Results of extended phenotyping of von Willebrand disease in the remote diagnostic program in children

Abstract

In the course of our earlier data obtained in remote diagnosis of von Willebrand disease (vWD) program, 16 samples were identified for extended laboratory work up in order to clarify a specific subtype of vWD. Purpose of the study: extended phenotyping of blood samples with suspected type 2 vWD. This study is supported by the Independent Ethics Committee and approved by the Academic Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology. Using 16 aliquoted frozen samples, collagen-binding (vWF:CB) and fVIII-binding activity of vWF (vWF:FVIIIB) tests were performed, as well as multimeric analysis of vWF. Isolated fVIII deficiency with no laboratory signs of 2N vWD subtype were detected in 7 (44%) of 16 patients with an initial decrease in the ratio of fVIII activity to vWF antigen. In the remaining 9 patients, vWF:CB was assessed, which showed a decrease in association with collagen in 6 patients, which allows one to suspect type 2A or 2B. In the remaining 3 with normal vWF:CB patients, type 2M was suspected. MA helped to further identify patients with suspected type 2B vWD. The use of remote diagnostics technologies allows phenotyping most forms of vWD even in patients living in regions with limited laboratory capabilities.