The absence of factor II in a child with systemic lupus erythematosus.

This report describes a patient with active system lupus erythematosus (SLE), who developed haemorrhagic diathesis due to a lowering of plasma factor II activity. No evidence was found suggesting a plasma inhibitor of factor II. The present case indicates that in some patients with SLE, factor II activity may be low or completely absent due to impairment of factor II synthesis, further that prednisone, but not azathioprine, may ameliorate this defect.