Cells from 6 PD patients on antiparkinson drugs, 4 PD patients who never received dopaminergic substitution treatment and 4 HS were tested, and no difference was observed in IL-17 production either in resting conditions or after PHA, while other cytokines such as IFN-γ and TNF-α were hugely increased in cells from patients (30). This evidence concerns the gene TNF and Parkinson disease.