Increased Plasma Lipocalin-2 Levels in Patients with Myelin Oligodendrocyte Glycoprotein-IgG-Positive Optic Neuritis

This study aimed to evaluate the correlation between plasma lipocalin-2 (LCN2) levels and myelin oligodendrocyte glycoprotein (MOG)-immunoglobulin G (IgG) seropositivity in patients with optic neuritis. Peripheral blood samples were collected from 19 patients with optic neuritis and 20 healthy controls. Plasma LCN2 and MOG-IgG levels were measured using enzyme-linked immunosorbent assay and a cell-based assay, respectively. The correlation between plasma LCN2 levels and MOG-IgG titers in patients with optic neuritis was analyzed. Receiver operating characteristic (ROC) curves were constructed to assess and compare the ability of plasma LCN2 and MOG-IgG levels for predicting optic neuritis recurrence. Patients with MOG-IgG-positive optic neuritis had significantly higher mean plasma LCN2 levels than controls and patients with MOG-IgG-negative optic neuritis (p = 0.037). Plasma LCN2 and MOG-IgG levels were significantly correlated in patients with optic neuritis (r = 0.553, p = 0.0141). There were no significant differences in the areas under the ROC curve (AUC) of plasma LCN2 (0.693, 95% confidence interval [CI] 0.443-0.880, p = 0.133) and MOG-IgG (0.641, 95% CI, 0.400-0.840, p = 0.298) levels (95% CI, -0.266-0.448, p = 0.618). Plasma LCN2 levels may aid differentiation of MOG-IgG-positive optic neuritis from MOG-IgG-negative optic neuritis.