Myelin oligodendrocyte glycoprotein and aquaporin‐4 antibodies are highly specific in children with acquired demyelinating syndromes

Abstract

Aims: Our objectives were to evaluate the utility of measuring MOG and AQP4 antibodies (Ab) in clinical practice and describe their associated neurological phenotypes in children. / Methods: Between 2012-2017, 371 children with suspected acquired demyelinating syndromes (ADS) seen in 3 tertiary centres were tested for MOG-Ab and AQP4-Ab. Medical notes were retrospectively reviewed and clinical and demographic data compiled. Clinical phenotyping was performed blinded to the antibody results. / Results: Following review, 237 of the 371 were diagnosed with ADS. Of these, 76/237(32.1%) were MOG-Ab positive and 14/237(5.9%) were AQP4-Ab positive. None were positive for both autoantibodies. All 134 patients with non-ADS were negative for MOG-Ab. MOG-Ab were identified in 45/70(64.3%) of patients presenting with acute disseminated encephalomyelitis (ADEM) and in 24/25 (96%) of patients with relapsing ADEM. 36/75(48%) MOG-Ab positive patients relapsed. Of the 33 children with neuromyelitis optic spectrum disorder: 14(42.4%) were AQP4-Ab positive, 13(39.4%) were MOG-Ab positive and 6(18.2%) were seronegative. Of the children with longitudinal samples, 8/13(61.5%) AQP4-Ab remained positive during the disease course compared to 35/43(81.4%) MOG-Ab (13/16 monophasic and 22/27 relapsing). / Conclusion: MOG-Ab were identified in a third of children with ADS. Almost half of the MOG-Ab positive children relapsed and the majority of them remained antibody positive over 4years follow-up. / Key points from this paper: 1. MOG-Ab is highly specific for acquired demyelinating syndromes and is not identified in children with peripheral demyelination or genetic leukodystrophies/hypomyelination. / 2. Up to 48% of MOG-Ab ADS paediatric patients relapse, higher than previously thought. / 3. Seroconversion to MOG-Ab negative status is infrequent and therefore patients may be tested MOG-Ab positive at interval sampling even when asymptomatic. / 4. MOG-Ab status should only be used in conjunction with the clinical information to guide maintenance therapy