Analysis of von Willebrand factor in platelets of patients with various forms of von Willebrand disease: is there a clinical relevance?

UNLABELLED: Besides the investigation of coagulation factor VIII:c and von Willebrand factor in plasma. vWF antigen and vWF collagen-binding activity in platelets of 24 patients with various forms of von Willebrand disease were analysed. No platelet vWF:Ag or vWF:CBA was detectable in type 3 patients (n = 4). In contrast 6 out of 7 patients with type 2 vWD had normal or increased vWF levels. Two type I patients (out of n = 13) with low von Willebrand factor in platelets had no increased bleeding tendency. In two other individuals with normal amounts of von Willebrand factor in platelets and low plasmatic vWF and factor VIII:c, more frequent bleeding episodes reflecting the low plasmatic levels were observed in a long-term follow-up. CONCLUSION: In our patients, bleeding history corresponded to plasmatic levels of FVIII:c and vWF.