[Factor VIII complex activities in acute leukemia].

Factor VIII procoagulant activity (VIII:C), factor VIII related antigen (VIIIR:AG) and von Willebrand factor activity (ristocetin cofactor, VIII:WF) were estimated in plasma from 37 patients with acute leukaemia. Of 25 patients in the active state of the disease, before or during cytostatic treatment, 19 (76%) showed abnormally high VIIIR:AG levels, between 240 and 780 U/100 ml. Fifteen of them also had elevated VIII:C and VIII:WF (184--480 U/100 ml and 182--360 U/100 ml respectively). The ratio of VIIIR:AG to VIII:C in this group of patients ranged from 0.53 to 4.39 with a mean of 1.35 +/- 0.8. Of 12 patients in partial or complete remission, only 3 (25%) had elevated VIIIR:AG. Four other patients showed high levels of VIII:C and normal values for VIIIR:AG and VIII:WF. The ratio of VIIIR:AG to VIII:C in the patients during remission ranged from 0.46 to 2.86 with a mean of 0.98 +/- 0.7. No relationship was apparent between the factor VIII-related activities and cytochemical type of leukaemia or leucocyte count in peripheral blood. Crossed antigen-antibody electrophoresis of factor VIII protein which was performed in 5 patients with high levels of VIIIR:AG turned up to be completely normal. In the vast majority of patients, plasma fibrinogen and serum fibrinogen degradation products were within the normal range.