A quantitative study of monocyte procoagulant activity in acute monoblastic and chronic myelomonocytic leukaemias.

Monoblasts from 7 patients with acute monoblastic leukaemia produced significantly less procoagulant activity (PCA) in response to endotoxin (mean 0.7 U/10(6) monocytes, range 0.4-1.4) than monocytes from 6 patients with chronic myelomonocytic leukaemia (mean 6.0 U/10(6) monocytes, range 1.25-10.7) and 15 normal subjects (mean 8.9 U/10(6) monocytes, range 3.1-21.2). However, when expressed as the quantity of monocyte-related PCA generated per millilitre of blood, there was no significant difference between patients with acute monoblastic or chronic myelomonocytic leukaemias, though both types of patients generated significantly higher amounts of PCA than normal subjects or patients in haematological remission. The relationship of these findings to the occurrence of disseminated intravascular coagulation is discussed.