Immunoelectrophoretic Mobility of Factor VIII in Patients Treated with DDAVP

5 patients suffering fr om Willebrand 's disease or mild Hemophilia A were treated once or several times with DDAVP (1-Deamino-8-D-Arginine Vasopressin), administered intravenously (0,4 μg/Kg BW). Beside other parameters like F.VIII related activities and bleeding time, the F.VIII migration pattern of each patient was examined in crossed immunoeletrophoresis before and several times after DDAVP therapy. In all cases a relatively slower mobility of this protein could be observed up to 24 hours after infusion. When the administration of DDAVP was repeated within 24 hours, the change of the F.VIII migration pattern was less pronounced than after the first therapy. The results indicate that DDAVP stimulates the release of subpopulations of F.VIII in plasma which cannot be readily detected in circulation before treatment. After repeated administrations in short intervals the portion of these slow migrating subfractions progressively decreases, probably because of a depletion of the respective stores. These observations complete those of other authors who noted the exhaustion of DDAVP effects in the course of longer treatments.