IL6 and Parkinson disease: Indeed, from postmortem analysis, it was found that PD patients presented increased levels of tumor necrosis factor (TNF-α) [20], interleukin-1β (IL-1β) [21], IL-2 [22], IL-4, IL-6 [21], basic fibroblast growth factor (bFGF) [22], and transforming growth factor beta 1 (TGF-β1) [21,23] in the brain.