However, IL-6 level was higher in the normal control group of one study than the PD-nNPSs group in our study, which might be related to the different demographic variables, particularly, the age, or the kit used for the measurement of NO, etc. In the future, we will try our best to collect CSF samples and add neuroimaging information to further demonstrate the conclusion of this investigation. This evidence concerns the gene IL6 and Parkinson disease.