The suppression of factor VIII antibodies in haemophilia.

Three severely affected haemophiliacs who had developed antibodies to factor VIII are described in whom the administration of cyclophosphamide was thought to have prevented reappearance of the antibody after factor VIII infusion. Some of the possible causes which might have led to the favourable outcome in these and three other, previously reported, patients in whom the antibody, which was raised at the time of IS therapy, dropped to zero and failed to reappear, are discussed. It is suggested that immunosuppressive therapy was effective in these patients as it was given during or soon after the primary immune response. As the antibody response becomes increasingly well established, so the chances of successful immunosuppressive therapy recede.