Fig. 4

Evaluation of the prognostic potential of the candidates identified and preliminary validation. a Distribution of the patients’ discriminant scores according to the disease duration. Patients were grouped into 3 classes (until 5 years, 5 to 9 years, and more than 9 years of disease duration). The number of patients in each group is indicated at the top of the graphic, as well as, the number of misclassified cases (red markers). b Scatter-plot of the discriminant scores considering the disease duration, with the respective trend line (dot-line), equation, and coefficient of determination (R²). The red dots correspond to misclassified cases. Discriminant scores (patients classification) present a low but significant correlation with the disease duration (Spearman’s Rank correlation coefficient (r) of 0.388 and a p-value of 0.031). (c-d) ELISA results using an independent cohort of samples. c Distribution of the absolute absorbances of GFP, Clusterin, and VPS35 proteins measured in each sample. The graphic indicates the median value ± interquartile range of 12 and 21 samples from Ctrl and PD groups, respectively. The line represents the median tendency between groups. *, p < 0.05, indicates significant differences for the control condition using the Mann–Whitney U test. d Distribution of the Clusterin and VPS35 normalized absorbances (protein absorbance normalized to the IS absorbance). The graphic indicates the median value ± interquartile range of 12 and 21 samples from Ctrl and PD groups, respectively. The line represents the median tendency between groups. *, p < 0.05, indicates significant differences for the control condition using the Mann–Whitney U test. e Principal component analysis using the normalized absorbance values of Clusterin and VPS35. The contribution of each principal component for explaining the total variance is indicated on top of the graphic. PCA processing was performed using the Pareto scaling