Serum Neurofilament Light Chain in NMOSD and Related Disorders: Comparison According to Aquaporin-4 and Myelin Oligodendrocyte Glycoprotein Antibodies Status

Background: Neurofilament light chain (NF-L) levels reflect axonal damage in different conditions, including demyelinating disorders. Objectives: We aimed to compare serum NF-L levels in patients with aquaporin-4 antibodies (AQP4-Ab), myelin oligodendrocyte antibodies (MOG-Ab) and seronegative cases with neuromyelitis optica spectrum disorders and related disorders. Methods: We analysed AQP4-Ab and MOG-Ab with cell-based assay and NF-L with ultrasensitive electrochemiluminescence immunoassay. Results: Median NF-L levels were increased in 25 AQP4-Ab-positive patients (59 pg/ml) as compared with 22 MOG-Ab-positive cases (25 pg/ml), 52 seronegative patients (18 pg/ml), 25 multiple sclerosis patients (12 pg/ml) and 14 healthy controls (12 pg/ml). Conclusions: Increased serum levels of NF-L in patients with AQP4-Ab or MOG-Ab might reflect an ongoing axonal damage and a more malignant disease course.