1. von Willebrand factor neutralizing and non-neutralizing alloantibodies in 213 subjects with type 3 von Willebrand disease enrolled in 3WINTERS-IPS
- Author
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Maria Teresa Pagliari, Ulrich Budde, Luciano Baronciani, Peyman Eshghi, Minoo Ahmadinejad, Zahra Badiee, Mohammad-Reza Baghaipour, Olga Benítez Hidalgo, Eugenia Biguzzi, Imre Bodó, Giancarlo Castaman, Jenny Goudemand, Mehran Karimi, Bijan Keikhaei, Riitta Lassila, Frank W.G. Leebeek, Maria Fernanda Lopez Fernandez, Renato Marino, Johannes Oldenburg, Ian Peake, Cristina Santoro, Reinhard Schneppenheim, Andreas Tiede, Gholamreza Toogeh, Alberto Tosetto, Marc Trossaert, Hamideh Yadegari, Eva M.K. Zetterberg, Pier Mannuccio Mannucci, Augusto B. Federici, Jeroen Eikenboom, Flora Peyvandi, and Hematology
- Subjects
Hematology - Abstract
Background: Type 3 von Willebrand disease (VWD) is the most severe form of this disease owing to the almost complete deficiency of von Willebrand factor (VWF). Replacement therapy with plasma-derived products containing VWF or recombinant VWF rarely cause the development of alloantibodies against VWF that may be accompanied by anaphylactic reactions. Objective: The objective of this study was to assess the prevalence of anti-VWF alloantibodies in subjects with type 3 VWD enrolled in the 3WINTERS-IPS. Methods: An indirect in-house enzyme-linked immunosorbent assay has been used to test all the alloantibodies against VWF. Neutralizing antibodies (inhibitors) have been tested with a Bethesda-based method by using a VWF collagen binding (VWF:CB) assay. Samples positive for anti-VWF antibodies were further tested with Bethesda-based methods by using the semiautomated gain-of-function glycoprotein-Ib binding (VWF:GPIbM) and a VWF antigen (VWF:Ag) enzyme-linked immunosorbent assay. Results: In total, 18 of the 213 (8.4%) subjects tested positive for anti-VWF antibodies and 13 of 213 (6%) had VWF:CB inhibitors. These 13 were among the 18 with anti-VWF antibodies. Of the 5 without VWF:CB inhibitors, 3 had non-neutralizing antibodies, 1 only inhibitor against VWF:GPIbM, and one could not be tested further. Ten of the 13 subjects with VWF:CB inhibitors also had VWF:GPIbM inhibitors, 6 of whom also had VWF:Ag inhibitors. Subjects with inhibitors were homozygous for VWF null alleles (11/14), homozygous for a missense variant (1/14), or partially characterized (2/14). Conclusions: Anti-VWF antibodies were found in 8.4% of subjects with type 3 VWD, whereas neutralizing VWF inhibitors were found in 6%, mainly in subjects homozygous for VWF null alleles. Because inhibitors may be directed toward different VWF epitopes, their detection is dependent on the assay used.
- Published
- 2023