Multiple sclerosis – a review Dobson, R.; Giovannoni, G.
European journal of neurology,
January 2019, Volume:
26, Issue:
1
Journal Article
Peer reviewed
Open access
Multiple sclerosis (MS) is the commonest non‐traumatic disabling disease to affect young adults. The incidence of MS is increasing worldwide, together with the socioeconomic impact of the disease. ...The underlying cause of MS and mechanisms behind this increase remain opaque, although complex gene–environment interactions almost certainly play a significant role. The epidemiology of MS indicates that low serum levels of vitamin D, smoking, childhood obesity and infection with the Epstein–Barr virus are likely to play a role in disease development. Changes in diagnostic methods and criteria mean that people with MS can be diagnosed increasingly early in their disease trajectory. Alongside this, treatments for MS have increased exponentially in number, efficacy and risk. There is now the possibility of a diagnosis of ‘pre‐symptomatic MS’ being made; as a result potentially preventive strategies could be studied. In this comprehensive review, MS epidemiology, potential aetiological factors and pathology are discussed, before moving on to clinical aspects of MS diagnosis and management.
Based on the known and emerging biology of autoimmune diseases and COVID‐19, it was hypothesised that whilst B‐cell depletion should not necessarily expose people to severe SARS‐CoV‐2‐related issues, ...it may inhibit or blunt the protective immunity following infection and vaccination. This is supported clinically, as the majority of SARS‐CoV‐2 infected, CD20‐depleted people with autoimmunity, have recovered. However, in CD‐20 treated people until naïve B‐cells repopulate, based on B‐cell repopulation‐kinetics and vaccination responses, from published rituximab, and unpublished ocrelizumab (NCT00676715, NCT02545868) trial data shown here suggests that it may be possible to undertake dose‐interruption to maintain inflammatory disease control, whilst allowing effective vaccination against SARS‐CoV‐29, if and when an effective vaccine is available.
Summary
Although most autoimmune diseases are considered to be CD4 T cell‐ or antibody‐mediated, many respond to CD20‐depleting antibodies that have limited influence on CD4 and plasma cells. This includes rituximab, oblinutuzumab and ofatumumab that are used in cancer, rheumatoid arthritis and off‐label in a large number of other autoimmunities and ocrelizumab in multiple sclerosis. Recently, the COVID‐19 pandemic created concerns about immunosuppression in autoimmunity, leading to cessation or a delay in immunotherapy treatments. However, based on the known and emerging biology of autoimmunity and COVID‐19, it was hypothesised that while B cell depletion should not necessarily expose people to severe SARS‐CoV‐2‐related issues, it may inhibit protective immunity following infection and vaccination. As such, drug‐induced B cell subset inhibition, that controls at least some autoimmunities, would not influence innate and CD8 T cell responses, which are central to SARS‐CoV‐2 elimination, nor the hypercoagulation and innate inflammation causing severe morbidity. This is supported clinically, as the majority of SARS‐CoV‐2‐infected, CD20‐depleted people with autoimmunity have recovered. However, protective neutralizing antibody and vaccination responses are predicted to be blunted until naive B cells repopulate, based on B cell repopulation kinetics and vaccination responses, from published rituximab and unpublished ocrelizumab (NCT00676715, NCT02545868) trial data, shown here. This suggests that it may be possible to undertake dose interruption to maintain inflammatory disease control, while allowing effective vaccination against SARS‐CoV‐29, if and when an effective vaccine is available.
Oligoclonal bands (OCBs) unique to the cerebrospinal fluid are used in the diagnosis of multiple sclerosis (MS). The precise prevalence of OCBs in MS and clinically isolated syndrome (CIS) is ...unknown. The influence of OCBs on clinical outcomes has not been quantified. OCB prevalence has been associated with latitude in a single study, if confirmed this would provide avenues for further study.
Using a systematic review and meta-analysis approach, the proportion of OCB-positive MS and CIS and the influence of OCBs on clinical outcomes were calculated. The relationship between latitude and OCB prevalence was calculated using linear regression.
