Chronic stress and immunosenescence: a review.

This paper reviews recent work suggesting that human immunosenescence may be closely related to both chronic stress and stress hormones. The age-related immunological changes are also similarly found during chronic stress or glucocorticoid exposure. These data further suggest that endogenous glucocorticoids could be associated with immunosenescence. When compared with young subjects, healthy elders are emotionally distressed in parallel to increased cortisol/dehydroepiandrosterone ratio. Furthermore, chronically stressed elderly subjects may be particularly at risk of stress-related pathology because of further alterations in glucocorticoid-immune signaling. Age-related increase in cortisol/dehydroepiandrosterone ratio could be understood as a major determinant of immunological changes observed during aging. Strictly healthy elders are somewhat protected from chronic stress exposure and show normal cortisol levels and increased T cell function. This information adds a new key dimension to the biology of aging and stress. Copyright 2008 S. Karger AG, Basel.