Tissue factor activity in leukemia cells. Special reference to disseminated intravascular coagulation.

Tissue factor activity (TFA) of 10(8) leukemia cells was measured in 82 patients with acute nonlymphoid leukemia by the clotting method. The TFA bore a significant correlation to the development of disseminated intravascular coagulation (DIC) in these cases. Mean TFA value with standard deviation (SD) was 8.3 +/- 6.3 U in 48 cases with DIC, which was significantly higher than 0.3 +/- 4.2 U in 34 cases without DIC. Whereas Mean TFA in non-M3 was 0.9 +/- 6.3 U which was significantly lower than 37.2 +/- 2.3 U in M3, some non-M3 showed TFA as high as M3 and were complicated by DIC. In heparin treatment, dosage of heparin could not be controlled by either APTT or AcCT but was controlled by the extent of TFA of leukemia cells. Retrospective analysis of clinical features revealed that 97000X + 9000 units/day (X = logarithm value of TFA) of heparin is an adequate dosage for the successful treatment of DIC when TFA of leukemia cells is 0.8 U or more.