title: Decreased immunorejection in unmatched blood transfusions by attachment of methoxypolyethylene glycol on human red blood cells and the effect on D antigen.
abstract: BACKGROUND
  Pegylation of red blood cells (RBCs) has been the primary focus of research on the immunocamouflage of cell. The aim of this study was to demonstrate pegylation homogeneity, its shielding effect on D antigens, and its storage stability. In addition, methoxypolyethylene glycol (mPEG)-modified RBCs (mPEG-RBCs) were tested serologically against a panel of serum samples that was difficult to match to find a solution to the difficulty in matching.
  
  
  METHODS
  In this study, fluorescein-PEG and a confocal laser scanning microscope were used to monitor PEG attachment on RBC population and observe reaction homogeneity, the stability of mPEG combined with RBCs in vitro was evaluated by the RBC ghost agglutination test, the pegylation sites on membrane were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with two dye methods, and the effect of pegylation on D antigen was detected by immunoblotting techniques. Compatibility tests were carried out between 66 cases of serum with difficulty in blood matching and mPEG-camouflaged RBCs by use of four blood matching methods including direct agglutination, indirect antiglobulin test (IAT), microtyping gel cards (MTS), and the manual polybrene technique (MPT).
  
  
  RESULTS
  The results indicated the homogeneity of pegylation, the absence of RhD protein in mPEG-modified D+ RBCs by Western blotting, and attachment of PEG to RBCs after 30 days of storage, while RBCs still remained antigenically silent. All pegylation RBCs showed a negative reaction with ABO-matched patients' serum samples by direct agglutination, IAT, and MTS, which indicated that pegylation RBCs and patients' serum samples were compatible. MPT was not suitable for detecting blood matching of mPEG-RBCs, because modification changed the RBCs' biophysical properties.
  
  
  CONCLUSIONS
  In conclusion, mPEG-RBCs have acceptable in vitro properties and provide a useful solution to problems with clinical blood matching, although such masking leaves much to be desired.
authors.affiliation: Department of Blood Biochemistry and Molecular Biology Laboratory, Institute of Transfusion Medicine, Beijing, China.
authors.forename: Yingxia
authors.initials: Y
authors.lastname: Tan
authors.forename: Yan
authors.initials: Y
authors.lastname: Qiu
authors.forename: Hua
authors.initials: H
authors.lastname: Xu
authors.forename: Shouping
authors.initials: S
authors.lastname: Ji
authors.forename: Subo
authors.initials: S
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Gong
authors.forename: Yangpei
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D001788:Blood Grouping and Crossmatching; D015153:Blotting, Western; D004912:Erythrocytes / Q000276:immunology*; D006801:Humans; D007518:Isoantibodies / Q000097:blood; D018613:Microscopy, Confocal; D011092:Polyethylene Glycols / Q000494:pharmacology*; D012204:Rh-Hr Blood-Group System / Q000276:immunology*; D065227:Transfusion Reaction
chemical_list: D007518:Isoantibodies; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen; D011092:Polyethylene Glycols; C028210:monomethoxypolyethylene glycol