Variations in consecutive serum neurofilament light levels in healthy controls and multiple sclerosis patients

• Published in: Multiple sclerosis and related disorders Vol. 47; p. 102666
• Main Authors: Bridel, C., Verberk, I.M.W., Heijst, J.J.A., Killestein, J., Teunissen, C.E.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2021
• Subjects: Biomarkers; Humans; Intermediate Filaments; Multiple Sclerosis; Multiple Sclerosis, Relapsing-Remitting - diagnostic imaging; Neurofilament Proteins
• ISSN: 2211-0348; 2211-0356
• DOI: 10.1016/j.msard.2020.102666

Background Neurofilament light is a neuronal protein detectable in serum (sNfL), with high potential as disease activity biomarker in multiple sclerosis (MS). To date, little is known about sNfL fluctuations between 2 consecutive measurements in healthy controls (HC) and MS patients. Yet this information is critical, as it will help define a clinically significant variation. Methods sNfL was measured at 2 consecutive time points in a cohort of 90 MS patients (untreated relapsing remitting MS (uRRMS), n=35; treated relapsing remitting MS (tRRMS), n= 21; secondary progressive MS, SPMS, n=21; primary progressive MS, PPMS, n=13), and 90 age-matched HC, using the Simoa NfL light® assay. Results Mean sNfL was elevated in all MS subtypes compared to HC (p<0.0001), and positively associated with age in HC (r=0.70, p<0.001), confirming previous reports. Mean sNfL was higher at follow-up compared to baseline in HC (p<0.001), and lower in uRRMS(p=0.036) and tRRMS (p=0.008). At follow-up, a similar proportion of HC (50.0%), untreated RRMS (51.4%), treated RRMS (33.3%), SPMS (45.0%) and PPMS (46.2%) had variations in sNfL levels exceeding 20% of baseline levels. Conclusions Our data suggest variations in sNfL occur both in HC and MS populations to a similar extent and magnitude. Variations between two consecutive sNfL measurements may reflect natural variations and not necessarily variations in inflammatory disease activity.