Serological and molecular biological analysis of ABO blood subgroup samples

Objective To explore the serological and molecular biological mechanisms of 2 cases of ABO blood subgroup samples. Methods A total of 2 unconfirmed blood samples which were investigated at the Institute of Blood Transfusion of Qingdao Blood Center for ABO blood group identification, on 21 October 2015 and 12 November 2015, were included in this study as study objects, respectively. Phenotypes of blood samples were detected with forward and reverse blood grouping testing, absorption and irradiation test. PCR-sequence specific primer (SSP) and direct sequencing methods were carried out to identify the genotypes of the samples. The haplotypes of exon 6, 7 and intron 6 were also analyzed by haplotype sequencing method. Results ① The serological identification of sample 1 was identified as Ael type. Direct sequencing showed that there was c. 940A>G heterozygous mutation in exon 7 of ABO gene. The results of haplotype sequencing showed that ABO genotype of this sample was Ax13/O02. ② The serological identification of the other sample was identified as Bel type. The results of the direct sequencing showed that there was c. 784G>A heterozygous mutation in exon 7 of the ABO gene. The haplotype sequencing results showed that the ABO genotype of this sample was Bw17/O01. Conclusions The combination of serological typing and gene sequencing is a reliable method for typing ABO blood subgroups of unconformity blood type individuals. Key words: ABO blood-group system; Gene sequence; Blood group serology; ABO genotyping; ABO blood subgroup