Seventy-one articles were included. Overall, 87.7% of 12 253 MS and 68.6% of 2685 CIS patients were OCB positive. OCB-positive MS patients had an OR of 1.96 of reaching disability outcomes, although a number of negative studies did not provide data. OCB-positive CIS patients had an OR of 9.88 of conversion to MS. Latitude predicted OCB status in MS patients (p=0.009) but not in CIS patients.
This is the largest study of OCB prevalence in MS and CIS. OCB positivity strongly predicts conversion from CIS to MS. The relationship between latitude and OCBs is confirmed, and this finding warrants further investigation.
Month of birth has previously been described as a risk factor for multiple sclerosis (MS). This has been hypothesised to be related to maternal vitamin D levels during pregnancy, although conclusive ...evidence to support this is lacking. To date, no large studies of latitudinal variation in the month of birth effect have been performed to advance this hypothesis.
Previously published data on month of birth from 151 978 MS patients were compared to expected birth rates. A linear regression model was used to assess the relationship between latitude and observed:expected birth ratio of MS patients for each month.
Analysis of all reported data demonstrated a significant excess of MS risk in those born in April (observed:expected 1.05, p=0.05) and reduction in risk in those born in October (0.95, p=0.04) and November (0.92 p=0.01). A conservative analysis of 78 488 patients revealed an excess MS risk in those born in April (1.07, p=0.002) and May (1.11, p=0.0006), and a reduced risk in those born in October (ratio 0.94, p=0.004) and November (0.88, p=0.0002). A significant relationship between latitude and observed:expected ratio was demonstrated in December, and borderline significant relationships in May and August.
Month of birth has a significant effect on subsequent MS risk. This is likely to be due to ultraviolet light exposure and maternal vitamin D levels, as demonstrated by the relationship between risk and latitude.
Reviews of therapeutic drugs usually focus on the highly selected and closely monitored patient populations from randomized controlled trials. The objective of this study was to review systematically ...the tolerability and adherence of multiple sclerosis disease-modifying therapies, using data from both randomized controlled trials and observational settings. Relevant literature was identified using predefined search terms, and adverse event and study discontinuation data were extracted and categorized according to study type (randomized controlled trial or observational) and study duration. A total of 151 papers were selected for analysis; 33% were classified as randomized controlled trials and 62% as observational studies. Most of the papers concerned interferon preparations and glatiramer acetate; the limited available information on mitoxantrone and natalizumab precluded extensive examination of these. The most common adverse events were flu-like symptoms (interferon therapies only) and injection-site reactions. Mean discontinuation rates ranged from 16% to 27%. There were no marked differences in tolerability or adherence data from randomized controlled trials and observational studies, but the incidence of adverse events remained high in lengthy studies and discontinuations accumulated with time. The present systematic review of randomized clinical trial and observational data highlights the tolerability and adherence issues associated with commonly used first-line multiple sclerosis treatments.
Clinical trials are probably the most informative experiments to help an understanding of multiple sclerosis (MS) biology. Recent successes with CD20‐depleting antibodies have focused attention ...towards B cell subsets as important mediators in MS. The trial of tabalumab (NTC00882999), which inhibits B cell activation factor (BAFF), is reported and reviewed and this trial is contrasted with the trial on the inhibition of a proliferation‐inducing ligand (APRIL) and BAFF using atacicept (NCT00642902). Both tabalumab and atacicept induce depletion of mature B cells and inhibit antibody formation, but they fail to deplete memory B cells and do not inhibit relapsing MS. Atacicept is reported to augment memory B cell responses and may precipitate relapse, suggesting the importance of APRIL. However, BAFF inhibition can enhance peripheral blood memory B cell responses, which was not associated with augmented relapse. Although other interpretations are possible, these data further support the hypothesis that memory B cells may be of central importance in relapsing MS, as they are the major CD20+ B cell subset expressing APRIL receptors. They also suggest that quantitative and/or qualitative differences in B cell responses or other factors, such as an immune‐regulatory effect associated with APRIL, may be important in determining whether MS reactivates following neutralization of peripheral B cell maturation and survival factors.
To describe 16 patients with a coincidence of 2 rare diseases: aquaporin-4 antibody (AQP4-Ab)-mediated neuromyelitis optica spectrum disorder (AQP4-NMOSD) and acetylcholine receptor antibody ...(AChR-Ab)-mediated myasthenia gravis (AChR-MG).
