Adrenal androgens and the immune system.

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) are the main adrenal androgens (AAs) produced in humans. Production of these steroids, like that of cortisol, is under the control of hypothalamic corticotropin-releasing hormone (CRH) and pituitary ACTH. Other factors, however, appear to be involved in AA secretion because there are many instances in which their circulating levels do not change in parallel to those of cortisol. Apart from physiological alterations associated with fetal adrenal regression, adrenarche and aging, the main instances of divergence in AA production compared with those of corticosteroids occur when immune function is activated or is aberrant. Relative reductions in DHEA and DHEAS have been noted in subjects with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), human immunodeficiency virus (HIV) and autoimmune deficiency syndrome (AIDS), sepsis, and trauma. In some instances, differences in the AA responses have been linked to a clinical course. The mechanisms for impairments in AA production in the absence of suppressed corticoid secretion are unclear but may involve circulating cytokines or locally released mediators from immune system cells in the adrenal gland. There also is evidence that DHEA and DHEAS play a role in immune competence, displaying biological effects opposite to those of corticosteroids.