What percentage of AQP4-ab-negative NMOSD patients are MOG-ab positive? A study from the Argentinean multiple sclerosis registry (RelevarEM).

BACKGROUND: Myelin oligodendrocyte glycoprotein antibodies (MOG-ab) have been described in aquaporin-4-antibodies(AQP4-ab)-negative neuromyelitis optica spectrum disorder (NMOSD) patients. We aimed to evaluate the percentage of AQP4-ab-negative NMOSD patients who are positive for MOG-ab in a cohort of Argentinean patients included in RelevarEM (Clinical Trials registry number NCT03375177). METHODS: RelevarEM is a longitudinal, strictly observational multiple sclerosis (MS) and NMOSD registry in Argentina. Of 3031 consecutive patients (until March 2020), 165 patients with phenotype of suspected NMOSD, whose relevant data for the purpose of this study were available, were included. Data on demographic, clinical, paraclinical and treatment in AQP4-ab (positive, negative and unknown) and MOG-ab (positive and negative) patients were evaluated. RESULTS: A total of 165 patients (79 AQP4-Ab positive, 67 AQP4-Ab negative and 19 unknown) were included. Of these, 155 patients fulfilled the 2015 NMOSD diagnostic criteria. Of 67 AQP4-Ab-negative patients, 36 (53.7%) were tested for MOG-Ab and 10 of them (27.7%) tested positive. Serum AQP4-ab levels were tested by means of cell-based assay (CBA) in 48 (35.2%), based on tissue-based indirect immunofluorescence assays in 58 (42.6%) and enzyme-linked immunosorbent assay in 4 (2.9%). All MOG-ab were tested by CBA. Optic neuritis (90%) was the most frequent symptom at presentation and optic nerve lesions the most frequent finding (80%) in neuroimaging of MOG-ab-associated disease. Of these, six (60%) patients were under immunosuppressant treatments at latest follow-up. CONCLUSION: We observed that 27.7% (10/36) of the AQP4-ab-negative patients tested for MOG-ab were positive for this antibody, in line with results from other world regions.

Multiple sclerosis and neuromyelitis optica spectrum disorders in Argentina: comparing baseline data from the Argentinean MS Registry (RelevarEM).

The objective of this study was to describe and compare the baseline epidemiological data of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) patients included in RelevarEM (Clinical Trials registry number NCT03375177). METHODS: RelevarEM is a longitudinal, strictly observational MS and NMOSD registry in Argentina. Epidemiological and comorbidity data from MS and NMOSD patients were described and compared. For comorbidities, the Charlson comorbidity index (CCI) was used to calculate the burden at entry. CCI was stratified in 0 and ≥ 1 and described for the entire cohort. RESULTS: A total of 1588 and 75 MS and NMOSD patients (respectively) were included. For MS patients, the mean age was 42 ± 7 years, female sex 65.3%, mean EDSS 2, and mean disease duration 8 ± 6 years. In NMOSD, the mean age was 40 ± 7 years, female sex 78.7%, mean disease duration 5 ± 3.5 years, and mean EDSS 2.5. The most frequent MS phenotype was RRMS in 82.4%. In MS, the CCI was 0 in 85.8.2% while ≥ 1 was in 14.2% of patients. Regarding phenotype stratification, CCI ≥ 1 was 3.9% in CIS, 13.5% in RRMS, 28.7% in SPMS, and 17.4% in PPMS (p < 0.001 between groups). In NMOSD, the CCI was 0 in 64% while ≥ 1 was in 36%. The MS/NMOSD ratio found was 21/1. CONCLUSIONS: This is the first analysis of the longitudinal Argentinean registry of MS and NMOSD describing and comparing conditions that contributes to provide reliable real-world data in the country.

The Argentinean multiple sclerosis registry (RelevarEM): Methodological aspects and directions.

Despite that different registries already exist in various countries in Europe and North America, no ongoing nationwide registry exists in Latin America (LATAM), a region where the disease behaves differently than in other regions. The objective of this document is to describe the methodology behind RelevarEM, the first nationwide MS registry in Argentina and LATAM. METHODS: In this article, we described the creation, implementation and data management of the nationwide MS registry in Argentina. The registry contains information on the structure, ethical aspects, implementation and variables of the registry (Clinical Trials registry number NCT NCT03375177). CONCLUSION: RelevarEM is the first MS nationwide registry in Argentina, as well as in LATAM, with the objective of providing reliable real-world data of MS in the country.