The fibrinolytic system in a group of 23 patients with vasculitis and 10 patients with the cutaneous vasculitis atrophie blanche were studied. These patients were found to have markedly suppressed release of vascular tissue plasminogen activator (t-PA) stores whether the disease was active or in remission. The control group had releasable t-PA levels of 0.70 +/- 0.10 IU/ml of plasma. Levels of releasable t-PA in the patient population were 0.09 +/- 0.03 IU/ml for those with active vasculitis (p less than 0.0001 compared with the control group by the Student t test), 0.23 +/- 0.12 IU/ml for those with inactive vasculitis (p less than 0.001), and 0.03 +/- 0.01 IU/ml for those with atrophie blanche (p less than 0.0001). It is concluded that there is a generalized defect in plasminogen activator in a variety of vasculitides. Such a defect may contribute to the pathogenesis of lesions as well as the thromboembolic disease that may be observed in these patients.