Search

Background: Aging is one factor believed to contribute to processes that underlie chronic low-grade inflammation in older adults. Moreover, more recent studies have suggested that cytokine levels are influenced by ethnicity., Methods: In this study, we determined plasma cytokine profiles in a population-based sample (n = 1,411; aged 25-91 years) to determine the relationship between circulating cytokine levels, aging, and ethnicity. We measured interleukin-1 receptor antagonist (IL-1ra), interleukin (IL)-6, -10, C-reactive protein (CRP), and tumor necrosis factor-receptor 1 (TNF-r1)., Results: IL-6 and TNF-r1 significantly increased with age, whereas IL-1ra, IL-10, and CRP did not significantly increase with age. After adjusting for age, non-Hispanic whites had significantly higher levels of IL-1ra than Mexican Americans, whereas non-Hispanic blacks had significantly higher levels of IL-6 and CRP than Mexican Americans as well as non-Hispanic whites. CRP levels in non-Hispanic blacks were no longer significantly higher after adjusting for body mass index (BMI), indicating that BMI is an important predictor of this inflammatory marker., Conclusions: These results demonstrate that cytokine levels are influenced by both age and ethnicity. Furthermore, these results show that inflammatory profiles for Mexican Americans are lower than non-Hispanic whites and non-Hispanic blacks.

Introduction: Hypokinesia is associated with spaceflight and prolonged illnesses and may lead to secondary immune deficiency., Methods: The distribution of immunocytes in whole blood, mitogen-induced cytokine secretion in vitro, Epstein-Barr virus (EBV) reactivation, and plasma cortisol levels were studied in 13 healthy volunteers subjected to a horizontal bed rest (BR) regime for 28 d. Samples were collected before the study, weekly during BR, and then 3-5 d after the regime ended. Additionally, subjects were treated with hydrocortisone on the 1st and 27th d of BR to simulate the hypercortisolemia that occurs during stress., Results: The factors of 28-d BR regime accompanied by acute hypercortisolemia significantly decreased the relative and absolute number of total lymphocytes, CD3+ T-cells, T-helper subset, and monocytes, but increased the percentage of the CD8+ T-cells, and NK cells at the 4th wk compared with the baseline. A significant decrease in mitogen-activated secretion of IL-2, IFN-gamma, TNF-beta, IL-6, and IL-10 was registered at the same interval. Also, secretion of IL-2 and IFN-gamma declined at the 2nd week of the BR regime. Secretion of IL-4 was significantly higher at the 2nd and 3rd weeks compared with the baseline. A significant increase in the shedding of EBV DNA in saliva was observed as early as the 3rd wk of BR., Conclusions: Stress factors associated with BR significantly alter immune responsiveness in vitro and in vivo. Changes in the cytokine secretion and cytokine imbalance precede latent EBV reactivation. PHA/LPS-activated cytokine secretion in whole blood can be used as a test system for predicting latent virus activation.

Stressful environmental conditions are a major determinant of immune reactivity. This effect is pronounced in Australian National Antarctic Research Expedition populations exposed to prolonged periods of isolation in the Antarctic. Alterations of T cell function, including depression of cutaneous delayed-type hypersensitivity responses and a peak 48.9% reduction of T cell proliferation to the mitogen phytohaemagglutinin. were documented during a 9-month period of isolation. T cell dysfunction was mediated by changes within the peripheral blood mononuclear cell compartment. including a paradoxical atypical monocytosis associated with altered production of inflammatory cytokines. There was a striking reduction in the production by peripheral blood mononuclear cells of the predominant pro-inflammatory monokine TNF-α and changes were also detected in the production of IL-1, IL-2, IL-6, IL-Ira and IL-10. Prolonged Antarctic isolation is also associated with altered latent herpesvirus homeostasis. including increased herpesvirus shedding and expansion of the polyclonal latent Epstein-Barr virus-infected B cell population. These findings have important long-term health implications. [ABSTRACT FROM AUTHOR]

Self-rated health (SRH) is a reliable predictor of health outcomes including morbidity and mortality. Immune dysregulation is one hypothesized mechanism underlying the association between SRH and health outcomes. Indeed, poorer SRH is associated with greater inflammation. The association between SRH and reactivation of latent herpesviruses is unknown, representing an important gap in the literature given that reactivation of latent herpesviruses leads to enhanced inflammation. The present study addressed this important gap in the literature by examining associations between SRH, inflammation (i.e., peripheral cytokines in the blood), and reactivation of latent herpesviruses among a sample of 1208 individuals participating in the Texas City Stress and Health Study. Participants completed a self-report measure of SRH and a blood draw. Results indicated that higher SRH was associated with lower reactivation of latent herpesviruses and inflammation. Moreover, reactivation of latent herpesviruses partially mediated the association between SRH and inflammation. Accordingly, findings add to our growing understanding of the association between SRH and immune dysfunction. [ABSTRACT FROM AUTHOR]