Systematic literature review and meta-analysis of the prevalence of secondary progressive multiple sclerosis in the USA, Europe, Canada, Australia, and Brazil.

BACKGROUND: Secondary progressive multiple sclerosis (SPMS) is a subtype of multiple sclerosis (MS), which is a chronic neurological disease, characterised by inflammation of the central nervous system. Most of MS patients eventually progress to SPMS. This study estimates the prevalence of SPMS in the United States of America, Europe, Canada, Australia, and Brazil. METHODS: A systematic literature search of the Medline and Embase databases was performed using the OVID™ SP platform to identify MS epidemiological studies published in English from database inception to September 22, 2020. Studies reporting the prevalence of MS and proportion of SPMS patients in the included population were selected. The pooled prevalence of SPMS was calculated based on the proportion of SPMS patients. The Loney quality assessment checklist was used for quality grading. A meta-analysis of the proportions was conducted in RStudio. RESULTS: A total of 4754 articles were retrieved, and prevalence was calculated from 97 relevant studies. Overall, 86 medium- and high-quality studies were included in the meta-analysis. Most studies were conducted in European countries (84 studies). The estimated pooled prevalence of SPMS was 22.42 (99% confidence interval: 18.30, 26.95)/100,000. The prevalence of SPMS was more in the North European countries, highest in Sweden and lowest in Brazil. A decline in SPMS prevalence was observed since the availability of oral disease-modifying therapies. We also observed a regional variation of higher SPMS prevalence in urban areas compared with rural areas. CONCLUSION: High variability was observed in the estimated SPMS prevalence, and the quality of the studies conducted. The influence of latitude and other factors known to affect overall MS prevalence did not fully explain the wide range of inter-country and intra-country variability identified in the results.

The four self-efficacy trajectories among people with multiple sclerosis: Clinical associations and implications.

BACKGROUND: Longitudinal studies among people with Multiple Sclerosis (pwMS) have shown that self-efficacy is linked to physical, cognitive and psychological functioning. OBJECTIVES: To determine the distribution of self-efficacy in a large sample of pwMS, examining whether there are distinct groups which show different self-efficacy trajectories over time, and the health status characteristics of any groups identified. METHODS: Participants completed serial questionnaire packs, including Unidimensional Self-efficacy-MS (USE-MS) scale, for the Trajectories of Outcome in Neurological Conditions-MS (TONiC-MS) study over an average 46-month period. The resulting longitudinal data were analysed by a group-based trajectory model. RESULTS: 5887 pwMS were studied: mean age 50.2 years (SD 12.0); 73.6% female; Relapsing Remitting MS (61.8%), Secondary Progressive (22.9%), Primary Progressive (11.1%), Rapidly Evolving Relapsing Remitting MS (4.2%). Four distinct self-efficacy trajectories emerged, with declining, slightly declining, stable or improving self-efficacy, each showing different patterns of health status indicators such as EQ-5D-5L, disability and depression. USE-MS ≤ 18 at baseline detected all participants in the two declining groups. CONCLUSION: Future trials on interventions for self-efficacy should assume a priori that those with low levels of self-efficacy (USE-MS ≤ 18 at baseline) are likely to be on a declining trajectory and may need different interventions from those with stable self-efficacy.

Paediatric myasthenia gravis: Prognostic factors for drug free remission.

Our aim was to identify clinical outcomes, serological features and possible prognostic indicators of paediatric myasthenia gravis (MG). We collected 74 MG patients with disease onset before the age of 16 years (73% pre-pubertal onset defined as ≤10 years), seen regularly at two UK specialist centres, over a period of 11 years. The cohort was multi-ethnic, with a high number of non-Caucasians (52%). Ocular presentation was seen in 38 (51%) and only 8 (21%) of these generalised. Fifty-two (70%) patients had antibodies to the acetylcholine receptor (AChR) measured by radioimmunoprecipitation, 10 (14%) had antibodies only to clustered AChRs detected by a cell based assay, 3 (4%) had muscle-specific kinase and one (1%) low-density lipoprotein receptor-related protein 4 antibody. Only 8 (11%) had no detectable antibodies. Seventeen patients attained drug free remission (Kaplan Meyer survival curve estimates 25% by 7 years). Several factors were associated with a higher likelihood of free remission: onset age ≤10 years, Asian and Caucasian races, lack of AChR antibodies on RIA, and normal repetitive nerve stimulation at diagnosis. However, in a multifactorial regression analysis, the antibody status was the only significant predictor for drug free remission, with 60% of patients with antibodies only to clustered AChR achieving this outcome. Complete drug free remission is not uncommon in paediatric MG and several factors appear to influence this outcome with antibody status being the most important. These factors can be easily evaluated at diagnosis, and may help to determine whose patients are likely to require more intensive treatments.

