Serum neurofilament light chain in a cohort of multiple sclerosis, MOG-antibody diseases and neuromyelitis optica spectrum disorders patients

Background and aims To compare serum Neurofilament light chain (sNfL) levels in patients with Multiple Sclerosis (MS), MOG-Antibody Disease (MOGAD) and Neuromyelitis Optica Spectrum Disorders (NMOSD). Methods We performed a propensity score (PS)-based nearest-neighbor matching within a caliper of 0.05 to select patients with homogeneous baseline characteristics. Using ultrasensitive single molecule array assays (SIMOA), we measured sNfL in the sera of adult patients with MS (n = 17), MOGAD (n = 15), NMOSD with AQP4-Ab (n = 16) and Healthy Controls (HCs) (n = 24). MOG-IgG and AQP4-IgG were analysed by a semiquantitative ratiometric method. SNfL levels were compared among the different disease groups. Spearman test was used to evaluate the correlation between sNfL and EDSS score in each group and to estimate the correlation between MOG-IgG titer and sNFL levels. Results MOGAD patients showed a significant lower sNFL levels compared to MS (median 16,47 pg/mL range 5,10–71,78 vs 7,34 range 2,43-115,43; p = 0.01) and NMOSD adult patients (median 16,46 pg/mL range 4,2-196,47; p = 0.02)[Fig.1]. All groups had an increased sNFL value compared to HCs (median 5,64 pg/mL range 2,47-8,84; p b 0.0001). A positive significant correlation was found between sNfL and EDSS scores in MOGAD (r = 0.636; p = 0.005), NMO-AQP4 (r = 0.908; p b 0.0001) and MS patients (r = 0.534; p = 0.014) [Fig.2]. No correlation was found between MOG-IgG titers and sNfL levels (p = 0.294).. Conclusions Our results confirm the value of sNfL as a clinically meaningful blood biomarker of disability levels in different demyelinating diseases. In MOGAD patients MOG-IgG titers are not correlated with the sNfL levels, suggesting that they are more related to inflammatory processes.