Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, China.
Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
Transfusion. 2020 Nov;60(11):2675-2683. doi: 10.1111/trf.16013. Epub 2020 Aug 13.
The distribution of DI1/DI2 antigens of the Diego blood group system is polymorphic in Mongoloid populations and the corresponding alloantibodies are clinically significant. Here a novel DI variant was found by donor screening, and the effect of the novel and previously reported mutations on expression of DI1/DI2 antigens and Band 3 protein was explored.
DNA samples of 1150 Chinese donors were collected. DI01/DI02 genotyping was determined by Sanger sequencing. For the carrier of novel allele, the expression of Band 3 and DI1/DI2 antigens on red blood cells (RBCs) was detected by Western blot and flow cytometry, respectively. in vitro expression studies were conducted by transfecting the mutant (including the novel and three reported DI02(2534T), DI02(2358_2359insCAC), and DI02(2572T) alleles) or wild-type DI02 constructs into HEK 293T cells, the expression of Band 3 and DI1/DI2 antigens was analyzed.
A novel heterozygous mutation (c.2558C>T, p.Thr853Met), which is located near the DI1/DI2 polymorphism site (c.2561T>C), was identified in a donor with DI:-1,2 phenotype. Reduced expression of DI2 antigen was observed on the RBCs, while weakened expression of Band 3 and absence of DI2 antigen were detected in cells transfected with the mutant DI*02(2558T) construct. In addition, absent or decreased expression of Band 3 and DI2 antigen was also detected in cells transfected with three reported mutant constructs.
The novel DI02(2558T) allele and three previously described DI mutations can affect the expression of Band 3 protein and/or DI2 antigen and/or interfere with DI01/DI*02 genotyping result.
Diego 血型系统的 DI1/DI2 抗原在蒙古人种中分布多态性，相应的同种异体抗体具有临床意义。本研究通过供者筛查发现了一种新的 DI 变异型，并探讨了新的和先前报道的突变对 DI1/DI2 抗原和 Band 3 蛋白表达的影响。
收集了 1150 名中国供者的 DNA 样本。通过 Sanger 测序确定 DI01/DI02 基因型。对于携带新等位基因的供者，通过 Western blot 和流式细胞术分别检测红细胞（RBC）上 Band 3 和 DI1/DI2 抗原的表达。通过转染突变（包括新的和三个已报道的 DI02(2534T)、DI02(2358_2359insCAC)和 DI02(2572T)等位基因）或野生型 DI02 构建体到 HEK 293T 细胞中进行体外表达研究，分析 Band 3 和 DI1/DI2 抗原的表达。
在具有 DI:-1,2 表型的供者中发现了一个新的杂合突变（c.2558C>T，p.Thr853Met），位于 DI1/DI2 多态性位点（c.2561T>C）附近。在转染突变 DI*02(2558T)构建体的细胞中观察到 DI2 抗原表达减少，而在转染的细胞中则观察到 Band 3 表达减弱和 DI2 抗原缺失。此外，在转染三个已报道的突变构建体的细胞中也检测到 Band 3 和 DI2 抗原的缺失或减少表达。
新的 DI02(2558T)等位基因和三个先前描述的 DI 突变可影响 Band 3 蛋白和/或 DI2 抗原的表达，并/或干扰 DI01/DI*02 基因分型结果。