MAGNIMS consensus recommendations on the use of brain and spinal cord atrophy measures in clinical practice.

Early evaluation of treatment response and prediction of disease evolution are key issues in the management of people with multiple sclerosis (MS). In the past 20 years, MRI has become the most useful paraclinical tool in both situations and is used clinically to assess the inflammatory component of the disease, particularly the presence and evolution of focal lesions - the pathological hallmark of MS. However, diffuse neurodegenerative processes that are at least partly independent of inflammatory mechanisms can develop early in people with MS and are closely related to disability. The effects of these neurodegenerative processes at a macroscopic level can be quantified by estimation of brain and spinal cord atrophy with MRI. MRI measurements of atrophy in MS have also been proposed as a complementary approach to lesion assessment to facilitate the prediction of clinical outcomes and to assess treatment responses. In this Consensus statement, the Magnetic Resonance Imaging in MS (MAGNIMS) study group critically review the application of brain and spinal cord atrophy in clinical practice in the management of MS, considering the role of atrophy measures in prognosis and treatment monitoring and the barriers to clinical use of these measures. On the basis of this review, the group makes consensus statements and recommendations for future research.

A multicentre randomiSed controlled TRial of IntraVEnous immunoglobulin compared with standard therapy for the treatment of transverse myelitis in adults and children (STRIVE).

BACKGROUND: Transverse myelitis (TM) is an immune-mediated disorder of the spinal cord that affects adults and children and that causes motor, sensory and autonomic dysfunction. There is a prolonged recovery phase, which may continue for many years. Neuromyelitis optica (NMO) is an uncommon relapsing inflammatory central nervous system condition in which TM can be the first presenting symptom. As TM and NMO affect many patients in the prime of their working life, the disorder can impose a significant demand on health resources. There are currently no robust controlled trials in children or adults to inform the optimal treatment of TM. However, treatment with intravenous immunoglobulin (IVIG) is being effectively used in the management of a range of neurological conditions. Although other interventions such as plasma exchange (PLEX) in addition to intravenous (IV) methylprednisolone therapy can be beneficial in TM, PLEX is costly and technically challenging to deliver in the acute setting. IVIG is more readily accessible and less costly. OBJECTIVE: To evaluate whether additional and early treatment with IVIG is of extra benefit in TM compared with standard therapy with IV steroids. DESIGN: A multicentre, single-blind, parallel-group randomised controlled trial of IVIG compared with standard therapy for the treatment of TM in adults and children. PARTICIPANTS: Patients aged ≥ 1 year diagnosed with either acute first-onset TM or first presentation of NMO. Target recruitment was 170 participants (85 participants per arm). INTERVENTIONS: Participants were randomised 1 : 1 to treatment with IV methylprednisolone only or treatment with IV methylprednisolone plus 2 g/kg of IVIG in divided doses within 5 days of the first commencement of steroid therapy. MAIN OUTCOME MEASURES: Primary outcome measure - American Spinal Injury Association (ASIA) Impairment Scale at 6 months post randomisation, with a good outcome defined by a two-grade change. Secondary and tertiary outcome measures - ASIA motor and sensory scales, Expanded Disability Status Scale, health outcome, quality of life, Client Service Receipt Inventory and International Spinal Cord Injury Pain, Bladder and Bowel Basic Data Sets. RESULTS: In total, 26 participants were screened and two were randomised into the study. With the limited sample size, treatment effect could not be determined. However, we identified barriers to accrual that included strict inclusion criteria, the short enrolment window, challenges associated with the use of the ASIA Impairment Scale as an outcome measure and estimation of the incidence of TM. CONCLUSIONS: The study did not reach the end point and the effect of IVIG in TM/NMO could not be determined. Investigators should be aware of the potential challenges associated with carrying out a rare disease trial with a short enrolment window. The study question is one that still necessitates investigation. Preliminary work to ameliorate the effect of the barriers encountered in this study is vital. TRIAL REGISTRATION: EudraCT 2014-002335-34, ClinicalTrials.gov NCT02398994 and Current Controlled Trials ISRCTN12127581. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 31. See the NIHR Journals Library website for further project information. Funding was also received from Biotest AG, Germany (supply of IVIG) and the Transverse Myelitis Society (excess research cost to facilitate study initiation).

