The relationship between serum astroglial and neuronal markers and AQP4 and MOG autoantibodies.

BACKGROUND: Certain demyelinating disorders, such as neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) exhibit serum autoantibodies against aquaporin-4 (αAQP4) and myelin oligodendrocyte glycoprotein (αMOG). The variability of the autoantibody presentation warrants further research into subtyping each case. METHODS: To elucidate the relationship between astroglial and neuronal protein concentrations in the peripheral circulation with occurrence of these autoantibodies, 86 serum samples were analyzed using immunoassays. The protein concentration of glial fibrillary acidic protein (GFAP), neurofilament light chain (NFL) and tau protein was measured in 3 groups of subcategories of suspected NMOSD: αAQP4 positive (n = 20), αMOG positive (n = 32) and αMOG/αAQP4 seronegative (n = 34). Kruskal-Wallis analysis, univariate predictor analysis, and multivariate logistic regression with ROC curves were performed. RESULTS: GFAP and NFL concentrations were significantly elevated in the αAQP4 positive group (p = 0.003; p = 0.042, respectively), and tau was elevated in the αMOG/αAQP4 seronegative group (p < 0.001). A logistic regression model to classify serostatus was able to separate αAQP4 seropositivity using GFAP + tau, and αMOG seropositivity using tau. The areas under the ROC curves (AUCs) were 0.77 and 0.72, respectively. Finally, a combined seropositivity versus negative status logistic regression model was generated, with AUC = 0.80. CONCLUSION: The 3 markers can univariately and multivariately classify with moderate accuracy the samples with seropositivity and seronegativity for αAQP4 and αMOG.

Proportion of Life Spent in Canada and the Incidence of Multiple Sclerosis in Permanent Immigrants.

BACKGROUND AND OBJECTIVES: While immigrants to high-income countries have a lower risk of multiple sclerosis (MS) compared with host populations, it is unknown whether this lower risk among immigrants increases over time. Our objective was to evaluate the association between proportion of life spent in Canada and the hazard of incident MS in Canadian immigrants. METHODS: We conducted a population-based retrospective cohort study in Ontario, using linked health administrative databases. We followed immigrants, who arrived in Ontario between 1985 and 2003, from January 1, 2003, to December 31, 2016, to record incident MS using a validated algorithm based on hospital admission or outpatient visits. We derived proportion of life spent in Canada based on age at arrival and time since immigration obtained from linked immigration records. We used multivariable proportional hazard models, adjusting for demographics and comorbidities, to evaluate the association between proportion of life in Canada and the incidence of MS, where proportion of life was modelled using restricted cubic spline terms. We further evaluated the role of age at migration (15 or younger vs older than 15 years), sex, and immigration class in sensitivity analyses. RESULTS: We included 1.5 million immigrants (49.9% female, mean age 35.9 [SD 14.2] years) who had spent a median of 20% (Q1-Q3 10%-30%) of their life in Canada. During a mean follow-up of 13.9 years (SD 1.0), 934 (0.44/100,000 person-years) were diagnosed with MS. Compared with the median, a higher risk of MS was observed at higher values of proportion of life spent (e.g., hazard ratio [70% vs 20% proportion of life] 1.38; 1.07-1.78). This association did not vary by sex (p(sex × proportion of life) = 0.70) or immigration class (p(immigration class × proportion of life) = 0.13). The results did not vary by age at migration but were statistically significant only at higher values of proportion of life for immigrants aged 15 years or younger at arrival. DISCUSSION: The risk of incident MS in immigrants varied with the proportion of life spent in Canada, suggesting an acculturation effect on MS risk. Further work is required to understand environmental and sociocultural factors driving the observed association.

Myelin oligodendrocyte glycoprotein antibody titers by fixed cell-based assay: positive predictive value and impact of sample collection timing.

