PHENOTYPING AUTOLOGOUS RED-CELLS WITHIN 1 DAY AFTER ALLOGENEIC BLOOD-TRANSFUSION BY USING IMMUNOMAGNETIC ISOLATION OF RETICULOCYTES

Background: When a transfused patient develops multiple or weak blood group antibodies, posttransfusion phenotyping is useful in antibody id entification To perform a correct phenotyping after transfusion, isola tion of autologous red bells is necessary. However, mature autologous red cells are impossible to separate from their donor counterparts. Si nce the proportion of autologous reticulocytes compared to donor retic ulocytes increases rapidly after transfusion, selective isolation of r eticulocytes provides autologous cells for antigen typing. Study Desig n and Methods: Extensive phenotyping was performed on red cells from 1 0 surgical patients before transfusion and on red cells and reticulocy tes after the transfusion of 5 or more red cell units. Reticulocytes w ere isolated by using an antibody against the human transferrin recept or coupled to magnetic beads. Results: The data showed nearly full agr eement between pretransfusion phenotyping of red cells and posttransfu sion typing of reticulocytes. Correct phenotyping of transfused patien ts could be obtained 8 to 10 hours after transfusion using isolated re ticulocytes. Conclusion: This method is helpful in selecting compatibl e blood when patients have developed antibodies and have an urgent nee d for further transfusions.