Aging related changes of circadian rhythmicity of cytotoxic lymphocyte subpopulations

<p>Abstract</p> <p>Background</p> <p>Immunosenescence is a process that affects all cell compartments of the immune system and the contribution of the immune system to healthy aging and longevity is still an open question. Lymphocyte subpopulations present different patterns of circadian variation and in the elderly alteration of circadian rhythmicity has been evidenced. The aim of our study was to analyze the dynamics of variation of specific cytotoxic lymphocyte subsets in old aged subjects.</p> <p>Methods</p> <p>Lymphocyte subpopulation analyses were performed and cortisol serum levels were measured on blood samples collected every four hours for 24 hours from fifteen healthy male young-middle aged subjects (age range 36-55 years) and fifteen healthy male old aged subjects (age range 67-79 years).</p> <p>Results</p> <p>In healthy young-middle aged subjects CD20 were higher and at 06:00 h CD8+ dim correlated positively with CD16+ and positively with γδTCR+ cells, CD16 correlated positively with γδTCR+ cells At 18:00 h CD8+ dim correlated positively with CD16+ and positively with γδTCR+ cells, CD16+ correlated positively with γδTCR+ cells and a clear circadian rhythm was validated for the time-qualified changes of CD3+, CD4+, CD20+, CD25+ and HLA-DR+ cells with acrophase during the night and for the time-qualified changes of CD8+, CD8+ bright, CD8+ dim, CD16+ and γδTCR+ cells with acrophase during the day. In old aged subjects CD25, DR+ T cells and cortisol serum levels were higher, but there was no statistically significant correlation among lymphocyte subpopulations and a clear circadian rhythm was evidenced for time-qualified changes of CD3+ and CD25+ cells with acrophase during the night and for the time-qualified changes of CD8+ cells and cortisol with acrophase during the day.</p> <p>Conclusion</p> <p>Our study has evidenced aging-related changes of correlation and circadian rhythmicity of variation of cytotoxic lymphocyte subpopulations that might play a role in the alteration of immune system function in the elderly.</p

Immune system alterations in lung cancer patients.

The immune system plays an important role in the defense against neoplastic disease and immune responses show temporal changes related to circadian variations of antibodies, total lymphocytes in the peripheral blood and cell mediated immune responses. In this study we evaluate, lymphocyte subpopulations and interleukin-2 (IL-2) serum levels in peripheral blood samples collected at four-hour intervals for 24-hours starting at 06.00h from ten healthy subjects aged 65–79 years (mean age ± S.E. 67.28 ±3.11) and from ten subjects suffering from untreated non small cell lung cancer aged 65–78 years (mean age ± S.E. 68.57 ± 1.81). Areas under the curve, mean diurnal levels (mean of 06.00–10.00–14.00 h) and mean nocturnal levels (mean of 18.00–22.00–02.00 h) were calculated, and the presence of circadian rhythmicity was evaluate. When we compared AUC values there was a decrease in CD8bright (T suppressor subset) and an increase in CD16 (natural killer cells) and of IL-2 serum levels in cancer patients. When we compared mean diurnal levels, CD8 (T suppressor/cytotoxic subset) and CD8bright levels were lower, and CD16 levels were higher in cancer patients. When we compared mean nocturnal levels, CD16 and CD25 (T and B activated lymphocytes with expression of the a chain of IL-2 receptor) levels were higher, while CD8, CD8bright, CD20 (total B-cells), TcRd1 (epitope of the constant domain of d chain of T-cell receptor 1) and dTcS1 (epitope of the variable domain of d chain of T-cell receptor1) levels were lower in cancer patients. A clear circadian rhythm was validated for the time-qualified changes in CD4, CD20, HLA-DR with acrophase at night, and CD8, CD8bright, CD8dim, CD16, TcRd1 and dTcS1 with acrophase in the morning in the control group. A clear circadian rhythm was validated for the time-qualified changes in CD4 with acrophase at night, in the group of cancer patients. Results obtained in our study show that lung cancer is associated with anomalies of proportion and circadian variations of lymphocyte subsets that must be considered when adoptive immunotherapy has to be planned

