Decreased clearance of von Willebrand factor in a patient with type 2B von Willebrand disease following development of immune thrombocytopenia

We report a case of concurrent type 2B von Willebrand disease (VWD) and immune thrombocytopenia (ITP). The patient had characteristic loss of von Willebrand factor (VWF) high molecular weight multimers (HMWM) but a normal platelet count in the initial 8 years after diagnosis of type 2B VWD. When he developed severe thrombocytopenia, however, both his VWD indices and VWF HMWM normalized. As his platelet count increased, he again lost the HMWM and his VWD indices decreased. These results suggest that the severe thrombocytopenia led to decreased clearance of VWF, especially the HMWM. Pediatr Blood Cancer 2008;51:416–418. © 2008 Wiley‐Liss, Inc.