Evaluation of a blood group genotyping platform (BLOODchip? Reference) in Japanese samples

摘要

Background: Blood-group genotyping arrays have been widely used in Caucasian and African American populations, but have not been thoroughly tested in Japanese subjects. Aim: To evaluate, using the BLOODchip? Reference genotyping system, the concordance of previously typed samples with expected phenotypes and the coverage of the Japanese variants. Methods: Blood samples from 100 Japanese donors were obtained. DNA was extracted with QIAsymphony (Qiagen, Hilden, Germany). Samples were typed by serological methods and processed with the BLOODchip?. When a non-concordant result was identified, further sequencing by polymerase chain reaction-single specific primer (PCR-SSP) was performed. Results: Concordance between systems was 98% (736/751), and 98.8% (742/751) if only non-software-related non-concordances were considered. In the ABO group, 6 'No Call' (NC, inability of the BLOODchip? to assign a result) were ascribed to a variant of blood subtype A1 (A102; 467CT), a common subtype in Asian populations, whereas three NC presented additional polymorphisms not contained in the BLOODchip? (A102/A205, A102/O06 and A204/O02). In the RhD group, one discrepancy was correctly genotyped as RHD*1227A (Del phenotype) by the BLOODchip? (phenotyped as partial D, RHD*DIVb). Another was phenotyped as D+ by the BLOODchip? (phenotyped weak D by serology) and confirmed as RHD*D-CE(2)-D heterozygous by sequencing. The 3 RhD NC can be solved by further software update. For RhCE, one discrepancy was correctly genotyped for both systems; however, only the BLOODchip? was able to detect RHCE*CX allele. Conclusions: By programming the A102 ABO variant into the system software with the new allele combinations, the BLOODchip? Reference is a suitable genotyping tool to be applied to Asian samples.