Naturally Occurring Alpha-Synuclein Autoantibodies in Parkinson’s Disease: Sources of (Error) Variance in Biomarker Assays

摘要: Alpha-synuclein ($α$-Syn) plays a pivotal role in the pathophysiology of Parkinson's disease (PD), which can partly be modulated by innate and adaptive immune functions, vice versa. Here, naturally occurring $α$-Syn autoantibodies ($α$-Syn-nAbs) may effective against pathoetiology serve as PD biomarker. However, serum cerebrospinal fluid $α$-Syn-nAbs levels still lack consistent evidence required for reliable Serum 66 patients 69 healthy controls were assessed using validated ELISA assay. Moreover, potential sources error variance including unspecific background signals, free hemoglobin concentrations, plate coating procedures, differences standards, investigated. did not differ (p = .49) nor (p = .29) levels. Interestingly, concentrations negatively correlated with (Spearman $ρ$ = -.41, p<.001), but ($ρ$ = .16, p = .21). procedures impacted inter-assay variability (same day coating: 8-16%; on different days: 16-58%). standards from purification batches differed regarding optical density measured ELISAs suggesting affinity. While represent biomarker, several methodological issues have to considered increase reproducibility findings. Further studies standardized protocols minimizing necessary establish