Distribution of extended red blood cell phenotypes among blood donors: experience from a low- and middle-income country

Abstract Although information on minor blood group antigen frequencies is limited in many low- and middle-income countries, extended red blood cell (RBC) phenotyping is crucial for reducing alloimmunization in patients undergoing chronic transfusions. This study aimed to characterize the distribution of extended red blood cell antigens across multiple clinically significant blood group systems among blood donors in a low- and middle-income country to inform transfusion strategies. Between April and September 2024, we carried out a cross-sectional pilot study involving 200 healthy blood donors recruited from five blood banks in a low- and middle-income country. In accordance with the AABB guidelines, the antigen frequencies for the Kell (K, k, Kpa, Kpb), Duffy (Fya, Fyb), Kidd (Jka, Jkb), MNS (M, N, S, s), Lewis (Lea, Leb), Lutheran (Lua, Lub), and P1 systems were determined via manual tube agglutination. Lutheran and Lewis systems were examined in randomly chosen subgroups (n = 120 and n = 110, respectively) due to resource scarcity. Phenotype match probabilities were calculated as Σ(pi 2) and compared with published population data using chi-square tests with Bonferroni correction. The following unique antigen distributions were found: S (88.5%, 83.4–92.4), Jka (72.5%, 65.8–78.3), P1 (70.5%, 63.9–76.4), K (7.0%, 95% CI: 4.2–11.3), and k (97.0%, 93.8–98.9). Significant gene flow from Africa was demonstrated by the 17.5% (12.8–23.4) that had the Fy(a − b−) null phenotype. There were differences in phenotype matching within the population, ranging from 28.2% (Kidd) to 66.7% (Lutheran). The highest cross-population compatibility was found with African donors for Duffy (29.6%) and P1 (67.3%) and Israeli donors for Kidd (43.7%). Importantly, Duffy’s compatibility with Asian people was only 10.9%, meaning that using Asian donors would result in a 90% sensitization risk. These pilot results show that Palestinians have unique RBC antigen patterns that call for transfusion techniques tailored to their demographics. The results encourage the introduction of extended phenotyping in tiers, starting with the Kell, Duffy, and Kidd systems, and the creation of a national phenotyped donor registry (achievable within 2–3 years given 35,000 annual donations). However, before policy is mandated, further extensive molecularly validated investigations involving Gaza and Jerusalem are needed.