Factor 8 and antibody levels in plasma fractions prepated by cryoprecipitation.
Most of the antibody activity of plasma was found to remain in the supernatant fraction following the preparation of factor-VIII-rich cryoprecipitates. The low level of antibody remaining in these cryoprecipitates indicated that they could safely be used as a source of factor VIII for replacement therapy. Washing the cryoprecipitates farther reduced their antibody titres without materially affecting their factor VIII content.