VIII: C And VIII: CAg Response In Haemophilia A After Infusion Of F VIII Concentrates, Fresh Citrated Plasma Or Heparin Plasma

VIII:C (one-stage) and VIII:CAg (solid phase IRMA using both two homologous nonhaemophilic antibodies and a haemophilic antibody against VIII: C, Holmberg et al 1979, Scand. J. Haemat. 23, 17) were studied in 8 patients with severe, and 2 with mild, haemophilia A after administration of 3 different f VIII concentrates (AHF-Kabi, Hemofil, high purity Factorate) or fresh citrated plasma or heparin plasma. The recovery of VIII: C was about the same for all the preparations (70–100 %), but that of VIII: CAg considerably less (30–50 %). When the concentrates were added in vitro to the haemophilia plasma (the patients all multitransfused) the recovery of VIII:C was about 100 % but that of VIII: CAg only 30–50 %. In normal plasma the recovery of VIII: CAg was 100 %. When the concentrates were added to haemophilia plasma depleted from IgG (protein A Sepharose) the recovery of VIII: CAg was about 100 %. This indicates that most haemophiliacs have antibodies reacting with the f VIII coagulant protein with little or no interference with the coagulant activity. The half-life of VIII:C was about 12 h, but that of VIII:CAg only 3 h or less. We also infused fresh citrated plasma into 2 haemophiliacs, but the results were the same. The response to transfusion observed in haemophilia indicates a change in the native properties of f VIII already on collection of blood. This might be due to the decalcification with citrate. Thus, in preliminary experiments using fresh heparin plasma the curves for the disappearance rate of VIII: C and VIII: CAg were parallel.