Using a newly developed protocol, we enriched ODEVs from the serum of subjects with clinically isolated syndrome (CIS), i.e., a single episode of CNS dysfunction suggestive of MS, RRMS, PPMS, and healthy controls (HC) to verify whether ODEVs MBP and MOG concentrations could be used as a diagnostic and prognostic biomarker for MS. Here, MBP is linked to in situ carcinoma.