Red blood cell alloimmunization in transfused patients with myelodysplastic syndromes: a retrospective study from northern China

Objective Alloimmunization against red blood cell (RBC) antigen is an important concern in myelodysplastic syndromes (MDSs) patients with chronic transfusion, causing potential risk for hemolytic reaction and limited supply of compatible blood. However, there is little data addressing RBC alloimmunization in this patient cohort among the Chinese population. This study aims to evaluate the incidence, specificity of antibodies, and RBC units transfused before antibody formation and its significance in a population of patients consistently receiving RhD-matched RBC units.Methods We retrospectively reviewed the transfusion and clinical information of all transfused patients with MDS enrolled in our hospital from 2012 to 2022. The cumulative incidence of alloimmunization was analyzed by a Kaplan-Meier plot. Alloimmunization incidence was compared based on different transfused RBC units using the log-rank test.Results A total of 103 patients with MDS were included in this study; alloantibody formed in 8 (7.8%) patients. Before reaching 32 RBC units, 87.5% of the alloimmunized patients had developed their alloantibodies. All but 1 of the alloantibodies developed were antibodies to Rh antigens. The RBC transfusion intensity and frequency were significantly higher following alloimmunization in the alloimmunized patients (P = .008, P = .008, respectively).Conclusion The antibodies detected mostly involve the Rh system among MDS patients in China. The alloimmunization tended to occur early prior to reaching 32 RBC units in patients with MDS. Rh antigen matching should be considered early in the patient's transfusion history and completed before receiving 32 RBC units.