Abstract: A multi-step process for purifying an immune serum globulin fraction from a crude plasma protein fraction involves precipitating non-serum globulin proteins from an aqueous suspension of the crude plasma protein fraction using a protein precipitant, adding a virus-inactivating agent to the clarified immune serum globulin-containing liquid, absorbing the immune serum globulins onto a cation exchange resin and washing non-serum globulin contaminants from the resin, subjecting the eluate to ultrafiltration to concentrate the immune serum globulins and separate them from low molecular weight species, contacting the concentrate with an anion exchange resin to absorb non-serum globulin contaminants, passing the imune-serum globulins through the anion exchange resin under conditions that leave non-serum globulin contaminants bound to the resin, and subjecting the filtrate to a molecular washing step to produce a purified immune serum globulin fraction.

Abstract: An improved method of recovering antihemophilic factor (AHF) from cryoprecipitated blood plasma is provided. The improved method incorporates the addition of a calcium ion source during the step of cold precipitation of fibrinogen and fibronectin contaminants, as well as the addition of polyethylene glycol (PEG) at one of various stages of the recovery process. PEG may be added during the cold precipitation of fibrinogen and fibronectin, during the precipitation of AHF, or prior to the filtration of AHF solution. The method of the present invention results in a final AHF product having greatly increased solubility, higher specific activity, and lower fibrinogen and fibronectin content.