Relevance of dedicated multiple sclerosis serum biomarkers in predicting contrast enhancement with gadolinium: Results from the REDUCE-GAD trial.

BACKGROUND: The presence of contrast enhancement (CE) on magnetic resonance imaging (MRI) is one of the principal criteria for diagnosis and disease activity of multiple sclerosis (MS). Therefore, MS patients are frequently exposed to contrast agents, which may cause deposition in the brain, restricting its use in repeat examinations. Thus, serum biomarkers may be valuable as surrogate parameters to evaluate MS activity. METHODS: REDUCE-GAD was a prospective, multicentric, biobanking study to determine whether established serum markers (neurofilament light chain [NfL], glial fibrillary acidic protein [GFAP], tau protein, ubiquitin-carboxyl-terminal-hydrolase (UCH-L1), S100B and matrix-metalloproteinase 9 [MMP9]) are predictive of CE-positive MRI lesions. Blood samples were obtained from patients undergoing MRI 5 days before or after collection. RESULTS: Patients (N = 102) from four different centers with confirmed MS or related disorders were included; n = 57 (55.9%) showed CE on MRI versus n = 45 (44.1%) without CE. Only higher NfL values indicated CE (odds ratio [OR] 1.05; 95% CI 1.0-1.09) and were correlated with number (ρ = 0.47; p < 0.001) and diameter of CE lesions (ρ = 0.58; p < 0.001). Nfl Z-scores improved diagnostic accuracy (OR 1.52; 95% CI 1.06-2.18). Receiver operator characteristic analysis revealed a reasonable cut-off value for NfL at 14.1 pg/mL (sensitivity 49.1%; specificity 82.2%; positive predictive value 77.8%; negative predictive value 56.0%). NfL ≥59.2 pg/mL was exclusively observed in patients with CE. CONCLUSIONS: Evaluation of several possible serum biomarkers for CE in MS patients provided the most robust results for NfL, particularly as Z-scores. Following further evaluation, biomarkers may help stratify the application of contrast agents for brain imaging in MS patients.