A recent meta-analysis of a large number of antidepressant treatment studies examining links between inflammation and treatment response, found that lower baseline levels of IL-8, but not other biomarkers (i.e., IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, TNF-α, IFN-γ, GM-CSF, MIP-1α, Eotaxin-1, and CRP) were associated with depression treatment response39, although sex differences were not systematically evaluated. Here, CXCL8 is linked to depressive disorder.