Endogenous factor V synthesis in megakaryocytes contributes negligibly to the platelet factor V pool.

Background And Objectives: Coagulation factor V (FV) is distributed between two pools: 80% circulates in plasma and 20% is stored in platelets. The aim of the study was to determine the origin of platelet FV.

Design And Methods: We investigated a FV Leiden heterozygous patient who had received an allogeneic bone marrow transplant from a normal donor.