Cho D, Lee J S, Yazer M H, Song J W, Shin M G, Shin J H, Suh S P, Jeon M J, Kim J Y, Park J T, Ryang D W
Department of Laboratory Medicine, Chonnam National University Hospital & Medical School, Gwangju, Republic of Korea.
Immunohematology. 2006;22(4):183-7.
Discrepancies between blood group genotype and RBC phenotype are important to recognize when implementing DNA-based blood grouping techniques. This report describes two such cases involving the ABO blood group in the Korean population. Propositus #1 was a 22-year-old healthy man undergoing pretransfusion testing for minor surgery. Propositus #2 was a 23- year-old male blood donor. RBCs from both propositi were determined to be group AB and demonstrated unusual agglutination patterns on forward typing, which were inconsistent with their ABO genotype determined by allele-specific (AS) PCR. RBCs from propositus #1 demonstrated mixed field agglutination with both anti-A and -B, while RBCs from propositus #2 demonstrated mixed field only with anti-A reagents. Both had B/O genotypes by AS-PCR. Cloning and sequencing of ABO exons 6 and 7 revealed three alleles in both propositi: propositus #1: A102/B101/O04; propositus #2: A102/B101/O01. A panel of nine short-tandem repeat (STR) loci was tested on DNA extracted from blood, buccal mucosal cells, and hair from the propositi and on DNA isolated from their parents' blood. In all tissues tested from propositus #1, three loci demonstrated a double paternal and a single maternal DNA contribution, indicating that he was a chimera or a mosaic; in those from propositus # 2, one STR locus demonstrated a double paternal DNA contribution, indicating that he was a tetragametic chimera. Chimerism and mosaicism are uncommon but important causes of ABO genotype and phenotype discrepancies. The evaluation of patients and donors with unusual or unexpected serology in pretransfusion testing and consensus ABO alleles may include the evaluation of STR loci to detect these phenomena.
在应用基于DNA的血型分组技术时,认识到血型基因型与红细胞表型之间的差异很重要。本报告描述了韩国人群中涉及ABO血型的两例此类病例。先证者#1是一名22岁的健康男性,因小手术接受输血前检测。先证者#2是一名23岁的男性献血者。两名先证者的红细胞均被确定为AB型,并且在正向定型时表现出异常的凝集模式,这与通过等位基因特异性(AS)PCR确定的ABO基因型不一致。先证者#1的红细胞与抗A和抗B均呈现混合视野凝集,而先证者#2的红细胞仅与抗A试剂呈现混合视野凝集。通过AS-PCR检测,两人均为B/O基因型。对ABO外显子6和7进行克隆和测序后发现,两名先证者均有三个等位基因:先证者#1:A102/B101/O04;先证者#2:A102/B101/O01。对从先证者的血液、口腔黏膜细胞和毛发中提取的DNA以及从其父母血液中分离的DNA,检测了一组9个短串联重复序列(STR)位点。在检测的先证者#1的所有组织中,三个位点显示出两份父系DNA贡献和一份母系DNA贡献,表明他是嵌合体或镶嵌体;在检测的先证者#2的组织中,一个STR位点显示出两份父系DNA贡献,表明他是四配子嵌合体。嵌合体和镶嵌体是ABO基因型和表型差异的罕见但重要的原因。在输血前检测中对具有异常或意外血清学结果的患者和献血者以及一致的ABO等位基因进行评估时,可能包括对STR位点的评估以检测这些现象。