A case of recurrent MOG antibody positive bilateral optic neuritis and anti-NMDAR encephalitis: Different biological evolution of the two associated antibodies.

We report the clinical association of myelin-oligodendrocyte-glycoprotein (MOG) IgG-associated encephalomyelitis (MOG-EM) and anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. A 47-year old male presented to our hospital with right eye optic neuritis in February 2018. He had a history of recurrent bilateral optic neuritis since 2001 and in 2013 was treated of a anti-NMDAR encephalitis. He never had any CNS demyelination event besides optic neuritis. At the time of anti-NMDAR encephalitis both NMDAR and MOG antibodies were positive in serum and CSF. At the last visit, serum aquaporin-4 (AQP-4) and NMDAR antibodies were negative but MOG antibodies remained positive. MOG-EM and NMDAR encephalitis can present over an extended period of time without other signs of CNS demyelination and with a different temporal evolution of the associated antibodies.