Seroprevalence and clinical phenotype of MOG-IgG-associated disorders in Sri Lanka

Antibodies targeting myelin oligodendrocyte glycoprotein immunoglobulin (MOG-IgG) detected by cell-based assays1 are recognised biomarkers of a subgroup of central nervous system inflammatory demyelinating disorders (CNS IDDs) termed MOG-IgG-associated disorders (MOGAD).2 Single episode and recurrent ON are the most common presentations of MOGAD followed by transverse myelitis (TM), acute disseminated encephalomyelitis (ADEM) and brainstem syndromes or combination of such manifestations.1 3 4 Population-based studies have demonstrated, in aquaporin-4 immunoglobulin (AQP4-IgG)-positive neuromyelitis optica spectrum disorders (NMOSD), that ethnicity plays an important role in determining risk for NMOSD. Afro-Carribeans from Martinique have a threefold higher prevalence of NMOSD compared with Caucasians in Olmsted County, Minnesota.5 It remains unclear whether ethnicity is a risk factor for the development of MOGAD. Sri Lanka located in South Asia has predominant Sinhalese ethnicity. The AQP4-IgG and MOG-IgG serostatus of CNS IDDs in these populations have not been previously determined. Serum samples of 726 consecutive Sri Lankan patients undergoing evaluation for suspected IDDs at the National Hospital of Sri Lanka, a tertiary care centre, between January 2013 and March 2018 were tested for AQP4-IgG and MOG-IgG by Clinical Laboratory Improvement Amendments approved flow cytometric assays. Infectious, granulomatous (eg, sarcoidosis) and neoplastic aetiologies were excluded. MOG-IgG1 serostatus was defined as persistent when seropositivity confirmed at or more than 6 months after the onset attack. Clinical information was available for 550 patients (113 children and 437 adults). SAS V.9.4 and JMP V.13 were used. χ2 or Fisher’s exact tests were applied to compare categorical variables. Continuous data …