Low-dose immune tolerance induction in hemophilia A patients with
inhibitors
EP Mauser-Bunschoten, HK Nieuwenhuis, G Roosendaal and HM van den Berg
Van Creveld Clinic, National Hemophilia Center, University Hospital,
Utrecht, The Nertherlands.
In patients with hemophilia A and inhibitory alloantibodies against factor
VIII, various dosage schedules are used to obtain immune tolerance. In this
study, we have evaluated the results of 13 years of low-dose immune
tolerance induction and factors that are predictive of a positive result.
The effect of immune tolerance induction in relation to age at inhibitor
development, number of exposure days, age at start of therapy, maximum
inhibitor titer, factor VIII products involved, and virologic status were
determined. We evaluated 24 patients with severe hemophilia A and
inhibitors who were treated with regular infusions with low-dose (25 U/kg
every other day) factor VIII to obtain immune tolerance. In 21 of 24
patients (87%), immune tolerance induction was successful. The response
time was determined by two factors: the highest inhibitor level and the age
at inhibitor development. In patients with maximum inhibitor levels of less
than 40 Bethesda units (BU)/mL, immune tolerance was obtained sooner than
in patients with inhibitor levels exceeding 40 BU/mL (P = .005). Patients
in whom an inhibitor developed before the age of 2.5 years also tended to
have a quick immune response (P = .014). Immune tolerance with low-dose
factor VIII is often successful in hemophilia A patients with inhibitors.
Young children and patients with maximum inhibitors of less than 40 BU/mL
show a relatively rapid response.
Volume 86,
Issue 3,
pp. 983-988,
08/01/1995
Copyright © 1995 by The American Society of Hematology
