• acquired von Willebrand's syndrome;
  • lupus inhibitor;
  • intravenous immunoglobulin


We are reporting on a 47-year-old man who presented with a prolongation of the activated partial thromboplastin time (APTT) prior to orthopedic surgery. An evaluation suggested an inhibitor when his plasma prolonged a normal control APTT upon 50:50 solution of patients with normal plasma. The platelet-neutralizing procedure (PNP), anticardiolipin antibody, and antinuclear antibody (ANA) were positive. Further studies revealed decreased von Willebrand factor ristocetin cofactor (vWF:RCoF), von Willebrand factor antigen (vWF:Ag), an inhibitor to vWF, and absent high-molecular-weight vWF multimeters. Assays of FVIII:C, FIX, and FXI were nonparallel to the standard curve. Intravenous immunoglobulin (IVIG) corrected the APTT, multimeric pattern, and FVIII:C by the 7th day postinfusion. This case demonstrates the efficacy of IVIG for acquired von Willebrand's syndrome (vWS) and also represents a unique combination of a lupus-like anticoagulant and acquired vWS in a patient without the full serological requirement for systemic lupus erythematosus (SLE). Whether patients with acquired vWS and lupus inhibitors are more or less susceptible to either a thrombotic complication or hemorrhage is not established. Prospective studies for the incidence of lupus inhibitor/antiphospholipid syndromes and vWF deficiencies are needed to assess this question. © 1994 Wiley-Liss, Inc.