AGE-RELATED RANGES OF MEMORY, ACTIVATION, AND CYTOTOXIC MARKERS ON CD4 AND CD8 CELLS IN CHILDREN

The expression of markers defining functional subpopulations on the su rface of CD4 and CD8 cells changes with disease. To monitor these chan ges in children, it is important to establish the age-related normal c hanges in marker expression due to maturation of the immune system. We have studied the expression of several functionally important molecul es on bath CD4 and CD8 cells in 168 children (aged 0-122 months) using monoclonal antibodies and flow cytometry. Our results show that the p ercentage of CD4 cells decreases with age, while the CD8 percentage in creases, resulting in a decrease in the CD4/CD8 ratio. The expression of CD45RO and CD29 increases with age, while CD45RA expression decreas es, bath on CD4 and CD8 cells. The expression of HLA-DR on both CD4 an d CD8 cells, and of CD11a and CD57 on CD8 cells, is less clearly age d ependent. The relationships between the marker percentages and age wer e not straightforward; the standard deviations and the skewness, as we ll as their mean values, varied as a function of age. The changes were modeled for each marker and age-specific centiles are presented.