Immunogenicity of red cell alloantigens in the Japanese population

Aims: To elucidate transfusion-related blood group antigen immunogenicity among Japanese, a retrospective single center study was done. Methods: For 49,884 transfusion recipients from late 2006 to early 2018, antibodies were tested with two techniques: saline immediate spin test and polyethylene glycol-enhanced indirect antiglobulin test. From male recipients with an average of 4.2 donor exposures, we calculated the immunogenicity of blood group alloantigens with a mathematical model. Results: Indirect antiglobulin test detected 638 alloantibodies, 391 (1.53%) among 25,563 women and 247 (1.02%) among 24,321 men. Anti-E (489.1 per 100,000), followed by anti-Lea (238.6 per 100,000) and anti-Fyb (100.2 per 100,000) were most frequently found in the whole. Immunogenicity calculations among male recipients based on 4-donor exposure revealed Jra (67.4 per 1000, 95% CI: 1.7–323.3) as the possibly highest potency antigen, followed by: Lea (23.5 per 1000, 95% CI: 17.4–29.6), Dib (20.1 per 1000, 95% CI: 0.5–109.3), E (11.9 per 1000, 95% CI: 9.4–14.4), and Jka (5.7 per 1000, 95% CI: 1.7–9.6) among Japanese male recipients. Conclusion: Jra and Diego blood group antigens might be highly immunogenic in the Japanese population, but more recipients would need to be investigated to establish statistical significance.