EXPRESSION OF CD80/CD86-CD28 COSTIMULATORY MOLECULES BY PERIPHERAL BLOOD MONONUCLEAR CELLS AND SALIVARY GLANDS OF PATIENTS WITH SJÖGREN'S SYNDROME

Abstract

Objective. To investigate the expression of costimulatory molecules CD80, CD86, and CD28 on peripheral blood monouclear cells (PBMC) and in salivary gland (SG) biopsy tissues of patients with Sjögren's syndrome (SS). Methods. Monoclolal antibodies against CD80, CD86, and CD28 were used for flow cytometry and immunohistochemistry. PBMC CD80, CD86, and CD28 were studied in 21 patients with primary SS and 22 healthy controls, and biopsy tissues were studied in 12 patients with primary SS and 5 with secondary SS (3 with systemic lupus erythematosus and 2 with rheumatoid arthritis). Results. CD28 expression on CD4^+ and CD8^+ T cells was lower in SS patients than in normal controls. CD80 and CD86 were expressed on infiltrating mononuclear cells (MNC) in SG biopsy specimens ; the majority were adjacent to acini and ducts, with a few MNC in large lymphoid aggregates. Staining for CD80 and CD86 also revealed positive acinar and ductal endothelial cells in SG biopsy specimens. Conclusion. A costimulatory signal CD80 and CD86 may be required for the induction of lymphoepithelial lesions of SG, but not for progression of SS. CD80 and/or CD86 expressed on acinar and ductal endothelial cells is associated with activation of T cell in SG tissues of SS patients.