TNF and major depressive disorder: Commonly, general chronic inflammation is measured by either an array of pro- and anti-inflammatory cytokines such as interleukin-6 (IL-6) or tumor necrosis factor α (TNF-α) of is measured indirectly by acute phases reactants such as C-reactive protein (CRP), which become elevated in response to pro-inflammatory cytokines, mostly IL-6.2 There is less robust literature representing the association between depression and T cell (lymphocyte) dysfunction [17].