Genetic diversity in RHD and RHCE genes among a selected Kenyan blood donor population

Serologic typing for ABO and RhD is standard in transfusion services, with extended serology and genotyping performed to reduce red cell alloimmunization risk. In Kenya, RH typing is limited to RhD, and genotyping is unavailable. This study used RHD/RHCE genotyping to predict phenotypes and their distribution in a Kenyan blood donor population.

A total of 191 donors (114 D-, 74 D+, and 3 weak D) from the Kenya National Blood Transfusion Service were selected. Next-generation sequencing was performed on DNA extracts using a targeted blood group sequencing panel (Illumina MiSeq). Variant call format (VCF) files were annotated with wANNOVAR, and phenotypes were predicted by matching VCF data to the International Society of Blood Transfusion (ISBT) Blood Group database.

RHD*01N.01, RHD*08N.01 (RHD*Ψ), and RHD*03N.01 alleles were identified predicting D- phenotype. Discordant phenotype results were observed in 11 samples with genotype predicting nine D+ (partial D) in 114 D-, one D- in 74 D+, and one D- in three weak D phenotypes. For RHCE, 15 allele types produced 30 genotypes with 63% carrying at least one RHCE variant allele linked to: 1) weak and/or partial c and e, 2) hr^B-, and 3) V+/-, VS+, phenotypes.

Genotyping revealed RhD/RHD phenotype/genotype discrepancies and RH allele diversity among Kenyan donors, including RHCE variants affecting high- and low-prevalence antigen expression. These findings highlight the role of genotyping to improve accuracy for RH typing to minimize the risk of patient alloimmunization.