Acquired Factor‐IX Inhibitor in a Nonhaemophilic Patient with Autoimmune Disease*

Abstract

S ummary . An acquired inhibitor directed against factor IX was demonstrated in the blood of a patient with autoimmune disease. The inhibitor could be removed from the patient's plasma using PPSB or specific antisera insolubilized by polymerization. It could be recovered from these immunoadsorbents and characterized as an IgG‐immunoglobulin using specific antisera.