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Frequency of inhibitor development in severe haemophilia A children treated with cryoprecipitate and low‐dose immune tolerance induction
Author(s) -
El Alfy M. S.,
Tantawy A. A. G.,
Ahmed M. H.,
Abdin I. A.
Publication year - 2000
Publication title -
haemophilia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.213
H-Index - 92
eISSN - 1365-2516
pISSN - 1351-8216
DOI - 10.1046/j.1365-2516.2000.00449.x
Subject(s) - medicine , cryoprecipitate , haemophilia , haemophilia a , confidence interval , incidence (geometry) , gastroenterology , surgery , fibrinogen , physics , optics
The frequency of factor VIII inhibitor development was evaluated in a hundred severe haemophilia A patients < 18 years of age (mean 10.4 ± 5.1 years); 25 were previously untreated patients (PUPs), with a mean age of 11.2 ± 2.9 months. All were followed up for 3 years from December 1996. Immune tolerance (IT) was induced with low‐dose factor VIII (FVIII); 25–50 IU kg –1 every other day for the 10 haemophiliacs who developed persistent inhibitors. The incidence of inhibitors for PUPs was 3/25 (12%; 95% confidence interval [CI], 0.7–24.7%) and were detected after 4, 15 and 20 exposure days (mean 13 ± 8.2 days; 95% CI, 3.7–22.2%). Children with maximum inhibitor levels of > 40 Bethesda units (BU) per mL ( n =4) received IT therapy as 25 U kg –1 FVIII in the form of cryoprecipitate every other day for 1–4 months (mean 2.4 ± 1.6 months; 95% CI, 0.8–3.9%), which was successful in all of them. FVIII (50 U kg –1 ) was given every other day for six patients with maximum inhibitor level > 40 BU mL –1 for 3–9 months (mean 5.4 ± 3.2 months; 95% CI, 2.9 –7.9%) with success in 4/6 (66.6%; 95% CI, 28.8–104.3%). Patients who showed a good IT response had an inhibitor level ≤ 30 BU mL –1 , were ≤ 9 years of age at inhibitor development with few exposure days to FVIII and had an early immune tolerance. In conclusion, inhibitor development in severe haemophilia A children exclusively treated with cryoprecipitate is low. Early low‐dose IT induction for high responders may be achieved successfully if inhibitor level is ≤ 50 BU mL –1 .