Transfusions to group O subjects of 2 units of red cells enzymatically converted from group B to group O

Abstract

Background: It has previously been shown that full‐unit (200 mL) transfusions of red cells (RBCs) enzymatically converted from group B to group O by treatment with α‐galactosidase (ECO RBCs) are both safe and efficacious for normal group O or A subjects.Study Design and Methods: The present study describes the results of a comprehensive clinical and serologic assessment of 2‐unit (400 mL) ECO RBC transfusions to each of four normal group O subjects (after each had donated 1 unit of whole blood).Results: Clinical (hematologic tests, chemistry analysis, urinalysis) and serologic analyses revealed no evidence of immediate or delayed transfusion reaction, despite a threefold to fivefold elevation in pre‐existing anti‐B antiglobulin titer. ⁵¹Cr‐labeled ECO RBCs were administered to one of the four subjects to allow direct measurement of ECO RBC survival in the circulation, which indicated that it was normal (24‐hour survival, 95%; t½, 29.5 days). The observed increases in hemoglobin (by 1.3 ± 0.4 g/dL [13 ± 4 g/L]) and hematocrit (by 3.2 ± 0.8% [0.032 ± 0.008]) in transfused subjects provide further evidence of the efficacy of these cells in vivo.Conclusion: These results extend those observed in our earlier 1‐unit transfusion studies and suggest that ECO RBCs pose little risk and will be useful in transfusion medicine.