FY*X real-time polymerase chain reaction with melting curve analysis associated with a complete one-step real-time FY genotyping.

BACKGROUND AND OBJECTIVES

The Duffy (FY) blood group system is controlled by four major alleles: FYA and FYB, the Caucasian common alleles, encoding Fy(a) and Fy(b) antigens; FYX allele responsible for a poorly expressed Fy(b) antigen, and FYFy a silent predominant allele among Black population. Despite the recent development of a real-time fluorescent polymerase chain reaction (PCR) method for FY genotyping FYX genotyping has not been described by this method. This study focused on the real-time FYX genotyping development associated with a complete, one-step real-time FY genotyping, based on fluorescence resonance energy transfer (FRET) technology.

MATERIALS AND METHODS

Seventy-two blood samples from Fy(a+b-) Caucasian blood donors were studied by real-time PCR only. Forty-seven Caucasian and Black individual blood samples, referred to our laboratory, were studied by PCR-RFLP and real-time PCR. For each individual, the result of the genotype was compared to the known phenotype.

RESULTS

The FYX allele frequency calculated in an Fy(a+b-) Caucasian blood donors population was 0.014. With the Caucasian and Black patient samples we found a complete correlation between PCR-RFLP and the real-time PCR method whatever the alleles combination tested. When the known phenotype was not correlated to FYX genotype, the presence of the Fy(b) antigen was always confirmed by adsorption-elution.

CONCLUSION

The real-time technology method is rapid and accurate for FY genotyping. From now, we are able to detect the FYX allele in all the alleles combinations studied. Regarding its significant frequency, the detection of the FYX allele is useful for the correct typing of blood donors and recipients considering the therapeutic use of blood units and the preparation of test red blood cells for antibody screening.