CCL2 and major depressive disorder: In this study, we aimed to explore the role of IL-2, IL-4, IL-12, TNF-α,and TGF-β1, which represent the cytokines of the Th1, Th2, and Th3 types, andMCP-1 in major depression, and to investigate the effects of sertraline therapy.Our results suggest that the proinflammatory cytokines (IL-2, IL-12, and TNF-α) and MCP-1 were significantlyhigher, whereas anti-inflammatory cytokines IL-4 and TGF-β1 were significantlylower in patients with major depression than those of healthy controls.