An Alberta Cree Indian with a rare Duffy antibody, anti-Fy 3

Anti-Fy3, found in the serum of an Fy(a-b-) Cree Indian woman believed to have been transfused 5 years previously, caused moderate hemolytic disease of the newborn in her eighth live-born baby. Only three examples of anti-Fy3 are know. It is striking that two were made by non-negro people, amongst whom Fy(a-b-) is extremely rare, and only one by a Negro, in whose people Fy(a-b-) is by far the commonest phenotype. This suggests that Fy(a-b-) may be a heterogeneous phenotype, with the negro version conferring some impediment to immunization by Fya, Fyb or Fy3 antigens. The rare allele Fyx is also present in the kindred of the propositus, and is shown to correspond to weak Fy3 as well as weak Fyb anitgen.