Depression is associated with an altered balance in the Th1/Th2 ratio, that is, higher pro-inflammatory Th1 cytokines (IL-1, IL-12, INF-γ), higher pro-inflammatory monocytic cytokines (IL-6, TNF-α) [69–71], and lower anti-inflammatory Th2 cytokines (IL-4, IL-10) [72]. Here, TNF is linked to major depressive disorder.