B(A)血型分子生物学鉴定及家系调查——附6例报告

Molecular biological and genetic analysis of B( A) alleles

目的探讨稀有B(A)血型的遗传特性、鉴定方法及输血策略。方法对6例ABO定型正反不符的标本,采用试管法做血清学鉴定、流式细胞分析仪做表型鉴定、DNA序列测定方法等做分子生物学鉴定及相关家系分析,研究B(A)血型的遗传学特点,并讨论B(A)血型献血者与受血者临床安全和合理用血。结果血清学表现为ABO血型正反定型不一致,正定型为AB型,且H抗原明显增强,反定型血清中存在抗-A1,初定为AwB型。测序表明:第7外显子在B101序列的基础上,出现了B(A)02型nt700C/G的典型等位基因突变。结论通过血清学及分子生物学方面的分析,确定6例标本的基因型皆为B(A)02型与O01型杂合,B(A)血型患者应尽量配合性输注O型或B型洗涤红细胞及AB型血浆。

Objectives To discuss the characteristics of rare B（ A） alleles,the identification method and the strategies for clinical infusion. Methods The blood type of B（ A） alleles was determined by serology. The absolute membrane potential of erythrocytes was tested by flow cytometry（ FCM）. PCR products of exons 6 and 7 were cloned and sequenced. Results The B（ A） phenotype was discovered as a result of discrepancies between forward and reverse typing in routine ABO grouping by standard hemagglutination test. The blood sample was identified as B（ A） from forward typing results,in addition to the increasing strength of H antigens. In reverse typing results,the presence of anti- A1 was discovered,resulting in the AB phenotype. Sequencing analysis showed that the sample had a 700 C G mutation in the exon 7 of B gene. Conclusion From serological and molecular analysis,the genotype of the samples was determined to be B（ A） 02 / O 01. Patients with B（ A） phenotype should be treated with washed group O or B red blood cells and AB type plasma.