Lymphocyte subpopulations in depressed elderly women.

Dexamethasone Suppression Tests (DST) and measurement of lymphocyte subpopulations were conducted in 21 medically healthy elderly women with major depressive disorder and 77 healthy elderly women volunteers. Depressed women revealed significantly reduced absolute lymphocytes (p less than 0.01), T cells (p less than 0.01), and T helper cells (p less than 0.02) compared to normal elderly women. Of the depressed women, 50% had positive DSTs (postdexamethasone cortisols greater than 5 micrograms/dl) compared to 5.4% of the normal women (p less than 0.0001). Within the depressed group, patients with positive DSTs had significantly reduced absolute lymphocytes (p less than 0.05) and T helper cells (p less than 0.025) compared with depressed women who had normal DSTs. Further, a significant negative correlation was found between postdexamethasone cortisols (at both 4:00 and 11:00 PM) and absolute lymphocyte count and T helper cells. These data suggest that the hypercortisolemia seen in some patients with major depressive disorder is sufficient to alter leukocyte distribution in the peripheral circulation, particularly that of the T helper cell subset. The association between cortisol and lymphopenia appears to be more pronounced in an elderly population than in younger depressed patients.