Clinical, prognostic and pathophysiological implications of MOG-IgG detection in the CSF: the importance of intrathecal MOG-IgG synthesis.

BACKGROUND: Cerebrospinal fluid myelin oligodendrocyte glycoprotein IgG (CSF MOG-IgG) are found in a proportion of patients with MOG antibody-associated disorder (MOGAD) and have been associated with severe disease presentations. However, most studies did not systematically investigate the role of MOG-IgG intrathecal synthesis (ITS). METHODS: We retrospectively studied 960 consecutive patients with paired serum and CSF samples screened for MOG-IgG using a live cell-based assays. MOG-IgG-specific antibody index (AIMOG) was systematically calculated using serum and CSF titres to assess MOG-IgG ITS, and clinical features were compared between MOG-IgG CSF+/CSF- and ITS+/ITS- patients. RESULTS: MOG-IgG were found in 55/960 patients (5.7%; serum+/CSF-: 58.2%, serum+/CSF+: 34.5%; serum-/CSF+: 7.3%). Serum/CSF MOG-IgG titres showed a moderate correlation in patients without ITS (ρ=0.47 (CI 0.18 to 0.68), p<0.001), but not in those with ITS (ρ=0.14 (CI -0.46 to -0.65), p=0.65). There were no clinical-paraclinical differences between MOG-IgG CSF+ vs CSF- patients. Conversely, patients with MOG-IgG ITS showed pyramidal symptoms (73% vs 32%, p=0.03), spinal cord involvement (82% vs 39%, p=0.02) and severe outcome at follow-up (36% vs 5%, p=0.02) more frequently than those without MOG-IgG ITS. A multivariate logistic regression model indicated that MOG-IgG ITS was an independent predictor of a poor outcome (OR: 14.93 (CI 1.40 to 19.1); p=0.03). AIMOG correlated with Expanded Disability Status Scale (EDSS) scores at disease nadir and at last follow-up (p=0.02 and p=0.01). CONCLUSIONS: Consistently with physiopathology, MOG-IgG ITS is a promising prognostic factor in MOGAD, and its calculation could enhance the clinical relevance of CSF MOG-IgG testing, making a case for its introduction in clinical practice.

Spinal Fluid Myeloid Microvesicles Predict Disease Course in Multiple Sclerosis.

OBJECTIVE: In vivo measures of myeloid activity are promising biomarkers in multiple sclerosis. We previously demonstrated that cerebrospinal fluid (CSF) myeloid microvesicles are markers of microglial/macrophage activity and neuroinflammation in multiple sclerosis. Here, we aimed at investigating the diagnostic and prognostic value of myeloid microvesicles in a clinical setting. METHODS: Six hundred one patients discharged with a diagnosis of neuroinflammatory, neurodegenerative, or no neurological disease were enrolled. Myeloid microvesicles were measured with flow cytometry as isolectin B4-positive events in fresh CSF. Clinical, demographical, and magnetic resonance imaging (MRI) data were collected at diagnosis (all patients) and during follow-up (n = 176). RESULTS: CSF myeloid microvesicles were elevated in neuroinflammatory patients compared to the neurodegenerative and control groups. In multiple sclerosis, microvesicles were higher in patients with MRI disease activity and their concentration increased along with the number of enhancing lesions (p < 0.0001, Jonckheere-Terpstra test). CSF myeloid microvesicles were also higher in patients with higher disease activity in the month and year preceding diagnosis. Microvesicles excellently discriminated between the relapsing-remitting and control groups (receiver operator characteristic curve, area under the curve = 0.939, p < 0.0001) and between radiologically isolated syndrome and unspecific brain lesions (0.942, p < 0.0001). Furthermore, microvesicles were independent predictors of prognosis for both the relapsing-remitting and progressive groups. Microvesicles independently predicted future disease activity in relapsing-remitting patients (hazard ratio [HR] = 1.967, 95% confidence interval [CI] = 1.147-3.372), correcting for prognostic factors of standard clinical use. In the progressive group, microvesicles were independent predictors of disability accrual (HR = 10.767, 95% CI = 1.335-86.812). INTERPRETATION: Our results confirm that CSF myeloid microvesicles are a clinically meaningful biomarker of neuroinflammation and microglial/macrophage activity in vivo. These findings may support a possible use in clinical practice during diagnostic workup and prognostic assessment. ANN NEUROL 2021;90:253-265.