Therapeutic options in neuromyelitis optica spectrum disorders.

Neuromyelitis optica is a relapsing inflammatory disorder of the central nervous system that manifests predominantly with attacks of optic neuritis and longitudinally extensive transverse myelitis; attacks are often severe. In contrast to multiple sclerosis, a secondary progressive phase is rare, and disability in neuromyelitis optica spectrum disorders is related to relapses. Thus, prompt and effective treatment of relapses, and early initiation of long-term immunosuppression to prevent subsequent attacks is required in order to prevent morbidity and mortality.

Aquaporin-4 antibody isoform binding specificities do not explain clinical variations in NMO.

OBJECTIVE: To assess the clinical relevance of the differential binding of antibodies against the 2 main aquaporin-4 (AQP4) isoforms in neuromyelitis optica (NMO) patient sera using stably transfected human embryonic kidney cells. METHODS: Flow cytometry of human embryonic kidney cells stably transfected with either M23 or M1 AQP4 was used to measure antibody endpoint titers in 52 remission samples and 26 relapse samples from 34 patients with clinically well-characterized AQP4 antibody-positive NMO/NMO spectrum disorder. RESULTS: The AQP4 M23 (40-61,440) and AQP4 M1 (<20-20,480) titers varied widely between patients, as did the M23:M1 antibody ratio (1-192). In 76 of 78 samples, binding to M23 was higher than binding to M1, including during relapses and remissions (p < 0.0001), and the M23:M1 ratio was relatively constant within an individual patient. Titers usually fell after immunosuppression, but the titers at which relapses occurred varied markedly; no threshold level for relapses could be identified, and relapses could occur without a rise in titers. Relapse severity did not correlate with M23 or M1 antibody titers, although there was a correlation between the earliest M23 titers and annualized relapse rates. The M23:M1 ratio and absolute M23 and M1 titers did not relate to age at disease onset, ethnicity, disease severity, phenotype, or relapses at different anatomical sites. CONCLUSION: Relative AQP4 antibody binding to M23 and M1 isoforms differs between patients but there is no consistent association between these differences and clinical characteristics of disease. Nevertheless, the M23 isoform provided a slightly more sensitive substrate for AQP4-antibody assays, particularly for follow-up studies.

Catastrophic brain relapse in seronegative NMO after a single dose of natalizumab.

Natalizumab, an effective treatment for MS, has been shown to exacerbate neuromyelitis optica (NMO) with aquaporin-4 antibodies, but whether this is the case in antibody negative NMO and atypical MS/NMO spectrum disorder overlap syndromes is unknown. We describe a patient with a relapsing optico-spinal demyelinating syndrome, negative for aquaporin-4 antibodies, who experienced a catastrophic brain relapse shortly after a single dose of natalizumab, highlighting that MS immunomodulatory drugs may worsen demyelination in patients with seronegative NMO and atypical MS/NMO overlap syndromes even if they are aquaporin-4 antibody negative. We summarise the treatments considered safe and effective in NMO, and those with potential to exacerbate disease.

Long-term efficacy, tolerability and retention rate of azathioprine in 103 aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder patients: a multicentre retrospective observational study from the UK.

