Antithrombin supplementation III in childhood acute lymphoblastic leukemia treated with L-asparaginase.

The change of plasma antithrombin III (AT) levels after supplementation of AT concentrates was examined in ALL children with acquired AT deficiency following L-asparaginase (ASP) administration. The patients received AT concentrates of 34.5 +/- 7.6 U/kg. The increase of plasma AT activity and antigen was 2.07 +/- 0.62% and 0.70 +/- 0.16 mg/dL per unit AT infused per kilogram of body weight, respectively. The activity decreased to 62.0 +/- 7.7% of the peak values by 48 hours after supplementation. The administration of AT concentrates constantly increased the plasma AT activity in ALL children treated with ASP, which may minimize the acquired prothrombotic state.