The clinical details and antibody results of 16 patients with AChR-MG and AQP4-NMOSD were analyzed retrospectively.
All had early-onset AChR-MG, the majority with mild generalized disease, and a high proportion achieved remission. Fifteen were female; 11 were Caucasian. In 14/16, the MG preceded NMOSD (median interval: 16 years) and 11 of these had had a thymectomy although 1 only after NMOSD onset. In 4/5 patients tested, AQP4-Abs were detectable between 4 and 16 years prior to disease onset, including 2 patients with detectable AQP4-Abs prior to thymectomy. AChR-Abs decreased and the AQP4-Ab levels increased over time in concordance with the relevant disease. AChR-Abs were detectable at NMOSD onset in the one sample available from 1 of the 2 patients with NMOSD before MG.
Although both conditions are rare, the association of MG and NMOSD occurs much more frequently than by chance and the MG appears to follow a benign course. AChR-Abs or AQP4-Abs may be present years before onset of the relevant disease and the antibody titers against AQP4 and AChR tend to change in opposite directions. Although most cases had MG prior to NMOSD onset, and had undergone thymectomy, NMOSD can occur first and in patients who have not had their thymus removed.
Understanding the pathogenesis of complex immunologic disorders such as multiple sclerosis (MS) is challenging. Abnormalities in many different cell types are observed in the immune system and CNS of ...patients with MS and the identification of the primary and secondary events is difficult. Recent studies suggest that the model of MS as a disorder mediated only by T cells is overly simplistic and propose an important role for B cells in the propagation of the disease. B-cell activation in the form of oligoclonal bands (OCB) production is the most consistent immunologic finding in patients with MS. Notably, markers of B-cell activation within the CSF of patients with MS predict conversion from clinically isolated syndrome to clinically definite MS and correlate with MRI activity, onset of relapses, and disability progression. In addition, the main genetic risk factor in MS is associated with OCB production, and environmental agents associated with MS susceptibility (vitamin D and the Epstein-Barr virus) influence B-cell proliferation and function. Finally, the only cell-specific treatments that are effective in patients with MS are monoclonal antibodies targeting the B-cell antigen CD20, suggesting a potentially causative role for B cells. Based on current evidence there is no longer doubt that B cells are relevant to the etiology and pathogenesis of MS. Elucidating the role of B cells in MS will be a fruitful strategy for disease prevention and treatment.
Neurofilaments (Nf) are major structural proteins that occur exclusively in neurons. In spinal cord injury (SCI), the severity of disease is quantified by clinical measures that have limited ...sensitivity and reliability, and no blood-based biomarker has been established to further stratify the degree of injury. We aimed to examine a serum-based NfL immunoassay as predictor of the clinical outcome in SCI.
Longitudinal measurement of serum NfL was performed in patients with central cord syndrome (CCS, n=4), motor-incomplete SCI (iSCI, n=10), motor-complete SCI (cSCI, n=13) and healthy controls (HC, n=67), and correlated with clinical severity, neurological outcome, and neuroprotective effect of the drug minocycline.
Baseline NfL levels were higher in iSCI (21 pg/mL) and cSCI (70 pg/mL) than in HC (5 pg/mL, p=0.006 and p<0.001) and CCS (6 pg/mL, p=0.025 and p=0.010). Levels increased over time (p<0.001) and remained higher in cSCI versus iSCI (p=0.011) and than in CCS (p<0.001). NfL levels correlated with American Spinal Injury Association (ASIA) motor score at baseline (r=-0.53, p=0.004) and after 24 h (r=-0.69, p<0.001) and 3-12-month motor outcome (baseline NfL: r=-0.43, p=0.026 and 24 h NfL: r=-0.72, p<0.001). Minocycline treatment showed decreased NfL levels in the subgroup of cSCI patients.
Serum NfL concentrations in SCI patients show a close correlation with acute severity and neurological outcome. Our data provide evidence that serum NfL is of prognostic value in SCI patients for the first time. Further, blood NfL levels may qualify as drug response markers in SCI.
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