Plasma levels of urokinase-type plasminogen activator (u-PA) were meas
ured with an enzyme-linked immunosorbent assay in patients with leukem
ias. As compared with healthy subjects (0.73 +/- SD 0.17 ng/ml), plasm
a u-PA antigen level was markedly elevated in patients with acute prom
yelocytic leukemia (APL) (1.76 +/- 0.89 ng/ml) at disease onset. Mean
u-PA concentrations in patients with other acute nonlymphoblastic leuk
emia (0.57 +/- 0.51 ng/ml), acute lymphoblastic leukemia (0.77 +/- 0.8
2 ng/ml) and chronic myelocytic leukemia in blastic crisis (1.30 +/- 1
.35 ng/ml) were not significantly elevated, but some of them showed an
elevation of plasma u-PA. Plasma u-PA Values were correlated with som
e of the fibrinolytic parameters such as FDP and D-dimer. Plasma u-PA
antigen was decreased after the administration of antileukemic drugs i
n patients with APL. These results suggest that the coagulopathy in pa
tients with various leukemias may in part be associated with u-PA rele
ase from the leukemic cells, especially in patients with APL.