[citation needed] The presence of anti-MOG autoantibodies has been described in association with the following conditions:[3] The most common presenting phenotypes are acute disseminated encephalomyelitis (ADEM) in children and optic neuritis (ON) in adults.
They are similar to pattern-II multiple sclerosis[10] with T-cells and macrophages surrounding blood vessels, preservation of oligodendrocytes and signs of complement system activation.
Several studies performed during 2020 have shown that MOGAD lesions differ from those seen in MS in many aspects, including their topographical distribution in the CNS, the type of demyelination, and the nature of the inflammatory response.
[1][26][27] Cerebrospinal fluid oligoclonal bands, the diagnostic mainstay in multiple sclerosis (MS), are rare in MOG-EM, both in adults[28] and in children.
[28][29] The intrathecal, polyclonal antiviral immune response (so-called MRZ reaction), which is present in around 63% of MS patients, is absent in MOG-EM.
[28][29] Proposed diagnostic criteria require serum positivity for MOG antibody as detected by CBA, a clinicoradiological presentation consistent with an acquired demyelinating syndrome (VEP can replace radiological evidence only in patients with acute ON), and exclusion of alternative diagnoses;[1][11] in addition, so-called 'red flags' have been defined, which, if present, should prompt physicians to challenge the diagnosis and to prompt re-testing for MOG-IgG, ideally using a second, methodologically different assay.
[31] Two clinical courses have been described:[32] Acute therapy consists of high-dose corticosteroids, IVIG, or plasma exchange, and long-term immunosuppression may be necessary in recurrent cases.
[39] The turning point was in 2011, when Mader et al. developed a cell-based assay using HEK 293 cells which increased the detection rate of these antibodies in the serum.