title: Expansion of the Kell blood group system: two new high-prevalence antigens and two novel K0 (Kellnull ) phenotypes.
abstract: BACKGROUND
  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.
  
  
  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.
  
  
  RESULTS
  Proband 1, an Asian woman with Kp(b+) RBCs, presented with alloanti-Kp(b) . 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-Kp(b) , 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).
  
  
  CONCLUSIONS
  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-Kp(b) .
authors: Laboratory of Immunohematology and Genomics, New York Blood Center, New York, New York.
authors: Christine
authors: C
authors: Lomas-Francis
authors: Sunitha
authors: S
authors: Vege
authors: Randall W
authors: RW
authors: Velliquette
authors: Akiko
authors: A
authors: Fuchisawa
authors: Makoto
authors: M
authors: Uchikawa
authors: Yoshihiko
authors: Y
authors: Tani
authors: Hiroko
authors: H
authors: Moro
authors: Asim K
authors: AK
authors: Debnath
authors: Connie M
authors: CM
authors: Westhoff
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001803:Blood Transfusion; D005260:Female; D005787:Gene Frequency; D020868:Gene Silencing; D006801:Humans; D007626:Kell Blood-Group System / Q000235:genetics* / Q000276:immunology*; D008297:Male; D020125:Mutation, Missense; D010641:Phenotype; D011247:Pregnancy; D055815:Young Adult
chemical_list: D007626:Kell Blood-Group System