AQP4 and optic neuritis: Although both GFAP and AQP4 astrocytopathy have specific IgGs targeting astrocytes and are involved in myelitis, optic neuritis, and brain symptoms, it seems that GFAP astrocytopathy is quite different from AQP4 astrocytopathy in many clinical manifestations, including fever, headache, and psychiatric symptoms, suggesting immune encephalitis features (2, 3).