IFNG and Parkinson disease: Whereas elevation of innate pro-inflammatory cytokines (IL-1b, IL-6, TNFa, TGFa, TGFb1, EGF) was reported in the brain or cerebrospinal fluid (CSF) of PD patients [49, 50], only an increase of two T cell-associated cytokines IL-4 in PD brain tissues [50] and IFNg in the CSF of cognitively impaired PD [51] was demonstrated.