BACKGROUND: Azathioprine (AZA) is a common immunosuppressive drug used for relapse prevention in neuromyelitis optica (NMO). OBJECTIVES: The objective of this paper is to assess efficacy, tolerability and retention of AZA in a large NMO cohort. METHODS: We conducted a retrospective review of medical records of 103 aquaporin-4 antibody-positive NMO and NMO spectrum disorder (NMOSD) patients treated with AZA. RESULTS: This is the largest reported cohort of AQP4-Ab positive patients treated with AZA. Eighty-nine per cent (n = 92) had reduction in median annualised relapse rates from 1.5 (IQR 0.6-4.0) to 0 (IQR 0-0.27, p < 0.00005) with treatment. Sixty-one per cent (n = 63) remained relapse free at a median follow-up of 18 months. Neurological function improved or stabilised in 78%. At last follow-up, treatment was discontinued in 46% (n = 47). Of these, 62% (n = 29) were because of side effects, 19% (n = 9) because of death, 15% (n = 7) because of ongoing disease activity, and 2% (n = 1) because of pregnancy. Using Kaplan-Meyer curves, we estimate that 73%, 58%, 47% and 33% of patients will remain on AZA for longer than one, three, five and 10 years, respectively, after initiation of treatment. CONCLUSIONS: AZA is a modestly effective treatment for NMO. However, many patients discontinue AZA over time and this seems to reflect poor tolerability more than lack of efficacy.

Methotrexate is an alternative to azathioprine in neuromyelitis optica spectrum disorders with aquaporin-4 antibodies.

BACKGROUND: Neuromyelitis optica (NMO) is a severe autoimmune inflammatory disorder associated with considerable relapse-related disability. Immunosuppression is the mainstay of treatment but many patients do not tolerate first-line immunosuppressive agents, or experience ongoing relapses. OBJECTIVE: To evaluate the effectiveness and tolerability of methotrexate in aquaporin-4 antibody seropositive NMO spectrum disorders. METHODS: Retrospective observational case series of 14 aquaporin-4 antibody positive NMO and NMO spectrum disorder patients treated with methotrexate at two specialist centres within the UK. Annualised relapse rates, Expanded Disability Status Scale scores and tolerability were evaluated. RESULTS: Median duration of treatment with methotrexate was 21.5 months (range 6-28 months) and only three patients were prescribed it first line. Median annualised relapse rate significantly decreased following treatment (0.18 during methotrexate therapy vs 1.39 premethotrexate; p<0.005). On treatment, 43% patients were relapse free, although this increased to 64% when relapses occurring within the first 3 months of treatment or on subtherapeutic doses were excluded. Disability stabilised or improved in 79%. No patients stopped methotrexate due to adverse effects. CONCLUSIONS: Methotrexate is a commonly prescribed drug in general practice and when used in NMO it reduces relapse frequency, stabilises disability and is well tolerated, even in patients who have failed one or more other treatments. We would therefore recommend methotrexate as a treatment option in NMO patients who do not tolerate first-line therapy, experience ongoing relapses or in situations where financial constraints limit the available treatment options.

Myelin water imaging reflects clinical variability in multiple sclerosis.

Whilst MRI is routinely used for the assessment and diagnosis of multiple sclerosis, there is poor correspondence between clinical disability in primary progressive multiple sclerosis (PPMS) patients and conventional MRI markers of disease activity (e.g., number of enhancing lesions). As PPMS patients show diffuse and global myelin loss, the aim of this study was to evaluate the efficacy of whole-brain myelin water fraction (MWF) imaging in PPMS. Specifically, we sought to use full-brain analysis techniques to: 1) determine the reproducibility of MWF estimates in PPMS brain; 2) compare MWF values in PPMS brain to healthy controls; and 3) establish the relationship between MWF and clinical disability, regionally and globally throughout the brain. Seventeen PPMS patients and seventeen age-matched controls were imaged using a whole-brain multi-component relaxation imaging technique to measure MWF. Analysis of MWF reduction was performed on three spatial levels: 1) histogram; 2) white matter skeleton; and 3) voxel-wise at the single-subject level. From histogram analysis, PPMS patients had significantly reduced global normal appearing white matter MWF (6%, p=0.04) compared to controls. Focal lesions showed lower MWF values than white matter in controls (61%, p<0.001) and patients (59%, p<0.001). Along the white matter skeleton, MWF was diffusely reduced throughout the PPMS brain, with significant correlations between reduced MWF and increased clinical disability (more severe symptoms), as measured by the Expanded Disability Status Scale, within the corpus callosum and frontal, temporal, parietal and occipital white matter. Correlations with the more specific mental and sensory functional system scores were localized to clinically eloquent locations: reduced MWF was significantly associated with increased mental scores in anterior regions (i.e., frontal lobes and genu of the corpus callosum), and increased sensory scores in more posterior regions closer to the sensory cortex. Individual patient MWF maps were also compared to a normative population atlas, which highlighted areas of statistical difference between the individual patient and the population mean. A significant correlation was found between the volume of significantly reduced MWF and clinical disability (p=0.008, R=0.58). Our results show that clinical disability is reflected in particular regions of cerebral white matter that are consistent between subjects, and illustrates a method to examine tissue alteration throughout the brain of individual patients. These results strongly support the use of MWF imaging to evaluate disease activity in PPMS.

