TNF and Parkinson disease: In this study, in PD patients, we assessed probable RBD (PRBD) by RBD Screening Questionnaire (RBDSQ), detected the levels of iron and related proteins, including transferrin, ferritin and lactoferrin, and inflammatory factors, including nitric oxide (NO), hydrogen peroxide (H2O2), interleukin (IL)-1β, prostaglandin (PG) E2 and tumor necrosis factor (TNF) -α in CSF and serum, and analyzed the correlations among RBDSQ score and the levels of above factors, so as to figure out the potential underlying mechanisms of PD with RBD relating iron metabolism and inflammation.