CD63 and Parkinson disease: The CD63 Alexa fluor 488 antibody-labeled sEV concentration was observed to be higher in PD compared to HC (p = 0.0006), as shown in Fig. 2E. The ROC analysis reported the AUC value relative to the antibody-tagged sEV (AUC = 0.9191) with a sensitivity of 94.12% and specificity of 75% (Fig. 2F).