T-CELL CLONES FROM A SJOGRENS-SYNDROME SALIVARY-GLAND BIOPSY PRODUCE HIGH-LEVELS OF IL-10

Sjogren's syndrome (SS) is characterized by a focal periductal salivar y gland infiltrate consisting mainly of T and B lymphocytes. Most of t he T cells bear the memory CD4(+) Thl-like phenotype and express high levels of class II, though CD8(+) cells are also present. We have stud ied 17 labial salivary gland and 15 peripheral blood T cell clones fro m a patient with primary SS. The tissue clones were 71% CD8(+) and 29% CD4(+), and the peripheral blood-derived clones were 60% CD8(+) and 4 0% CD4(+). The CD4(+) T cell clones from both the salivary gland and a utologous peripheral blood were of the Th 1 phenotype, in that they pr oduced interferon-gamma (IFN-gamma) and IL-2 but very little IL-4 afte r 24 h stimulation with phorbol myristate acetate and anti-CD3 antibod y. The salivary gland-derived CD4(+) clones produced 15 times more IL- 10 (7.92 ng/ml) than peripheral blood-derived CD4(+) clones (0.52 ng/m l, P less than or equal to 0.02). The tissue CD8(+) clones produced 1. 2 times (P < 0.04) more IFN-gamma and CD4(+) clones produced 3.5 times less IL-2 (P < 0.02) than the respective PPM-derived clones. The accu mulation of Th 1-type cells producing high levels of IL-10 in the sali vary gland suggests a specific immunoregulatory function at the site o f inflammation in SS.