A range of about 20 medicinal protein products can be extracted from human plasma. Among those are various coagulation factor concentrates, such as factor VIII, and immunoglobulins preparations that are essential as replacement therapy of bleeding and immunological disorders. These products are obtained by the industrial fractionation process of batches of several thousands liters of plasma. The current plasma fractionation technology combines the traditional cold ethanol precipitation process with more specific chromatographic methods. The purity and quality profile of these products has improved dramatically in the last few years. Due to their human origin, these products can potentially transmit pathogenic agents. However, the margin of safety against the risk of viral transmission has improved in the last 15 years thanks to (a) the use of efficient industrial viral inactivation and removal procedures, (b) the increasingly refined viral screening tests performed of the plasma raw material, most specifically by nucleic acid testing, and (c) the increasingly selective criteria prevailing for donor screening. There has been no transmission of AIDS, hepatitis B, nor hepatitis C by licensed plasma products in the last 15 years. Recently, four cases of transmission of variant Creutzfeldt-Jakob disease (vCJD) have been identified and ascribed to the infusion of non leucoreduced red blood cell concentrates from donors who subsequently developed the disease. However, to date, no case of transmission of prions by plasma products have been observed, possibly because, as demonstrated by experimental validation studies, several fractionation steps have the capacity to remove the presumably low infectivity present in the plasma. Therefore, the risk of transmission of vCJD by human plasma products appears very remote, but caution should prevail since the biochemical nature of the infectious agent in human blood is still unknown. Under current regulations, licensed fractionated plasma products are among the safest therapeutic biological products available. Still, constant vigilance against emerging human pathogenic agents is in place.
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