Antibody Nature of the Inhibitor to Antihaemophilic Globulin (Factor VIII)

Abstract

ABOUT 5 per cent of haemophilic patients develop in their blood an inhibitor to factor VIII. The most likely explanation is that this is due to an immunological response to antihaemophilic factor of human origin given therapeutically on some previous occasion, since most haemophilic patients receive multiple transfusions of human blood or plasma; but development of an inhibitor is comparatively rare and therapeutic use of factor VIII of animal origin does not increase the incidence. A similar inhibitor is known as a rare complication of other conditions in patients with no previous history of haemophilia or transfusion. No direct cause-and-effect relationship between intravenous therapy and development of inhibitor has ever been established. For these reasons, and partly because of the uncertainty as to whether the inhibitor acts in the manner of an enzyme or an antibody^1,2, there has been doubt about the antibody nature of inhibitor.