Abstract Number: PB1379
Meeting: ISTH 2020 Congress
Background: The monoclonal antibody immobilization of platelets (MAIPA) assay, developed by Kiefel et al., is the standard assay for the detection of auto-/alloantibodies in patients with thrombocytopenia. Labile glycoprotein that dissociates from older platelets require fresh platelets, especially to detect antibodies against antigens of the HPA-3 and HPA-15 systems. We established a potentially novel diagnostic tool based on the use of hematopoietic stem cell-derived megakaryocytes (MKs) instead of donor-derived platelets.
Aims: To develop a diagnostic tool, based on megakaryocytes, as alternative to the standard MAIPA assay for providing fresh megakaryocytes with consistent antibody expression.
Methods: CD34+ cells were magnetically isolated from buffy coat and differentiated for 28 days in vitro into MKs. We performed a flow cytometry analyses to characterize the MK cell lines (CD41, CD42a expression and DNA content). The alloantigens of MKs and platelets were determined using a MAIPA derived assay whit WHO standard sera containing antibodies directed against HPA-1a, -3a and -5b.
Results: Lower number of MKs was needed for MAIMA in comparison to the number of PLTs used in MAIPA (100×103 vs. 20×106, respectively). Most importantly, the monoclonal antibody immobilization of megakaryocyte antigens (MAIMA) assay showed similar OD amplitudes compared to MAIPA when WHO reference reagents were used: Anti-HPA-1a (optical density [OD]: 1.35 vs 1.16), Anti-HPA-1a (minimum potency OD: 0.437 vs 0.543), Anti-HPA-3a (OD: 0.349 vs 0.284) and Anti-HPA-5b (OD: 0.134 vs 0.335), for PLT and MKs, respectively.
Conclusions: Our preliminary results demonstrate that the MAIMA assay has similar performance characteristics compared with MAIPA suggesting it as a suitable donor independent assay for laboratory investigations of alloimmunisation.
To cite this abstract in AMA style:Lucic J, Althaus K, Rigoni F, Nowak-Harnau S, Lyshy F, Marini I, Bakchoul T. Monoclonal Antibody Immobilization of Megakaryocyte Antigens (MAIMA) Assay: A Novel Tool for Detecting Human Platelet Antigens [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/monoclonal-antibody-immobilization-of-megakaryocyte-antigens-maima-assay-a-novel-tool-for-detecting-human-platelet-antigens/. Accessed December 10, 2023.
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