As time goes by: Treatment challenges in elderly people with multiple sclerosis.

A demographic shift in multiple sclerosis (MS) is leading to an increased number of elderly people with MS (pwMS) and a rise in late-onset MS (LOMS) cases. This shift adds complexity to the treatment management of these patients, due to enhanced treatment-associated risks and the possible interplay between immunosenescence and disease-modifying therapies (DMTs). In the present paper, we performed a systematic review of the current evidence concerning the relationship between aging and treatment management in elderly pwMS. Our literature search identified 35 original studies relevant to this topic. The gathered evidence consistently indicates a diminished efficacy of DMTs in older pwMS, particularly in preventing disability accrual. Against this background, high-efficacy therapies (HETs) appear to show less benefit over moderate-low-efficacy DMTs in older patients. These data mainly derive from observational retrospective studies or meta-analyses conducted on randomized clinical trials (RCTs). RCTs, however, exclude pwMS older than 55 years, limiting our ability to acquire robust evidence regarding this patient group. Regarding treatment discontinuation in elderly pwMS with stable disease, the available data, which mainly focuses on older injectable DMTs, suggests that their suspension appears to be relatively safe in terms of disease activity. Nevertheless, the first RCT specifically targeting treatment discontinuation recently failed to demonstrate the non-inferiority of treatment discontinuation over continuation, in terms of MRI activity. On the other hand, the evidence on the impact of discontinuation on disease progression is more conflicting and less robust. Furthermore, there is an important lack of studies concerning sequestering DMTs and virtually no data on the discontinuation of anti-CD20 monoclonal antibodies. De-escalation strategy is gaining attention as a de-risking approach alternative to complete treatment discontinuation. It may be defined as the decision to shift from HETs to less potent DMTs in elderly pwMS who have a stable disease. This strategy could reduce treatment-related risks, while minimizing the risk of disease activity and progression potentially associated with treatment discontinuation. This approach, however, remains unexplored due to a lack of studies. Given these findings, the present scenario underlines the urgent need for more comprehensive and robust studies to develop optimized, data-driven treatment strategies for elderly pwMS and LOMS, addressing the unique challenges of MS treatment and aging.

Tixagevimab and cilgavimab use in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder during anti-CD20 treatment: A single-center experience.

BACKGROUND: B-cell-depleting treatments, such as ocrelizumab and rituximab (anti-CD20), reduce humoral response to SARS-CoV-2 in people with Multiple Sclerosis (pwMS) and Neuromyelitis Optica Spectrum Disorder (NMOSD) and are associated with an increased risk of a more severe course of COVID-19 disease. The combination of tixagevimab and cilgavimab was authorized for COVID-19 prevention in immunocompromised subjects at high risk of severe COVID-19 disease, including patients treated with anti-CD20. Few real-world studies are available regarding the use of tixagevimab/cilgavimab in pwMS/NMOSD. In the present study, we describe the use of tixagevimab/cilgavimab for SARS-CoV-2 pre-exposure prophylaxis in a cohort of pwMS and NMOSD, treated with ocrelizumab and rituximab respectively. METHODS: 26 subjects were treated with tixagevimab/cilgavimab, while we used 18 patients as the control group. We collected clinical data at baseline in all patients and during scheduled follow up evaluations. SARS-CoV-2 serological status pre- and post-tixagevimab/cilgavimab treatment was available for 10 patients. RESULTS: We observed no adverse events following tixagevimab/cilgavimab treatment. Post-tixagevimab/cilgavimab anti-Spike-1-RBD IgG were significantly higher when compared to baseline values. No difference was found when comparing the percentage of COVID-19 infections between groups. All patients infected with SARS-CoV-2 had mild disease which did not require hospitalization. In patients treated with tixagevimab/cilgavimab, the rate of infection among patients exposed to SARS-CoV-2 was lower, without reaching statistical significance. We observed a significantly longer negativization time in the treated group. CONCLUSIONS: Our results are not consistent with what was observed in the registration trial and some more recent studies. We did not observe a difference in COVID-19 incidence nor in disease severity in MS and NMOSD between treated and untreated patients. Our different results may be partially explained by the change in SARS-CoV-2 variants epidemiology (i.e. reduced efficacy of tixagevimab and cilgavimab against the currently dominant variants) as well as different patient selection included in the trial and different dose of tixagevimab/cilgavimab used in other studies. The present report provides a real-life experience with tixagevimab/cilgavimab in pwMS and NMOSD treated with anti-CD20, with findings that are in line with the current SARS-CoV-2 epidemiology and the recent evidence regarding SARS-CoV-2 variants. Our results warrant further research to best treat patients in the present and future pandemic scenario.

