中国北方汉族骨髓供者HLA-B＊15组基因多态性的PCR-SBT分型研究

为了研究中国北方汉族骨髓供者HLA—B＊15等位基因的分布特征，探讨其可能对临床供体选择的影响，从中华骨髓库陕西分库内随机抽取815名已知低分辨分型结果中国北方汉族骨髓供者，采用聚合酶链反应-碱基序列直接测序（PCR—SBT）方法对其中206例HLA—B＊15阳性样本和另外附加17例样本进行HLA—B位点DNA测序分析，并应用同源模建分子模拟技术对所有结果模拟出三维结构，用计算机软件Swiss—PdbViewer比较模拟结构间的差异大小。结果表明：随机抽取的815例样本HIJA—A、B、DRB1基因分布符合Hardy—Weinberg平衡定律，HIJA—B＊15基因频率为0．1379，总共检出16种HIJA—B＊15等位基因，分属7种血清学特异性，以B＊1501、B＊1511、B＊1502和B＊1518为主，频率分别为0．0485、0．0215、0．0178和0．0160，累计频率构成比占全部B＊15的75．11％，其余12种B＊15等位基因频率均〈0．0100。19例HIJA—B＊15，-测序分析表明，其中10例中低分辨水平上的纯合子中仅4例为真正意义上的B＊15xx，-纯合子，且均由各自优势基因构成。三维结构模拟分析发现同一血清型中既存在结构差异微小的等位基因，如B＊1501、1505、1507、1525、1527、1532（RMSD≤0．02nm），也存在差异较大的等位基因，如B＊1502、1511、1521之间以及B＊1503、1546之间（RMSD均为0．29nm），而一些分属不同血清型的等位基因之间结构却近似（RMSD值≤0．02nm）。结论：本研究应用PCR—SBT，首次取得了中国北方汉族样本量最大的高分辨水平HLA—B＊15基因多态性分布特征，这将有助于临床患者寻找合适供者，并为移植免疫及本地区群体遗传学等方面的研究提供了重要依据，且对于临床选择最适供者，像HLA—B＊15这样血清学特异性及基因亚型高度多态性的家族进行准确的高分辨分型是必要的。

HLA-B*15 Gene Polymorphism of Registered Bone Marrow from Donors in North Chinese Han Poputation Typed by PCR-SBT

To investigate the characteristics of the allele distribution of HLA-B*15 gene family in Chinese Han population and to study its influence on the selection of clinical transplantation donor, population of a 815 Han in north China from Shaanxi sub-registry of Chinese National Marrow Donor Project was randomly selected and out of them 206 HLA-B*15 positive samples according to the previous known low-resolution typing results were acquired. HLA-B*15 gene polymorphisms of above-mentioned samples and other 17 individuals were analyzed for the first time by polymerase chain reaction sequence-based typing (PCR-SBT) at high-resolution level. The structure differentiation of all HLA-B*15 alleles were analyzed by HLA three-dimensional structure modeling and software Swiss-PdbViewer. The results showed that the distribution of HLA-A, -B, -DRB1 gene of randomly selected 815 samples accorded with Hardy-Weinberg equilibrium and the gene frequency of HLA-B*15 was 0.1379. There were a total of 16 kinds of alleles of HLA-B*15 gene family to be obtained, which belonged to 7 kinds of serologic specificities. HLA-B*1501, B*1511, B*1502 and B*1518 were the major alleles with a frequency of 0.0485, 0.0215, 0.0178 and 0.0160 respectively, and the constituent ratio of their accumulated frequencies was 75.11%. The each frequency of the other 12 kinds of B*15 alleles was lower than 0.0100. Among the homozygote of 10 samples at low/medial-resolution level, there were only 4 samples to be pur sang homozygote of HLA-B*15xx, --at high-resolution lever, and all the homozygote were constituted by respective dominating alleles. HLA three-dimensional structure modeling demonstrated that within the same specificity, gentle structure differentiation not only existed, such as B*1501, 1505, 1507, 1525, 1527, 1532 (each RMSD