Type IIB von Willebrand's Disease: Unusual Response to Cryoprecipitate Infusion

Abstract

A 16 yr old boy had IIB von Willebrand''s disease. The disorder is characterized by prolonged bleeding times, normal plasma levels of factor VIII-coagulant activity, factor VIII-ristocetin cofactor activity, and factor VIII-related antigen, abnormal (anodal) mobility of plasma factor VIII-related antigen on 2-dimensional crossed immunoelectrophoresis, and enhanced binding of plasma factor VIII-related antigen to normal platelets in the presence of ristocetin. These variables were measured at time periods after an infusion of normal cryoprecipitate into the patient. The electrophoretic mobility of his plasma factor VIII-related antigen was normal 15 min after the infusion but became abnormal (anodal) by 4 h. His bleeding times were normal after 24 h and did not correlate with plasma levels of factor VIII-coagulant activity, factor VIII-ristocetin cofactor, factor VIII-related antigen, or the electrophoretic mobility of his plasma factor VIII-related antigen. The abnormal factor VIII/von Willebrand factor multimers in the plasma of these patients evidently can associate with normal factor VIII/von Willebrand factor multimers and delay the deposition of the normal multimers into subendothelial surfaces. This may require cryoprecipitate infusions 24 h before elective surgical procedures.