Erythrocyte Rh antigens increase with red cell age.

Certain blood group antigens may play a role in the removal of senescent red cells from the circulation. In order to elucidate this hypothesis, we have investigated the effect of red cell aging on Rh blood group antigens. Red cells from volunteer donors were separated into subpopulations of uniformly defined densities on discontinuous Stractan density gradients. The number of the five major Rh antigen sites of each fraction was determined both by enzyme-linked immunosorbent assay (ELISA) and by hemagglutination-scoring technique. All Rh antigens tested increased with cell age (p less than 0.01). The data indicate that there is a positive correlation between red cell age and the Rh blood group antigen site number.