Table 1
Human Clusters of Differentiation (CDs)
| CD3 | the signaling component of the T cell receptor (TCR) complex, found on T cells |
| CD4 | a co-receptor for MHC Class II, found on T helper/inducer subset |
| CD8 | a co-receptor for MHC Class I, found on T suppressor/cytotoxic subset |
| CD16 | FcγRIII, a low-affinity Fc receptor for IgG, found on NK cells, macrophages, and neutrophils |
| CD20 | a type III transmembrane protein found on B cells |
| CD25 | a type I transmembrane protein found on activated T cells that associates with CD122 to form a heterodimer that can act as a high-affinity receptor for IL-2 |
| HLA-DR | a transmembrane human major histocompatibility complex (MHC) II family member expressed primarily on B cells on which it presents antigenic peptides for recognition by the T cell receptor on CD4+ T cells. |
| TcRδ1 | epitope of the constant domain δ of chain of TCR found on γδTCR expressing cells |
Table 2
Integrated time-qualified 24-hours values expressed as AUC ± SE
| Healthy young-middle aged subjects | Healthy old aged subjects | |
|---|---|---|
| CD3 | 1545.41 ± 42.23 | 1576.07 ± 25.85 |
| CD4 | 891.33 ± 60.52 | 837.41 ± 32.41 |
| CD8 | 603.73 ± 92.12 | 615.24 ± 30.21 |
| CD4/CD8 ratio | 39.40 ± 12.71 | 31.53 ± 1.35 |
| CD16 | 142.50 ± 45.30 | 171.72 ± 31.63 |
| CD20 | 264.12 ± 30.84 | 132.78 ± 21.23• |
| CD25 | 76.12 ± 14.21 | 140.02 ± 24.25• |
| DR+T cells | 61.8 ± 10.23 | 109.5 ± 8.31• |
| HLA-DR | 327.05 ± 23.40 | 282.57 ± 20.42 |
| TcRδ1 | 61.72 ± 13.71 | 86.23 ± 9.25 |
| Cortisol | 258.2 ± 13.4 | 310.6 ± 32.7• |
Units: % for lymphocyte subpopulations, μg/dl for cortisol all; parameters analyzed in all the subjects; p < 0.05•
Table 3
Chronobiological data derived from best fitting sine curves (fitted period:24 hours = 360°)
| Healthy young-middle aged subjects | |||||
|---|---|---|---|---|---|
| Factor | p | MESOR ± SE | Amplitude ± SE | Acrophase ± SE(°) | Time (Hh:Mn) |
| CD3 | 0.002 | 78.06 ± 0.10 | 1.12 ± 0.22 | 25.1 ± 12.4 | 01:40 ± 00:50 |
| CD4 | 0.001 | 45.23 ± 0.85 | 3.14 ± 1.12 | 3.3 ± 24.5 | 00:13 ± 01:38 |
| CD8 | 0.003 | 29.52 ± 0.23 | 1.94 ± 0.25 | 181.3 ± 2.4 | 12:05 ± 00:10 |
| CD8 bright | 0.001 | 21.43 ± 0.11 | 1.49 ± 0.21 | 187.3 ± 10.2 | 12:29 ± 00:41 |
| CD8 dim | 0.002 | 8.09 ± 0.14 | 1.33 ± 0.09 | 192.1 ± 3.8 | 12:48 ± 00:15 |
| CD4/CD8 ratio | 0.001 | 1.53 ± 0.02 | 0.23 ± 0.1 | 16.0 ± 0.2 | 01:04 ± 00:01 |
| CD16 | 0.030 | 6.26 ± 0.42 | 0.81 ± 0.21 | 212.1 ± 21.3 | 14:08 ± 01:25 |
