Present status of the Duffy blood group system.

In 1950 a new blood group antibody was recognized in the serum of a multi-transfused hemophiliac patient. The reactive red-cell antigen was identified in 65% of random caucasians, and the systemic name Duffy was proposed. Two common antigens, Fy-a and Fy-b, were recognized and shown to be products of autosomal allelic genes, but the great majority of negro individuals were found to lack both antigens. In 1968 genetic studies showed Duffy to be linked to Un-1, which is an inherited structural variation of chromosome number 1. Duffy thus became the first autosomal blood group gene to be allocated to a specific chromosome. Recent studies have allowed recognition of three new antibodies (anti-Fy3, anti-Fy4, and anti-Fy5) in the Duffy system. The Rh blood group locus has also been assigned to chromosome 1, and there is evidence that the antigen defined by anti-Fy5 is a product of interaction between Duffy and Rh genes. The Duffy blood group appears to be one of importance in clinical blood transfusion practice, and possibly makes the greatest distinction of any of the red cell systems between different groups of the world population.