Clinical implications of serum thrombomodulin in PR3-ANCA-associated vasculitis

BACKGROUND Vascular injury is the main mechanism in pathophysiology of PR3-ANCA-associated vasculitis. Soluble serum thrombomodulin (sTM) is a membrane-bound receptor for thrombin expressed by vascular endothelial cells. - OBJECTIVE The aim of study was to determine the blood levels of sTM in patients with PR3-ANCA-associated vasculitis. MATERIAL AND METHODS Twenty five patients with Wegener's granulomatosis (WG), 13 with generalized WG and 12 with limited WG, with histologically proven disease, and 15 healthy subjects as a control were investigated. An ELISA for detection of sTM and PR3-ANCA was performed. The disease activity was evaluated according to BVAS and DEI indexes. RESULTS Significant increases in sTM were found in both active generalized and limited active WG compared with control values: 108 +/- 12, 56 +/- 2, and 12 +/- 4 ng/ml, respectively. Elevated ANCA titer correlated with disease activity, but more weakly than sTM levels did. Elevated sTM concentration is a result of vascular endothelial injury in the course of PR3-ANCA associated vasculitis. CONCLUSIONS Soluble serum thrombomodulin is a promising, both diagnostic and therapeutic, marker of endothelial cell injury in relation to disease activity and progression in autoimmune disorders, reflecting the degree of endothelial cell damage.