Serum neurofilament light-chain levels in children with monophasic myelin oligodendrocyte glycoprotein-associated disease, multiple sclerosis, and other acquired demyelinating syndrome.

Objective: To assess the diagnostic and prognostic potential of serum neurofilament light chain (sNfL) in children with first acquired demyelinating syndrome (ADS).
Methods: We selected 129 children with first ADS including 19 children with myelin oligodendrocyte glycoprotein (MOG)-antibody associated disease (MOGAD), 36 MOG/AQP4-seronegative ADS, and 74 with multiple sclerosis (MS) from the BIOMARKER study cohort. All children had a complete set of clinical, radiological, laboratory data and serum for NfL measurement using a highly sensitive digital ELISA (SIMOA). A control group of 35 children with non-inflammatory neurological diseases was included. sNfL levels were compared across patient groups according to clinical, laboratory, neuroradiological features and outcome after 2 years.
Results: sNfL levels were significantly increased in MOGAD, seronegative ADS and MS compared to controls ( p -value < 0.001), in particular in children with an acute disseminated encephalomyelitis (ADEM)-like magnetic resonance imaging (MRI) pattern ( p  < 0.001) or longitudinally extensive myelitis ( p  < 0.01). In pediatric MS, elevated sNfL levels were significantly associated with higher numbers of cerebral ( p  < 0.001) and presence of spinal ( p  < 0.05) MRI lesions at baseline and predicted a higher number of relapses ( p  < 0.05).
Conclusion: sNfL levels are significantly elevated in all three studied pediatric ADS subtypes indicating neuroaxonal injury. In pediatric MS high levels of sNfL are associated with risk factors for disease progression.