Introduction: In January 2023, our laboratory began performing serum myelin oligodendrocyte glycoprotein antibody (anti-MOG) titers by fixed cell-based assay (CBA). As a quality assurance (QA) assessment, we evaluated titer positive predictive value (PPV) as well as impact of sample collection timing on titers. Methods: Among patients who underwent antibody titers to distinguish between low-positive (<1:100) and clear-positive (≥1:100) anti-MOG, records were reviewed to classify results as true-positive (TP) or false-positive (FP) and facilitate PPV calculation. Timing of sample collection relative to administration of immunotherapy and symptom onset was determined for TP results. Results: Overall PPV of anti-MOG was 70/85 (82%). The PPV of low-positive anti-MOG was significantly lower than clear-positive anti-MOG (72% vs. 95%, p = 0.009). The difference in PPV between low-positive and clear-positive anti-MOG was significant among adults tested, but not children. Among patients with TP anti-MOG, the proportion who received immunotherapy prior to sample collection was significantly higher and median time from symptom onset to sample collection was significantly longer for low-positive compared to clear-positive results. Conclusion: Overall PPV of anti-MOG testing by fixed CBA was reasonably high. The PPV of low-positive anti-MOG was significantly lower than clear-positive anti-MOG. This was driven by the significantly lower PPV of low-positive anti-MOG in adults, possibly reflecting the lower prevalence of MOG antibody-associated disease among adults tested. Timing of sample collection relative to administration of immunotherapy and symptom onset may substantially impact titers, indicating that testing should ideally be performed prior to immunotherapy and close to time of attack.

Predicting time to serologic diagnosis of AQP4+ NMOSD based on clinical factors and social determinants of health.

BACKGROUND: Early serologic diagnosis and initiation of targeted therapy are associated with better outcomes in aquaporin-4 IgG positive (AQP4+) neuromyelitis optica spectrum disorder (NMOSD). OBJECTIVE: To determine predictors of time to serologic diagnosis of AQP4+ NMOSD. METHODS: In CANOPTICS, a multi-centre, Canadian cohort study of NMOSD, we retrospectively evaluated time from the first clinical attack to first positive AQP4-IgG serology. We used a multivariable negative binomial regression model to evaluate possible predictors of time to diagnosis. RESULTS: We identified 129 participants with AQP4+ NMOSD from 7 centres. Diagnostic delay of >1 month was observed in 82 (63.6 %). Asian compared to European (White) ethnicity (IRR:0.40, 95 % CI:0.21-0.78), female sex (IRR:0.56, 95 % CI:0.32-0.99), later calendar year (IRR:0.84, 95 % CI:0.81-0.86), and hospitalization for the first attack (IRR:0.35, 95 % CI:0.20-0.62) were associated with shorter times to serologic diagnosis. We did not observe any overall effect of Afro-Caribbean ethnicity, but in exploratory analyses, Afro-Caribbean individuals with low income had longer times to diagnosis. CONCLUSION: More than 60 % of patients with NMOSD experienced delays to AQP4-IgG serologic diagnosis in this cohort. Given evidence of more adverse long-term outcomes in Afro-Caribbean individuals with NMOSD, intersectional effects of ethnicity and social determinants of health merit further study.

The relationship between serum astroglial and neuronal markers and AQP4 and MOG autoantibodies.

Background: Certain demyelinating disorders, such as neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) exhibit serum autoantibodies against aquaporin-4 (αAQP4) and myelin oligodendrocyte glycoprotein (αMOG). The variability of the autoantibody presentation warrants further research into subtyping each case. Methods: To elucidate the relationship between astroglial and neuronal protein concentrations in the peripheral circulation with occurrence of these autoantibodies, 86 serum samples were analyzed using immunoassays. The protein concentration of glial fibrillary acidic protein (GFAP), neurofilament light chain (NFL) and tau protein was measured in 3 groups of subcategories of suspected NMOSD: αAQP4 positive (n = 20), αMOG positive (n = 32) and αMOG/αAQP4 seronegative (n = 34). Kruskal-Wallis analysis, univariate predictor analysis, and multivariate logistic regression with ROC curves were performed. Results: GFAP and NFL concentrations were significantly elevated in the αAQP4 positive group (p = 0.003; p = 0.042, respectively), and tau was elevated in the αMOG/αAQP4 seronegative group (p < 0.001). A logistic regression model to classify serostatus was able to separate αAQP4 seropositivity using GFAP + tau, and αMOG seropositivity using tau. The areas under the ROC curves (AUCs) were 0.77 and 0.72, respectively. Finally, a combined seropositivity versus negative status logistic regression model was generated, with AUC = 0.80. Conclusion: The 3 markers can univariately and multivariately classify with moderate accuracy the samples with seropositivity and seronegativity for αAQP4 and αMOG.

