MOG antibodies associated with demyelinating syndromes or encephalitis in children
A Spanish prospective multicentre study has identified a wider spectrum of paediatric demyelinating and encephalitic syndromes associated with myelin oligodendrocyte glycoprotein (MOG) antibodies than previously reported.
The observational study included 535 children (median age, 6.2 years; 49 percent female): 239 with demyelinating syndromes (cohort A) and 296 with encephalitis other than acute disseminated encephalomyelitis (ADEM) (cohort B). A total of 116 children (22 percent) had MOG antibodies, including 94 (39 percent) from cohort A and 22 (7 percent) from cohort B. [Lancet Neurol 2020, doi: 10.1016/S1474-4422(19)30488-0]
In cohort A, the syndromes that were most commonly associated with MOG antibodies were ADEM (46 of 71 children with ADEM; 65 percent), optic neuritis (20 of 52; 38 percent), myelitis (13 of 50; 26 percent), and neuromyelitis optica spectrum disorder (NMOSD; 6 of 14; 43 percent). In cohort B, among the 64 patients with autoimmune encephalitis, MOG antibodies were the most common autoantibodies (22 patients; 34 percent), surpassing all neuronal antibodies combined.
“The diagnosis of most of these patients would have been missed if it were not for the systematic screening [for MOG antibodies] in our study. The importance of these findings is emphasized by the fact that 85 percent of all patients with MOG antibody-associated syndromes responded to treatment,” commented the researchers.
Of the 116 patients found to have MOG antibodies from both cohorts, 16 (14 percent) were not treated at initial diagnosis and 100 (86 percent) received first-line immunotherapy (steroids, intravenous immunoglobulins, or plasma exchange). Additional treatments included rituximab (three patients, one of whom was treated with biosimilar anakinra).
After a median follow-up of 42 months, 17 of 100 patients (17 percent) diagnosed at disease onset had relapses; four (24 percent) had more than one relapse. The median time from disease onset to the first relapse was 4.7 months. During relapses, 32 of 33 patients (97 percent) received first-line immunotherapy and 19 (58 percent) received other immunotherapies, mainly rituximab (11 patients). “Only one of 14 patients (7 percent) treated with rituximab at disease onset (three patients) or at a relapse (11 patients) developed further relapses (median follow-up since rituximab treatment, 18 months),” highlighted the researchers.
“Findings from this study should raise awareness of a broader spectrum of syndromes associated with MOG antibodies. In children, testing for these antibodies should be considered not only in demyelinating syndromes, but also in all types of encephalitis after excluding the infectious causes and others that might be clinically recognizable (eg, anti-NMDA receptor and opsoclonus-myoclonus encephalitis),” advised the researchers.