Figure 3.

X-Y plot showing 24-hour time qualified profiles of lymphocyte subset percentages and cortisol serum levels. Values are expressed as mean ± SE calculated on single time point values from fifteen young-middle aged and fifteen old aged subjects. Percentages of circulating CD8 dim+, CD16+ and γδTCR+ T cell subpopulations and cortisol serum levels show circadian rhythmicity with acrophase during the day in young-middle aged subjects. In old aged subjects CD8 dim+ T cells and cortisol serum levels show circadian rhythmicity with acrophase during the day. Cubic regression function data interpolation represented as best fit solid line in young-middle aged subject and medium-dashed line in old aged subjects, superimposed on the raw data (dotted line).