Chemical Modification On RhD Positive Red Blood Cells

The purpose of this study is to choose a proper methoxy polyethylene glycol(mPEG) derivative to camouflage RhD antigen located on red blood cells(RBCs) and to convert RhD positive RBCs to RhD negative.In this study, the effects of four kinds of mPEG derivatives modification on RhD positive red blood cells were compared. The effects of mPEG modification on cell morphology, structure and function were observed. The modification ratio of mPEG was analysed by using an aqueous-2-phase system to separate the modified and unmodified red blood cells. The record of modified RBCs' storage lives in 4C and the stability of mPEG modification were measured. And the modified RBCs' in vivo survival were estimated by using mPEG-modified mouse RBC experiment.The results showed that the effect of mPEG-BTC modification was best among the four kinds of mPEG derivatives. mPEG-BTC could camouflage RhD antigen under the mildest condition. mPEG modification didn't effect the RBCs function and structure, including osmotic fragility, hemolysis, AchE, cholesterol, ATP, 2,3-DPG, deformability and morphology. The modification degree was over 80%. Modified RBCs could store in 4C for 21 days and the modification was stable during the storage period. In vivo survival of modified-mouse-RBCs were normal.We also collected 6 serum samples from patients who were mostly received repeated transfusion and their serum had RhD antibodies which made it too difficult to find suitable donor blood in clinic. The agglutination between patients' serum and donors' RBCs disappeared after mPEG-BTC camouflage donor RBCs by polybrene and antihuman globulin tests. It demonstrated that the mPEG-BTC modified RhD positive blood could be used for those patients even though RhD antibodies existed in their serum. The result suggested that the donor RBCs camouflaged by mPEG-BTC were able to resolve the problem of RhD matching in clinical transfusion.