Activated microglia have been detected in vivo by PET in basal ganglia and cortical regions of patients suffering with PD (Gerhard et al., 2006), and correspond to immunohistochemistry postmortem analyses that showed significant increase of TNF-α, and IL-6 in the putamen of PD patients (Sawada et al., 2006). This evidence concerns the gene IL6 and Parkinson disease.