IL6 and Parkinson disease: In this study, the levels of iron and the proteins related to iron metabolism, including ferritin, H-ferritin and L-ferritin, transferrin, and lactoferrin, and inflammatory mediators, including interleukin (IL)-6, IL-1β, prostaglandin (PG) E2, nitric oxide (NO), and hydrogen peroxide (H2O2), were detected in both the CSF and serum in the PD-TD, PD-PIGD, and the healthy control groups.