Objective: An imbalance in immunoregulatory cytokines may contribute to the etiopathogenesis of Sjogren's syndrome (SS). We investigated systemic abnormalities in cytokine production in the peripheral blood in patients with SS.
Methods: ELISPOT assays were used to detect and enumerate cells spontaneously secreting interleukin 2 (IL-2), IL-6, IL-10, and interferon-gamma (IFN-gamma) in freshly isolated peripheral blood mononuclear cells from 20 patients with SS and 20 healthy controls.
Results: The number of cells spontaneously secreting type 1 cytokines IL-2 and IFN-gamma was decreased in the peripheral blood of patients with SS compared to controls. There was no change observed in the number of cells spontaneously secreting IL-6 and IL-10. Cells spontaneously secreting IL-4 were too rare in peripheral blood to evaluate, although cells capable of secreting IL-4 in response to phytohemagglutinin did not differ from controls. Patients with severe extraglandular symptoms (such as vasculitis) had a significantly lower frequency of IFN-gamma secreting cells in their peripheral blood than those without extraglandular involvement.
Conclusion: These results suggest that decreased type 1 cytokine production may contribute to or reflect the pathogenesis of SS.