High-throughput Kell, Kidd, and Duffy matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry-based blood group genotyping of 4000 donors shows close to full concordance with serotyping and detects new alleles.
BACKGROUND
After the ABO (ABO) and Rh (RHD and RHCE) blood group systems, Kell (KEL), Kidd (SLC14A1), and Duffy (DARC) represent the second most important clinically relevant antigens.


METHODS
Samples from 4000 Swiss blood donors, with serologic prevalues for K/k, Kp(a/b), Jk(a/b), and Fy(a/b), and 48 additional samples of presumptive black African origin were genotyped using high-throughput matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry, applying one single-multiplex polymerase chain reaction/primer-extension reaction simultaneously detecting 15 single-nucleotide polymorphisms.


RESULTS
Genotype/phenotype concordance for K/k, Kp(a/b), Jk(a/b), and all Fy(a/b) specificities were 100, 99.98, 99.93, and 99.20%, respectively. Discrepancies were caused by erroneous serologic profiles (n = 33), mainly attributed to weakly expressed Fy(x) (n = 28). Only three discrepancies had a genetic basis. They could all be explained by newly observed silenced alleles: one KEL*02N.34 and one FY*02N.03 with predicted R700Q and G261R amino acid exchanges, respectively, and one JK*B, with an as-yet-unidentified silencing cause. According to NCBI SNP database entry for rs8176034, another new allele, KEL*02.38, had been expected, and we formally demonstrated its presence. We furthermore identified individuals with rare phenotypes, such as Js(a/b) heterozygotes among Caucasians, rare alleles, the "Swiss" JK*01N.03, and rare genotypes, such as one Fy(x) homozygote.


CONCLUSIONS
Genotyping proved its practicability in the daily routine setting and qualitatively outperformed serology. Technology is ideal for time-insensitive donor genotyping and allows for a broad range of throughput needs. Consequently, from a technologic point of view, serotyping should be replaced by genotyping for donors' blood groups encoded by KEL, SLC14A1, and DARC.
Department of Molecular Diagnostics & Cytometry (MOC), Swiss Red Cross, Schlieren, Switzerland.
Stefan
S
Meyer
Caren
C
Vollmert
Nadine
N
Trost
Chantal
C
Brönnimann
Jochen
J
Gottschalk
Andreas
A
Buser
Beat M
BM
Frey
Christoph
C
Gassner
D000328:Adult; D000483:Alleles; D030561:Databases, Nucleic Acid; D004375:Duffy Blood-Group System / Q000737:chemistry / Q000235:genetics*; D005260:Female; D060005:Genotyping Techniques / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007667:Kidd Blood-Group System / Q000737:chemistry / Q000235:genetics*; D008297:Male; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics*; D008666:Metalloendopeptidases / Q000737:chemistry / Q000235:genetics*; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods*; D013557:Switzerland
C473745:ACKR1 protein, human; D004375:Duffy Blood-Group System; D007667:Kidd Blood-Group System; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C585978:KEL protein, human; D008666:Metalloendopeptidases