To investigate the plasma levels of IL-18, MIP-1α, MCP-1, SDF-1 and RANTES in major depression before and after treatment.

Twenty healthy volunteers and 40 patients with major depressive disorder (MDD) were involved in the current study. Depressed subjects had moderate or major depression according to the DSM-IV criteria. The HAMD scale was used to measure the efficacy after the 8-week treatment with fluoxetine hydrochloride. All subjects gave their written informed consents and were recruited from outpatients and inpatients of Sir Run Run Shaw Hospital between October 2004 and November 2005.The plasma levels of IL-18, MIP-1α, MCP-1, SDF-1 and RANTES in major depression were measured by ELISA before and after fluoxetine treatment.

HAMD score were significantly decreased after the treatment (P<0.001), there were seven cases score of after treatment <7,. At the time of admission, the plasma levels of IL-18, MCP-1, MIP-1α, SDF-1 and RANTES were significantly higher in the MDD than those in the healthy controls (P<0.001). In MDD, the cytokine values were significantly decreased after the treatment, including IL-18 (P=0.005), MCP-1 (P=0.001), MIP-1α (P<0.001, SDF-1 (P=0.004) and RANTES (P<0.001), but still significantly higher than those in the healthy controls (P<0.001).

These findings suggest that major depression is accompanied by the immune activation, and the antidepressant treatments have anti-inflammatory effects. The remaining depression symptom after treatment may be related to the higher level of cytokines.