A Canadian case control study investigating demographic and environmental factors associated with MOGAD.

BACKGROUND: Little is known about demographic and environmental factors associated with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). OBJECTIVE: To investigate factors associated with MOGAD using a case-control design and validated questionnaire from the Environmental Risk Factors in Multiple Sclerosis Study (EnvIMS). METHODS: We enrolled patients with positive MOG antibody serology and diagnosis of MOGAD at six Canadian centres. MOGAD participants completed the EnvIMS questionnaire, and were compared to unaffected controls from the Canadian arm of EnvIMS. We calculated crude and adjusted odds ratios (OR) using logistic regression models and Firth's procedure for rare events. RESULTS: We enrolled 39 MOGAD participants with mean (SD) age 45.0 (14.4) years, 28 (71.8 %) women, 25 (64.1 %) White, 26 (66.7 %) residents of Ontario, and mean BMI 28.6 (7.1). They were compared to 956 controls. Using multivariable logistic regression, larger body size at age 10 years (OR: 3.57, 95 % CI:1.23 - 10.33) and non-White ethnicity (OR:3.81, 95 % CI:1.93-7.54) were associated with higher odds of MOGAD. Among Ontario residents, current BMI ≥30 was associated with higher odds of MOGAD (OR:2.79, 95 % CI:1.03-7.53). CONCLUSION: Our findings are hypothesis-generating due to the sample size, but suggest that obesity and ethnicity should be explored as potential risk factors for MOGAD in other settings.

Etiology, effects and management of comorbidities in multiple sclerosis: recent advances.

Comorbid conditions commonly affect people with multiple sclerosis (MS). Population-based studies indicate that people with MS have an increased incidence of ischemic heart disease, cerebrovascular disease, peripheral vascular disease, and psychiatric disorders as compared to people without MS. People with MS from underrepresented minority and immigrant groups have higher comorbidity burdens. Comorbidities exert effects throughout the disease course, from symptom onset through diagnosis to the end of life. At the individual level, comorbidity is associated with higher relapse rates, greater physical and cognitive impairments, lower health-related quality of life, and increased mortality. At the level of the health system and society, comorbidity is associated with increased health care utilization, costs and work impairment. A nascent literature suggests that MS affects outcomes from comorbidities. Comorbidity management needs to be integrated into MS care, and this would be facilitated by determining optimal models of care.

International Delphi Consensus on the Management of AQP4-IgG+ NMOSD: Recommendations for Eculizumab, Inebilizumab, and Satralizumab.

BACKGROUND AND OBJECTIVES: Neuromyelitis optica spectrum disorder (NMOSD) is a rare debilitating autoimmune disease of the CNS. Three monoclonal antibodies were recently approved as maintenance therapies for aquaporin-4 immunoglobulin G (AQP4-IgG)-seropositive NMOSD (eculizumab, inebilizumab, and satralizumab), prompting the need to consider best practice therapeutic decision-making for this indication. Our objective was to develop validated statements for the management of AQP4-IgG-seropositive NMOSD, through an evidence-based Delphi consensus process, with a focus on recommendations for eculizumab, inebilizumab, and satralizumab. METHODS: We recruited an international panel of clinical experts in NMOSD and asked them to complete a questionnaire on NMOSD management. Panel members received a summary of evidence identified through a targeted literature review and provided free-text responses to the questionnaire based on both the data provided and their clinical experience. Responses were used to generate draft statements on NMOSD-related themes. Statements were voted on over a maximum of 3 rounds; participation in at least 1 of the first 2 rounds was mandatory. Panel members anonymously provided their level of agreement (6-point Likert scale) on each statement. Statements that failed to reach a predefined consensus threshold (≥67%) were revised based on feedback and then voted on in the next round. Final statements were those that met the consensus threshold (≥67%). RESULTS: The Delphi panel comprised 24 experts, who completed the Delphi process in November 2021 after 2 voting rounds. In round 1, 23/25 statements reached consensus and were accepted as final. The 2 statements that failed to reach consensus were revised. In round 2, both revised statements reached consensus. Twenty-five statements were agreed in total: 11 on initiation of or switching between eculizumab, inebilizumab, and satralizumab; 3 on monotherapy/combination therapy; 7 on safety and patient population considerations; 3 on biomarkers/patient-reported outcomes; and 1 on research gaps. DISCUSSION: An established consensus method was used to develop statements relevant to the management of AQP4-IgG-seropositive NMOSD. These international statements will be valuable for informing individualized therapeutic decision-making and could form the basis for standardized practice guidelines.

