Decreased plasma α-synuclein in idiopathic Parkinson’s disease patients after adjusting hemolysis factor

Lewy bodies are pathological hallmarks for the diagnosis of Parkinson’s disease, where the core components are composed of aggregated forms of α-synuclein (α-syn). Although α-syn has been investigated as a potential biomarker for PD, its usage has been limited and still remains controversial. An accurate enzyme-linked immunosorbent assay (ELISA) was developed for the detection of α-syn in plasma. The hemolysis score was calculated to eliminate the additive α-syn levels from RBCs. Human plasma samples were collected in heparinized blood tubes from idiopathic Parkinson disease (IPD) and healthy control (HC). Hemolysis score had a strong correlation with the level of plasma α-syn. From the limited set of samples in this preliminary study, decreased α-syn concentrations were observed in patients with IPD in comparison to HC after adjusting for hemolysis factor. Similar results with a commercial ELISA kit were found for measuring α-syn from the same set of samples with lower correlation and the reduced accuracy of diagnosis than the current study. The adjustments for the hemolysis factor would be indispensable, supporting plasma α-syn as a potential surrogate biomarker for distinguishing IPD from HC.