Chronobiologic study of the GH-IGF1 axis and the ageing immune system

One of the many systems that weakens as we age is our immune system and there is a reduction in the GH-IGF1 axis activity with increasing age. In this study we evaluated the immune system and the GH-IGF1 axis function in healthy ageing. CD3, CD4, CD20, CD25, HLA-DR and GH showed acrophase during the night, whereas CD8, CD16 and TCRγδ expressing cells showed acrophase during the day. MESOR of CD3 was higher in the old aged subjects, MESOR of CD20 and CD20 values at 14:00h and at 02:00h were higher in the young middle aged subjects, MESOR of CD25 and CD25 values at 10:00 were higher in the elderly subjects, MESOR of HLA-DR was higher in the young middle aged subjects, whereas MESOR of DR+T cells and HLA-DR at 02:00h were higher in the elderly subjects, MESOR of TCRγδ bearing cells was higher in the elderly subjects, GH value at 18:00h was also higher in the elderly subjects, and MESOR of IGF1 was higher in the young middle aged subjects. There was a statistically significant difference for the acrophases of CD25, HLA-DR and IGF1. There were different and opposing correlations among lymphocyte subpopulations and GH-IGF1 axis hormones in young and middle aged subjects in comparison with old aged subjects. Linear regression evidenced a statistically significant positive trend between age and the 24h mean of CD3 and CD25 and a statistically significant negative trend between age and the 24h mean of CD20 and GH. In conclusion, ageing is associated with an altered GH and IGF1 secretion, with decreased peripheral B cell compartment, increased peripheral T cell compartment and alterations of circadian rhythmicity

Altered time structure of neuro-endocrine-immune system function in lung cancer patients

<p>Abstract</p> <p>Background</p> <p>The onset and the development of neoplastic disease may be influenced by many physiological, biological and immunological factors. The nervous, endocrine and immune system might act as an integrated unit to mantain body defense against this pathological process and reciprocal influences have been evidenced among hypothalamus, pituitary, thyroid, adrenal, pineal gland and immune system. In this study we evaluated differences among healthy subjects and subjects suffering from lung cancer in the 24-hour secretory profile of melatonin, cortisol, TRH, TSH, FT4, GH, IGF-1 and IL-2 and circadian variations of lymphocyte subpopulations. </p> <p>Methods</p> <p>In ten healthy male volunteers (age range 45-66) and ten male patients with untreated non small cell lung cancer (age range 46-65) we measured melatonin, cortisol, TRH, TSH, FT4, GH, IGF-1 and IL-2 serum levels and percentages of lymphocyte subpopulations on blood samples collected every four hours for 24 hours. One-way ANOVA between the timepoints for each variable and each group was performed to look for a time-effect, the presence of circadian rhythmicity was evaluated, MESOR, amplitude and acrophase values, mean diurnal levels and mean nocturnal levels were compared.</p> <p>Results</p> <p>A clear circadian rhythm was validated in the control group for hormone serum level and for lymphocyte subsets variation. Melatonin, TRH, TSH, GH, CD3, CD4, HLA-DR, CD20 and CD25 expressing cells presented circadian rhythmicity with acrophase during the night. Cortisol, CD8, CD8^bright, CD8^dim, CD16, TcRδ1 and δTcS1 presented circadian rhythmicity with acrophase in the morning/at noon. FT4, IGF-1 and IL-2 variation did not show circadian rhythmicity. In lung cancer patients cortisol, TRH, TSH and GH serum level and all the lymphocyte subsubsets variation (except for CD4) showed loss of circadian rhythmicity. MESOR of cortisol, TRH, GH, IL-2 and CD16 was increased, whereas MESOR of TSH, IGF-1, CD8, CD8^bright, TcRδ1 and δTcS1 was decreased in cancer patients. The melatonin/cortisol mean nocturnal level ratio was decreased in cancer patients.</p> <p>Conclusion</p> <p>The altered secretion and loss of circadian rhythmicity of many studied factors observed in the subjects suffering from neoplastic disease may be expression of gradual alteration of the integrated function of the neuro-immune-endocrine system</p

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