Increased IL-6 levels can be observed in serum of PD patients (Sliter et al., 2018), 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine- (MPTP-) mediated PD mice (Rojo et al., 2010), 1-methyl-4-phenyl-1,2, 3, 6-tetrahyd-ropyridiniumion- (MPP+-) induced SHSY5Y cells (Yao et al., 2019), and BV2 cells (Chen et al., 2015). Here, IL6 is linked to Parkinson disease.