CCL2 and major depressive disorder: MCP-1 was 25% higher (MD: 1.25; 95% CI 1.06–1.47; p = 0.009) and MIP-1β was 16% higher (MD: 1.16; 95% CI 1.02–1.33; p = 0.025) among patients with depression as compared to healthy controls, but neither survived correction for multiple testing.