Factor VIII was purified from cryoprecipitate by ion exchange chromatography on solid phase polyelectrolyte E-5 (PE-E5). The product was highly purified (3.5 u VIII:C/mg protein) compared to conventional concentrate (0.3 u VIII:C/mg protein) with low fibrinogen, low isoagglutinin titre, and a ratio of factor VIII coagulant activity (VIII:C) to factor VII related antigen (VIIIR:Ag) of 16:1. Trial infusions of this material (PE VIII) were given to three patients with severe haemophilia A and one patient with homozygous von Willebrand's disease. These patients also each received separate infusions of intermediate purity concentrate (IPC) for comparison. There were no adverse effects. The mean half life of VIII:C after PE VIII infusion in the haemophiliacs was 10.9 h and after IPC was 12.1 h, a statistically insignificant difference. The survival of factor VIII coagulant antigen (VIII:CAg) was similar to that of VIII:C. In contrast, the half life of VIII:C and of VIII:CAg was very short after infusion of PE VIII in the patient wih von Willebrand's disease (2.4 h). IPC when infused in this patient produced a typical secondary rise of VIII:C. Two bleeding episodes in severe haemophiliacs were satisfactorily treated with PE VIII. PE-E5 deserves further study as a means of preparing clinical concentrates of factor VIII.
Summary. An intermediate‐ and a high‐purity factor‐VIII concentrate for clinical use have been prepared on a large scale by cryoethanol precipitation, extraction of the precipitate with tris buffer, and fractionation with polyethylene glycol. With bench‐scale fractionation, the intermediate material is 22‐fold purified on the average and the mean yield is 63%, while the high‐purity factor VIII is 274‐fold purified with a mean yield of 62%. With fractionation of 100 1. or more of fresh frozen plasma, the intermediate material shows a 30% yield and 14‐30‐fold purification; the high‐purity factor VIII shows an 18% yield and 125–350‐fold purification using 5.8 g/100 ml polyethylene glycol (PEG). A yield of nearly 30% should be possible with PEG, 4–5 g/100 ml. Both factor‐VIII preparations are stable for over a year in the lyophilized state at 4°C. Other plasma proteins can be fractionated from the residual plasma by routine Cohn procedures.
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