Fig. 4

Inflammation correlates with UPDRS and predicts disease phenotype with sensitivity and specificity across the day. When measured at baseline (time 0 = 5:30 AM), CSF IFNγ positively correlates with the UPDRS (a; p = 0.004), as well as the Activities of Daily Living Score component of the UPDRS (b; p = 0.003) and the Complication of Therapy Score (c; p = 0.005). Serum IL-8 positively correlated with the Activities of Daily Living Score (d; p = 0.04). There were no other significant correlations between inflammation and disease severity or number of years with disease. Serum TNF alone (e) and serum TNF with CSF α-synuclein (f) demonstrated ascending accuracy and precision in discriminating between HC and PD subjects when analyzed with linear discriminant analyses (LDA; see Additional file 9: Figure S2 for all LDA factors considered)