The study shows that transfusion of blood matched for Rh and Kell systems would reduce alloimmunization to 27% and reduce delayed hemolytic transfusion reaction, but would not prevent it. Delayed hemolytic transfusion reactions were mild and did not cause hyperhemolysis in sickle cell patients. However, the cause of hyperhemolysis, which is a severe problem, was neither due to allo- nor autoimmunization, and could not be prevented by matching for RBC antigens. Hyperhemolysis may be triggered by transfusion, but its cause seems to be multifactorial. Therefore, the authors conclude that the use of costly extended antigen-matched RBCs is not necessary. Unfortunately, the authors give no details of the further investigation of the autoantibodies (eluates, etc.) in order to be sure that no alloantibodies were imitating them. Further studies should use flow cytometry in order to follow up the survival of antigen-matched and -unmatched allogeneic RBCs as well as autologous RBCs.
– V. Kretschmer.