The transfusion of non‐prophylactically RH‐KEL1 antigen‐matched red blood cells is feasible in selected myelodysplastic syndrome and acute myeloid leukaemia patients

Most myelodysplastic syndromes (MDS) patients become red blood cell (RBC) transfusion‐dependent. Transfusing MDS patients with prophylactically RH‐KEL1 antigen‐matched (PAM) RBC units is recommended to avoid RBC allo‐immunization. D+C−E−c+e+, D+C−E+c+e− and D+C+E−c−e+ phenotypes are infrequent among French blood donors. To preserve infrequent phenotype RBC units for patients other than MDS, and to manage frequent phenotype RBC unit stocks, we let, for 1 year, higher‐risk non‐immunized chronically transfused MDS and acute myeloid leukaemia (AML) patients receive RBC transfusions matched only for D. Our objectives were to evaluate the impact of non‐PAM transfusions on the transfusion policy (which would be modified in case of RBC allo‐immunization) for frequent and infrequent phenotypes patients and to estimate the number of infrequent phenotypes RBC units that could be redistributed to other patients.