Anti-A in factor VIII concentrate: a cause of severe hemolysis in a patient with acquired factor VIII:C antibodies.

The authors report a case of acute macrohematuria in a patient with spontaneously acquired antibodies against factor VIII:C. Severe hemolysis was observed under factor VIII concentrate therapy. In 4 batches of the factor VIII concentrate high titers up to 1:512 of 'immune' anti-A were found.