We report here a novel HLA-DPA1*02:01 allele, now named DPA1*02:01:21 that carries one nucleotide substitution in exon 4 when compared with the DPA1*02:01:01:03 allele, identified in identified in a patient awaiting kidney transplantation. The HLA typing was performed using Next Generation Sequencing (AllType NGS, One Lambda, Canoga Park, CA) on the Ion S5 system platform (ThermoFisher Scientific, Waltham, MA),¹ from exons 1 to 4. The reads were analyzed using the TypeStream Visual Software version 2.1 (One Lambda). This patient was found to have a new DPA1*02:01 allele and was consequently typed A*01:02, 24:02; B*18:01, 53:01; C*02:10,16:01; DRB1*03:02, 07:01; DRB3*01:01; DRB4*01:03; DQA1*02:01, 04:01; DQB1*02:02, 04:02; DPA1*02:01:21, 02:02:02; DPB1*01:01, 17:01. Using the IPD-IMGT/HLA Database,² nucleotide sequence alignment with HLA-DPA1 alleles shows that this new allele differs from DPA1*02:01:01:03 in codon 190 in exon 4, where G → A (ACG → ACA, Figure 1) not resulting in a coding change. This nucleotide change was confirmed by performing the typing twice in two different laboratories. We were confident in the phasing as the sample displayed a mean read length of 295 base pairs over all the loci, the mismatched A base was attributed 169 times to the new HLA-DPA1*02:01:21 allele. HLA typing by Luminex reverse sequence-specific oligonucleotide (SSO) was performed (One Lambda Labtype HD, Canoga Park, CA).³ With this assay (lot 010, catalog RSSO2P_010_02), the HLA-typing of the HLA-DPA1*02 allele was HLA-DPA1*02:01:01, 02:02:02 without any bead modification. Indeed the IPD-IMGT/HLA Database 3.50.0 release describes few other HLA-DPA1 allele displaying an ACA sequence in codon 190, explaining why the manufacturer did not include probes targeting this codon. The coding nucleotide sequence of the exons 1–4 of the new allele has been submitted to the GenBank database (Accession No. ON809566) and to the IPD-IMGT/HLA Database (Submission No. HWS10061882). The name DPA1*02:01:21 has been officially assigned by the WHO Nomenclature Committee for Factors of the HLA System in September 2022. This follows the agreed policy that, subject to the conditions stated in the most recent Nomenclature Report,⁴ names will be assigned to new sequences as they are identified. Lists of such new names will be published in the following WHO Nomenclature Report.

AUTHOR CONTRIBUTIONS

Marine Cargou and Jonathan Visentin contributed to the design of the study. Marine Cargou and Jonathan Visentin participated in the writing of the paper. Marine Cargou, Marco Andreani, Paola Giustiniani, Gwendaline Guidicelli and Jonathan Visentin participated in the performance of the research. Marine Cargou, Marco Andreani, Paola Giustiniani, Gwendaline Guidicelli and Jonathan Visentin participated in data analysis. Marco Andreani, Paola Giustiniani and Gwendaline Guidicelli were involved in critical revision of the manuscript.

CONFLICT OF INTEREST

The authors confirm that there are no conflicts of interest.