Relatively consistent findings showed an increase in several cytokines, including interleukin-6 (IL-6), interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP) in patients with depressive disorder versus healthy controls (HCs) [10,11,12,13,14,15]. This evidence concerns the gene IL6 and depressive disorder.