Ambiguous results of the HLA-DPB1 genotyping results: Based on AllType NGS 11-loci sequencing reagent / 中国输血杂志

【Objective】 To statistically analyze the characteristics of ambiguous results of HLA-DPB1 genotyping given by AllType NGS 11-loci sequencing reagent via two next generation sequencing platforms, i. e. Ion Torrent S5 and Illumina Miseq. 【Methods】 A total of 434 samples from patients or donors were genotyped for HLA-DPB1 locus using AllType NGS 11-loci sequencing reagent from One Lambda company; 336 samples of them were sequenced via the Ion Torrent S5 platform and other 98 samples were sequenced via the Illumina Miseq platform. All 434 samples were genotyped for HLA-DPB1 gene simultaneously using PCR-SSO flow fluorescent bead method. The ambiguous genotypes of HLA-DPB1*13∶01∶01/107∶01 were distinguished by Sanger sequencing. The HLA-DPB1 genotype results by NGS method were assigned by TypeStream Visual professional software, and the ratio of ambiguous combination was calculated by direct count method. 【Results】 Ambiguous results were found in 357 out of 434 samples, accounting for 82.3% (357/434) when HLA-DPB1 allele was assigned to the third field using NGS method. Ambiguous results with 45 types were given in 275 out of 336 samples by the Ion Torrent S5 platform, accounting for 81.8% (275/336) and 82(with 27 types) out of 98 samples by the Illumina Miseq platform, accounting for 83.7% (82/98). All samples were re-genotyped for HLA-DPB1 gene by PCR-SSO, and none HLA-DPB1 allele had been missed by NGS. A total of 43 ambiguous alleles in HLA-DPB1*13∶01∶01/107∶01 involving 41 samples were distinguished by Sanger sequencing; HLA-DPB1*13∶01∶01 were detected in 25 (58.1%, 25/43) and HLA-DPB1*107∶01 in 18 (41.9%, 18/43). 【Conclusion】 There were still a high proportion of HLA-DPB1 ambiguous combinations using the AllType NGS 11-loci sequencing reagent. Sequencing exon 1 of HLA-DPB1 gene by Sanger sequencing can resolve part of the ambiguous results in HLA-DPB1*13∶01∶01/107∶01 alleles.

Analysis of loss of heterozygosity at HLA loci in a patient with leukemia / 中华医学遗传学杂志

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.

Sequence analysis and identification of two novel HLA alleles HLA-B*9536 and HLA-B*4612 / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify two novel HLA alleles HLA-B*9536 and B*4612, in an individual.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>Two novel HLA-B alleles were identified in one individual and have been officially named by the WHO Nomenclature Committee.</p>