Serum chemokine levels in major depressive disorder.
To examine the role of chemokines of two major chemokine families, CC and CXC, in major depressive disorder (MDD) in a population-based sample. The serum levels of CC chemokines MCP-1 and MIP-1beta, and CXC chemokine IL-8 were measured from 122 participants (MDD group, n=61; controls, n=61). Depression severity was assessed with the 29-item Hamilton Depression Rating Scale. The MDD group had lower levels of MCP-1, MIP-1beta and IL-8 than the healthy controls. The likelihood of major depressive disorder for participants with chemokine levels below the median (MCP-1: < 26.26 pg/mL; MIP-1beta: < 42.57 pg/mL; IL-8: < 2.86 pg/mL) was 3.6 (p=0.002) for MIP-1beta and 2.4 (p=0.037) for IL-8 in regression models adjusted for age, gender, body mass index, smoking, and alcohol consumption. MCP-1 did not associate with the presence of MDD after adjustments for potential confounders. Further adjustments for somatic illnesses or medications did not affect these findings. Our findings suggest that depression-related alterations of inflammatory markers may be more complex than previously assumed, and that at least some of the chemokines may be down-regulated.