CHARACTERIZATION OF FOLLICULAR DENDRITIC CELLS IN LABIAL SALIVARY-GLANDS OF PATIENTS WITH PRIMARY SJOGREN SYNDROME - COMPARISON WITH TONSILLAR LYMPHOID FOLLICLES

Objective-To localise and characterise follicular dendritic cells (FDC ) present in autoimmune lesions of primary Sjogren syndrome. Methods-C ryostat sections of labial salivary glands from 15 patients with prima ry Sjogren syndrome were examined by an indirect immunoperoxidase tech nique and monoclonal antibodies to a panel of dendritic cell markers. Tonsils from two controls were also examined for the same markers. Res ults-FDC were localised in the centre of 75% of lymphoid focal structu res in labial salivary gland biopsies. FDC in labial salivary glands o f patients with primary Sjogren syndrome expressed CD35, CD11c, and CD 106 (VCAM-1) in a pattern similar to FDC in tonsils, but they did not express either CD14 or CD11b. This indicates that they may not be of m yeloid origin, while FDC in tonsillar lymphoid follicles strongly expr essed both CD14 and CD11b. FDC in labial salivary glands of patients a lso lacked VLA-2 alpha and VLA-3 alpha, which were expressed by FDC in tonsils. Conclusions-The characteristic phenotype and origin of these cells may be of importance in the immune responses involved in Sjogre n syndrome and the retention of infiltrating lymphocytes in the glands .