LYMPHOCYTE SUBSETS ASSOCIATED WITH MAJOR DEPRESSION AND DYSTHYMIA - MODIFICATION BY ANTIDEPRESSANT TREATMENT

Major depression and dysthymia (chronic, low grade depression) were as sociated with an increase in the number of CD16/56 (natural killer; NK ) cells in blood, whereas other lymphocyte subsets (CD3, CD4, CD8, CD1 9, and the CD4/CD8 ratio) did not differ from control subjects. After treatment with a specific serotonin reuptake inhibitor, the symptoms o f depression were alleviated in both the major depressive and dysthymi c patients. Likewise, NK cell numbers declined to control values in th ese treated groups. Among the major depressive patients, the NK cell n umber reached control values within 4 weeks, whereas 6 months of treat ment was required for such an effect to be achieved in the dysthymic p atients. Although plasma levels of epinephrine, norepinephrine, cortis ol, and ACTH were not different between groups, among the major depres sive patients ACTH was inversely correlated with total lymphocytes, CD 3, and CD19, and epinephrine was directly related to the CD4 and CD4/C D8 ratio. Among dysthymics, ACTH was unrelated to ally of the lymphocy te subsets, but norepinephrine was directly related to total lymphocyt es, CD3, CD4, and NK cells. The data are interpreted in terms of stres s perception among major depressive and dysthymic patients and the pot ential impact of stressor experiences on immune processes.