[Sequence analysis and identification of a novel HLA-DPB1*02:01:69 allele by third-generation sequencing]

To analyze the sequence of a novel HLA-DPB1 allele in an individual.

A individual identified from the database of blood donors for matched platelet transfusion at the Blood Center of Zhejiang Province in May 2022 was selected as the study subject. HLA genotype of the individual was determined by next-generation sequencing (NGS) on an Ion Torrent S5 platform. The sequence of the HLA-DPB1 locus was also determined by NGS on an Illumina Miseq platform and third-generation sequencing using Oxford Nanopore MinION. This study was approved by the Blood Center of Zhejiang Province (Ethics No. 2021-001).

A novel HLA-DPB1*02 allele was identified in the specimen, for which the closest genotype was HLA-DPB1*02:new,17:01:01G, with the variant located in exon 3. Meanwhile, the NGS also revealed a novel HLA-DPB1*17 allele, with the closest genotype being HLA-DPB1*02:01,17:new. Both the HLA-DPB1*17:01:01:01 and HLA-DPB1*02 alleles were identified by third-generation sequencing. Compared with the HLA-DPB1*02:01:02:01 allele, the novel allele had a G>A variation at position 369 in the exon 3, which however did not result in amino acid change.

A novel HLA-DPB1 allele has been identified and validated by both NGS and TGS, which has been named as HLA-DPB1*02:01:69 by the World Health Organization Committee on Nomenclature of Factors of the HLA System.