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

RATIONALE: The percentage of regulatory T cells (T(Regs))—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 T(Reg) in stress-disease pathways has not yet been investigated. OBJECTIVES: The aim of the study was to investigate the association between biological responsivity to acute psychosocial stress and the percentage of T(Regs) in healthy older adults. The secondary purpose was to measure the associations between T(Reg) 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 T(Reg) 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 T(Reg) percentage independently of age, sex, BMI, smoking status, employment grade, time of testing, and baseline measures of cortisol and IL-6, respectively. Percentage of T(Regs) 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 T(Regs) may act as a defence against increased inflammation and may be a pre-indication for chronically stressed individuals on the cusp of clinical illness.