In Parkinson's disease (PD) mice, CD200 remarkably suppressed proinflammatory factors, such as IFN‐γ, TNF‐α, and IL‐1β release, and inhibited microglial activation and the release of inflammatory factors to protect dopaminergic (DA) neurons against damage and alleviate PD signs (Lyons et al., 2017; Ren et al., 2016). Here, CD200 is linked to Parkinson disease.