The involvement of inflammation in the course of PD is underlined by a variety of studies reporting that the levels of several proinflammatory cytokines (e.g., TNF, IL-1β, IL-6) are increased in the brain and in the CSF of PD patients (Mogi et al., 1996; Brodacki et al., 2008; Karpenko et al., 2018; Lin et al., 2019; Tan et al., 2020). Here, IL6 is linked to Parkinson disease.