An easy and efficient strategy for KEL genotyping in a multiethnic population

Abstract

BackgroundThe Kell blood group system expresses high and low frequency antigens with the most important in relation to transfusion including the antithetic KEL1 and KEL2; KEL3 and KEL4; KEL6 and KEL7 antigens. Kell is a clinically relevant system, as it is highly immunogenic and anti-KEL antibodies are associated with hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. Although required in some situations, Kell antigen phenotyping is restricted due to technical limitations. In these cases, molecular approaches maybe a solution. This study proposes three polymerase chain reaction genotyping protocols to analyze the single nucleotide polymorphisms responsible for six Kell antithetic antigens expressed in a Brazilian population. MethodsDNA was extracted from 800 blood donor samples and three polymerase chain reaction-restriction fragment length polymorphism protocols were used to genotype the KEL*1/KEL*2, KEL*3/KEL*4 and KEL*6/KEL*7 alleles. KEL*3/KEL*4 and KEL*6/KEL*7 genotyping was standardized using the NlaIII and MnlI restriction enzymes and validated using sequencing. KEL*1/KEL*2 genotyping was performed using a previously reported assay. ResultsKEL genotyping was successfully implemented in the service; the following distribution of KEL alleles was obtained for a population from southeastern Brazil: KEL*1 (2.2%), KEL*2 (97.8%), KEL*3 (0.69%), KEL*4 (99.31%), KEL*6 (2.69%) and KEL*7 (97.31%). Additionally, two individuals with rare genotypes, KEL*1/KEL*1 and KEL*3/KEL*3, were identified. ConclusionKEL allele genotyping using these methods proved to be reliable and applicable to predict Kell antigen expressions in a Brazilian cohort. This easy and efficient strategy can be employed to provide safer transfusions and to help in rare donor screening.

An innovative test for non‐invasive Kell genotyping on circulating fetal DNA by means of the allelic discrimination of K1 and K2 antigens

“…The SNP causes an aminoacidic change at residue 193, from threonine (in K2) to methionine (in K1). This change eliminates a consensus sequence for glycosylation of residue 191 and may be responsible for the strong immunogenicity of the K1 antigen . The K1 antigen is the main antigen responsible for severe HDFN after the D antigen of the Rh blood group .…”

Clinical Significance of an Alloantibody against the Kell Blood Group Glycoprotein

“…KEL genotyping was performed in maternal genomic DNA by polymerase chain reaction (PCR) restriction fragment length polymorphism strategies [14] and showed KEL*02/02, KEL*04/04 and KEL*07/07 genotypes. Because of the discrepancy between serologic and molecular findings, each of the 19 exons of KEL gene and intron-exon boundaries were sequenced using the Sanger dideoxy method [15].…”

Molecular assays as tools to facilitate new discoveries and to enhance immunohematology in daily transfusion practice

“…Kell antigen phenotyping is hampered by technical limitations and genotyping can be of great assistance to solve this problem. The development of easy and efficacious strategies for KEL genotyping is fundamental to provide the needed information about the allelic frequency in multiethnic populations and to identify individuals with rare genotypes such as K*1/K*1 and K*3/K*3 (5) .…”