 concentrations were elevated in both patient groups (SS = 3.05 pg/ml, PBC = 3.07 pg/ml, he althy subjects = 0.843 pg/ml). Mean stimulated salivary IL-6 concentra tions were elevated only in the patients with SS (16.21 pg/ml) compare d to the PBC (1.07 pg/ml) and healthy subjects (0.769 pg/ml). No corre lation was found between serum and salivary IL-6 concentrations for an y group. Positive correlations were found between salivary IL-6 concen trations and serum IgG concentrations and between salivary IL-6 and er ythrocyte sedimentation rate, Higher IL-6 concentrations were associat ed with increased disease activity. Conclusion, Salivary IL-6 concentr ation is elevated in SS compared to healthy subjects and patients with another systemic autoimmune disease without salivary gland involvemen t. Elevated salivary IL-6 concentrations in SS are reflective of local exocrine involvement and may serve as a useful monitor of disease act ivity.