The Role of the Spleen in Regulating the Plasma Levels of Factor Vill-von Willebrand’s Factor After DDAVP

Organ transplantation and perfusion studies indicate that the spleen plays an important role in the regulation of plasma levels of factor VIII-von Willebrand’s factor (FVlllvWF). To better understand the mechanisms that regulate the FVIII-vWF increases after infusion of 1 -deamino-8D-arginine vasopressin (DDAVP). we have measured factor VIII coagulant activity (FVIII:C) and antigen (FVIII:CAg) and von Willebrand’s factor antigen (vWF:Ag) and ristocetin cofactor (vWF:RCof) in 9 asplenic subjects with normal baseline concentrations, in 7 asplenic subjects with high concentrations. and in 1 4 normal controls with intact spleens. In “normal” asplenics, all the FVIII-vWF-related measurements increased significantly over baseline values. indicating that responsiveness to DDAVP is not abolished