Dexamethasone effects on numbers of cells in lymphocyte subpopulations: changes associated with major depression and...

1. The authors studied the effects of administration of 1 mg of dexamethasone on the number of cells in discrete subpopulations of lymphocytes in major depressed and psychiatric control patients with depressive symptoms. 2. Dexamethasone significantly decreased the total lymphocyte count and numbers of T and helper T lymphocytes in control patients. 3. In contrast, dexamethasone failed to significantly decrease the numbers of cells in any of the subpopulations of lymphocytes studied in major depressed patients. 4. Among major depressed patients both DST suppressors and nonsuppressors were insensitive to the suppressive effects of dexamethasone on lymphocyte numbers. 5. However, in DST nonsuppressors, but not in DST suppressors, dexamethasone administration significantly increased the number of cytotoxic/suppressor T lymphocytes and natural killer cells. 6. The authors conclude that insensitivity to the suppressive effects of dexamethasone on lymphocyte numbers is specific to major depression and is not associated with DST status. However, DST nonsuppression is associated with a facilitating effect of dexamethasone on the number of cells in some subpopulations of lymphocytes.