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

Examined the concentrations of immunoglobulin IgM, complement C3c, complement C4, positive acute phase proteins (e.g., haptoglobin, ?-sub-1-acid glycoprotein, ?-sub-1-antitrypsin), and negative acute phase proteins (e.g., albumin, transferrin) in 20 unipolar depressed patients and 8 healthy controls. The levels of the immunoglobulin IgM, complement C3c, C4, ?-sub-1-antitrypsin and haptoglobin significantly increased in the depressed Ss compared to the controls. The concentrations of total protein and albumin were significantly reduced in these patients. The concentrations of ?-sub-1-protein (which is related to ?-sub-1-antitrypsin) and ?-sub-2-protein (which is related to haptoglobin) were also significantly elevated in depressed Ss. 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.