[Acquired von Willebrand syndrome with autoimmune hemolytic anemia].

Acquired von Willebrand syndrome is reported in a 31-year-old woman with autoimmune hemolytic anemia (AIHA). The patient, who had no family history of bleeding, presented with a hemorrhagic diathesis of recent origin. Routine coagulation studies showed a normal platelet count, prolonged bleeding time and abnormal glass bead retention. Plasma levels of factor VIII-von Willebrand factor (F VIII-vWF) were low and ristocetin-induced platelet aggregation (RIPA) was decreased. In vitro, the patient's plasma exhibited inhibitory activity against vWF: ristocetin cofactor activity (vWF: Rco) but had no effect on RIPA. The multimeric pattern of the patient's vWF resembled that of patients with inherited type II von Willebrand disease, in that the largest multimers were missing. Clinical improvement resulted after treatment of AIHA with prednisolone (PSL), and F VIII-vWF returned to normal levels with normalization of vWF multimers. However, following tapering the dose of PSL, plasma levels of F VIII-vWF again decreased.