Our results show that the presence of MOG-abs strongly depends on the age at disease onset and that high MOG-ab titers were associated with a recurrent non-MS disease course.

Results MOG antibodies (median 1:2560; range 1:160-1:20 480) were detected in 19 children with ADEM. The majority of children showed a decline of serum MOG-IgG titres over time. Children with MOG antibodies did not differ in their age at presentation, sex ratio, the presence of oligoclonal bands, clinical symptoms or initial severity, apart from a higher CSF cell count ( p=0.038), compared with children without MOG antibodies. In addition, further relapsing demyelinating episodes associated with MOG antibodies were observed only in children with MOG antibodies. All 19 children with MOG antibodies had a uniform MRI pattern, characterised by large, hazy and bilateral lesions and the absence of atypical MRI features (eg, mainly small lesions, well-defined lesions), which was significantly different compared to that of children without MOG antibodies ( p=0.003; and p=0.032, respectively). In addition, children with MOG antibodies had involvement of more anatomical areas ( p=0.035) including the myelon characterised by a longitudinally extensive transverse myelitis ( p=0.003), more often a complete resolution of lesions ( p=0.036) and a better outcome ( p=0.038). Conclusions Patients with ADEM with MOG antibodies in our cohort had a uniform MRI characterised by large, bilateral and widespread lesions with an increased frequency of longitudinal extensive transverse myelitis and a favourable clinical outcome in contrast to children lacking MOG antibodies.

ADEM followed by ON is a rare but distinct clinical phenotype among pediatric patients. Further studies are needed to allow recommendations on treatment or prognosis.

Children with MDEM and persisting MOG antibodies constitute a distinct entity of relapsing demyelinating events and extend the spectrum of MOG antibody-associated diseases.

To study the humoral immune response directed at myelin oligodendrocyte glycoprotein (MOG) in pediatric patients with isolated and recurrent optic neuritis (ON).Design: Observational prospective case series.Setting: Six pediatric hospitals in Germany and Austria.Patients: Thirty-seven patients 18 years or younger with single or recurrent episodes of ON were recruited from 6 different hospitals.Main Outcome Measures: Clinical features, magnetic resonance imaging findings, intrathecal IgG synthesis, and outcome were recorded. A live cell-based immunofluorescence assay was used to measure serum IgG antibodies to MOG and aquaporin 4.Results: A single episode of ON was observed in 10 patients, and 15 experienced 2 to 12 episodes. The acute episode of ON was part of a clinically isolated syndrome in 12 patients, of whom 8 were subsequently classified as having multiple sclerosis. High-titer serum MOG-IgG antibodies (Ն1:160) were detected in 17 patients (46%). In addition, high titers of MOG-IgG antibodies were more frequently observed in 12 of the 15 patients with recurrent episodes of ON (80%; median titer, 1:640) compared with 2 of the 10 patients with monophasic ON (20%; median titer, 0) and 3 of the 12 patients with ON as part of a clinically isolated syndrome (25%; median titer, 0). Conclusion:High-titer MOG-IgG antibodies are predominantly detected in pediatric patients with recurrent ON, indicating that anti-MOG-specific antibodies may exert a direct role in the pathogenesis of ON in this subgroup.