Abstract: | A patient with Factor XII (Hageman) deficiency and fulminant systemic lupus erythematosus is presented. The Factor XII deficiency was noted prior to the onset of clinical systemic lupus erythematosus and persisted throughout the patient's course without associated hemorrhagic manifestations. There was no evidence for a circulating anticoagulant. The patient had a rapidly progressive fatal course unresponsive to corticosteroid therapy. Factor XII levels did not increase during therapy with steroids. Despite absence of Hageman factor, evidence for activation of complement by the classic pathway and thromboembolic phenomenon was observed. The role of Factor XII in coagulation and inflammatory pathways and the influence of the factor deficiency on the course of the patient's illness are discussed. |