Abstract
Adverse reactions from donor-recipient sex-mismatched transfusions have been reported in the field of transfusion medicine. Immature CD71+ red blood cells (CD71+ RBCs) may influence these reactions through an immunomodulatory mechanism potentially linked to enriched intracellular reactive oxygen species (ROS). This study was conducted to investigate the effect of CD71+ RBCs on erythrophagocytosis, a common in vitro test for hemolysis risk in incompatible blood transfusions. Enriched CD71+ RBCs and CD71- RBCs were exposed to allogenic peripheral blood mononuclear cells (PBMCs). CD71+ RBCs were also incubated with anti-D sensitised CD71- RBCs and PBMCs, in varying ratios, to assess any dose-dependent behaviour. An ROS scavenger, apocynin, was applied to understand how CD71+ RBCs impact erythrophagocytosis. The phagocytosis index (RBC PI or CD71+ RBC PI) was measured using image flow cytometry. Supernatant haemoglobin was examined spectrophotometrically. The enriched CD71+ RBC group showed a significantly higher RBC PI and a reduction in the monocyte number compared to the CD71- RBC group. Compared to the non-treated group, the reduction of monocyte number and the increase of the phagocytosis index of CD71+ RBCs was partially reversed in the apocynin-treated group. There were positive correlations between the dose of CD71+ RBC and CD71+ RBC PI and supernatant haemoglobin. Donated CD71+ RBCs enhance in vitro erythrophagocytosis of CD71+ RBCs in a dose-dependent manner and reduce monocyte number. This work contributes to our understanding of immature CD71+ RBCs' role in post-transfusion immunobiology.