CD81 and Alzheimer disease: Validation of PsEVs was done using immunoblot for sEVs-specific markers (CD63, CD81, and TSG101), which showed a significant increase in expressions in MCI and AD than in AMC (CD63, p = 0.0489, 0.0478 (Additional File 1: Fig. S1); CD81, p = 0.0172, 0.0133 (Additional File 1: Fig. S2); TSG101 p = 0.0240, 0.0329 (Additional File 1: Fig. S3)) for AD and MCI respectively (Fig. 2A–D).