Serum neurofilament light chain concentration in a phase 1/2 trial of autologous mesenchymal stem cell transplantation

BACKGROUND: Serum neurofilament light chain concentration is a proposed biomarker of axonal injury in multiple sclerosis. Mesenchymal stem cells have anti-inflammatory and repair-promoting activities, making them of interest for potential multiple sclerosis treatment. OBJECTIVES: The purpose of this study was to assess correlation of serum neurofilament light chain concentration and measures of multiple sclerosis disease activity/severity, longitudinal stability of serum neurofilament light chain concentration, and treatment effect of mesenchymal stem cell transplantation on serum neurofilament light chain concentration. METHODS: Twenty-four multiple sclerosis patients underwent intravenous infusion of autologous mesenchymal stem cells. Clinical assessments, serum collection, and brain magnetic resonance imaging were performed at months –1, 0 (transplant), 1, 3, and 6. Matched control serum was collected once (n = 10). Serum neurofilament light chain concentration was measured by single-molecule array. Serum neurofilament light chain concentration correlations with disease measures were analyzed by Spearman correlations and linear mixed effect models. Pre-post transplant serum neurofilament light chain concentration was compared by Wilcoxon signed rank testing. RESULTS: There were significant (p<0.01) correlations between serum neurofilament light chain concentration and gadolinium-enhancing lesion number (rho = 0.55) and volume (rho = 0.65), and new/enlarging T2 lesions (rho = 0.65). Patients without disease activity had lower fluctuation in serum neurofilament light chain concentration (p = 0.01). Mean pre- versus post-treatment serum neurofilament light chain concentration values were not significantly different. CONCLUSIONS: Serum neurofilament light chain concentration correlated with magnetic resonance imaging measures of disease activity cross sectionally and longitudinally, and was stable in patients without disease activity. There was no clear treatment effect of mesenchymal stem cell transplantation on serum neurofilament light chain concentration.