Study of human von Willebrand factor immunogenicity in pigs with severe von Willebrand disease

Replacement therapy is the treatment of choice for patients with von Willebrand disease who are unresponsive to desmopressin. In order to prevent transmission of non-enveloped viruses, a solvent/detergent-treated plasma-derived von Willebrand factor available in France since 1989 has been subjected to additional removal/inactivation steps by 35 nm filtration and dry heating for 72 h at 80 degrees C. This preclinical study evaluates the potential immunogenicity of this new product by comparing the antibodies raised in pigs affected with von Willebrand disease after intravenous injection of either a solvent/detergent-treated product or a triple-secured product. Our data showed that there is no difference between the two products in terms of the rate and intensity of the humoral response measured by both binding and neutralizing antibody levels. It was concluded that no antigenic alterations of von Willebrand factor molecules during the nanofiltration and final dry-heating steps were detected in our animal model.