Previous studies investigating relationships between CSF and serum/plasma cytokines in PD have reported elevated TNF‐α in CSF compared to serum and correlations between CSF and serum levels of IL‐6, IL‐1β, and IL‐10 in PD and controls.11 The different findings compared with our study may reflect variations in cohort demographics, disease stage, and methodology. This evidence concerns the gene IL6 and Parkinson disease.