The role of glial cells in neuroinflammation and PD is supported by a recent meta-analysis reporting increased cerebral spinal fluid (CSF) concentrations of TNF-α, IL-6, IL-1β, nitric oxide (NO), chemokine ligand 2 (CCL2), and c-reactive protein (CRP) in individuals with this disease [199]. Here, TNF is linked to Parkinson disease.