Background: Serum neurofilament light chain (sNfL) is a marker of neuroaxonal injury. There is a lack of studies investigating the dynamics of relationships between sNfL levels and radiological disease activity over long-term follow-up in multiple sclerosis (MS).
Objectives: To investigate the relationship among repeated measures of sNfL, lesion burden accumulation, brain volume loss and clinical measures.
Methods: We investigated 172 patients in the early stages of MS (McDonald 2017 criteria). Clinical exams were performed every 3 months and brain magnetic resonance imaging (MRI) scans were collected annually over 48 months. sNfL levels were measured in serum by Simoa assay at the time of treatment initiation and then annually over 36 months.
Results: In repeated-measures analysis, considering all time points, we found a strong relationship between percentage changes of sNfL and lesion burden accumulation assessed by T1 lesion volume (p < 0.001) and T2 lesion number (p < 0.001). There was no relationship between percentage changes of sNfL and brain volume loss over 36 months (p > 0.1). Early sNfL levels were associated with delayed brain volume loss after 48 months (p < 0.001). Patients with No Evidence of Disease Activity (NEDA-3) status showed lower sNfL levels compared with active MS patients.
Conclusions: sNfL is associated with ongoing neuroinflammation and predictive of future neurodegeneration in early MS.
Keywords: Neurofilament light chain; atrophy; inflammation; lesion; multiple sclerosis; neurodegeneration.