Continuous high-dose factor VIII for the induction of immune tolerance in haemophilia A patients with high responder state: a description of eleven patients treated.

Eleven severely affected haemophilia A patients (aged 6-42 y) with F VIII:C inhibitor (high responders) were treated with high-dose F VIII in order to eliminate the inhibitors. The patients comprise Danish high responder patients treated during the period 1977-1985. In all patients the inhibitors decreased significantly. In six, the inhibitor apparently disappeared (detection limit 0.4 Bethesda Units per ml) (BU/ml), in four patients a low level inhibitor of 0.4-1.4 BU/ml persisted. One patient is still on high-dose schedule. The duration of high-dose treatments ranged from less than one month up to 18 months. In all patients the tendency to spontaneous bleedings vanished when a measurable VIII:C level appeared in the post-infusion sample. The inhibitor suppression has allowed for extensive physical training and rehabilitation orthopaedic surgery. The patients are now able to conduct a normal haemophilic life on self-administered prophylactic doses of F VIII.