AQP4 and neuromyelitis optica: However, when a conformationally correct and glycosylated human MOG was used to identify MOG autoantibodies in serum and CSF, they were not found in patients with MS but were rather found in about 40% of patients diagnosed with ADEM or aquaporin 4 IgG–negative (AQP4-IgG–) neuromyelitis optica spectrum disorder (NMOSD) (3–7).