An elevated expression of TNF-α, IL-6, and other proteins related to innate immunity, such as interleukin 1β (IL-1β) and toll-like receptors 3 (TLR3) and 4 (TLR4), has been observed also in the brain of patients with MDD (Pandey et al., 2014, 2018). The gene discussed is TLR3; the disease is major depressive disorder.