四川骨髓库人群HLA-DQA1和DQB1等位基因及其单体型分布研究

Distribution of HLA-DQA1 and DQB1 alleles and haplotypes in Sichuan Marrow Donor Program population

目的探索四川骨髓库人群HLA-DQA1和DQB1等位基因及HLA-DQA1~DQB1单体型分布。方法 2018年2月—2019年2月,四川骨髓库收集664(人)份造血干细胞捐献志愿者样本,利用NGS技术对其进行基因测序,使用Type StreamTM Visual 1.3.0软件对HLA-DQA1和DQB1进行高分辨率分型,使用Arlequin 3.1软件的EM算法计算HLA-DQA1和DQB1等位基因频率和HLA-DQA1~DQB1连锁不平衡参数。结果本组人群检测到16种HLA-DQA1和25种HLA-DQB1,DQA1*01∶02、DQA1*03∶02、DQB1*03∶01∶01G、DQB1*03∶03、DQB1*05∶02和DQB1*06∶01为高频等位基因。与美洲印第安人、非洲黑人和西班牙高加索人相比,四川骨髓库人群HLA-DQA1等位基因种类最多,高频等位基因频率差异较大(P<0.05),DQA1*05∶06、DQA1*05∶08和DQA1 * 06∶01为其特有的等位基因。本研究检测24种可用于人群调查且连锁不平衡差异具有统计学意义的HLA-DQA1~DQB1单体型(P<0.05)。结论四川骨髓库人群HLA-DQA1等位基因多态性程度高,高频等位基因分布相对集中,HLA-DQA1~DQB1单体型种类较多。

Objective To study the high-resolution characterization of allelic and haplotypic HLA-DQA1 and DQB1 frequency distribution in Sichuan Marrow Donor Program population using high-throughput next-generation sequencing(NGS).Methods 664 samples of hematopoietic stem cells donated by volunteers from Chinese Marrow Donor Program of Sichuan were collected from Feb. 2018 to Feb. 2019. These samples were subjected to high-resolution genotyping of HLA-DQA1 and DQB1 genes using next-generation sequencing,. The genotyping results were analyzed using the software Type StreamTM Visual 1.3.0. The allelic and haplotypic frequencies were calculated via an expectation maximization(EM) algorithm using Arlequin version 3.1 software.Results A total of 16 HLA-DQA1 and 25 HLA-DQB1 alleles were identified. The most frequent alles in each locus with frequencies of ≥10% were, in decreasing order of frequency, as follows: DQA1*01∶02, DQA1*03∶02, DQB1*03∶01∶01G, DQB1*03∶03, DQB1*05∶02 and DQB1*06∶01. Compared to American Indians, African blacks and Caucasians of Spain, more types of HLA-DQA1 alleles and larger differences among the frequencies of the most frequent HLA-DQA1 alleles were presented by Sichuan Marrow Donor Program population(P <0.05). Among them, DQA1*05∶06, DQA1*05∶08 and DQA1*06∶01 were unique to Sichuan Marrow Donor Program population. 24 HLA-DQA1-DQB1 haplotypes,with statistically significant linkage disequilibrium differences were reliable for population surveys. Conclusion The distribution of HLA-DQA1 alleles in Sichuan Marrow Donor Program population has its own characteristics, which presents highly polymorphism, relatively concentrated commom allelic frequency distribution and various HLA-DQA1-DQB1 haplotypes.