1份正反定型不符献血者标本的血清学及分子特性分析

Serological and Molecular Characteristics of A Blood Sample from Donor with ABO Blood Grouping Discrepancy

目的对1份正反定型不符的献血者标本进行血清学及分子特性分析。方法采用吸收放散试验进行红细胞弱抗原检测,SSP-PCR方法进行基因分型,PCR产物克隆后进行测序分析。结果该标本血清学反应格局符合Ax亚型,分子生物学检测为A型。测序结果表明,Exon4含有2个连续碱基错义突变位点,分别为nt187G>A,nt188C>T,导致第63位氨基酸的改变(Arg63His)。结论该Ax亚型是由于Exon42个碱基突变,引起氨基酸的改变,导致糖基转移酶活性的降低,从而使红细胞上表达的A抗原大大减少。

Objective To analyze the serological and molecular characteristics of a blood sample from donor with ABO blood grouping discrepancy. Methods The sample was determined for weak erythrocyte antigen by adsorption and elution test, and for genotype by SSP-PCR. The PCR product was cloned and sequenced. Results The serological reaction pattern of the sample was consistent with that of Ax subgroup. Molecular biological test proved the sample as group A. Sequencing result showed missense mutation of two serial bases, i. e. nt187G 〉 A and nt188C 〉 T, at the Exon4 of ABO gene, resulting the change of amino acid at site 63 from Arg to His. Conclusion The Ax subgroup was due to the mutation of two bases at Exon4, which resulted the change of amino acid as well as the decrease of glycosyltransferase activity and expression of A antigen.