Defective Ristocetin-Induced Platelet Aggregation in von Willebrand's Disease and its Correction by Factor VIII

摘要: Abstract The antibiotic ristocetin, in concentrations of 1.0-1.5 mg/ml, aggregated normal platelets citrated platelet-rich plasma by a mechanism which the release reaction played only minor role. Platelet aggregation ristocetin concentration 1.2 mg/ml was absent or markedly decreased 10 patients with von Willebrand's disease. Lesser degrees abnormality were obtained 1.5 mg/ml. The magnitude defect ristocetin-induced platelet correlated well degree bleeding time and levels antihemophilic factor (AHF, VIIIAHF) procoagulant activity. In all patients, corrected vitro plasma. Correction also fraction cryoprecipitate that eluted void volume VIIIAHF after chromatography on gel excludes molecules larger than 5 × 106. A similar fraction, devoid activity, from disease had no corrective effect, but fractions hemophilia just as effective those subjects. correction activity partially purified VIII inhibited rabbit antibody to human not against studies provide further evidence are deficient is necessary for function. this appears be associated unrelated