IL-1 RECEPTOR ANTAGONIST IN SALIVA - CHARACTERIZATION IN NORMAL SALIVA AND REDUCED CONCENTRATION IN SJOGRENS-SYNDROME (SS)

The characterization of a salivary factor cross-reacting with IL-1 rec eptor antagonist (IL-1Ra) is described. The apparent molecular weights of two species were 23 kD, consistent with the secreted peptide (sIL- 1Ra), and 20 kD, consistent with the intracellular peptide (icIL-1Ra). It had an inhibitory activity on IL-1-stimulated fibroblasts, which i s characteristic of IL-1Ra. Its source was the oral mucosa and not the salivary glands. Saliva from patients with SS contained significantly less IL-1Ra than saliva from controls. The decrease was marked in pat ients with early dental loss but whose xerostomia was still partial. I n SS, the salivary IL-1/IL-1Ra imbalance may promote inflammatory lesi ons in the mouth and impede mucosal cell differentiation.