Reduced generation of procoagulant activity by endotoxin-stimulated mononuclear cells from patients with chronic myeloid leukaemia.

The capacity of blood mononuclear cells to produce procoagulant activity upon stimulation with bacterial endotoxin in vitro was studied in 21 untreated patients with chronic myeloid leukaemia (CML). Procoagulant activity developed by patients' cells after prolonged incubation with endotoxin was significantly lower than that produced by cells from a matched control group (P less than 0.001). Reduced activity was seen in all patients when each of them was compared to a matched control studied simultaneously. It was below 50% of the control in 19 patients, and in eight of these it was less than 10%. These findings suggest that qualitative abnormalities in mononuclear cell function may exist in CML and might explain why these patients are less prone to thrombotic complications than those with other myeloproliferative diseases.