Myelin Oligodendrocyte Glycoprotein Antibodies are Associated with Bilateral and Recurrent Optic Neuritis and have a Distinct Radiological Profile to Multiple Sclerosis or Aquaporin-4 Antibody-associated Optic Neuritis (P3.001)

Objective: We performed clinical and radiological characterisation of first episode optic neuritis (ON) in patients with myelin oligodendrocyte glycoprotein antibody-associated ON(MOG-ON), aquaporin-4 antibody-associated ON(AQP4-ON), and multiple sclerosis(MS-ON). We hypothesised there would be specific radiological predictors depending on the cause of ON. Background: Early recognition of the etiology of ON affects treatment decisions and prognosis. Design/Methods: We performed a flow cytometry cell-based assay using live HEK293 cells expressing full-length human MOG to test the serum of 23 adults with AQP4 antibody-negative neuromyelitis optica spectrum disorders. Blinded neuroradiological assessment was subsequently performed on magnetic resonance imaging of fifty patients (mean age 24 years, range 3-58, 41 females) with a first episode of ON, including MOG-ON (n=19), AQP4-ON (n=11), MS-ON (n=13), and unclassified ON (n=7). Results: MOG antibodies were detected in 9/23 patients, all of whom had bilateral ON. MOG-ON patients were more likely to have a relapsing course and be steroid responsive. Bilateral involvement was more common in MOG-ON and AQP4-ON than MS-ON (84[percnt] v.82[percnt] v.23[percnt]), optic nerve head swelling was more common in MOG-ON (53[percnt] v.9[percnt] v.0[percnt]), chiasmal involvement was more common in AQP4-ON (5[percnt] v.64[percnt] v.15[percnt]), and bilateral optic tract involvement was more common in AQP4-ON (0[percnt] v.45[percnt] v.0[percnt]). Retrobulbar optic nerve involvement was more common in MOG-ON, whereas intracranial optic nerve involvement was more common in AQP4-ON. MOG-ON and AQP4-ON had longer lesion lengths and lesion extent scores than MS-ON. AQP4-ON more frequently had severe and sustained visual impairment. Conclusions: MOG antibodies are associated with a bilateral ON phenotype and are steroid responsive. MOG and AQP4-ON are frequently bilateral and longitudinally extensive, compared with MS-ON. MOG-ON tends to involve the anterior optic pathway whereas AQP4-ON tends to involve the posterior optic pathway. These radiological predictors may expedite diagnosis at the first presentation of ON, with therapeutic and prognostic implications. Disclosure: Dr. Ramanathan has received personal compensation from NHMRC Australia and the Petre Foundation. Dr. Prelog has nothing to disclose. Dr. Barnes has nothing to disclose. Dr. Tantsis has nothing to disclose. Dr. Reddel has received research support from Genzyme Sanofi, Biogen, CSL, and Baxter. Dr. Henderson has nothing to disclose. Dr. Vucic has received research support from Biogen Idec, Novartis, Bayer, CSL, and Genzyme. Dr. Gorman has nothing to disclose. Dr. Benson has nothing to disclose. Dr. Alper has nothing to disclose. Dr. Riney has received research support from Novartis. Dr. Barnett has received research support from Novartis Pharmaceuticals. Dr. Parratt has received research support from Multiple Sclerosis Research Australia, Genzyme, Novartis, Merck Serono and Bayer Schering, Biogen Idec and CSL. Dr. Hardy has nothing to disclose. Dr. Leventer has nothing to disclose. Dr. Merheb has nothing to disclose. Dr. Nosadini has nothing to disclose. Dr. Fung has nothing to disclose. Dr. Brilot-Turville has received research support from Star Scientic Foundation, Trish MS Research Foundation, MSRA, MS Angels Melbourne, NHMRC, and the Petre Foundation. Dr. Dale has received research support from Star Scientific Foundation, Trish MS Research Foundation, MSRA, NHMRC Australia, and the Petre Foundation.