title: Acquired von Willebrand syndrome: von Willebrand factor propeptide to von Willebrand factor antigen ratio predicts remission status.
abstract: We investigated a case of acquired von Willebrand syndrome (AVWS) secondary to a nonneutralizing anti-von Willebrand factor (VWF) antibody associated with an autoimmune disorder. At diagnosis, VWF activity (VWF:Act), antigen (VWF:Ag), multimers, and factor VIII coagulant activity were virtually absent. VWF propeptide (VWFpp) was elevated with an infinitely high VWFpp to VWF:Ag ratio (VWFpp:Ag) consistent with rapid VWF clearance. Immunosuppressive treatment resulted in phenotypic remission 1 with normalization of VWF/factor VIII levels and multimer pattern. However, VWFpp:Ag remained elevated (∼2× normal), consistent with ongoing VWF clearance by the remaining anti-VWF antibody still present by enzyme-linked immunosorbent assay. This suggests that increased VWF secretion was compensating for the incomplete remission state. Relapse occurred when VWFpp:Ag was again infinitely high, with associated decreased VWFpp but unchanged anti-VWF titers; switching the balance to favor VWF clearance over secretion. Complete remission with undetectable anti-VWF occurred only when VWFpp:Ag was normal. This case of relapsing-remitting AVWS demonstrates the use of VWFpp:Ag for predicting remission status.
authors.affiliation: Department of Medicine.
authors.forename: Adrienne
authors.initials: A
authors.lastname: Lee
authors.affiliation: Department of Pathology & Laboratory Medicine, and Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, AB, Canada; Calgary Laboratory Services, Calgary, AB, Canada; and.
authors.forename: Gary
authors.initials: G
authors.lastname: Sinclair
authors.affiliation: Department of Medicine.
authors.forename: Karen
authors.initials: K
authors.lastname: Valentine
authors.affiliation: Department of Medicine, Queen's University, Kingston, ON, Canada.
authors.forename: Paula
authors.initials: P
authors.lastname: James
authors.affiliation: Department of Medicine, Calgary Laboratory Services, Calgary, AB, Canada; and.
authors.forename: Man-Chiu
authors.initials: MC
authors.lastname: Poon
mesh_terms: D000293:Adolescent; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D001778:Blood Coagulation Disorders / Q000097:blood* / Q000175:diagnosis / Q000276:immunology / Q000628:therapy; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D011498:Protein Precursors / Q000097:blood* / Q000276:immunology; D012074:Remission Induction; D014841:von Willebrand Factor / Q000276:immunology / Q000378:metabolism*
chemical_list: D001323:Autoantibodies; D011498:Protein Precursors; C029417:Von Willebrand antigen; D014841:von Willebrand Factor; C067003:von Willebrand factor propolypeptide