B*4440: a novel HLA‐B allele identified by sequence‐specific oligonucleotide hybridization and sequence‐specific amplification

:  A novel human leukocyte antigen B (HLA-B) allele, B*4440, is described. The allele was identified in an adult stem cell donor of Caucasian origin. HLA-B*4440 most closely matches to B*4403 differing by a substitution of three nucleotides at codon 44, 45, and 50. Thus, low-resolution HLA typing using sequence-specific oligonucleotide hybridization or amplification using sequence-specific primers gave inconclusive results. DNA sequencing confirmed a variation of codons 44 and 45 (AGG AAGAGA GAG) and codon 50 (CCACCG), resulting in an amino acid substitution LysGlu at codon 45.