Time course of VWF:Ag and VWFpp after administration of desmopressin. (A) VWF:Ag levels were determined before (t = 0), 1, 2, and 4 hours after desmopressin administration. In most patients, VWF:Ag levels increased after desmopressin administration. While VWF:Ag levels in some patients diminished slowly over time, in other patients VWF:Ag levels rapidly decreased. (B) VWFpp levels were determined before (t = 0), 1, 2, and 4 hours after desmopressin administration. VWFpp levels in the plasma of all patients increased after administration of desmopressin and decreased over 4 hours.