Research groups  Participants  Analyte  Method  Main findings 

Herbert et al73  PD n=43, MSA n=23, controls n=30  DJ1  ELISA 

Constantinescu et al78  PD n=6, MSA n=13, PSP n=18, CBD n=6, HC n=18  Urate  Enzymatic method on a modular system  No difference 
Wennstrom et al47  PD n=38, PDD n=22, DLB n=33, AD n=46, HC n=52  Neurosin  ELISA 

Goldstein et al82  PD n=34, MSA n=54, PAF n=20, HC n=38  Dihydroxyphenylatic acid (DOPAC)  Batch alumina extraction followed by liquid chromatography with electrochemical detection 

Salvesen et al72  PD n=30, DLB n=17, MSA n=14, PSP n=19  DJ1  ELISA  No difference among groups 
Maetzler et al77  PD n=55, PDD n=20, DLB n=20, controls n=76  Uric acid  ADVIA analyser+photometric methods  Increase in PD vs DLB 
Shi et al22  Discovery cohort: PD n=126, MSA n=32 AD n=50, controls n=137 Validation cohort: PD n=83  DJ1 Fractalkine  Beadbased multianalyte assay (Luminex) 

LeWitt et al81  PD n=217 (samples collected ×2 occasions) HC n=26  Homovallinic acid/xanthine ratio  Gas chromatographymass spectrometry 

Wang et al79  PD n=86, MSA n=20, AD n=38 HC n=91  Complement C3/factor H (FH)  Beadbased multianalyte assay (Luminex) 

Maetzler et al80  PD n=38, PDD n=20, DLB n=21 m, controls n=23  Neprilysin  Fluorometric assay  Decrease in DLB+PDD vs PD+ controls 
Hong et al52  PD n=117, AD n=50, HC n=132  DJ1  Beadbased multianalyte assay (Luminex) 

AD, Alzheimer's disease; CBD, corticobasal degeneration; CSF, cerebrospinal fluid; DLB, dementia with Lewy bodies; HC, healthy controls; MSA, multiple system atrophy; PAF, pure autonomic failure; PD, Parkinson's disease; PDD, Parkinson's disease dementia; PSP, progressive supranuclear palsy.