Ligation of CD47 mediates phosphatidylserine expression on erythrocytes and a concomitant loss of viability in vitro.

CD47 ligation has been shown to induce phosphatidylserine (PS) expression as part of a death pathway in nucleated blood cells. Using Annexin V binding assays we showed that ligation of CD47 with the specific CD47-binding peptide 41NK, anti-CD47 monoclonal antibody, and its natural ligand thrombospondin-1 also induced PS expression on enucleated erythrocytes. PS expression was associated with a concomitant loss of erythrocyte viability in vitro. Further characterisation of the CD47-PS signalling pathway on erythrocytes may help develop clinical strategies to further preserve the life of blood donations and improve our understanding of certain types of haemolytic anaemias.