A repeated measures two-way analysis of variance (ANOVA) by time and disease state for each analyte (Fig. 2 and Additional file 3) revealed that certain serum and CSF analytes changed over time but not in a disease-specific manner (CSF TNF; Fig. 2a and serum IL-6; Fig. 2b, left side of Fig. 2 diagram), while others were different between PD and HCs but not stable across time (CSF IL-8; Fig. 2c, CSF α-synuclein; Fig. 2d, CSF Aβ40; Fig. 2e, and CSF Aβ42; Fig. 2f, middle in Fig. 2 diagram). The gene discussed is CXCL8; the disease is Parkinson disease.