[Anti-Myelin Oligodendrocyte Glycoprotein Antibodies in Paediatric Patients with Optic Neuritis].

Myelin oligodendrocyte glycoprotein (MOG) is located on the surface of oligodendrocytes and myelin in the central nervous system. MOG-IgG is associated with acute disseminated encephalomyelitis (ADEM), relapsing and bilateral optic neuritis (NNO), and transverse myelitis (TM) in both paediatric and adult patients. The combination of NNO and TM or other inflammatory brain lesions is a typical feature of neuromyelitis optica spectrum disorders (NMO-SD) which are associated with specific pathogenic autoantibodies against the water channel aquaporin-4 (AQP4-IgG). However, children with NMO-SD are often seronegative for AQP4-IgG but seropositive for MOG-IgG. Therefore, the course and therapy of MOG-IgG positive NNO in children were of special interest. The course of disease of two male patients with acute NNO is presented (bilateral NNO, age of onset 8 years each, AQP4-IgG negative, MOG-IgG positive). Several relapses of NNO occurred in patient 1 with persisting MOG-IgG in spite of immunsuppressive therapy. He suffered from increasing optic atrophy, considerable visual loss and transient brainstem affection. Patient 2 showed a monophasic course of disease with a rapid decline in MOG-IgG titre and only minor asymmetric optic atrophy. MOG-IgG in children is associated with recurrent NNO and cerebral lesions characteristic of ADEM or NMO-SD. High titres of MOG-IgG are observed during the acute phase of clinical symptoms. Relapses of NNO lead to increasing loss of retinal nerve fibre layer. Diagnostic investigation includes the determination of AQP4-IgG and MOG-IgG as well as magnetic resonance imaging (MRI) of brain and spinal cord. The therapeutic consequence of this is consistent immunsuppressive treatment, starting with intravenous steroids and followed by second-line therapy with steroid sparing immunosuppressants, including mycophenolate or azathioprine, followed in refractory cases by rituximab. The therapeutic effect should be controlled by laboratory tests of MOG-IgG titre.