The impact of storage on extracellular vesicles: A systematic study.

Mounting evidence suggests that storage has an impact on extracellular vesicles (EVs) properties. While -80°C storage is a widespread approach, some authors proposed improved storage strategies with conflicting results. Here, we designed a systematic study to assess the impact of -80°C storage and freeze-thaw cycles on EVs. We tested the differences among eight storage strategies and investigated the possible fusion phenomena occurring during storage. EVs were collected from human plasma and murine microglia culture by size exclusion chromatography and ultracentrifugation, respectively. The analysis included: concentration, size and zeta potential (tunable resistive pulse sensing), contaminant protein assessment; flow cytometry for the analysis of two single fluorescent-tagged EVs populations (GFP and mCherry), mixed before preservation. We found that -80°C storage reduces EVs concentration and sample purity in a time-dependent manner. Furthermore, it increases the particle size and size variability and modifies EVs zeta potential, with a shift of EVs in size-charge plots. None of the tested conditions prevented the observed effects. Freeze-thaw cycles lead to an EVs reduction after the first cycle and to a cycle-dependent increase in particle size. With flow cytometry, after storage, we observed a significant population of double-positive EVs (GFP+ -mCherry+ ). This observation may suggest the occurrence of fusion phenomena during storage. Our findings show a significant impact of storage on EVs samples in terms of particle loss, purity reduction and fusion phenomena leading to artefactual particles. Depending on downstream analyses and experimental settings, EVs should probably be processed from fresh, non-archival, samples in majority of cases.

Encephalopathy as a prognostic factor in adults with acute disseminated encephalomyelitis following COVID-19.

Numerous reports support the possible occurrence of acute disseminated encephalomyelitis (ADEM) following COVID-19. Herein, we report a case of ADEM in a 53-year-old man 2 weeks after SARS-CoV-2 infection. We reviewed the reports of adult cases of ADEM and its variant acute necrotizing hemorrhagic leukoencephalitis (ANHLE) to check for possible prognostic factors and clinical/epidemiological peculiarities. We performed a descriptive analysis of clinical and cerebrospinal fluid data. Ordinal logistic regressions were performed to check the effect of clinical variables and treatments on ADEM/ANHLE outcomes. We also compared ADEM and ANHLE patients. We identified a total of 20 ADEM (9 females, median age 53.5 years) and 23 ANHLE (11 females, median age 55 years). Encephalopathy was present in 80% of ADEM and 91.3% of ANHLE patients. We found that the absence of encephalopathy predicts a better clinical outcome in ADEM (OR 0.027, 95% CI 0.001-0.611, p = 0.023), also when correcting for the other variables (OR 0.032, 95% CI 0.001-0.995, p = 0.05). Conversely, we identified no significant prognostic factor in ANHLE patients. ANHLE patients showed a trend towards a worse clinical outcome (lower proportion of good/complete recovery, 4.5% vs 16.7%) and higher mortality (36.4% vs 11.1%) as compared to ADEM. Compared to pre-pandemic ADEM, we observed a higher median age of people with post-COVID-19 ADEM and ANHLE, a shorter interval between infection and neurological symptoms, and a worse prognosis both in terms of high morbidity and mortality. Despite being affected by the retrospective nature of the study, these observations provide new insights into ADEM/ANHLE following SARS-CoV-2 infection.

Atrioventricular block after fingolimod resumption: a consequence of sphingosine-1-phosphate axis alteration due to COVID-19?

