Study design. Participants were followed for at least 4 years after cerebrospinal fluid (CSF) collection. Clinical assessment was performed every 6 months, Magnetic resonance imaging (MRI) scans were obtained at least annually. *Second-line treatments were administered to patients who experienced at least two relapses during 1 year of therapy with immunomodulatory agents. EDSS, Expanded Disability Status Scale; MSFC, Multiple Sclerosis Functional Composite; OCT, optical coherence tomography.