Sequence‐based typing of a novel HLA‐DRB1*04 allele, DRB1*0461, in a Taiwanese volunteer marrow donor

Abstract

We report here a novel HLA-DRB1 allele, DRB1*0461, discovered in a Taiwanese volunteer marrow donor. The new sequence has nucleotide variation at positions 260 (C-->A) and 261 (C-->G), i.e. codon 58, as compared to DRB1*0408. Nucleotide change caused an amino acid substitution from alanine to glutamic acid. We believe that the gene conversion took place between DRB1*0405 and DRB1*1101 based on sequence homology and gene frequency in population studies. In comparison to DRB1*0405, DRB1*0461 has two amino acid changes at codons 57 and 58. Amino acid residue substitution at position 57 may affect peptide-binding environment at pocket P9 of the antigen-binding groove of the MHC molecule. This would have potential effect in peptide binding as well as in T-cell recognition, which could have clinical significance in bone marrow and organ transplantations.

Discovery of the novel HLA‐DRB1*04:05:14 allele in a Taiwanese unrelated haematopoietic stem cell donor by a sequence‐based typing method

“…We estimate the frequency of DRB1*04:05:14 is about 1 in 20 000 to 1 in 30 000 based on our SBT typing experience. Similar to the DRB1*04:61 allele that we discovered in Taiwanese (Chen et al ., ), DRB1*04:05:14 may be considered as one of the uncommon DRB1*04 alleles detected in Taiwanese.…”

Polymorphism and uniqueness of Taiwanese in HLA and beyond

“…Genomic DNA typing of HLA-A, -B, -C and -DRB1 loci were first performed using the Dynal Reli SSOP (sequence-specific oligonucleotide probe) HLA-A, -B, -C and -DRB1 Typing Kits (Dynal Biotech, Bromborough, Wirral, UK). For sequence-based typing (SBT), exons 2 and 3 for class I and exon 2 for class II were sequenced to verify rare or novel alleles as described previously [1][2][3][4][5]. Serological investigation of WBC surface antigen was performed according to the standard NIH microlymphocytotoxicity test in Terasaki microtitre wells using either eosin dye exclusion or fluorescence staining methods or both.…”

A conserved HLA‐A*02:28 associated HLA haplotype, A*02:28‐B*15:11‐DRB1*09:01, restricted to Taiwanese

“…In our routine, HLA typing exercise on Taiwanese unrelated volunteer bone marrow stem cell donors from 2010 to 2012, we found eight individuals bearing A*02:28. Our SBT (sequence-based typing) protocol (Chen et al, 2007(Chen et al, , 2008a(Chen et al, ,b, 2009(Chen et al, , 2010 confirmed the DNA sequence of A*02:28, in exons 2 and 3, is identical to the sequence of A*02:06:01 except a nucleotide at residue 238 where G was replaced by A. The DNA sequence of A*02:28 varies with the sequences of A*02:01:01:01, A*02:03:01 and A*02:07:01 with 3, 6 and 4 nucleotides, respectively ( Table 1).…”