High neurofilament levels are associated with clinically definite multiple sclerosis in children and adults with clinically isolated syndrome

Background: A promising biomarker for axonal damage early in the disease course of multiple sclerosis (MS) is neurofilament light chain (NfL). It is unknown whether NfL has the same predictive value for MS diagnosis in children as in adults. Objective: To explore the predictive value of NfL levels in cerebrospinal fluid (CSF) for MS diagnosis in paediatric and adult clinically isolated syndrome (CIS) patients. Methods: A total of 88 adult and 65 paediatric patients with a first attack of demyelination were included and followed (mean follow up-time in adults: 62.8 months (standard deviation (SD) +/- 38.7 months) and 43.8 months (SD +/- 27.1 months) in children). Thirty control patients were also included. Lumbar puncture was done within 6 months after onset of symptoms. NfL was determined in CSF using enzyme-linked immunosorbent assay (ELISA). COX regression analyses were used to calculate hazard ratios (HR) for clinically definite multiple sclerosis (CDMS) diagnosis. Results: After adjustments for age, oligoclonal bands (OCB), and asymptomatic T2 lesions on baseline magnetic resonance imaging (MRI), increased NfL levels in both paediatric and adult CIS patients were associated with a shorter time to CDMS diagnosis (children HR = 3.7; p = 0.007, adults HR = 2.1; p = 0.032). For CIS patients with a future CDMS diagnosis, children showed higher NfL levels than adults (geometric mean 4888 vs 2156 pg/mL; p = 0.007). Conclusion: CSF NfL levels are associated with CDMS diagnosis in children and adults with CIS. This makes NfL a promising predictive marker for disease course with potential value in clinical practice.