Post-hoc comparisons determined that these differences were driven by higher IL-2 levels in PDD with respect to both PD-MCI [t(507) = − 4.4; p < 0.05] and PD-NC [t(507) = − 28; p < 0.005], and by higher IL-6 values in PDD with respect to PD-NC [t(507) = − 6.6; p < 0.05]. The gene discussed is IL6; the disease is Parkinson disease.