[Factor VIII (von Willebrand antigen) in patients with acquired thrombocytopathies].

Factor VIII/von Willebrand antigen (VA), part of the molecule of plasma factor VIII, realizes the interaction between platelets and vascular endothelium and the triggering of primary hemostasis. The modern diagnostics and treatment of the complicated acquired thrombocytopathies are impossible without the investigation on the concentration of factor VIII/von Willebrand antigen. The immune coagulation method used allows the objective, exact and fast determination of VA--referent values have been developed in healthy subjects. The patients with blastic leukosis studied--28 and with chronic myeloleukemia--18, all with severe endogenous complicated thrombocytopathy, functionally and biochemically confirmed, showed normal values of VA/von Willebrand antigen. On the contrary, a slightly elevated VA was established in patients with diabetes with no vascular-degenerative syndrome, corresponding to the activation of platelet functions and to enhanced adhesiveness in particular, contributing to thrombotic complications. The data obtained are discussed in connection with the etiopathogenesis of the separate kinds of thrombocytopathies and the necessity of substitutive therapy.