Precipitating Antibodies to Factor Vill/von Willebrand Factor in Von Willebrand’s Disease: Effects on Replacement Therapy

Precipitating antibodies to factor VlIl/von Willebrand factor can develop in patients with severe homozygouslike von Willebrand’s disease following multiple transfusions with blood derivatives. This study of 4 patients treated with cryoprecipitate for 1 3 different bleeding episodes demonstrates that the occurrence of such antibodies interferes with the management of the disease. The control of mucosal bleeding was poor. whereas more favorable responses were obtained in soft-tissue hemorrhages. These findings probably relate to failure of replacement therapy to shorten the prolonged bleeding time. Immediately after treatment. measurement of plasma factor VIII/von Willebrand factor-related antigen and ristocetin cofactor showed either no increase, or very