title: Increased percentages of regulatory T cells are associated with inflammatory and neuroendocrine responses to acute psychological stress and poorer health status in older men and women.
abstract: BACKGROUND
  The percentage of regulatory T cells (TRegs)-a subtype of T lymphocyte that suppresses the immune response-appears to be reduced in a number of stress-related diseases. The role of the TReg in stress-disease pathways has not yet been investigated.
  
  
  OBJECTIVE
  The aim of the study was to investigate the association between biological responsivity to acute psychosocial stress and the percentage of TRegs in healthy older adults. The secondary purpose was to measure the associations between TReg percentage and psychological and physical well-being in the participants.
  
  
  METHODS
  Salivary cortisol and plasma interleukin (IL)-6 samples were obtained from 121 healthy older men and women from the Whitehall II cohort following acute psychophysiological stress testing. Three years later at a follow-up visit, we measured TReg percentages and psychological and physical well-being were recorded using the Short Form 36 Health Survey and the Center for Epidemiologic Studies Depression Scale.
  
  
  RESULTS
  Blunted cortisol responses (p = 0.004) and elevated IL-6 responses (p = 0.027) to acute psychophysiological stress were associated with greater TReg percentage independently of age, sex, BMI, smoking status, employment grade, time of testing, and baseline measures of cortisol and IL-6, respectively. Percentage of TRegs was associated cross-sectionally with lower physical (p = 0.043) and mental health status (p = 0.008), and higher levels of depressive symptoms (p = 0.002), independently of covariates.
  
  
  CONCLUSIONS
  Increased levels of TRegs may act as a defence against increased inflammation and may be a pre-indication for chronically stressed individuals on the cusp of clinical illness.
authors: Department of Epidemiology and Public Health, University College London, 1-19, Torrington Place, London, WC1E 6BT, UK. a.ronaldson@ucl.ac.uk.
authors: Amy
authors: A
authors: Ronaldson
authors: Department of Academic Rheumatology, Division of Immunology, Infection and Inflammatory Disease, School of Medicine, Kings College London, Guy's Campus, London, SE1 1UL, UK.
authors: Ahmad M
authors: AM
authors: Gazali
authors: Department of Epidemiology and Public Health, University College London, 1-19, Torrington Place, London, WC1E 6BT, UK.
authors: Argita
authors: A
authors: Zalli
authors: Department of Microbial Diseases, UCL-Eastman Dental Institute, London, WC1X 8LD, UK.
authors: Frank
authors: F
authors: Kaiser
authors: Department of Academic Rheumatology, Division of Immunology, Infection and Inflammatory Disease, School of Medicine, Kings College London, Guy's Campus, London, SE1 1UL, UK.
authors: Stephen J
authors: SJ
authors: Thompson
authors: Department of Microbial Diseases, UCL-Eastman Dental Institute, London, WC1X 8LD, UK.
authors: Brian
authors: B
authors: Henderson
authors: Department of Epidemiology and Public Health, University College London, 1-19, Torrington Place, London, WC1E 6BT, UK.
authors: Andrew
authors: A
authors: Steptoe
authors: Department of Epidemiology and Public Health, University College London, 1-19, Torrington Place, London, WC1E 6BT, UK.
authors: Livia
authors: L
authors: Carvalho
mesh_terms: D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology / Q000276:immunology; D005260:Female; D006304:Health Status; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007249:Inflammation / Q000276:immunology*; D015850:Interleukin-6 / Q000378:metabolism; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D009490:Neurosecretory Systems / Q000276:immunology*; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D013315:Stress, Psychological / Q000276:immunology* / Q000523:psychology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6; D006854:Hydrocortisone
keywords: Depression; HPA axis; Inflammatory response system; Psychological stress; Regulatory T cell