Reversal of acquired von Willebrand syndrome with allogeneic stem cell transplant for chronic lymphocytic leukemia.

ABSTRACT

Acquired von Willebrand syndrome (AVWS) is a rare, potentially fatal bleeding disorder caused by low activity of von Willebrand factor (VWF) in patients without congenital deficiency. The majority of adult cases are associated with hematological malignancy, including lymphoproliferative (48%) or myeloproliferative (15%) disorders (Federici et al., 2000). Both qualitative and quantitative defects occur, due to antibody-mediated clearance or functional interference, increased proteolysis, absorption to malignant cells or platelets, or increased shear stress due to valvular defects or mechanical vascular devices (Tiede et al., 2011). The predominant mechanism for decreased or absent VWF in malignancy is autoantibodies that are inhibitory to VWF function or shorten VWF survival (Kumar et al., 2002 [3]). Antibody-mediated clearance occurs through inactivating antibody directed towards VWF, antibody binding the non-active sites of VWF, and nonspecific antibodies that form circulating immune complexes with VWF, enhancing clearance by the reticuloendothelial system (Mannucci et al., 1984). Bleeding may be very difficult to treat due to reduced half-life of VWF-concentrates.