[Tissue-type plasminogen activator in patients with lupus nephritis]

ELISA was used to measure tissue plasminogen activator antigen in blood plasma and urine of 42 patients with active lupus nephritis (16 with isolated urinary syndrome, 13 with nephrotic syndrome, 13 with rapidly progressive LN). Control groups consisted of 17 patients with inactive LN and 15 healthy subjects. Inhibition of fibrinolysis in vascular system correlating with the disease severity was found in patients with active LN. This may result from both defective synthesis of tissue plasminogen activator and neutralizing action of antiactivator. Urinary fibrinolytic activity was inhibited only in patients with rapidly progressive LN because of hyperactive synthesis of antiactivator. The above changes occur as endothelial cell dysfunction due to activating and damaging action of immune complexes, antibodies, cytokines on vascular endothelium. Zero activator activity of plasma and urine in patients with active LN reflects severe dysfunction of endothelial cell caused by its structural disorganization.