[The young hemophiliac, inhibitors and immune tolerance].

The occurrence of inhibitor in a hemophilic patient is the greatest therapeutic complication in 1999. The inhibitor incidence is higher in hemophilia A (20-30%) than in hemophilia B (3%). At the moment, the best management is immune tolerance induction. This consists in frequent infusion of antihemophilic factor (every day or every other day). The risk of inhibitor development is higher in a young child than in an adult. Consequently, a venous access device is essential for this treatment although not devoid of complications in the young boy. Moreover, the probability of inhibitor disappearance is higher in a child (recent inhibitor) than in an adult ("old" inhibitor).