AQP4 and optic neuritis: None of the patients developed a clinical phenotype reminiscent of MOG-IgG-associated diseases such as acute disseminated encephalomyelitis (ADEM), MS, aquaporin-4-seronegative neuromyelitis optica spectrum disorder (NMOSD), isolated optic neuritis or transverse myelitis, or bilateral optic neuritis (BON) within the observation period of six months after onset of acute IM.