Fig. 4

Reduced levels of high affinity anti-α-synuclein NAbs in plasma from MSA and PD patients. Binding of anti-α-synuclein NAbs in plasma to immobilized α-synuclein monomer (5 μg/mL) in competitive ELISA assay in the presence of a, b 50 nM or c, d 2 nM free α-synuclein. Non-specific binding is defined as the binding to the plate in the presence of 1000 nM free α-synuclein monomer. Maximal binding is defined as the binding observed in the absence of added free α-synuclein monomer. Horizontal bars represent the mean values +/− SEM. Plasma samples from Parkinson’s Disease (PD), Multiple System Atrophy (MSA) patients and normal controls (NC) were tested at two dilutions, i.e. a, c 1:100 and b, d 1:200. Significance was tested using Man–Whitney’s U test (P < 0.05)