A national case-control study investigating demographic and environmental factors associated with NMOSD.

BACKGROUND: Risk factors for aquaporin-4 (AQP4+) antibody neuromyelitis optica spectrum disorder (NMOSD) are not well-established. OBJECTIVE: To investigate demographic and environmental factors associated with NMOSD using a validated questionnaire and case-control design. METHODS: We enrolled patients with AQP4 + NMOSD through six Canadian Multiple Sclerosis Clinics. Participants completed the validated Environmental Risk Factors in Multiple Sclerosis Study (EnvIMS) questionnaire. Their responses were compared to those of 956 unaffected controls from the Canadian arm of EnvIMS. We calculated odds ratios (ORs) for the association between each variable and NMOSD using logistic regression and Firth's procedure for rare events. RESULTS: In 122 participants (87.7% female) with NMOSD, odds of NMOSD in East Asian and Black participants were ⩾8 times that observed in White participants. Birthplace outside Canada was associated with an increased risk of NMOSD (OR = 5.5, 95% confidence interval (CI) = 3.6-8.3) as were concomitant autoimmune diseases (OR = 2.7, 95% CI = 1.4-5.0). No association was observed with reproductive history or age at menarche. CONCLUSION: In this case-control study, risk of NMOSD in East Asian and Black versus White individuals was greater than that observed in many previous studies. Despite the preponderance of affected women, we did not observe any association with hormonal factors such as reproductive history or age at menarche.

A prospective study of disease modifying therapy and retinal atrophy in relapsing-remitting multiple sclerosis.

BACKGROUND: To compare the rate of retinal atrophy over time in patients with relapsing-remitting multiple sclerosis (RRMS) treated with various disease-modifying therapies (DMT). METHODS: Patients with RRMS on various DMT and those observed without treatment were prospectively enrolled into the study between September 2015 and June 2018. All subjects with follow-up of 1-4 years were included and categorized into groups as "no drug", "low efficacy drug", "high efficacy drug", or "dimethyl fumarate" (DMF), based on treatment modality used for the longest duration of their follow-up. Ocular coherence tomography (OCT) was used to measure peripapillary retinal nerve fiber layer thickness (RNFL) and ganglion cell/inner plexiform layer (GC-IPL) thickness at baseline and every 6 months. A linear mixed effects regression model was performed to compare rates of retinal atrophy across treatment groups. RESULTS: Out of 67 participants who met inclusion criteria (mean age = 37; 76% female), 13 were untreated, 12 on low efficacy therapy, 18 on DMF, and 24 on high efficacy therapy. History of optic neuritis was associated with lower baseline GC-IPL thickness (p = 0.003). Higher baseline GC-IPL thickness was associated with increased rate of GC-IPL thinning (p = 0.009). Age, disease duration, and ethnicity were not predictors of baseline RNFL or GC-IPL thickness, or rate of atrophy of these layers. CONCLUSIONS: There were no differences in rate of GC-IPL atrophy between patients with RRMS on different treatments in this cohort. Age, disease duration, and ethnicity also did not predict retinal atrophy. History of ON was associated with reduced GC-IPL thickness at baseline, consistent with previous research. Rate of GC-IPL thinning was higher for subjects with higher baseline GC-IPL thickness, suggesting a plateau effect.

Association of NEDA-4 With No Long-term Disability Progression in Multiple Sclerosis and Comparison With NEDA-3: A Systematic Review and Meta-analysis.

