Assessing Abo and Kell Blood Group Phenotypes and Antigens in Donated Blood Units at University College Hospital, Ibadan, Nigeria

Introduction: The ABO blood group system is the most clinically recognized and routinely investigated blood group system in donated blood used for transfusions in Sub-Saharan Africa, due to its immunogenicity and the potential for antibodies against ABO antigens to cause the destruction of transfused red blood cells. However, research has shown that the unrecognized Kell antigen and its associated phenotypes also have potent immunogenic potential that could contribute to transfusion reactions. Therefore, this study aims to investigate the prevalence of ABO and Kell blood group antigens in 287 donated blood units at the University College Hospital in Ibadan, Nigeria.

Methods: A total of 287 blood units donated between February and November 2022 at the University College Hospital, Ibadan, were analyzed using standard serological techniques. Positive and negative controls for red blood cell antigens were included with each batch of samples to ensure accuracy. For each blood unit, 2 mL of blood was drawn into a plain container, and ABO and Kell blood grouping was carried out using the slide technique for direct agglutination of antigens with their corresponding antibodies and the tube method for the indirect antiglobulin test.

Results: Out of the 287 donated blood units, the distribution of ABO blood groups was as follows: A 62 (21.6%), B 46 (16.0%), AB 17 (5.9%), and O 162 (56.5%). The frequency of identified Kell blood group antigens was: K+ 17 (6.0%), K- 270 (94.0%); k+ 22 (7.7%), k- 265 (92.3%); Kpa+ 34 (11.9%), Kpa- 253 (88.1%); and Kpb+ 21 (7.3%), Kpb- 266 (92.7%). Distribution of Kell phenotypes was as follows: K+k- 80 (27.9%), K-k+ 95 (33.1%), K+k+ 77 (26.8%), K-k- 35 (12.2%); Kp (a+b+) 66 (23.0%), Kp (a+b-) 15 (5.2%), Kp (a-b+) 206 (72.0%), and Kp (a-b-) 0 (0%).

Conclusion: This study provides valuable data on the prevalence of Kell phenotypes and its blood group antigens in donated blood units at the University College Hospital, Ibadan. The findings call attention to the importance of considering these antigens, alongside the ABO system, as they may influence transfusion outcomes, in terms of immunogenicity and the risk of transfusion reactions.