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BACKGROUND AND PURPOSE: Gut microbiota dysbiosis may lead to proinflammatory conditions contributing to multiple sclerosis (MS) etiology. Pediatric-onset MS patients are close to biological disease onset and less exposed to confounders. Therefore, this study investigated gut microbiota composition and functional pathways in pediatric-onset MS, compared to monophasic acquired demyelinating syndromes (mADS) and healthy controls (HCs). METHODS: Pediatric participants were selected from the Dutch national prospective cohort study including ADS patients and HCs <18 years old. Amplicon sequence variants (ASVs) were generated from sequencing the V3/4 regions of the 16S rRNA gene. Functional MetaCyc microbial pathways were predicted based on Enzyme Commission numbers. Gut microbiota composition (alpha/beta diversity and individual microbe abundance at ASV to phylum level) and predicted functional pathways were tested using nonparametric tests, permutational multivariate analysis of variance, and linear regression. RESULTS: Twenty-six pediatric-onset MS (24 with disease-modifying therapy [DMT]), 25 mADS, and 24 HC subjects were included. Alpha/beta diversity, abundance of individual resident microbes, and microbial functional features were not different between these participant groups. Body mass index (BMI) showed significant differences, with obese children having a lower alpha diversity (Chao1 Index p = 0.015, Shannon/Simpson Diversity Index p = 0.014/p = 0.023), divergent beta diversity (R2 = 3.7%, p = 0.013), and higher abundance of numerous individual resident microbes and functional microbial pathways. CONCLUSIONS: Previous results of gut microbiota composition and predicted functional features could not be validated in this Dutch pediatric-onset MS cohort using a more sensitive 16S pipeline, although it was limited by sample size and DMT use. Notably, several other host-related factors were found to associate with gut microbiota variation, especially BMI.
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BACKGROUND: We recently described magnetic resonance imaging (MRI) features of children with transverse myelitis (TM) at first event with important and unique differences depending on the underlying disease entity. OBJECTIVE: To study the resolution of lesions over time in children with TM due to MOG-antibody associated disorders (MOGAD), multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD) or double seronegative TM. PATIENTS AND METHODS: In this prospective study, 78 children from 29 different medical centres with TM as part of MOGAD (n = 34), MS (n = 20), NMOSD (n = 5) and in double seronegative children (n = 19) were included. A grading system consisting of 4 grades (grade 0 = complete resolution; grade 3 = no resolution at all) was used to compare the degree of lesion resolution over time in the different disease entities. Time to lesion resolution was evaluated by Kaplan-Meier statistics and log-rank test. RESULTS: Significant differences of the interval between first MRI until resolution of lesions were observed between the four disease entities. The most rapid and complete resolution was seen in MOGAD, followed by double seronegative, MS and NMOSD. Median periods until total resolution (grade 0) were 191 days (MOGAD), 750 days (double seronegative), 1117 days (MS), while none of the patients with NMOSD reached a complete resolution during the observation period. The better prognosis of MOGAD compared to MS was independent of sex, age, oligoclonal bands and cell count in the multivariate Cox analysis (P < 0.001). CONCLUSION: Children with TM and antibodies to MOG show a faster resolution of radiological lesions compared to children with MS and NMOSD.