IL6 and Parkinson disease: Accumulation of proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) was reported in the brain, cerebrospinal fluid and serum of patients with PD, and animal models as well (Hunot and Hirsch, 2003).