Plasma Thrombomodulin in Wegener's Granulomatosis as an Indicator of Vascular Injuries

Abstract

To compare the concentrations of thrombomodulin (TM) and titers of antineutrophil cytoplasmic antibodies (ANCA) in plasma of patients with Wegener's granulomatosis (WG). Nine patients with WG were diagnosed according to the clinical criteria and histologic findings of biopsy specimens. The concentrations of plasma TM were measured by enzyme-linked immunosorbent assay (ELISA). Titers of ANCA were determined by immunofluorescence technique (cANCA) and by ELISA (anti-PR-3 Ab). The mean plasma TM concentration in patients with WG at an active stage was significantly higher than that of normal control, but that in remission was not significantly different from the normal value. More organs were involved, higher plasma TM levels were observed. The elevated plasma levels of TM returned to normal when the patients were treated successfully and in remission. The cANCA and anti-PR-3 Ab did not correlate with the severity of vasculitis in patients with active WG, although the antibodies determined by both methods were always negative in patients with inactive WG. Postmortem examination of one patient, who died of respiratory failure resulting from diffuse pulmonary hemorrhage, revealed pulmonary capillaritis with the total absence of TM in the lesions involved, suggesting that TM had been released totally from injured capillary endothelial cells. These results suggest that the plasma TM level may be a useful indicator of the extent of vascular injury in WG.