IMBALANCE OF THE CD4-BLOOD OF ADULTS AND CHILDREN WITH DOWN-SYNDROME(SUBPOPULATIONS EXPRESSING CD45RA AND CD29 ANTIGENS IN THE PERIPHERAL)

Peripheral blood lymphoid subsets expressing either CD45RA or CD29 ant igens, were quantified in 30 children and 59 adults with Down Syndrome and appropriate age-matched controls, by dual immunofluorescence and flow cytometry. Down's patients, both adults and children, displayed a significant decrease of CD4+CD45RA+ cells in comparison with the obse rved in their age-matched controls, but no difference was found in the CD4+CD29+ subset. These results show clearly the imbalance of these s ubpopulations in the peripheral blood of individuals with Down syndrom e that result in the inversion of the CD45RA/CD29 ratio, due to a majo r reduction of the CD45RA subset. No obvious difference was found in t he CD45RA/CD29 ratio within the CD4 negative cells. Abnormalities of t hese subpopulations could be indicative of early senescence of the imm une system, since age-related changes in Down's persons were in parall el with those observed in normal individuals and the proportion of bot h subpopulations were roughly similar in Down's children and normal ad ults.