IFNG and neurodegenerative disease: In addition to microglia and astrocyte hyperplasia in the brain of PD patients, peripheral inflammation, and PD risk-related genes can also promote chronic inflammatory responses that lead to the progression of this neurodegenerative disease (Pajares et al., 2020), and cytokine such as IL1β, IL2, IL6, IFN-γ, and TNF-α can be detected in peripheral blood (Reale et al., 2009).