Serum Cytokine Levels in Major Depressive Disorder and Its Role in Antidepressant Response

Cytokines have been reported to have key roles in major depressive disorder (MDD). However, much less is known about cytokines in MDD and antidepressant treatment due to the diversity of cytokines and the heterogeneity of depression. We investigated the levels of cytokines in patients with MDD compared with healthy subjects and their associations with antidepressant response. We investigated the changes of several cytokines (eotaxin, sCD40L, IL-8, MCP-1alpha, TNF-alpha, INF-gamma and MIP-1alpha) by Luminex assay in 66 patients with MDD and 22 healthy controls. The antidepressant response was assessed by 17-item Hamilton Rating Scale for Depression. We found the levels of sCD40L (p=0.001), IL-8 (p=0.004) and MCP-1 (p=0.03) of healthy controls were significantly higher than those of depressive patients. However, the level of eotaxin and TNF-alpha were not associated with MDD. In addition, we found the level of MCP-1 was significantly changed after antidepressant treatment (p=0.01). These findings suggest the roles of cytokines in MDD are complex, and could vary according to the individual characteristics of each patient. Further studies regarding the relationship between cytokines and MDD will be required.