Changes in immunoglobulin, complement and acute phase protein levels in the depressed patients and normal controls.

Recently, several authors have reported that immunoglobulin IgM, complement C3c, complement C4, and positive acute phase proteins (e.g., haptoglobin, alpha 1-acid glycoprotein and alpha 1-antitrypsin) were significantly increased, while negative acute phase proteins (e.g., albumin and transferrin), were decreased in depressed patients. In the present study, the levels of the immunoglobulin IgM, complement C3c, C4, alpha 1-antitrypsin and haptoglobin were found to be significantly increased in 20 unipolar depressed patients compared to healthy controls. The concentrations of total protein and albumin were significantly reduced in these patients. The concentrations of alpha 1-protein, (which is related to alpha 1-antitrypsin), and alpha 2-protein (which related to haptoglobin), were also significantly elevated in unipolar depressed patients. The results suggest that unipolar depression is associated with an acute phase response, which is possibly caused by changes in cytokines and corticosteroid secretion in depressed patients.