Plasminogen activators and their inhibitors in leukemic cell homogenates

Plasminogen activator (PA) and PA inhibitor (PAI) were measured in homogenates of leukemia cells. Both PA and PAI levels were higher in non-lymphoblastic leukemia than in lymphoblastic leukemia. The levels were below the sensitivity of determination in chronic myelocytic leukemia (CML) but showed significant increases in blast crisis (CML,bc). The level of the tissue type PA (t-PA) antigen was highest in acute myeloblastic leukemia (AML) and that of the urokinase type PA (u-PA) was highest in acute promyelocytic leukemia (APL). The PAI-I antigen showed no marked cell specificity, but the PAI-II antigen was markedly increased in myelomonocytic leukemia and acute monocytic leukemia (AMoL). From these findings, various PAs and PAIs are considered to be present in leukemia cells and to be involved in hemostatic disorders, thus they are of diagnostic value in leukemia.