Unité INSERM U76, Institut National de Transfusion Sanguine, Paris, France.
The Duffy blood group antigens are carried by the erythrocyte membrane glycoprotein gpD, which has a molecular weight of 35-45 kDa and which has been recently cloned. In this report, we have determined, at the nucleic acid level, the molecular basis for the blood group Fya/Fyb polymorphism. The gpD cDNAs isolated by reverse transcription/polymerase chain reaction (RT-PCR) from Fy(a+b-) and Fy(a-b+) donors differed by only one base substitution (G131A) changing Gly to Asp at position 44 of the gpD protein. When expressed in simian Cos-7 cells, the Gy(a+b-) and Fy(a-b+) gpD cDNA produce cell surface proteins that react with the anti-Fya and anti-Fyb antisera, respectively, demonstrating that they represent the FY*A and FY*B alleles of the Duffy blood group locus. The G131A nucleotide substitution has been correlated with a BanI restriction site polymorphism, which has allowed us to develop a method for the DNA typing of the main Duffy blood group antigens, by means of PCR/restriction fragment length polymorphisms.