Expression levels of CD47 on red blood cells during their storage in blood bank

Introduction: Red blood cells (RBCs) intended for transfusion can be stored under the blood bank conditions up to 42 days and prepared as leucodepleted (filtered) or non-leucodepleted units. During this time cells develop so-called "storage lesions" which can cause an adverse post-transfusion effect. It is suggested that senescent cell neoantigens appear among protein macrocomplexes: Rh, band 3 and glycophorin A (GPA) on the erythrocyte surface and initiate the binding of the natural autoantibody. CD47 is a transmembrane glycoprotein which is closely related to the Rh macrocomplex and is suspected to perform many roles in immunity, cell destruction and regulation of blood flow. Aim of the study: To compare the CD47 expression on RBCs from "fresh" and "old" units with and without leucocytes. Material and methods: The expression level of CD47 and percentage of labelled RBCs with anti-CD47-PE were measured by the flow cytometer FACSCanto II (BD) using 50000 cells. For statistical analysis, Anova, t-Student and Kruskal-Wallis tests were used and p < 0.05 was considered as significant. Results: FC parameters have shown a statistically important fluorescence increase in "old" compared to "fresh" RBCs but the number of labelled RBCs in samples of "fresh" and leucodepleted units was larger than in other groups. Conclusions: The expression of CD47 molecule changes during the RBCs storage and the presence of leucocytes in non-leucodepleted units significantly impacts its intensity.