TNF and major depressive disorder: Further, recent meta-analysis characterized the MDD-linked inflammatory profile: IL-6, TNF-α, IL-10, IL-13, IL-18, and IL-12 levels were increased in MDD patients compared with those of controls; in contrast, peripheral levels of IL-1ß, IL-2, IL-4, IL-8, IL-5, IL-17, and transforming growth factor ß1 (TGF-ß1) did not differ significantly between depressive patients and controls [14].