ABO*Ael03/O genotype with ABO discrepancy: the first case in Korea

Detection and phenotype analysis of a novel Ael blood group allele

BACKGROUND AND OBJECTIVES

The presence of blood subtypes may lead to difficulties in blood group identification; however, third-generation sequencing (TGS) can help in accurately identifying difficult blood groups, and study the serological characteristics and molecular mechanism of Ael subtypes.

MATERIALS AND METHODS

ABO blood group was identified by the standard serological technique, weak blood group antigen was identified by adsorption-elution experiments, ABH substance in the saliva was determined and glycosyltransferase activity of A and B was detected. The ABO gene full-length sequence and promoter region were amplified by specific primers using single-molecule real-time sequencing, with the amplified products being sequenced directly and analysed in real time.

RESULTS

The patient was serologically identified as Ael subtype, and TGS analysis revealed new intron mutations in Ael patients (c.467C>T; c.29-10T>A).

CONCLUSION

The discovery of the new allele and the identification of ABO subtypes can be combined with serological characterization and molecular biological methods.

Rapid rare ABO blood typing using a single PCR based on a multiplex SNaPshot reaction

BACKGROUND

ABO subgroups would be considered when discrepancies in ABO grouping occur. Serological methods including adsorption-elution test, salivary ABH inhibition test, and anti-A1 (lectin) saline method could be used. However, these serological methods are laboring and obscure. Therefore, reliable and affordable method to assess the ABO subgroups is of particular interest.

METHODS

To solve this problem, the multiplex SNaPshot-based assays were designed to determine rare A and B subgroups. Primers used as probes for determination of rare ABO blood groups known in Taiwanese population were designed. Many ABO subtype samples were used to validate the accuracy and reproducibility of our SNaPshot panel.

RESULTS

A panel of primer probes were successfully designed in determining 8 SNP sites (261, 539, 838, 820, 745, 664, IVS6 +5, and 829 in exon 6 and 7) for A phenotype and 6 SNP sites (261, 796, IVS3 +5, 247, 523, and 502 in exon 2, 6 and 7 and intron 3) for B phenotype. SNaPshot analysis for defining blood group A alleles (A₁, A₂, A₃, A_m and A_el) and blood group B alleles (B₁, B₃, B_w and B_el) was therefore available.

CONCLUSION

SNaPshot analysis could be used in reference laboratories for typing known rare subgroups of A and B without DNA cloning and traditional sequencing. Moreover, this method would help to construct databases of genotyped blood donors, and it potentially plays a role in determining fetal-maternal ABO incompatibility.

Evaluation of kodecytes using function-spacer-lipid constructs as a survey material for external proficiency testing for ABO subgrouping

BACKGROUND

It is not easy to find natural red blood cells (RBCs) with weak A (A_w ) or weak B phenotype (B_w ) for use as quality controls in ABO subgroup testing (subgrouping). The aim of this study was to prepare RBC kodecytes with synthetic blood group A and/or B function-spacer-lipid (FSL) constructs and to evaluate the possibility of using such kodecytes as a survey material for an external proficiency test (PT) to improve the quality of subgroup analysis.

METHODS

Three types of survey samples, including O phenotype RBCs and A kodecytes with A_w (0.02 mg/mL FSL-A solution) and B kodecytes with B_w (0.15 mg/mL FSL-B solution) were sent to 53 laboratories for an educational trial of PT for subgrouping. Cell typing was done using the manual tube technique.

RESULTS

Forty-three laboratories responded, and the re-activities of the survey samples varied from 0 to 4+ against anti-A and anti-B monoclonal reagents(MoAbs). Twenty-nine laboratories (67%) correctly grouped the B_w kodecytes as B_w . Fifteen (35%), 21 (48%), and 6 (13%) laboratories grouped the A_w kodecytes as A_w , A₂ , and O phenotypes, respectively. The anti-A MoAb clone affects the results of cell typing for A_w kodecytes. The stability of kodecytes was similar to that of natural O RBCs during storage.

CONCLUSION

Our kodecytes were useful as a survey material, and the survey results showed the necessity of materials for PT for subgrouping to improve the quality of laboratory analysis regardless of the different reactions according to the MoAb.