Circulating factor XI antibody and disseminated intravascular coagulation.

Association of a circulating factor XI anticoagulant and disseminated intravascular coagulation (DIC) is described in a 33-year-old woman. Although the patient had rheumatoid arthritis and a bacterial infection treated with antibiotics, the anticoagulant was thought to be secondary to systemic lupus erythematosus. Curiously, the low levels of factor XI did not prevent the DIC from developing.