BACKGROUND AND OBJECTIVES: No evidence of disease activity (NEDA)-4 has been suggested as a treatment target for disease-modifying therapy (DMT) in relapsing-remitting multiple sclerosis (RRMS). However, the ability of NEDA-4 to discriminate long-term outcomes in MS and how its performance compares with NEDA-3 remain uncertain. We conducted a systematic review and meta-analysis to evaluate (1) the association between NEDA-4 and no long-term disability progression in MS and (2) the comparative performance of NEDA-3 and NEDA-4 in predicting no long-term disability progression. METHODS: English-language abstracts and manuscripts were systematically searched in MEDLINE, Embase, and the Cochrane databases from January 2006 to November 2021 and reviewed independently by 2 investigators. We selected studies that assessed NEDA-4 at 1 or 2 years after DMT start and had at least 4 years of follow-up for determination of no confirmed disability progression. We conducted a meta-analysis using random-effects model to determine the pooled odds ratio (OR) for no disability progression with NEDA-4 vs EDA-4. For the comparative analysis, we selected studies that evaluated both NEDA-3 and NEDA-4 with at least 4 years of follow-up and examined the difference in the association of NEDA-3 and NEDA-4 with no disability progression. RESULTS: Five studies of 1,000 patients (3 interferon beta and 2 fingolimod) met inclusion criteria for both objectives. The median duration of follow-up was 6 years (interquartile range: 4-6 years). The prevalence of NEDA-4 ranged from 4.2% to 13.9% on interferon beta therapy and 24.9% to 25.1% on fingolimod therapy. The pooled OR for no long-term confirmed disability progression with NEDA-4 vs EDA-4 was 2.14 (95% confidence interval: 1.36-3.37; I2 = 0). We did not observe any significant difference between NEDA-4 and NEDA-3 in the comparative analyses. DISCUSSION: In patients with RRMS, NEDA-4 at 1-2 years was associated with 2 times higher odds of no long-term disability progression, at 6 years compared with EDA-4, but offered no advantage over NEDA-3.

Chronic Cognitive Impairment in AQP4+ NMOSD With Improvement in Cognition on Eculizumab: A Report of Two Cases.

Cognitive impairment may be associated with aquaporin-4 antibody positive (AQP4+) NMOSD, particularly where there is prominent cerebral, corpus callosum, or thalamic involvement. It is unclear to what extent this phenomenon may be treatable after months to years. We describe two cases of AQP4+ NMOSD with cognitive impairment persisting over more than 6 months, where cognition improved after eculizumab was initiated. In the first case, a 51-year-old woman presented with a 2-month history of cognitive decline and ataxia, and diffuse involvement of the corpus callosum on MRI. AQP4 antibody testing returned positive. Cognitive impairment persisted on therapy with mycophenolate, then rituximab. She was switched to eculizumab from rituximab 18 months after disease onset because of breakthrough optic neuritis; memory and cognitive function improved on eculizumab. In the second case, a 26-year-old woman initially presented with visual, auditory and tactile hallucinations, and impairment in activities of daily living, and was given a diagnosis of schizophrenia. Nine months later she was hospitalized for increasing confusion. MRI showed leukoencephalopathy and diffuse involvement of the corpus callosum with multiple enhancing callosal lesions. AQP4 antibody testing was positive and CSF testing for other antibodies of autoimmune encephalitis was negative. She had some improvement in cognition with high dose corticosteroids but remained significantly impaired. On follow-up, her repeat MRI showed a small new right inferomedial frontal enhancing lesion although she did not complain of any new cognitive issues, her MOCA score was 21/30, and she was started on eculizumab. Two months after eculizumab initiation she and her family reported cognitive improvement and MOCA score was 25/30. Common features of these two cases included extensive callosal involvement and an element of ongoing gadolinium enhancement on MRI. Our experience suggests the possibility that cognitive impairment may be amenable to immunotherapy in certain cases of NMOSD.

Association of No Evidence of Disease Activity With No Long-term Disability Progression in Multiple Sclerosis: A Systematic Review and Meta-analysis.

