Prolonged Activated Partial Thromboplastin Time in Systemic Lupus Erythematosus Overlap Syndrome: Fatal Bleeding Due to Factor VIII Inhibitor.

A prolonged partial thromboplastin time in a patient with systemic lupus erythematosus usually is due to a lupus anticoagulant. Antiphospholipid antibodies may be associated with thrombosis. We describe a patient with an overlap syndrome between systemic lupus erythematosus and mixed connective tissue disease who presented with a prolonged partial thromboplastin time due to a high titer of antibodies to factor VIII (acquired hemophilia). The clinical course resulted in a fatal hemorrhage, illustrating the importance of prompt distinction between lupus anticoagulants and clotting factor inhibitors.