Differential interleukin (IL)-10 and IL-13 gene expression in vivo in salivary glands and peripheral blood mononuclear cells from patients with primary Sjögren's syndrome.

Primary Sjögren's syndrome (PSS) is an autoimmune inflammatory disorder characterized by lymphocytic infiltration of exocrine glands, B cell hyperactivity and autoantibody production. The aim of this study was to determine the presence of IL-10 and IL-13 in this disease. We studied the IL-10 and IL-13 gene expression in vivo by peripheral blood mononuclear cells and minor salivary glands from PSS patients. We found a high expression of the IL-10 gene and its product by their peripheral blood mononuclear cells (PBMC) as well as by their salivary glands. Peripheral blood B cells and monocytes were responsible for 89% of total IL-10 secretion. IL-13 gene expression was not observed in PBMNC from either PSS patients or healthy controls, and was confined to PSS salivary glands. Our results suggest that IL-10 and IL-13 contribute to the pathogenesis of PSS and might explain the B cell abnormalities and the development of lymphoma observed in this autoimmune disease.