Circulating lymphocyte subsets in major depression and dysthymia with typical or atypical features.

OBJECTIVE: Inconsistent results have been reported concerning circulating lymphocyte subsets in depression. To establish whether the immune alterations in depression could be related to neurovegetative symptoms, lymphocyte subsets were assessed in major depressive and dysthymic patients who exhibited either typical or atypical features (ie, the latter characterized by mood reactivity and reversed neurovegetative features). METHOD: Blood was collected from major depressive, atypical depressive, typical dysthymic, or atypical dysthymic patients and from nondepressed control subjects. Circulating lymphocyte subsets (CD3, CD4, CD8, CD19, CD16/CD56) were determined by flow cytometry. In a subset of patients, lymphocyte subsets were also determined after a 12-week course of antidepressant medication. RESULTS: Although T and B cell populations did not differ between the depressive subtypes and control subjects, circulating natural killer (NK) cells were elevated in depressive illness, and varied as a function of depressive subtype and sex. Among male patients, NK cells were elevated to a greater extent in typical than in atypical depression, and more so in major depressive than in dysthymic patients. Among female patients, circulating NK cells were lower than in male patients, and only among the typical major depressive patients did NK cells exceed those of controls. Normalization of NK cells occurred with successful pharmacotherapy. CONCLUSIONS: Depression may be associated with elevated levels of circulating NK cells. Although the neurovegetative features associated with depression, particularly altered eating, may have contributed to the elevated NK cells, depressive affect itself also contributed in this respect. However, the relative contributions of these factors varied between male and female patients.

Increased serum interleukin-1-receptor-antagonist concentrations in major depression.

Recently, it has been shown that major depression may be accompanied by an increased production of interleukin-1 beta (IL-1 beta), an acute phase (AP) response and simultaneous signs of activation and suppression of cell-mediated immunity. The interleukin-1-receptor antagonist (IL-1-rA) is released in vivo during an AP response and serum levels are increased in many immune disorders. The release of IL-1-rA may limit the pro-inflammatory effects of IL-1. This study has been carried out to examine serum IL-1-Ra in 68 depressed subjects (21 minor, 25 simple major and 22 melancholic subjects) vs. 22 normal controls. Depressed subjects showed significantly higher serum IL-1-rA concentrations than healthy controls. 29% of all depressed subjects had serum IL-1-rA levels higher than the mean value +2 standard deviations of normal controls; 44% depressed subjects had IL-1-rA values greater than 0.215 ng/ml with a specificity of 90%. In depressed subjects, there was a significant and positive relationship between serum IL-1-rA and severity of illness. In depression, there were no significant relationships between serum IL-1-rA concentrations and indicants of hypothalamic-pituitary-adrenal (HPA)-axis activity, such as 24-h urinary cortisol and postdexamethasone cortisol values. Women had significantly higher serum IL-1-rA levels than men. The findings support the thesis that depression is accompanied by an immune-inflammatory response.