Increased levels of interleukin-10 in saliva of Sjögren's syndrome patients. Correlation with disease activity.

The aim of the study was to determine the levels of interleukin (IL)-10, IL-2, IL-4, and interferon-gamma in the saliva of patients with Sjögren's syndrome and to correlate them with laboratory and clinical parameters of disease activity. The levels of IL-2, IL-4, IL-10, and interferon-gamma were measured in salivary samples, obtained directly from the Stenone duct of 14 Sjögren's syndrome patients and 26 healthy controls by ELISA. A significant elevation of IL-10 was found in salivary fluids of Sjögren's syndrome patients compared with healthy controls (P=0.007). Elevated interferon-gamma levels were found in some patients. IL-2 and IL-4 were undetectable in all saliva samples. In patients, IL-10 levels significantly correlated with the degree of xerophthalmia and xerostomia (P=0.02 and P=0.01, respectively) and with the erythrocyte sedimentation rate (P=0.006). Our data suggest that elevated IL-10 levels are detectable in the saliva of Sjögren's syndrome patients and correlate with the severity of the disease.