In contrast, the levels of IL-1β, IL-2, IL-4, IL-8, soluble IL-6 receptor (sIL-6R), IL-5, Chemokine (C-C motif) ligand 3 (CCL-3), IL-17, and transforming growth factor beta (TGF-β 1) were not considered significant in relation to MDD. Here, CCL3 is linked to major depressive disorder.