Von Willebrand factor multimers in virus-inactivated plasmas and F VIII concentrates

The von Willebrand factor (vWf) stabilizes F VIII in plasma and is involved in platelet adhesion at high shear rates. While the first function is independent of the grade of multimerization, the latter needs the full range of large vWf multimers. Recently new virus-inactivated plasmas and F VIII concentrates, double-inactivated by heat and chemical treatment, became available. To evaluate whether these treatments have detrimental effects on the structure of the vWf protein we compared some of these products with fresh frozen plasma (FFP), and the Biotest F VIII concentrate with two F VIII concentrates inactivated by pasteurization or solvent/detergent (SD) treatment. The large vWf multimeres were preserved in single-donor plasmas and laboratory plasma pools. All commercial pool products showed a loss of the largest vWf multimers. While SD-treated plasma and the F VIII concentrates from Behring and Intersero contained enough large vWf multimers to allow treatment of patients with von Willebrand disease (vWd), the Biotest F VIII concentrate showed a loss of large and some intermediate multimers and is less suitable for the treatment of patients with vWd.