RED blood cell immunization (RBC) is independently associated with reduced survival in transfusion dependent patients with myelodysplastic syndromes, according to an analysis of nearly 500 patients that clarifies its prognostic significance. The study evaluated long term outcomes in patients with myelodysplastic syndromes receiving chronic transfusion support and assessed the clinical impact of developing red blood cell antibodies over time.
Study Design and Incidence of RBC Immunization
Researchers analysed data from 486 transfused patients with myelodysplastic syndromes and examined RBC immunization as a time dependent factor. Competing risk methods were used to estimate cumulative incidence. RBC immunization developed in 69 patients, representing 14.2% of the cohort, with anti K and anti E antibodies identified most frequently. Immunization occurred more often in patients who had received transfusions before diagnosis and in those with a RhD negative blood group. The strength of these associations was demonstrated with sub hazard ratios: 2.9; 95% confidence interval: 1.6–5.4; p=0.001 for pre diagnosis transfusion, and 1.9; 95% confidence interval: 1.1–3.2; p=0.026 for RhD negativity.
RBC Immunization and Survival Outcomes
RBC immunization was strongly associated with inferior survival. After adjustment for relevant factors, immunized patients showed a marked reduction in remaining survival compared with non-immunized individuals, with a hazard ratio: 11.9; 95% confidence interval: 7.3–19.6; p=0.001. This adverse prognostic effect was observed regardless of whether antibodies were autoantibodies or alloantibodies. Importantly, RBC immunization did not predict progression to acute myeloid leukaemia, indicating that its impact on survival was independent of leukaemic transformation.
Transfusion Burden and Treatment Considerations
Following the development of RBC immunization, transfusion intensity increased. However, transfusion requirements also rose progressively in patients without immunization, suggesting a broader relationship between disease course and transfusion burden. A trend towards fewer newly detected antibodies was observed during hypomethylating therapy, although this finding was exploratory. Overall, the data highlight RBC immunization as a clinically relevant marker associated with poorer outcomes in myelodysplastic syndromes and support further investigation into the mechanisms linking immunization, transfusion exposure, and survival.
Reference
Pedraza A et al. Red blood cell immunization as an independent predictor of survival in the myelodysplastic syndromes. BJ Haem. 2026;https://doi.org/10.1111/bjh.70330.
