Different immune patterns in melancholic and non-melancholic major depression.

The search for immune patterns in major depression has thus far resulted in ambiguous findings, probably because patient samples are psychiatrically heterogeneous. We therefore focused on a detailed classification of subtypes of major depression, comparing patients with melancholic and non-melancholic major depression. Inpatients suffering from acute major depression were diagnosed and subclassified according to DSM IV criteria. Cell counts were determined by FACS analysis and morphology. Cytokine production (IL-2, IFN-gamma, IL-10) upon mitogen stimulation was measured by ELISA in a whole blood assay. Non-melancholic patients showed increased counts of leukocytes, lymphocytes and NK-cells in the acute stage of disease and after two and four weeks of treatment. Their lymphokine production was unchanged compared to that of healthy controls. Melancholic patients on the other hand demonstrated normal cell counts but a decreased production of IL-2, IFN-gamma and IL-10 during the acute stage of disease followed by a normalization with clinical improvement. Melancholic and non-melancholic patients showed different immune patterns. Classifying melancholic and non-melancholic patients is helpful towards the identification of immune characteristics typical for these diseases.