Tissue Antigens ISSN 0001-2815 BRIEF COMMUNICATION Twenty-three novel HLA-B alleles identified during intermediate-resolution testing A. M. Lazaro 1 , K. Cao 1 , C. Masaberg 1 , N. K. Steiner 1 , Y. Xiao 1 , B. Tu 1 , V. Turner 2 , P. Nickerson 3 , S. Stoll 4 , C. Schall 4 , R. Valdez 4 , J. Ng 1 , R. J. Hartzman 5 & C. K. Hurley 1 1 Departments of Oncology and Pediatrics, Georgetown University Medical Center, Washington, DC, USA 2 HLA Laboratory, Pathology, MS 250 St Jude ChildrenÕs Research Hospital, Memphis, TN, USA 3 Canadian Blood Services, Winnipeg, Manitoba, Canada 4 Histocompatibility Laboratory, University of Michigan Health System, Ann Arbor, MI, USA 5 C.W. Bill Young Marrow Donor Program, Naval Medical Research Center, Rockville, MD, USA Key words DNA sequencing; HLA-B Correspondence Carolyn Katovich Hurley, PhD E404 Research Building Georgetown University Medical Center 3970 Reservoir Road NW, Washington DC 20057 USA Tel: 202 687 2157 Fax: 202 687 6440 e-mail: hurleyc@georgetown.edu Received 19 June 2006; revised 6 July 2006; accepted 9 July 2006 doi: 10.1111/j.1399-0039.2006.00661.x Abstract Twenty-three novel human leukocyte antigen-B alleles are described: B*070204, *0738, *0742, *0821, *130202, *1312, *1575, *1598, *1599, *270507, *2728, *350104, *3558, *3811, *3931, *3932, *4045, *4107, *420501, *4812, *510106, *5520, and *5616. Thirteen of the variants are single-nucleotide substitutions from their most homologous allele, eight resulting in amino acid changes (B*0742, *1312, *1598, *1599, *3558, *3931, *4107, and *5616) and five with silent substitutions (B*070204, *130202, *270507, *350104, and *510106). Three alleles (B*0738, *4812, and *5520) differ by five nucleotide changes, altering four amino acids. The remaining seven alleles differ from their most similar alleles by two to three nucleotides, altering from one to two amino acids. Twenty-three novel human leukocyte antigen (HLA)-B locus alleles were detected as unexpected hybridization patterns during intermediate-resolution DNA-based typ- ing. The majority of individuals were initially typed at intermediate resolution either by a sequence-specific oligo- nucleotide probe bead-based technology (One Lambda LABTypeÒ) SSO Kit (One Lambda, Canoga Park, CA, USA) or using probes designed in-house (1). Two samples were typed low resolution by sequence specific primers. The cells carrying novel alleles are listed in Table 1. Table 2 compares the novel sequences with the se- quences of the most homologous alleles. Several unique features of specific novel alleles should be noted. B*270507 introduces a new site of polymorphism, codon 161. Six new polymorphisms were found altering codons already described as polymorphic for the HLA-B locus. Three were silent mutations (B*070204, *130202, and *510106) and three resulted in new amino acid substi- tutions (B*0742, *1312, and *1575). For example, codon 57 is polymorphic in HLA-B alleles, being found as three alternative codons [CCG (Pro), CGG (Arg), and CCA (Pro)]. B*070204 introduces a new codon at 57, CCT (Pro). Differing from B*0727 by five nucleotides at codons 77–83, the introduced amino acid sequence motif (NLRIALR) in B*0738 adds the Bw4 epitope. Within the B*07 group, the Bw4 epitope sequence in B*0738 is shared only with B*0736. Two cells were described with B*4812. The sequence of exon 2 of this new allele is identical to that found in B*4801 but exon 3 differs by five nucleotides encodins three different amino acids. These five nucleotides are shared with B*4802. The predicted haplotype carrying the new alleles is A*0222, B*4812, ª 2006 The Authors Journal compilation 68 (245–248) ª 2006 Blackwell Munksgaard 245