Each year the United States population receives an estimated 12 to 14 million units of packed red blood cells (RBCs) and whole blood. It is estimated that 33% of transfusions associated with
trauma are with unmatched type O RBCs (UORBC). UORBCs have been proven effective and relatively safe however, by masking RBC
surface antigens the risk of
transfusion reaction may be further decreased. It is, therefore, important to evaluate and validate the stability of
antigen masked RBCs, which may play a part in avoiding
transfusion reactions. These
antigen-masked RBCs would be regularly subjected to abnormal in vivo conditions commonly associated with massive transfusion such as
lactic acidosis,
bacteremia, and in vitro irradiation, which is frequently used to sterilize and decrease T Lymphocyte counts in RBC units before transfusion. This study compared two methods of masking RBC
antigens by PEGylation:
maleimide-PEGylation and
cyanuric chloride-PEGylation. RBC PEGylation effectively masks the Rh(D)
antigen and PEG-RBC bond stability was evaluated by comparison of pre and post exposure agglutination with
anti-D sera. While the stability of
maleimide-PEG-RBCs remained unaffected, the
cyanuric chloride-PEG-RBCs remained stable in the
bacteremia and irradiation studies, but critical concentrations of
lactic acid caused dePEGylation. Further studies are warranted to ensure in vivo stability.