Preservation of motor skill learning in patients with multiple sclerosis.

BACKGROUND: Several studies have demonstrated benefits of rehabilitation in multiple sclerosis (MS). However, the neuroscientific foundations for rehabilitation in MS are poorly established. OBJECTIVES: As rehabilitation and motor learning share similar mechanisms of brain plasticity, we test whether the dynamics of skill learning are preserved in MS patients relative to controls. METHODS: MS patients and controls learned a repeating sequence of hand movements and were assessed for short-term learning. Long-term learning was tested in another cohort of patients and controls practising the same sequence daily for two weeks. RESULTS: Despite differences in baseline performance, the dynamics and extent of improvements were comparable between MS and control groups for both the short- and long-term learning. Even the most severely damaged patients were capable of performance improvements of similar magnitude to that seen in controls. After one week of training patients performed as well as the controls at baseline. CONCLUSIONS: Mechanisms for short- and long-term plasticity may compensate for impaired functional connectivity in MS to mediate behavioural improvements. Future studies are needed to define the neurobiological substrates of this plasticity and the extent to which mechanisms of plasticity in patients may be distinct from those used for motor learning in controls.

Clinical aspects of myasthenia explained.

Myasthenia gravis and myasthenic syndromes are diseases of the neuromuscular junction. Autoantibodies and toxins to or mutations in one of the synaptic proteins are the main causes of dysfunction. Myasthenic phenotypes can be classified according to the basic aetiological mechanisms or divided depending on the clinical phenotype.

Multiple sclerosis risk sharing scheme: two year results of clinical cohort study with historical comparator.

OBJECTIVE: To generate evidence on the longer term cost effectiveness of disease modifying treatments in patients with relapsing-remitting multiple sclerosis. DESIGN: Prospective cohort study with historical comparator. SETTING: Specialist multiple sclerosis clinics in 70 centres in the United Kingdom. PARTICIPANTS: Patients with relapsing-remitting multiple sclerosis who started treatment from May 2002 to April 2005 under the UK risk sharing scheme. INTERVENTIONS: Treatment with interferon beta or glatiramer acetate in accordance with guidelines of the UK Association of British Neurologists. MAIN OUTCOME MEASURES: Observed utility weighted progression in disability at two years' follow-up assessed on the expanded disability status scale (EDSS) compared with that expected by applying the progression rates in a comparator dataset, modified for patients receiving treatment by multiplying by the hazard ratio derived separately for each disease modifying treatment from the randomised trials. RESULTS: In the primary per protocol analysis, progression in disability was worse than that predicted and worse than that in the untreated comparator dataset ("deviation score" of 113%; excess in mean disability status scale 0.28). In sensitivity analyses, however, the deviation score varied from -72% (using raw baseline disability status scale scores, rather than applying a "no improvement" algorithm) to 156% (imputing missing data for year two from progression rates for year one). CONCLUSIONS: It is too early to reach any conclusion about the cost effectiveness of disease modifying treatments from this first interim analysis. Important methodological issues, including the need for additional comparator datasets, the potential bias from missing data, and the impact of the "no improvement" rule, will need to be addressed and long term follow-up of all patients is essential to secure meaningful results. Future analyses of the cohort are likely to be more informative, not least because they will be less sensitive to short term fluctuations in disability.

Immunocapture and identification of cell membrane protein antigenic targets of serum autoantibodies.