During the COVID-19 pandemic, concerns raised regarding the use of immunosuppressants in multiple sclerosis, even if current data do not support an increased risk of infection. Although fingolimod can be temporarily suspended during COVID-19, the benefit-risk balance of suspension can be challenging. Till now, no adverse events have been described after the resumption of fingolimod, following a previous discontinuation. We report the occurrence of atrioventricular block following fingolimod restart. Fingolimod acts on sphingosine-1-phosphate-axis, a pathway that is altered with COVID-19 and hypoxic conditions. Herein we discuss how these metabolic changes may have influenced fingolimod pharmacology leading to a cardiac event.

Neutrophil-to-lymphocyte ratio: a marker of neuro-inflammation in multiple sclerosis?

BACKGROUND: The significance of neutrophil-to-lymphocyte ratio (NLR) has been explored in different diseases. Few studies addressed its role in patients with multiple sclerosis (MS), with promising results regarding its association with disease activity or disability. OBJECTIVES: We aimed at confirming the role of NLR as a marker of neuro-inflammation in a cohort of newly diagnosed MS and clinically isolated syndrome (CIS) patients. Furthermore, we compared the validity of NLR with established markers of neuro-inflammation, such as serum neurofilament light chain (Nfl), CSF microvesicles (CSF-MVs) and CSF IgG indices. METHODS: We retrospectively selected, from a prospectively collected cohort of newly diagnosed MS/CIS patients hospitalized for diagnostic work-up, 121 patients who underwent CSF examination, brain MRI and blood cell count within the time of hospitalization and did not receive steroid treatment before sample collection. Patients were grouped according to presence of gadolinium enhancement at brain MRI. RESULTS: No association was found between NLR and disease activity, nor with other clinical measures. Nfl, CSF-MVs, Link and Tourtellotte indices were significantly higher in patients with brain MRI activity. CONCLUSIONS: Our negative results do not support the use of NLR as a marker of disease activity and disability in patients with MS.

Extracellular Vesicles in Neuroinflammation.

Extracellular vesicles (EVs) are a heterogenous group of membrane-bound particles that play a pivotal role in cell-cell communication, not only participating in many physiological processes, but also contributing to the pathogenesis of several diseases. The term EVs defines many and different vesicles based on their biogenesis and release pathway, including exosomes, microvesicles (MVs), and apoptotic bodies. However, their classification, biological function as well as protocols for isolation and detection are still under investigation. Recent evidences suggest the existence of novel subpopulations of EVs, increasing the degree of heterogeneity between EV types and subtypes. EVs have been shown to have roles in the CNS as biomarkers and vehicles of drugs and other therapeutic molecules. They are known to cross the blood brain barrier, allowing CNS EVs to be detectable in peripheral fluids, and their cargo may give information on parental cells and the pathological process they are involved in. In this review, we summarize the knowledge on the function of EVs in the pathogenesis of multiple sclerosis (MS) and discuss recent evidences for their potential applications as diagnostic biomarkers and therapeutic targets.

Diagnosing autoimmune encephalitis in a real-world single-centre setting.

BACKGROUND: Early recognition and treatment of autoimmune encephalitis (AE) are crucial for patients, but diagnosis is often difficult and time-consuming. For this purpose, a syndrome-based diagnostic approach was published by Graus et al. (Lancet Neurol 15:391-404, 2016), but very little is known in the literature about its application in clinical practice. AIM: Our aims are to test the feasibility of such approach in a real-world single-centre setting and to analyse the most relevant factors in criteria fulfilment. METHODS: We retrospectively applied these criteria to our cohort of patients discharged from our hospital with diagnosis of autoimmune encephalitis (n = 33, 58% antibody-positive). RESULTS: All the subjects fulfilled criteria for possible AE (pAE), with EEG and MRI playing a central role in diagnosis, while CSF was useful mainly to rule out other conditions. Three patients respected criteria for probable anti-NMDA-R encephalitis (pNMDA). Definite anti-NMDAR encephalitis was diagnosed in 4 patients with detection of the autoantibody but, surprisingly, none of these subjects had fulfilled criteria for pNMDA. 18 patients were diagnosed with definite limbic AE (15 patients were antibody-positive, three antibody-negative). Need for MRI bilateral involvement in antibody-negative limbic AE limited diagnosis. One patient fulfilled criteria for probable antibody-negative AE, while ten patients remained classified as pAE. CONCLUSION: From our retrospective analysis, some suggestions for a better definition of the criteria may emerge. Larger studies on prospective cohorts may be more helpful to explore possible important issues.