A inflammatory state typified by alteration in both humoral (pro/anti-inflammatory cytokines) and cellular factors (immune cells; CD4+ T cells, and macrophages) from the innate and adaptive immune system has been suggested to be associated with depression-anxiety like behaviors in humans and animal models (Dantzer et al., 2008; Dowlati et al., 2010; Kwon et al., 2011). Here, CD4 is linked to major depressive disorder.