CXCL8 and major depressive disorder: Elevated levels of interleukin-6 (IL-6) and interleukin-8 (IL-8) in MDD patients, as well as abnormal functional connectivity between the prefrontal cortex (PFC), anterior cingulate cortex (ACC), visual cortex, postcentral gyrus, and striatum, suggest that inflammation may contribute to the neuropathological mechanisms of MDD by altering the functional connectivity of key brain regions such as the PFC (11).