TNF and Parkinson disease: Higher expression of genes encoding proinflammatory cytokines such as tumor necrosis factor (TNF), interferon gamma (IFNγ), interleukin (IL)-6, IL-1β, C-X-C motif ligand (CXCL) 8, and others in colonic biopsies [9, 10], and higher levels of IL-1α, IL-1β, CXCL8, and C-reactive protein (CRP) in stool have been found in PD patients compared to controls [11].