IL6 and Parkinson disease: We next analyzed CSF cytokine levels in PD patients, and the results showed that PD patients had significantly higher CSF TGF-β1 (Hedges'g, 0.472; 95% CI, 0.147-0.798; P = 0.004), IL-6 (Hedges'g, 0.468; 95% CI, 0.049-0.887; P = 0.026) and IL-1β (Hedges'g, 0.370; 95% CI, 0.033-0.707; P = 0.031) levels than controls (Figure 3, Table 1), whereas CSF TNF-α (Hedges'g, 0.826; 95 % CI,−0.027-1.678; P = 0.058) levels had no significant ES estimate (Table 1).