EXPRESSION OF RED-CELL ANTIGENS-C AND C ON NEONATAL AND ADULT ERYTHROCYTES - A FLOW-CYTOMETRIC ANALYSIS

Red cell membrane proteins expressing Rh antigens appear to be important for the stabilization of the phospholipid membrane bilayer. Neonatal red cells possess a shorter in vivo life span and different deformability properties as compared to adult red blood cells, differences which could potentially be explained by different cell surface antigen densities of Rh-antigenic determinants. Although conventional serologic techniques have demonstrated Rh antigens on fetal and neonatal red cells, other more sensitive techniques are required when quantitative information is needed. Therefore, in this study, 40 adult and 45 neonatal red blood cell suspensions of differing Rh phenotypes were evaluated for C and c antigen density using flow cytometry. Neonatal and adult red blood cells had the same mean channel fluorescence intensity (expressed in mV) of c antigen in either the homozygous (cc) or heterozygous (cC) state: 485+/-44 versus 471+/-29 and 416+/-31 versus 411+/-23, respectively. In addition, neonatal and adult C antigen density was similar in heterozygous (Cc; 415+/-49 versus 455+/-44) and homozygous (CC; 438+/-53 versus 469+/-38 C states. As expected, homozygous (double dose) states for either C or c had greater intensities than heterozygous states for both neonates and adults. Although no differences were noted for C or c antigens, studies of other Rh antigens may indicate lower antigenic density in neonatal red cells.