EFFECTS OF LYOPHILIZATION AND REHYDRATION ON MEMBRANE SURFACE ANTIGENS OF HUMAN RED BLOOD CELLs.

BACKGROUND: Previous studies have demonstrated that human RBCs can survival from freeze-drying, but there is still some uncertainty on whether and how the cell properties change during the processes.

OBJECTIVE: The present study is to evaluate the effects of lyophilization and rehydration on the membrane surface antigens, such as CD antigens and blood group antigens, of human RBCs.

MATERIALS AND METHODS: Human RBCs were lyophilized first through a simplified protocol, in which glycerol were used in the lyoprotectant solution instead of trehalose. Upon rehydration, a series of in-vitro experiments were performed to examine the variation of cell count, cell level of ATP and 2,3 DPG, and the surface antigens on cell membrane.

RESULTS: The cell count recovery was 58.87%±0.74%, and the cell levels of ATP and 2, 3 DPG maintained well upon rehydration. Those results are comparable to the literature, demonstrating the simplified protocol has similar effects on RBCs comparing with the reported approaches. Flow cytometry assays demonstrated that there were no significant difference in CD35, CD44, CD45, CD47 and CD71 expressions before and after freeze-drying. In blood group tests, most of the blood group antigens maintained after lyophilization and rehydration, except that Le(a), Le(b) and JK1 showed high probabilities of falling off during the processes.