Cytokine gene and CD25 antigen expression by peripheral blood T cells from patients with primary Sjögren's syndrome.

We studied mononuclear cell subsets in 17 patients with primary Sjögren's syndrome (PSS) and in 11 normal controls by flow cytometry. We found a decreased percentage of CD4+ cells (p = 0.027) and a higher percentage of CD8+ cells in patients as compared to controls. In both, CD4+ cells and CD8+ cells, CD25 antigen was overexpressed (p = 0.005 and p = 0.025, respectively as compared to controls). We then measured spontaneous mRNA cytokine expression by T cells from 7 PSS patients and 5 normal controls by coupled reverse transcription-polymerase chain reaction. We found spontaneous mRNA expression for IFN-gamma, IL-10, IL-13 as well as for CD25. Our results suggest an overall T cell activation in PSS patients and provides evidence of a T cell cytokine regulatory imbalance which may play a role in the pathogenesis of this disease.