KEL*02 alleles with alterations in and around exon 8 in individuals with apparent KEL:1,-2 phenotypes.
OBJECTIVE
Antibodies to antigens in the Kell blood group system, especially anti-KEL1, are involved in both haemolytic disease of the newborn and foetus and haemolytic transfusion reactions. Correct typing results are important and discrepancies between serologic and genetic typing must be resolved. Here, we describe the investigation of three healthy individuals who were initially phenotyped as KEL:1,-2.


METHODS
Antigen typing was performed by standard serological techniques and by flow cytometric analysis. The KEL*01/02 polymorphism was tested by an allele-discrimination TaqMan assay as well as by PCR with allele-specific primers and PCR-RFLP. DNA sequencing of the KEL coding region was also performed.


RESULTS
Two KEL*02N alleles with mutated splice sites around exon 8 were identified: intron 7 -1g>c (novel) and intron 8 +1g>t (previously reported in one case of K(0)). In the third sample, a missense mutation in exon 8, 787G>A (novel) predicting Gly263Arg, was detected on a KEL*02 allele and associated with dramatically weakened KEL2 antigen expression.


CONCLUSIONS
Resolution of discrepant phenotype/genotype results identified silencing mutations in or around exon 8. A combination of molecular and serologic methods has the potential to improve the quality of test results and was required to ensure both the accurate KEL2 antigen status and KEL*01 zygosity of these individuals.
Wester
E S
ES
Department of Clinical Immunology and Transfusion Medicine, University and Regional Laboratories, Region Skåne, Lund, Sweden.
Steffensen
R
R
Ligthart
P C
PC
Vad
J
J
de Haas
M
M
Storry
J R
JR
Olsson
M L
ML
D000483:Alleles; D005091:Exons; D005260:Female; D005434:Flow Cytometry; D005838:Genotype; D006801:Humans; D007626:Kell Blood-Group System / Q000235:genetics* / Q000276:immunology; D008297:Male; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length
D007626:Kell Blood-Group System