1. Immunological tolerance and autoimmunity

A1 ALTERED PHAGOCYTIC ACTIVITY IN PRIMARY SJöGREN’S SYNDROME: SIMILARITY TO LUPUS AND ASSOCIATION WITH EXTRAGLANDULAR DISEASE

¹GE Fragoulis, ¹M Tsinti, ²M Herrmann, ¹HM Moutsopoulos, ¹MN Manoussakis. ¹Department of Pathophysiology, National and Kapodistrian University of Athens, Athens, Greece, ²Institute for Clinical Immunology, University of Erlangen, Nuremberg, Germany

Background and Objectives: The pathogenesis of systemic lupus erythematosus (SLE) has been thought to involve impaired clearance of apoptotic remnants, as suggested by altered uptake capacity of peripheral blood monocytes and granulocytes. In this study, we sought to assess the phagocytic capacity of peripheral blood monocytes and granulocytes of patients with primary Sjögren’s syndrome (SS). For this purpose, we examined comparatively the uptake of fluorescent microbeads and of necrotic cell-derived material in SS patients, SLE patients and healthy controls.

Methods: Patients studied included 29 with primary SS (American–European criteria 2002) and 13 with SLE (American College of Rheumatology criteria 1997). Healthy blood donors (HBD) matched for age and sex to the SS and SLE groups (HBD-1, n  =  13 and HBD-2, n  =  13, respectively) were also studied in all assays. The phagocytosis capacity was assessed according to previously established methods (Gaipl et al, J Autoimmun 2007) using heparinised whole blood from individuals studied mixed with a commercially available preparation of fluorescent microbeads (MB-phagocytosis; Polysciences, size 1 μm, 25 SS and 13 SLE patients studied) or a preparation of propidium iodide-stained necrotic cell-derived material obtained from heat-treated normal peripheral blood mononuclear cells (SNEC-phagocytosis, 11 SS and 8 SLE patients studied). The ingestion of particles was assessed by flow cytometry and the phagocytosis index (PInd) was calculated as the product of the percentage of fluorescent cells by the mean fluorescence intensity.

Results: In agreement with previous studies, SLE patients manifested significantly decreased capacity for MB-phagocytosis by granulocytes (median PInd 18, range 5–47), as well as by monocytes (median PInd 30, range 1–98), compared …