Dehydroepiandrosterone (DHEA) is a C19 steroid of adrenal origin. Notably, its secretion declines with age, a phenomenon referred to as the "adrenopause". For many years, the physiological significance of DHEA remained elusive. However, many studies have now shown that DHEA has significant immune modulatory function, exhibiting both immune stimulatory and anti-glucocorticoid effects. Although several of these studies are limited by the fact that they were carried out in rodents, who are incapable of adrenal DHEA production, and therefore have very low circulating levels of this steroid, evidence from the study of immune cells is now accumulating to suggest a role for DHEA in regulating human immunity. This ability to regulate immune function has raised interest in the therapeutic potential of DHEA as a treatment for the immunological abnormalities that arise in subjects with low circulating levels of this hormone. This has included attempts at reversing the impaired immune response of older individuals to vaccination and restoring immune regulation in patients with chronic autoimmune disease. This review summarises the reported effects of DHEA on immune function and discusses the therapeutic potential of this steroid in geriatric medicine and particularly in age-related disease with an immune component.
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