IMMUNE TOLERANCE - A SYNOPSIS OF THE INTERNATIONAL EXPERIENCE

Because of the increased morbidity and cost of care associated with in hibitor development, immune tolerance therapy (ITT) is of crucial valu e in the care of haemophilia. The 24-year experience with this modalit y, primarily in the treatment of factor Vm inhibitors, has included th e use of both high and low doses of clotting factor, with and without immune modulation. Overall success rates for ITT in haemophilia A have been similar (63-83%), while median time to IT has been variable (1.2 -24 months). The role of type and purity of clotting factor used remai ns unclear. Three immune tolerance registries have suggested the poten tial importance of treatment parameters such as pre-induction inhibito r titer and daily factor dose in the prediction of successful outcome. Ultimately, prospective randomized studies of ITT are required to def initively compare therapeutic regimens with respect to efficacy, safet y, and cost effectiveness.