OBJECTIVE: We conducted a systematic review and meta-analysis to evaluate the relationship between No Evidence of Disease Activity (NEDA) and no long-term disability progression on low and high efficacy therapy in relapsing-remitting multiple sclerosis (RRMS). METHODS: MEDLINE, Embase, and the Cochrane Database were searched from January 1, 2006 to January 26, 2021. We selected studies which evaluated NEDA-3 (no relapse, new MRI lesion, or confirmed disability progression) at one or two years and had a minimum of four years' follow-up for determination of disability progression. Data were extracted by two independent reviewers and were meta-analyzed using a random effects model. Primary outcome of no disability progression was defined as no confirmed progression on the Expanded Disability Status Scale (EDSS) during follow-up. We assessed the odds ratio for no disability progression with NEDA vs. Evidence of Disease Activity (EDA). Positive predictive value of NEDA for no disability progression was summarized for studies with prevalence of no progression >80% vs. <80% separately. RESULTS: We included 29 studies in our qualitative synthesis of which 27 (16 low efficacy, 11 high efficacy) were included in the meta-analysis (n=10,935 participants). Median follow-up was 5.6 years (IQR: 4.3, 8.0 years). The pooled odds ratios for no progression with NEDA-3 vs. EDA were 2.32 (95% CI: 1.58-3.42; I2=73%) for low efficacy therapy and 3.19 (1.86-5.47; I2=86%) for high efficacy therapy. Among studies with prevalence of no progression at follow-up >80%, the pooled positive predictive value for low efficacy therapy was 91% (95% CI: 89-93%) and for high efficacy therapy was 92% (95% CI: 88-94%). Among studies with prevalence of no progression <80%, the pooled positive predictive value for low efficacy therapy was 81% (95% CI: 75-86%) and for high efficacy therapy was 86% (95% CI: 80-90%). CONCLUSIONS: NEDA-3 is associated with no long-term disability progression in RRMS on both low and high efficacy therapies. Further studies of early composite outcome measures incorporating easily measurable biomarkers, and longer follow-up, may help to improve on prognostic value of NEDA-3 in RRMS.

Clinical characteristics and outcomes of multiple sclerosis patients with COVID-19 in Toronto, Canada.

OBJECTIVE: To report clinical characteristics and outcomes of people with multiple sclerosis (PwMS) who developed COVID-19 infection in Toronto, Canada. METHODS: Descriptive, retrospective, single-center study that included all known PwMS at the St. Michael's Hospital MS Clinic who had PCR-confirmed COVID-19 infection between March 2020 and May 2021. RESULTS: Of 7000 PwMS in our clinic, 80 (1.1%) tested positive for SARS-CoV-2. Fifty-four (67.5%) were on disease-modifying therapy (DMT) without over-representation of any single treatment. Seventy-one patients (88.8%) had mild symptoms, but nine (11.3%) were hospitalized and one 70-year-old male patient not on treatment died. Of those hospitalized, one-third were treated with ocrelizumab. CONCLUSION: In Toronto, PwMS did not appear to have higher prevalence of COVID-19 infection compared to the general population, but disease severity may be affected by DMT use. Our findings add to the accumulating global data regarding COVID-19 infection in PwMS.

Pathobiology, Diagnosis, and Current Biomarkers in Neuromyelitis Optica Spectrum Disorders.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is characterized by chronic inflammation of the central nervous system (CNS), particularly the optic nerves and spinal cord. Although it displays some clinical features similar to multiple sclerosis (MS), the etiology and treatment are distinct, and therefore accurate diagnosis is essential. Autoantibodies targeting the water channel protein aquaporin-4 (AQP4) and the myelin sheath protein myelin oligodendrocyte glycoprotein are the major antigen-specific serological biomarkers known to date, with destruction of astrocytes as the primary mode of CNS damage in AQP4-positive disease. CONTENT: This mini-review summarizes the pathobiology, clinical features, and current methods of serological testing used to assess NMOSD and differentiate this disorder from MS. A brief summary of emerging therapies is also presented. SUMMARY: NMOSD can be distinguished from MS through a combination of clinical findings, imaging investigations, and serological analysis. Seronegative cases are particularly difficult to diagnose and can pose a challenge to clinicians. As knowledge deepens, new therapies and biomarkers are expected to improve treatment of this rare debilitating disease.