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Objetive: To analyze the sequence of a novel HLA-DPB1 allele in an individual., Methods: 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)., Results: 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., Conclusion: 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.

Objective: To detect loss of heterozygosity (LOH) at human leukocyte antigen (HLA) loci in a Chinese patient with leukemia after haploidentical hematopoietic stem cell transplantation., Methods: HLA genotyping was carried out on peripheral blood, hair follicle and buccal swab samples derived from the patient after the transplantation as well as peripheral blood samples from his parents by using PCR-sequence specific oligonucleotide probe method and PCR-sequence based typing method. Short tandem repeat (STR) loci were detected by using a 23 site STR assay kit and a self-developed 6 STR loci assay for the HLA regions., Results: After the transplantation, the HLA genotype of the peripheral blood sample of the patient was identical to his father. The patient was HLA-A*02:01,24:02, C*03:03,03:04, B*13:01,15:01, DRB1*08:03,12:02, DQB1*03:01,06:01 for his hair follicle specimen. However, homozygosity of the HLA loci was found in his buccal swab sample. Only the HLA-A*24:02-C*03:03-B*15:01-DRB1*08:03-DQB1*06:01 haplotype from his father's was present, while the HLA-A*02:01-C*03:04-B*13:01-DRB1*12:02-DQB1*03:01 haplotype from his mother was lost. After the transplantation, the alleles of the 23 STR sites in the patient's peripheral blood sample were consistent to his father, with no allelic loss detected in his buccal swab sample. However, at least 4 STR loci in the HLA region were lost in his buccal swab sample., Conclusion: LOH at the HLA loci has been detected in the buccal swab sample of a patient with leukemia who received haploidentical hematopoietic stem cell transplantation.

Objective: To identify two novel HLA alleles HLA-B*9536 and B*4612, in an individual., Methods: DNA was extracted from whole blood by Invitrogen DNA extraction kit. The amplification for HLA-B exons 2-4 of the proband was performed separately with allele group specific primers and the PCR products were directly sequenced for exons 2-4 in both direction., Results: There were two novel HLA-B alleles in the proband. The sequences of the two alleles have been submitted to GenBank (EU081878 and EU081879). The two alleles have been officially named as B*9536 and B*4612 by the WHO Nomenclature Committee. The sequence of exons 2-4 of HLA-B*9536 showed one nucleotide difference in exon 3 at position 544 (G to A) comparing with the closest allele B*1505, which resulted in an amino acid change from Ala to Thr at codon 158. In the HLA-B*4612 allele, there was one nucleotide change in exon 3 at position 363 (G to A), when compared to the closest allele B*4601, which lead to an amino acid change from Arg to Ser at codon 97., Conclusion: Two novel HLA-B alleles were identified in one individual and have been officially named by the WHO Nomenclature Committee.