Spectrum of Pediatric MOG Antibody-Associated Syndromes Is Wider Than Believed

New evidence suggests that the spectrum of pediatric myelin oligodendrocyte glycoprotein (MOG) antibody-associated syndromes is wider than previously reported. According to a new study’s findings, the spectrum includes demyelinating syndromes and encephalitis.

To determine the frequency and distribution of pediatric demyelinating and encephalitic syndromes with MOG antibodies, their response to treatment, and the phenotypes associated with poor prognosis, the researchers conducted a prospective observational study.

Between June 1, 2013, and December 31, 2018, children with demyelinating syndromes and with encephalitis other than acute disseminated encephalomyelitis (ADEM) were recruited from 40 secondary and tertiary centers in Spain. In all, 239 children with demyelinating syndromes (cohort A) and 296 with encephalitis other than ADEM (cohort B) were recruited.

These children were then assessed for MOG antibodies; all MOG antibody-positive cases were included in the study. Of the 116 patients with MOG antibodies, 94 were from cohort A and 22 were from cohort B. The median age of these patients was 6.2 years, and 49% were girls.

According to the study authors, MOG antibodies were more common than all neuronal antibodies combined among the patients with autoimmune encephalitis in cohort B (n=64). 

The patients’ presenting syndromes included ADEM (68%), encephalitis other than ADEM (19%), optic neuritis (17%), myelitis (11%), neuromyelitis optica spectrum disorders (5%), and other disorders (8%).

After a median follow-up of 42 months, 33 (28%) of the 116 patients had relapses, including 17 of 100 diagnosed at first episode.

At diagnosis, 86% of patients had received steroids, intravenous immunoglobulin, or plasma exchange. These treatment methods were used at relapse for all but 1 patient. 

Substantial recovery was defined as a modified Rankin scale score less than 2. Of the 116 patients, 99 (85%) had substantial recovery. Meanwhile, 17 (15%) had moderate to severe deficits, which were defined as a modified Rankin scale score greater than 2.

ADEM-like relapses progressing to leukodystrophy-like features and extensive cortical encephalitis evolving to atrophy were identified as phenotypes of poor prognosis. Those who experienced relapses had a longer time to antibody negativity.

“Recognition of these disorders has important clinical and prognostic implications,” the researchers concluded.

—Colleen Murphy

Reference:

Armangue T, Olivé-Cirera G, Martínez-Hernandez E, et al; Spanish Pediatric anti-MOG Study Group. Associations of paediatric demyelinating and encephalitic syndromes with myelin oligodendrocyte glycoprotein antibodies: a multicentre observational study. Lancet Neurol. 2020;19(3):234-246. https://doi.org/10.1016/S1474-4422(19)30488-0.