S100B and Parkinson disease: Since increased CSF NSE and S100B levels showed a relatively high discriminatory value for differentiating between PD and control subjects, so their levels may be helpful in differential diagnosis, especially when used with other CSF biomarkers for PD (Parnetti et al., 2013; Oosterveld et al., 2019), as, when used alone, they reflect only one pathological process present in PD.