Associations between chronic caregiving stress and T cell markers implicated in immunosenescence

Chronic psychological stress is associated with accelerated biological aging, immune dysfunction, and premature morbidity and mortality. Changes in the relative proportions of T cell subpopulations are thought to be a characteristic of immunological aging; however, understanding of whether these changes are associated with chronic psychological stress is incomplete. This study investigated associations between chronic caregiving stress and distributions of T cell phenotypes in a sample of high stress mothers of children with Autism Spectrum Disorder (caregivers; n = 91) and low stress mothers of neurotypical children (controls; n = 88). Immune markers assessed were naïve (CD45RA + CD62L+), central memory (CD45RA-CD62L+), and effector memory (CD45RA-CD62L-) CD4+ and CD8+ T cells. We also examined the ratio of effector to naïve (E:N) CD4+ and CD8+ T cells. In models adjusted for age, body mass index, race/ethnicity, and antidepressant use, caregivers displayed higher percentages of effector memory CD8+ and CD4+ T cells as well as lower percentages of naïve CD8+ T cells and central memory CD8+ and CD4+ T cells compared to controls. Caregivers also displayed significantly higher E:N ratios for both CD4+ and CD8+ T cells. These findings were also independent of cytomegalovirus infection status. Furthermore, higher parental stress, across both groups, was related to several immune parameters. These findings provide preliminary evidence that chronic parental caregiving stress is associated with changes in relative proportions of T cell subpopulations that are consistent with accelerated immunological aging

Immune Cell Distribution, Effects of Stress on

The appropriate distribution of immune cells within the body is crucial for performance of the surveillance and effector functions of the immune system. Stress can significantly affect baseline leukocyte numbers as well as dynamic leukocyte distribution between different body compartments. Organs that are enriched with immune cells during stress may mount more robust immune responses, whereas those that are depleted may show suppressed immune function. It has been proposed that stress-induced changes in leukocyte trafficking may enhance immunoprotection during surgery, vaccination, or infection but may also exacerbate immunopathology during inflammatory (cardiovascular disease or gingivitis) or autoimmune (psoriasis, arthritis, or multiple sclerosis) diseases

Immune Function, Stress-Induced Enhancement

Stress has long been suspected to play a role in the etiology of many diseases, and numerous studies have shown that stress can be immunosuppressive and hence may be detrimental to health. However, there are reasons to believe that under certain conditions stress may enhance, rather than suppress, immune function. This article discusses those reasons and reviews evidence that suggests that stress can, under certain conditions, enhance immune function. It then goes on to explore the functional consequences of a stress-induced enhancement of immunity and proposes a model for examining the relationships among stress, immune function, and health

Immune Surveillance – Cancer, Effects of Stress on

Cancer is a stressor that triggers a variety of reactions in the body that can, in turn, complicate the course of cancer. Typical hormonal reactions to stress, especially the secretion of cortisol, which mobilizes glucose into the blood, can affect the body's response to the growth of tumors by shifting metabolic activity, altering protein production, and suppressing aspects of the immune system. The immune system plays a role in tumor control and is sensitive to stress

Photoperiod affects the expression of sex and species differences in leukocyte number and leukocyte trafficking in congeneric hamsters

Sex differences in immune function are well documented. These sex differences may be modulated by social and environmental factors. Individuals of polygynous species generally exhibit more pronounced sex differences in immune parameters than individuals of monogamous species, often displaying an energetic trade-off between enhanced immunity and high mating success. During winter, animals contend with environmental conditions (e.g. low temperatures and decreased food availability) that evoke energetic-stress responses; many mammals restrict reproduction in response to photoperiod as part of an annual winter coping strategy. To test the hypothesis that extant sex and species differences in immune surveillance may be modulated by photoperiod, we examined leukocyte numbers in males and females of two closely related hamster species ( Phodopus). As predicted, uniparental P. sungorus exhibited a robust sex difference, with total white blood cells, total lymphocytes, T cells, and B cells higher in females than males, during long days when reproduction occurs, but not during short days when reproduction usually stops. In contrast, biparental male and female P. campbelli exhibited comparable leukocyte numbers during both long and short days. To study sex differences in stress responses, we also examined immune cell trafficking in response to an acute (2 h) restraint stressor. During stressful challenges, it appears beneficial for immune cells to exit the blood and move to primary immune defense areas such as the skin, in preparation for potential injury or infection. Acute stress moved lymphocytes and monocytes out of the blood in all animals. Blood cortisol concentrations were increased in P. sungorus females compared to males at baseline (52%) and in response to restraint stress (38%), but only in long days. P. campbelli males and females exhibited comparable blood cortisol and stress responses during both long and short days. Our results suggest that interactions among social factors and the environment play a significant role in modulating sex and seasonal alterations in leukocyte numbers and stress responses