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.
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.
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.
These results suggest that decreased type 1 cytokine production may contribute to or reflect the pathogenesis of SS.