Similarly, more recent meta-analyses have also concluded that, in addition to TNF-α and IL-6, peripheral levels of IL-18, IL-10, the IL-1 receptor antagonist, the soluble IL-2 receptor, C-C chemokine ligand 2, IL-13, IL-12, and the soluble TNF receptor 2 [56], as well as IL-6 and TNF-alpha levels in CSF and brain parenchyma [57] are elevated in patients with MDD compared to healthy controls. This evidence concerns the gene TNF and major depressive disorder.