Native analysis of plasma-derived clotting factor VIII concentrates: "sponge effect" and contaminants.

In the present study, we analysed two commercially available plasma-derived FVIII preparations, Beriate and Emoclot, through native gel-based approaches (CN-PAGE). The rationale behind this study was to assess whether protein complexes from plasma resisted the aggressive manufacturing processes. A preliminary analysis of plasma complexes was performed focusing on the molecular weight range between 45 kDa and 1 MDa. As a result, we could evidence in both preparations the presence of complexes, which resisted the cryoprecipitation, chromatographic and heat treatment processing steps. These complexes behaved in a "sponge-effect"-like fashion through the enrichment of otherwise less abundant contaminants. The use of an alternative electrophoretic approach such as CN-PAGE allowed us to confirm 2DE-based observations and expand the list of non-FVIII proteins which contaminate the preparations.