Comparison of myelin oligodendrocyte glycoprotein (MOG)-antibody disease and AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) when they co-exist with anti-NMDA (N-methyl-D-aspartate) receptor encephalitis

Background: Myelin oligodendrocyte glycoprotein (MOG)-antibody (ab) disease and AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) can co-exist with anti-NMDA (N-methyl-D-aspartate) receptor encephalitis (NMDARe). Objectives: To characterize MOG-ab disease and AQP4-IgG-positive NMOSD during NMDARe. Methods: We analyzed all the patients with overlapping MOG-ab disease and NMDARe (MNOS) and patients with AQP4-IgG-positive NMOSD and NMDARe (ANOS) in our hospital and compared those data with data from systematically review of previously published reports. Results: In our cohorts, 11.9% patients with MOG-ab disease and 0.6% patients with NMOSD had overlapping NMDARe (P < 0.01). After treatment with steroids and/or intravenous immunoglobulin (IVIg), the median modified Rankin Scale (mRS) of the MNOS group decreased significantly during attacks associated with or without NMDARe (P < 0.01 for both), while that of the ANOS group did not (attack: P < 0.05; attack associated with NMDARe: P > 0.05). Analyzed together with previously reported cases, 6% patients with MNOS and 40% patients with ANOS also used rituximab or cyclophosphamide after steroids and/or IVIg (P < 0.05) during attacks associated with NMDARe. Conclusion: Compared with NMOSD, MOG-ab disease may more commonly co-exist with NMDARe. MNOS patients respond better to steroids and IVIg than do ANOS patients during attacks associated with NMDARe.