Monocytic parameters in patients with dysthymia versus major depression.

Background: The studies on monocytic function during depression are controversial. A better knowledge of affective disorders may improve the differential diagnosis of depression subtypes. Our goals are to examine if there are differences in monocytic function in patients with major depression and dysthymia.

Method: Twenty-two depressed patients (12 dysthymia and 10 major depression) and 15 healthy controls participated in the study. We analyzed monocyte count, monocyte subsets (CD14+, CD16+, and HLA class-II+), respiratory burst activity, phagocytic index and the interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNFalpha) production.

Results: Depressed patients showed elevated IL-1beta (P<0.05) and IL-6 (P<0.01), elevated monocytic respiratory burst activity (P<0.01); and reduced surface molecule expression HLA class-II and phagocytosis (P<0.01) compared with controls. We found no differences in any monocytic parameters between dysthymia and major depression.

Limitations: The small sample size and the short wash-out reduce the reliability of the results.

Conclusions: Major depression and dysthymia show similar signs of both monocytic activation and suppression. These alterations may be due to the depressive syndrome and not to the characteristics of depression subtypes studied.