Enhanced Expression of Integrins and CD66b on Peripheral Blood Neutrophils and Eosinophils in Patients with Rheumatoid Arthritis, and the Effect of Glucocorticoids

Authors


Ingunn Torsteinsdóttir Department of Clinical Biochemistry, University Hospital, Landspitalinn, IS-101 Reykjavik, Iceland

Abstract

The aim of this study was to elucidate signs of granulocyte activation by studying adhesion and phagocytosis receptors on peripheral blood granulocytes from patients with rheumatoid arthritis (RA), and to observe the effect of glucocorticoids. Analyses by flow cytometry showed elevation of the neutrophil and eosinophil expression of the α- and β-chains of the β2-integrin Mac-1 (CD11b/CD18) and of the CEA-gene family member 6 (CGM6, CD66b). Expression of the adhesion receptor antigens CD11a, CD29, CD49d, CD49f and CD44, and the Fcγ receptors II and III, was unaffected. Treatment with low-dose prednisolone reduced the expression of CD11b on neutrophils and of CD11b, CD18 and CD66b on eosinophils to the same level as that found in healthy controls. Metyrapone treatment increased the surface expression of CD35 and CD49f on eosinophils, but did not affect surface expression on neutrophils. Activation of blood granulocytes may be important for the increased recruitment of neutrophils and eosinophils to the synovial cavity in RA. Treatment with low doses of glucocorticoids in RA normalizes the enhanced expression of the studied adhesion molecules in eosinophils but has minor impact on neutrophil activation. Endogenous glucocorticoid production seems to have minimal or no effect on the expression of adhesion and phagocytosis receptors on circulating granulocytes.

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