Increased frequency of cells secreting interleukin-6 and interleukin-10 inperipheral blood of patients with primary Sjogren's syndrome

Sjogren's syndrome (SS) is a chronic autoimmune disease of exocrine glands. There is increasing evidence that interferon-gamma (IFN-gamma) plays a rol e in the pathogenesis of SS. It has also been suggested that other type 1 c ytokines, as well as interleukin-6 (IL-6), IL-10 and transforming growth fa ctor-beta, are important in the induction and/or maintenance of SS, The aim of this study was to investigate the type 1/type 2 cytokine pattern in per ipheral blood of primary SS patients. The enzyme-linked immunospot (ELISPOT ) assay was performed to quantify the number of mononuclear cells (MNC) sec reting IFN-gamma, IL-6 and IL-10 in peripheral blood samples from 33 patien ts with primary SS and 12 healthy controls. The mean number of cells secret ing IFN-gamma was 9/10(5) MNC in the SS patient group, and 4/10(5) MNC in t he control group (P = 0.73). Fifteen of the SS patients had anti-Re 52 kDa antibodies in serum. In this patient group the mean number of cells secreti ng IFN-gamma was 4/10(5) MNC, while in the patient group without such antib odies the mean number of cells secreting IFN-gamma was 14/10(5) MNC (P = 0. 04). The mean number of cells secreting IL-6 was 12 000/10(5) MNC in the SS patient group, and 5000/10(5) MNC in the control group (P = 0.01). The mea n number of cells secreting IL-10 was 270/10(5) MNC in the SS patient group , and 180/10(5) MNC in the control group (P = 0.04). The SS patients had a significantly higher number of cells secreting IL-6 and IL-10 in peripheral blood than the healthy controls, which may facilitate B-cell activation an d production of autoantibodies.