Background and Objective The spectrum of myelin oligodendrocyte glycoprotein (MOG) antibody–associated disorder (MOGAD) comprises monophasic diseases such as acute disseminated encephalomyelitis (ADEM), optic neuritis (ON), and transverse myelitis and relapsing courses of these presentations. Persistently high MOG antibodies (MOG immunoglobulin G [IgG]) are found in patients with a relapsing disease course. Prognostic factors to determine the clinical course of children with a first MOGAD are still lacking. The objective of the study is to assess the clinical and laboratory prognostic parameters for a risk of relapse and the temporal dynamics of MOG‐IgG titers in children with MOGAD in correlation with clinical presentation and disease course. Methods In this prospective multicenter hospital-based study, children with a first demyelinating attack and complete data set comprising clinical and radiologic findings, MOG-IgG titer at onset, and clinical and serologic follow-up data were included. Serum samples were analyzed by live cell-based assay, and a titer level of ≥1:160 was classified as MOG-IgG–positive. Results One hundred sixteen children (f:m = 57:59) with MOGAD were included and initially diagnosed with ADEM (n = 59), unilateral ON (n = 12), bilateral ON (n = 16), myelitis (n = 6), neuromyelitis optica spectrum disorder (n = 8) or encephalitis (n = 6). The median follow-up time was 3 years in monophasic and 5 years in relapsing patients. There was no significant association between disease course and MOG-IgG titers at onset, sex, age at presentation, or clinical phenotype. Seroconversion to MOG-IgG–negative within 2 years of the initial event showed a significant risk reduction for a relapsing disease course. Forty-two/one hundred sixteen patients (monophasic n = 26, relapsing n = 16) had serial MOG-IgG testing in years 1 and 2 after the initial event. In contrast to relapsing patients, monophasic patients showed a significant decrease of MOG-IgG titers during the first and second years, often with seroconversion to negative titers. During the follow-up, MOG-IgG titers were persistently higher in relapsing than in monophasic patients. Decrease in MOG-IgG of ≥3 dilution steps after the first and second years was shown to be associated with a decreased risk of relapses. In our cohort, no patient experienced a relapse after seroconversion to MOG-IgG–negative. Discussion In this study, patients with declining MOG-IgG titers, particularly those with seroconversion to MOG-IgG–negative, are shown to have a significantly reduced relapse risk.

Microglial activation in crossing white matter tracts is a hallmark of noncystic periventricular leukomalacia (PVL), the leading pathology underlying cerebral palsy in prematurely born infants. Recent studies indicate that neuroinflammation within an early time window can produce long-lasting defects in oligodendroglial maturation, myelination deficit, as well as disruption of transcription factors important in oligodendroglial maturation. We recently reported an ischemic mouse model of PVL, induced by unilateral neonatal carotid artery ligation, leading to selective long-lasting bilateral myelination deficits, ipsilateral thinning of the corpus callosum, ventriculomegaly, as well as evidence of axonopathy. Here, we report that permanent unilateral carotid ligation on postnatal day 5 in CD-1 mice induces an inflammatory response, as defined by microglial activation and recruitment, as well as significant changes in cytokine expression (increased IL-1β, IL-6, TGF-β₁, and TNF-α) following ischemia. Transient reduction in counts of oligodendrocyte progenitor cells (OPCs) at 24 and 48 h after ischemia, a shift in OPC cell size and morphology towards the more immature form, as well as likely migration of OPCs were found. These OPC changes were topographically associated with areas showing microglial activation, and OPC counts negatively correlated with increased microglial staining. The presented data show a striking neuroinflammatory response in an ischemia-induced model of PVL, associated with oligodendroglial injury. Future studies modulating the neuroinflammatory response in this model may contribute to a better understanding of the interaction between microglia and OPCs in PVL and open opportunities for future therapies.

Background and purpose: Rituximab (RTX) is frequently used off‐label in multiple sclerosis. However, studies on the risk–benefit profile of RTX in pediatric‐onset multiple sclerosis are scarce.Methods: In this multicenter retrospective cohort study, patients with pediatric‐onset multiple sclerosis from Sweden, Austria and Germany, who received RTX treatment were identified by chart review. Annualized relapse rates, Expanded Disability Status Scale scores and magnetic resonance imaging parameters (new T2 lesions and contrast‐enhancing lesions) were assessed before and during RTX treatment. The proportion of patients who remained free from clinical and disease activity (NEDA‐3) during RTX treatment was calculated. Side effects such as infusion‐related reactions, infections and laboratory abnormalities were assessed.Results: Sixty‐one patients received RTX during a median (interquartile range) follow‐up period of 20.9 (35.6) months. The annualized relapse rate decreased from 0.6 (95% confidence interval [CI] 0.38–0.92) to 0.03 (95% CI 0.02–0.14). The annual rate of new T2 lesions decreased from 1.25 (95% CI 0.70–2.48) to 0.08 (95% CI 0.03–0.25) and annual rates of new contrast‐enhancing lesions decreased from 0.86 (95% CI 0.30–3.96) to 0. Overall, 70% of patients displayed no evidence of disease activity (NEDA‐3). Adverse events were observed in 67% of patients. Six patients discontinued treatment due to ongoing disease activity or adverse events.Conclusion: Our study provides class IV evidence that RTX reduces clinical and radiological activity in pediatric‐onset multiple sclerosis.

Multiple sclerosis (MS) is an immune-mediated demyelinating disease. Epstein-Barr virus (EBV) encodes for the EBNA-1_381-452 region that induces autoreactive antibody responses, which are likely critically involved in MS pathogenesis. Here we investigate whether these EBNA-1_381-452-specific antibodies can serve as a biomarker to identify at-risk individuals for MS. We quantify EBNA-1_381-452-specific antibody titers from 324 relapsing-remitting MS patients and 324 matched controls in longitudinal follow-up plasma samples, starting from the individual’s EBV-seroconversion. In MS patients, significantly elevated EBNA-1_381-452-specific IgG titers are identified that are increased already as early as nine months after EBV-seroconversion (OR:5.7; 95% CI: 4.1-8.1; P < 0.0001) and a median 5.4 years prior to MS diagnosis. Especially, the presence of continuously high EBNA-1_381-452-specific antibody titers is associated with a more rapid MS diagnosis after EBV-seroconversion (P < 0.0001). Thus, the quantification of EBNA-1_381-452-specific IgG antibody levels may provide a prognostic biomarker to determine the individual’s risk for the diagnosis of MS.