Abstract

NATHALANG, Oytip et al. Genomic analysis of KEL*03 and KEL*04 alleles among Thai blood donors. Afr. J. Lab. Med. [online]. 2024, vol.13, n.1, pp.1-7. ISSN 2225-2010.  http://dx.doi.org/10.4102/ajlm.v13i1.2294.

BACKGROUND: The Kell blood group system is clinically important in transfusion medicine, particularly in patients with antibodies specific to Kell antigens. To date, genetic variations of the Kell metallo-endopeptidase (KEL) gene among Thai populations remain unknown OBJECTIVE: This study aimed to determine the frequencies of KEL*03 and KEL*04 alleles among Thai blood donors using an in-house polymerase chain reaction-sequence-specific primer (PCR-SSP) method. METHODS: Blood samples obtained from 805 unrelated central Thai blood donors at a blood bank in Pathumthani, Thailand, from March 2023 to June 2023, were typed for Kp^a and Kp^b antigens using the column agglutination test, and the results for 400 samples were confirmed using DNA sequencing. A PCR-SSP method was developed to detect the KEL*03 and KEL*04 alleles, and genotyping results were validated using known DNA controls. DNA samples obtained from Thai donors in central (n = 2529), northern (n = 300), and southern (n = 427) Thailand were also genotyped using PCR-SSP for comparison. RESULTS: All 805 (100%) donors had the Kp(a−b+) phenotype. The PCR-SSP genotyping results agreed with the column agglutination test and DNA sequencing. All 3256 Thai blood donors had the homozygous KEL*04/KEL*04 genotype. Frequencies of the KEL*03 and KEL*04 alleles among Thai donors differed significantly from those of Japanese, Native American, South African, Brazilian, Swiss, and German populations. CONCLUSION: This study found a 100% KEL*04 allele frequency in three Thai populations. These data could provide information on KEL*03 and KEL*04 allele frequencies to estimate the risk of alloimmunisation in Thai populations What this study adds: This study demonstrates that in-house PCR-SSP can be used to determine KEL*03 and KEL*04 alleles to predict Kp^a and Kp^b antigens. Even though only homozygous KEL*04/KEL*04 genotypes were found among Thai donor populations, the established PCR-SSP method may be useful for estimating the risk of alloimmunisation in other populations.

Keywords : Kell blood group system; phenotype; allele; genotype; Thai population.

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