There is increasing interest in the role of antibodies targeting specific membrane proteins in neurological and other diseases. The target(s) of these pathogenic antibodies is known in a few diseases, usually when candidate cell surface proteins have been tested. Approaches for identifying new antigens have mainly resulted in the identification of antibodies to intracellular proteins, which are often very useful as diagnostic markers for disease but unlikely to be directly involved in disease pathogenesis because they are not accessible to circulating antibodies. To identify cell surface antigens, we developed a "conformational membrane antigen isolation and identification" strategy. First, a cell line is identified that reacts with patient sera but not with control sera. Second, intact cells are exposed to sera to allow the binding of presumptive autoantibodies to their cell surface targets. After washing off non-bound serum components, the cells are lysed, and immune complexes are precipitated. Third, the bound surface antigen is identified by mass spectrometry. As a model system we used a muscle cell line, TE671, that endogenously expresses muscle-specific tyrosine receptor kinase (MuSK) and sera or plasmas from patients with a subtype of the autoimmune disease myasthenia gravis in which patients have autoantibodies against MuSK. MuSK was robustly detected as the only membrane protein in immunoprecipitates from all three patient samples tested and not from the three MuSK antibody-negative control samples processed in parallel. Of note, however, there were many intracellular proteins found in the immunoprecipitates from both patients and controls, suggesting that these were nonspecifically immunoprecipitated from cell extracts. The conformational membrane antigen isolation and identification technique should be of value for the detection of highly relevant antigenic targets in the growing number of suspected antibody-mediated autoimmune disorders. The approach would also be very suitable for the analysis of human or experimental antitumor responses.

T cell-mediated autoimmune disease due to low-affinity crossreactivity to common microbial peptides.

Environmental factors account for 75% of the risk of developing multiple sclerosis (MS). Numerous infections have been suspected as environmental disease triggers, but none of them has consistently been incriminated, and it is unclear how so many different infections may play a role. We show that a microbial peptide, common to several major classes of bacteria, can induce MS-like disease in humanized mice by crossreacting with a T cell receptor (TCR) that also recognizes a peptide from myelin basic protein, a candidate MS autoantigen. Structural analysis demonstrates this crossreactivity is due to structural mimicry of a binding hotspot shared by self and microbial antigens, rather than to degenerate TCR recognition. Biophysical studies reveal that the autoreactive TCR binding affinity is markedly lower for the microbial (mimicry) peptide than for the autoantigenic peptide. Thus, these data suggest a possible explanation for the difficulty in incriminating individual infections in the development of MS.

The Multiple Sclerosis Risk Sharing Scheme Monitoring Study--early results and lessons for the future.

BACKGROUND: Risk sharing schemes represent an innovative and important approach to the problems of rationing and achieving cost-effectiveness in high cost or controversial health interventions. This study aimed to assess the feasibility of risk sharing schemes, looking at long term clinical outcomes, to determine the price at which high cost treatments would be acceptable to the NHS. METHODS: This case study of the first NHS risk sharing scheme, a long term prospective cohort study of beta interferon and glatiramer acetate in multiple sclerosis (MS) patients in 71 specialist MS centres in UK NHS hospitals, recruited adults with relapsing forms of MS, meeting Association of British Neurologists (ABN) criteria for disease modifying therapy. Outcome measures were: success of recruitment and follow up over the first three years, analysis of baseline and initial follow up data and the prospect of estimating the long term cost-effectiveness of these treatments. RESULTS: Centres consented 5560 patients. Of the 4240 patients who had been in the study for a least one year, annual review data were available for 3730 (88.0%). Of the patients who had been in the study for at least two years and three years, subsequent annual review data were available for 2055 (78.5%) and 265 (71.8%) patients respectively. Baseline characteristics and a small but statistically significant progression of disease were similar to those reported in previous pivotal studies. CONCLUSION: Successful recruitment, follow up and early data analysis suggest that risk sharing schemes should be able to deliver their objectives. However, important issues of analysis, and political and commercial conflicts of interest still need to be addressed.

The congenital myasthenic syndromes.

The congenital myasthenic syndromes (CMS) are rare inherited disorders of neuromuscular transmission characterised by fatigable muscle weakness. Thus far, genetic analysis has identified mutations in eleven different genes but it is clear that additional phenotypic subgroups exist where the underlying genetics has not yet been defined. Although each syndrome results from defective synaptic transmission at the neuromuscular junction, the patients show a variable set of phenotypes. Here, we provide a brief clinical review.