Blood-group U antigen on Rhnull leukocytes

The red cell antigens A, B, D, U, Ge, Jk3 and Yta are not detected on human granulocytes

We report the inability to detect the following red blood cell antigens on human granulocytes: A, B, D, U, Gerbich (Ge), JkaJkb (Jk3) and Cartwright (Yta). To study each antigen, granulocytes were purified on density gradients, fixed in glutaraldehyde, and the uptake of specific antisera measured using two direct immunological techniques: 125I-staphylococcal protein A (125I-SPA) binding and avidin-biotin-complex (ABC) immunoperoxidase staining. Glutaraldehyde fixation was shown not to affect the antigenicity when the antisera were tested using red blood cells. Using three anti-A, three anti-B and three anti-A,B antisera, our 125I-SPA results of 47 tests with granulocytes from group A individuals and 39 tests with granulocytes from group B individuals indicate that A or B antigens are not expressed on human granulocytes. Tests using ABC were also negative with 37 and 36 granulocytes from group A or B individuals, respectively. In addition, no positive results using 125I-SPA were obtained with granulocytes from individuals having antigen positive red cells when tested with two anti-D (number of tests performed (n = 22), three anti-Ge (n = 22), three anti-U (n = 20), two anti-Jk3 (n = 17), and three anti-Yta (n = 25); control anti-NA1 or -NB1 antisera were invariably positive. Also, using these antisera, no positive results were obtained by ABC except with one anti-Yta antiserum which was positive with one of seven granulocytes tested. This anti-Yta was also positive with three of 10 granulocytes by 125I-SPA. This activity was shown to be due to a granulocyte-specific antibody; adsorption of the antiserum with human granulocytes removed all activity against granulocytes but did not reduce the activity against red cells. Thus, our results are in agreement with recent reports which demonstrated the absence of the A, B and D antigens on human granulocytes. However, we have been unable to confirm previous reports which indicated the presence of the U, Ge and Jk3 antigens on human granulocytes. Also, we have been unable to detect the Yta antigen on human granulocytes.

Failure to demonstrate dosage of U antigen

Tests in which 11 examples of anti-U were used in titration studies against the red blood cells of 9 obligate Uu heterozygotes, from 4 unrelated families, and random Negro and Caucasian donors (many of whom were of the presumptive UU genotype) have failed to demonstrate any dosage of the U antigen.

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.