Concomitant factor VIII inhibitor and lupus anticoagulant in an asymptomatic patient

Abstract

Acquired hemophilia A, caused by autoantibodies that bind to and neutralize the activity of coagulation factor VIII (FVIII), almost universally presents as a severe bleeding diathesis. Lupus anticoagulants (LAs), autoantibodies directed against phospholipids or protein-phospholipid complexes, manifest clinically with an increased risk of thrombosis. While these autoantibodies are uncommon, the distinctive clinical presentation in conjunction with the typical laboratory findings often enable straightforward identification of the underlying autoantibody. However, the presence of a concomitant acquired FVIII inhibitor and LA is exceedingly rare with fewer than 20 documented cases. All prior patients presented with life-threatening hemorrhage, thrombosis, or both, prompting comprehensive hematologic evaluation and subsequent identification of the pathologic antibodies. We describe a novel case of a patient with no signs of hemorrhage or thrombosis who was incidentally found to have both a FVIII inhibitor and LA during evaluation of a prolonged partial thromboplastin time (PTT). This finding resulted in FVIII inhibitor-directed management, including immunosuppressive therapy. The unique presentation of an incidental FVIII inhibitor and LA in an asymptomatic patient without thrombotic or bleeding complications highlights the potential challenge in elucidating the etiology of a prolonged PTT, as LAs and FVIII inhibitors both prolong the PTT, and each entity can interfere with assays designed to detect the presence of the other autoantibody. This case underscores the importance of recognizing that patients with major underlying disturbances in their hematologic physiology, but in whom clinical symptoms have yet to manifest, may potentially be overlooked until such symptoms are evident.

Keywords: Autoantibodies; Factor VIII; Hemophilia A; Hemorrhage; Lupus coagulation inhibitor.