T cell clones from a Sjogren's syndrome salivary gland biopsy produce high levels of IL-10

Sjogren's syndrome (SS) is characterized by a focal periductal salivary gland infiltrate consisting mainly of T and B lymphocytes. Most of the T cells bear the memory CD4(+) Thl-like phenotype and express high levels of class II, though CD8(+) cells are also present. We have studied 17 labial salivary gland and 15 peripheral blood T cell clones from a patient with primary SS. The tissue clones were 71% CD8(+) and 29% CD4(+), and the peripheral blood-derived clones were 60% CD8(+) and 40% CD4(+). The CD4(+) T cell clones from both the salivary gland and autologous peripheral blood were of the Th 1 phenotype, in that they produced interferon-gamma (IFN-gamma) and IL-2 but very little IL-4 after 24 h stimulation with phorbol myristate acetate and anti-CD3 antibody. 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/ml, 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 accumulation of Th 1-type cells producing high levels of IL-10 in the salivary gland suggests a specific immunoregulatory function at the site of inflammation in SS.