Immune cells and the hypothalamic-pituitary axis in major depression

To explore changes in immune cell status with changes in the hypothalamic-pituitary (HP) axis in 20 patients with major depression as compared with 20 age-, sex-, and race-matched control subjects, we examined peripheral blood mononuclear cells (PBMC) for total T-cells (T3), total B-cells (B1), two T-cell subsets (T4 and T8), and natural killer cells (NKH1), and we measured the plasma level of cortisol, adrenocorticotropic hormone (ACTH), growth hormone (GH), and prolactin (PRL). The ratio of T4/T8 was increased in the patients. Within the group of control subjects only, increasing age correlated significantly with decreasing plasma PRL. Within the group of patients only, GH positively correlated significantly with T8 and NKH1, as did PRL with NKH1. No between-groups difference was found for T3, B1, T4, T8, NKH1, cortisol, ACTH, GH, or PRL.