Basal and Stimulated Elastolytic Activity of Blood Monocytes Is Increased in Glucocorticoid-treated Giant Cell Arteritis

Abstract

The elastolytic capacity of live human blood monocytes was studied in patients with giant cell arteritis (GA) and in age-matched controls. Despite normalized acute-phase reactants during glucocorticoid (GC) therapy, the basic activity of monocytes from patients with newly diagnosed GA was elevated compared with controls (80 vs. 39 ng/h, p ± 0.01). The maximum response was enhanced by stimulation with immune complexes (224 vs. 125 ng/h, p ± 0.01) and with phorbol myristic acetate (324 vs. 214 ng/h, p ± 0.01). No age difference was found between healthy young and old people. Cell surface related human monocyte elastolytic activity could act as a sensitive marker of cell activation in vivo.

Key Words:

• giant cell arteritis
• human monocytes
• elastolysis
• immune complex
• phorbol ester
• glucocorticoid
• age