Detection of Platelet-Specific Patient Antibodies Using Human iPSC-Derived Megakaryocytes

Introduction Many diagnostic assays in transfusion medicine rely on fresh donor cells, posing challenges in availability and standardization, especially for rare antigens. Human induced pluripotent stem cells (iPSCs) offer a renewable alternative by generating test cells in vitro. The monoclonal antibody-specific immobilization of platelet antigens (MAIPA) assay, the gold standard for detecting human platelet antigen (HPA) antibodies, depends on HPA-genotyped donors, creating logistical hurdles. iPSC-derived megakaryocytes could provide a scalable and standardized test cell source for the detection of platelet specific antibodies. This study evaluates the feasibility of using iPSC-derived megakaryocytes as an alternative cell source for detecting HPA antibodies in a modified MAIPA assay. Method Human iPSCs were differentiated into megakaryocytes in vitro using stirred bioreactors, and the expression of key platelet glycoproteins (GPIIb/IIIa, GPIb/IX, and GPIa) was confirmed by flow cytometry. The performance of iPSC-derived megakaryocytes in the MAIPA assay was tested using the WHO reference reagent for HPA-1a and clinical samples containing well-characterized anti-HPA antibodies, specifically targeting HPA-1a, HPA-1b, HPA-3a, HPA-3b, and HPA-5b. Additional experiments assessed antibody binding to iPSC-derived megakaryocytes after incubation with samples containing platelet specific allo- or autoantibodies Results The WHO anti-HPA-1a reference reagent showed comparable binding patterns between platelets and iPSC-derived megakaryocytes, with a strong correlation in optical density (OD) values. Clinical samples containing anti-HPA-1a, anti-HPA-1b, and anti-HPA-3b antibodies were reliably detected using iPSC-derived megakaryocytes. However, samples with anti-HPA-3a and anti-HPA-5b antibodies exhibited lower OD values compared to the standard platelet-based MAIPA assay. Both allo- and autoantibodies bound to iPSC-derived megakaryocytes, suggesting a potential use of whole-cell megakaryocyte assay in flow cytometry for the detection of HPA antibodies. Conclusion iPSC-derived megakaryocytes show promise as an alternative source for diagnostic assays. However, their sensitivity for detecting antibodies against certain HPA systems, such as HPA-3 and HPA-5, may be limited. iPSC cells offer possibilities to be modified for the expression of certain antigens, such as enhancing glycoprotein expression or optimizing antigen presentation to improve sensitivity. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany