Abstract:

BACKGROUND: Most of novel alleles in China are found due to abnormal reaction patterns in low-resolution human leukocyte antigen (HLA) typing and identified by further gene sequencing or gene cloning. Thus, some novel alleles may be missed. Gene sequencing is considered to be the golden standard for HLA typing, which can obtain exact nucleotide sequence.
OBJECTIVE: To detect the samples in Chinese Bone Marrow Bank by gene sequencing typing, and to identify novel allele in Chinese Han population.
METHODS: Blood (5 mL) suspected as a new gene were redraw. An unknown HLA-A allele was detected by sequence-based typing (SBT) in a Chinese bone marrow donor. SBT showed that there was 1 difference compared with database in exon 2. Its anomalous patterns suggested the possible presence of either a novel A*03 or a novel A*11. To separate the two alleles and to determine whether the allele was novel, TOPO TA cloning was performed. The sequencing result was compared with known HLA allele sequence.
RESULTS AND CONCLUSION: Heterozygous allele was separated by cloning. A novel allele was identified with sequencing. The novel allele was most similar to A*1155 except for one nucleotide exchange in exon 2 at position nt 330 C>G, codon 86 N (AAC)>K (AAG), resulting in amino acid exchange. This allele is a novel HLA-A allele and has been officially named HLA-A*1155 by the Nomenclature Committee of World Health Organization on 31 October 2009.