Expansion of the Kell blood group system: two new high-prevalence antigens and two novel K0 (Kellnull) phenotypes
Article first published online: 22 AUG 2013
© 2013 American Association of Blood Banks
Special Issue: Twenty Years since the Cloning of the Blood Group Genes
Volume 53, Issue 11pt2, pages 2887–2891, November 2013
How to Cite
Lomas-Francis, C., Vege, S., Velliquette, R. W., Fuchisawa, A., Uchikawa, M., Tani, Y., Moro, H., Debnath, A. K. and Westhoff, C. M. (2013), Expansion of the Kell blood group system: two new high-prevalence antigens and two novel K0 (Kellnull) phenotypes. Transfusion, 53: 2887–2891. doi: 10.1111/trf.12377
- Issue published online: 12 NOV 2013
- Article first published online: 22 AUG 2013
- Manuscript Revised: 10 JUL 2013
- Manuscript Accepted: 10 JUL 2013
- Manuscript Received: 27 JUN 2013
The number of KEL alleles associated with new antigens or loss of expression of high-prevalence antigens continues to increase. We investigated KEL in five samples: two with K0 (null) phenotypes and three with normal Kell expression and antibodies to high-prevalence antigens.
Study Design and Methods
Red blood cell (RBC) typing and antibody identification were by standard methods. Genomic DNA was isolated from white blood cells and DNA array testing and sequencing of KEL exons was performed by standard methods.
Proband 1, an Asian woman with Kp(b+) RBCs, presented with alloanti-Kpb. Four years later, the antibody was reactive with all RBCs except K0. She was homozygous for KEL c.877C>T change (p.Arg293Trp), and the high-prevalence antigen absent from her RBCs was named KHUL. Probands 2 and 3, both Japanese and homozygous for KEL c.875G>A (p.Arg292Gln), presented with an antibody reactive with all except K0 RBCs. The antibody, named KYOR, recognizes an antigen antithetical to KYO (KEL31). Proband 4, a pregnant Middle Eastern woman, presented with alloanti-Kpb, but her RBCs did not express Kell antigens. She was homozygous for KEL c.230G>T (p.Cys77Phe). Proband 5, a multiply transfused Caucasian female with an antibody reactive with all RBCs except K0 and lacking Kell antigens, was a compound heterozygote carrying a silenced allele c.574C>T (p.Arg192Stop) in trans to c.1664G>A (p.Gly555Glu).
We describe two new high-prevalence Kell antigens, KHUL (ISBT 006037; KEL37) and KYOR (ISBT 006038; KEL38), and two novel alleles encoding K0 phenotypes. We caution that antibodies produced by individuals with K0 RBCs or lacking high-prevalence antigens can present as anti-Kpb.