| CD20 | 0.002 | 13.23 ± 0.24 | 1.51 ± 0.11 | 336.8 ± 12.2 | 22:27 ± 00:49 |
| CD25 | 0.002 | 3.82 ± 0.02 | 0.67 ± 0.21 | 9.2 ± 7.1 | 00:37 ± 00:28 |
| DR+T cells | 0.005 | 3.21 ± 0.30 | 0.83 ± 0.20 | 12.2 ± 51.2 | 00:49 ± 03:25 |
| HLA-DR | 0.010 | 16.22 ± 0.25 | 1.33 ± 0.33 | 332.6 ± 11.3 | 22:10 ± 00:45 |
| TcRδ1 | 0.002 | 2.12 ± 0.09 | 0.63 ± 0.12 | 159.5 ± 14.3 | 10:38 ± 00:57 |
| Cortisol | 0.001 | 10.23 ± 1.42 | 6.51 ± 2.52 | 141.6 ± 22.1 | 09:26 ± 01:28 |
| Old aged subjects | |||||
| Factor | p | MESOR ± SE | Amplitude ± SE | Acrophase ± SE (°) | Time (Hh:Mn) |
| CD3 | 0.002 | 84.91 ± 0.21 | 1.07 ± 0.02 | 71.2 ± 3.0 | 04:45 ± 00:12 |
| CD4 | 0.145 | 45.12 ± 0.89 | 3.10 ± 1.27 | 33.2 ± 22.1 | 02:13 ± 01:28 |
| CD8 | 0.005 | 29.21 ± 0.23 | 3.25 ± 0.53 | 188.9 ± 11.2 | 12:36 ± 00:45 |
| CD8 bright | 0.001 | 20.12 ± 0.08 | 1.47 ± 0.19 | 196.1 ± 12.3 | 13:04 ± 00:49 |
| CD8 dim | 0.002 | 9.09 ± 0.15 | 1.31 ± 0.87 | 191.7 ± 2.4 | 12:47 ± 00:10 |
| CD4/CD8 ratio | 0.001 | 1.48 ± 0.06 | 0.22 ± 0.04 | 17.9 ± 11.7 | 01:12 ± 00:47 |
| CD16 | 0.246 | 8.02 ± 0.31 | 2.42 ± 0.43 | 191.3 ± 7.5 | 12:45 ± 00:30 |
| CD20 | 0.210 | 8.36 ± 0.16 | 1.15 ± 0.11 | 287.2 ± 21.4 | 19:09 ± 01:26 |
| CD25 | 0.031 | 7.12 ± 0.13 | 1.02 ± 0.21 | 251.2 ± 12.3 | 16:45 ± 00:49 |
| DR+T cells | 0.057 | 5.12 ± 0.35 | 1.73 ± 0.2 | 141 ± 11.2 | 09:24 ± 00:45 |
| HLA-DR | 0.297 | 13.21 ± 0.12 | 1.21 ± 0.9 | 185.1 ± 33.2 | 12:20 ± 02:13 |
| TcRδ1 | 0.210 | 4.28 ± 0.12 | 0.32 ± 0.11 | 192.1 ± 30.4 | 12:48 ± 02:02 |
| Cortisol | 0.017 | 13.26 ± 0.40 | 5.42 ± 1.31 | 121.8 ± 10.2 | 08:07 ± 00:40 |
Units: % for lymphocyte subpopulations, g/dl for cortisol, all parameters analyzed in all the subjects
Figure 1
Correlations between lymphocyte subpopulations in the photoperiod. In the photoperiod (06:00h-10:00h-14:00h) CD8+ dim correlates positively with CD16+ (r = 0.803, p < 0.001) and positively with γδTCR+ cells (r = 0.603, p = 0.005), CD16 correlates positively with γδTCR+ cells (r = 1.138, p < 0.001. There is no statistically significant correlation in old aged subjects.
Figure 2
Correlations between lymphocyte subpopulations in the scotoperiod. In the scotoperiod (18:00h-22:00h-02:00h) CD8+ dim correlates positively with CD16+ (r = 0.852, p < 0.001) and positively with γδTCR+ cells (r = 1.012, p = 0.05), CD16+ correlates positively with γδTCR+ cells (r = 1.676, p < 0.001). There is no statistically significant correlation in old aged subjects
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).