Two-Color Immunofluorescene and Flow Cytometric Analysis of Peripheral Blood Lymphocyte Subsets in Aging Humans

Using two-color immunofluorescence, multiparameter flow cytometry has been used to examine the antigenic characteristics of the nature of changes due to aging in lymphocyte subests. The percentage and absolute numbers of T cells (CD3+T) declined in the aging humans. This decline was associated with a decreasing trend of CD8+T (cytotoxic/suppressor) cells in aging. The aged men had a slight but non-significant increased proportion of CD4+Leu8-T cells, which mediate the helper functions in B cell differentiation in association with an increasing tendency in the number of CD4+ T cells. A wide variety of changes took place in activated T cells expressing antigens such as Leu17(CD38), HLA-DR, or HLA-DQ, Although the decrease in the number of total CD8+ T cells was only slight, the proportion of CD8+ cell bearing Leu7 (CD57) antigen was strikingly increased in the elderly. For NK cells, a total number of NK cells (Leu19+CD3-) in the aged subjects was increased, but a subpopulation of cells having the high NK activity (Leu19+CD57-cells) decreased in the elderly men. The present study revealed various changes in lymphocyte subsets in aging humans