Treatment of Haemophilia Patients with Inhibitors; Induction of Immune Tolerance by Low or Intermediate Dose Regimen

Abstract

We report our experience of induction of immune tolerance by factor VIII or IX in low or intermediate dose carried out on 8 haemophiliacs with inhibitors (A; 5, B; 3) in 2 low-responders and 6 high-responders. All of the 2 low-responders and 3 of the 6 high-responders with previous maximal inhibitor levels between 45.6 and 624 Bethesda Units showed a decrease of inhibitor level to below 1.0 Bethesda Units and normal VIII C or IX C recovery in vivo.
In one of the other 3 patients, the inhibitors level has dropped to 5.0∼10.0 Bethesda Units with no anamnestic response. In the other 2 patients their inhibitor levels have been above 30 Bethesda Units, although they haven't showed typical anamnestic responses.
In the results of the previous reports including our report, 27 out of 41 haemophiliacs with inhibitors, who have been treated with low or intermediate dose regimens, showed a decrease of inhibitor level to below 1.0 Bethesda Units and normal VIII C or IX C recovery. In comparison with the high-dose long-term F VIII regimen of Brackmann (The Bonn Regimen) which the high cost make it impractical at most haemophilia centers, about the same results was obtained by low or intermediate dose regimens. We recommend that the low or intermediate dose regimen should be indicated for haemophiliacs with inhibitors who have suffered from bleeding episodes, in both aspects of the costs and patients' life.