MOG IgG antibody positivity from laboratory to clinical practice: A real world experience

Myelin oligodendrocyte glycoprotein (MOG) associated disease (MOGAD) is an antibody-mediated inflammatory demyelinating disorder of the CNS with varied presentations like optic neuritis (ON), transverse myelitis, and cortical encephalitis. This study aims to highlight the significance of low MOG IgG antibody positivity and its diagnostic implications in a real-world cohort.

In this retrospective observational study, serum and CSF from suspected MOGAD cases were tested at a tertiary healthcare centre's Neuroimmunology Laboratory. MOG autoantibodies were detected using a EUROIMMUN commercial kit, and seropositivity was determined by visual agreement of fluorescence by two trained observers. Patient data were retrieved from Electronic Medical records.

Out of 103 MOG IgG seropositive patients, 95 were included in the final analysis (Mean age: 32.47±4.63 years; 42 males, 53 females; 36 pediatric, 59 adult) after excluding those with alternate diagnoses. The most common clinical event was ON (37.89%). The 2023 International MOGAD Diagnostic Criteria was met by 35/67 low-strength and 27/28 high-strength patients. Adults were more likely to have atypical presentations and low serum MOG levels. Pediatric patients had better EDSS at discharge but relapsed more. There were no significant differences between low and high positive groups in terms of treatment received, EDSS, relapse, or outcome.

Low and high levels of MOG seropositivity showed similar diagnostic value in terms of clinical features, treatment outcome, and prognosis, except for age distribution. Many patients exhibited low-strength positivity and atypical disease presentations, requiring strong clinical judgement for diagnosis.