Novel strategy for overcoming interference from anti-CD47 agents in pretransfusion testing

CD47 is an important immune checkpoint in haematopoietic and solid malignancies. However, panreactivity of anti-CD47 agents leads to interference during pretransfusion compatibility testing binding to red blood cells. To address this issue, we created immunomagnetic beads (IMBs) to adsorb anti-CD47 monoclonal antibodies (mAbs): IMB-OVCAR3, coated with lysed protein from the OVCAR3 cell line, which was screened using flow cytometry and immunofluorescence staining, and IMB-CD47, coated with a recombinant CD47 protein. Plasma adsorbed by IMBs was collected for gel column agglutination testing and flow cytometry to verify elimination of anti-CD47 mAb interference. The effects of IMBs on irregular antibody screening and adsorption ability of IMBs over preservation time were also analysed. Following successful preparation, IMBs were shown to adsorb anti-CD47 mAb in plasma and reduce anti-CD47 mAb interference of simulated and clinical samples in 30 ​s. Moreover, IMBs did not adsorb irregular antibodies. Both IMBs retained their anti-CD47 mAb adsorption capacity for 3 weeks in a preservation solution. IMB-OVCAR3 and IMB-CD47 can serve as novel tools for the efficient removal of CD47 interference during transfusion compatibility testing in transfusion laboratories.