[Acquired von Willebrand syndrome with autoimmune hemolytic anemia].

A 17-year-old female underwent examination due to the chief complaints of epistaxis and bleeding from the gums. In addition to hemolytic anemia (Coombs positivity), she was found to have a marked reduction in the von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor activity (vWF:RCo). Anti vWF antibodies mainly comprised of IgG1 fractions were also detected, so acquired von Willebrand syndrome (AvWS) with autoimmune hemolytic anemia (AIHA) was diagnosed. The recovery of vWF:Ag and vWF:RCo following administration of a factor VIII concentrate containing vWF was good, but the half life was short at about two hours and the collagen binding activity and vWF:RCo in mixing tests with control plasma were only mildly inhibited. Therefore, the anti vWF antibody in the present case was thought not to inhibit vWF function but to be involved in clearance promotion. Hemostatic control during hemorrhage was performed using a factor VIII concentrate containing vWF. With the administration of prednisolone thereafter, anti vWF antibodies disappeared at the same time as there was improvement in the AIHA. Throughout the course the patient contracted acute hepatitis A, became pregnant and gave birth, but there were no clear effects on the clinical phenotype of AvWS.