Neurofilaments and 10-year follow-up in multiple sclerosis.

Background: The role of biomarkers to predict clinical outcome in multiple sclerosis (MS) is still debated.

Objective: To test whether cerebrospinal fluid (CSF) light-chain neurofilament (NfL) levels in newly diagnosed patients with MS could predict clinical outcome over a 10-year period.

Methods: Patients with newly diagnosed MS underwent standardized clinical assessments at baseline and 5 and 10 years of follow-up. Expanded Disability Status Scale (EDSS) progression between assessments was defined as an increase in one point or more if <6 and 0.5 or more if ≥6. CSF obtained at baseline was analyzed for levels of NfL using enzyme-linked immunosorbent assay technology.

Results: A total of 44 patients were included. In all, 35 patients (80%) had relapsing-remitting multiple sclerosis (RRMS). Patients who progressed in EDSS showed a trend for higher median baseline CSF-NfL levels than patients who did not progress after 5 years (947 ng/L vs 246 ng/L, p = 0.05), and although not statistically significant, after 10 years (708 ng/L vs 265 ng/L, p = 0.28). Patients who converted from RRMS to secondary-progressive multiple sclerosis (SPMS) at 5 years had a statistical significant higher median CSF level of NfL (2122 ng/L vs 246 ng/L, p = 0.01).

Conclusion: CSF levels of NfL at the time of diagnosis seems to be an early predictive biomarker of long-term clinical outcome and conversion from RRMS to SPMS.