An examination of interferon γ, Interleukin 10, Interleukin 18, Interleukin 1β, Interleukin 4, Interleukin 6, transforming growth factor β1, and TNF-α showed increased levels of microglial-derived interleukins in PSP and MSA when compared to PD [14]. Here, IL18 is linked to Parkinson disease.