CHANGES IN ABH ANTIGEN EXPRESSION ON RED-CELLS DURING IN-VIVO AGING - A FLOW CYTOMETRIC ANALYSIS

Background: During aging of red cells they undergo a multitude of physical and chemical changes. Study Design and Methods: Age-dependent changes in the expression of ABH major blood group antigens on red cells were studied in a two-variable flow cytometric analysis. The expression of the antigens was measured after staining with fluorescence antibodies (for A and B) or lectin (for H). Cell age was related to size as measured by forward light scattering. Aging senescent cells are smaller and have low forward light scattering properties. Results: The results indicated that, within a given population, the A and/or B and H antigens decreased with the decrease in forward light scattering (i.e., increase in age), but A and B antigen expression decreased to a greater extent than did H. Conclusion: During aging, red cells lose the antigens of the major blood groups, but the degree of this loss is related to the fact that these antigens are located on the cell surface.