VWF and von Willebrand disease (hereditary or acquired): The development of neutralizing antibodies (inhibitors) against VWF is a rare but potentially serious complication of replacement therapy in VWD patients that can lead to severe anaphylactic reactions and the patient can become unresponsive to VWF-containing concentrates.6, 7, 8Data on inhibitor development and management in VWD are, however, rather limited.