Double-negative neuromyelitis optica spectrum disorder.

Most patients with neuromyelitis optica spectrum disorders (NMOSD) test positive for aquaporin-4 antibody (AQP4-IgG) or myelin oligodendrocyte glycoprotein antibodies (MOG-IgG). Those who are negative are termed double-negative (DN) NMOSD and may constitute a diagnostic and therapeutic challenge. DN NMOSD is a syndrome rather than a single disease, ranging from a (postinfectious) monophasic illness to a more chronic syndrome that can be indistinguishable from AQP4-IgG+ NMOSD or develop into other mimics such as multiple sclerosis. Thus, underlying disease mechanisms are likely to be heterogeneous. This topical review aims to (1) reappraise antibody-negative NMOSD definition as it has changed over time with the development of the AQP4 and MOG-IgG assays; (2) outline clinical characteristics and the pathophysiological nature of this rare entity by contrasting its differences and similarities with antibody-positive NMOSD; (3) summarize laboratory characteristics and magnetic resonance imaging findings of DN NMOSD; and (4) discuss the current treatment for DN NMOSD.

Relapsing antibody-negative patients with features of neuromyelitis optica spectrum disorders: Differences in N-acetylaspartate level in the cervical spinal cord indicate distinct underlying processes.

BACKGROUND: Due to lack of biomarkers, antibody-negative patients with features of neuromyelitis optica spectrum disorders (NMOSD) are among the most challenging to diagnose and treat. Using unsupervised clustering, we recently identified 'MS-like', 'spinal MS-like', 'classic NMOSD-like' and 'NMOSD-like with brain involvement' subgroups in this cohort. OBJECTIVE: We used magnetic resonance spectroscopy (MRS) to examine differences in the level of key metabolites in the spinal cord between the four identified subgroups. METHODS: Twenty-five relapsing antibody-negative patients with NMOSD features classified by the unsupervised algorithm to one of the subgroups underwent a prospective cervical spinal cord MRS. Spectra from 16 patients fulfilled quality criteria and were included in the analysis. RESULTS: Total N-acetylaspartate (tNAA), but not total choline (tCho) or myo-inositol (Ins), was significantly different between the four subgroups (p = 0.03). In particular, tNAA was 47.8% lower in the 'MS-like' subgroup as compared with the 'classic NMOSD-like' subgroup (p = 0.02). While we found a negative overall correlation between tNAA and disability score (r = -0.514, p = 0.04) in the whole cohort, the disability score did not differ significantly between the subgroups to explain subgroup differences in tNAA level. CONCLUSIONS: Significant differences in the cervical spinal cord tNAA measurements confirm that the previously identified clinico-radiologic subgroups contain patients with distinct underlying disease processes.

Contrasting the brain imaging features of MOG-antibody disease, with AQP4-antibody NMOSD and multiple sclerosis.

BACKGROUND: Identifying magnetic resonance imaging (MRI) markers in myelin-oligodendrocytes-glycoprotein antibody-associated disease (MOGAD), neuromyelitis optica spectrum disorder-aquaporin-4 positive (NMOSD-AQP4) and multiple sclerosis (MS) is essential for establishing objective outcome measures. OBJECTIVES: To quantify imaging patterns of central nervous system (CNS) damage in MOGAD during the remission stage, and to compare it with NMOSD-AQP4 and MS. METHODS: 20 MOGAD, 19 NMOSD-AQP4, 18 MS in remission with brain or spinal cord involvement and 18 healthy controls (HC) were recruited. Volumetrics, lesions and cortical lesions, diffusion-imaging measures, were analysed. RESULTS: Deep grey matter volumes were lower in MOGAD (p = 0.02) and MS (p = 0.0001), compared to HC and were strongly correlated with current lesion volume (MOGAD R = -0.93, p < 0.001, MS R = -0.65, p = 0.0034). Cortical/juxtacortical lesions were seen in a minority of MOGAD, in a majority of MS and in none of NMOSD-AQP4. Non-lesional tissue fractional anisotropy (FA) was only reduced in MS (p = 0.01), although focal reductions were noted in NMOSD-AQP4, reflecting mainly optic nerve and corticospinal tract pathways. CONCLUSION: MOGAD patients are left with grey matter damage, and this may be related to persistent white matter lesions. NMOSD-AQP4 patients showed a relative sparing of deep grey matter volumes, but reduced non-lesional tissue FA. Observations from our study can be used to identify new markers of damage for future multicentre studies.

Increasing role of imaging in differentiating MS from non-MS and defining indeterminate borderline cases.

Multiple sclerosis (MS) is a heterogenous condition with differences between patients regarding disease presentation, imaging features, disease activity, prognosis and treatment responses. Following the discovery of new biomarkers, the concept of MS has evolved, with syndromes previously considered to be its variants now recognised as separate entities, including aquaporin-4 (AQP4)-antibody (Ab) neuromyelits optica spectrum disorders (NMOSD), and myelin oligodendrocyte glycoprotein (MOG)-Ab disease (MOGAD). In line with their distinct pathology, the newly emerging conditions have imaging characteristics which are dissimilar to typical MS. Progress in reclassifying such demyelinating CNS conditions has highlighted the challenge in meaningful categorisation of atypical presentations at the borders of MS, such as antibody-negative neuromyelitis optica-like syndromes, tumefactive demyelinating lesions, or Balo's concentric sclerosis. In this review, we discuss the increasing role of imaging in distinguishing MS from non-MS CNS inflammatory/demyelinating conditions and defining undetermined borderline cases. This progress relies both on better characterisation of imaging features of these conditions on conventional imaging in terms of their appearance and location, as well as on the implementation of novel image acquisition and/or post-processing techniques allowing for more in-depth lesion assessment, including the presence of a central vein sign or paramagnetic rim.

The role of pontine lesion location in differentiating multiple sclerosis from vascular risk factor-related small vessel disease.

BACKGROUND: Differentiating multiple sclerosis (MS) from vascular risk factor (VRF)-small vessel disease (SVD) can be challenging. OBJECTIVE AND METHODS: In order to determine whether or not pontine lesion location is a useful discriminator of MS and VRF-SVD, we classified pontine lesions on brain magnetic resonance imaging (MRI) as central or peripheral in 93 MS cases without VRF, 108 MS patients with VRF and 43 non-MS cases with VRF. RESULTS: MS without VRF were more likely to have peripheral pons lesions (31.2%, 29/93) than non-MS with VRF (0%, 0/43) (Exp(B) = 29.8; 95% confidence interval (CI) = (1.98, 448.3); p = 0.014) but there were no significant differences regarding central pons lesions between MS without VRF (5.4%, 5/93) and non-MS with VRF patients (16.3%, 7/43) (Exp(B) = 0.89; 95% CI = (0.2, 3.94); p = 0.87). The presence of peripheral pons lesions discriminated between MS and VRF-SVD with 100% (95% CI = (91.8, 100)) specificity. The proportion of peripheral pons lesions in MS with VRF (30.5%, 33/108) was similar to that seen in MS without VRF (31.2%, 29/93, p = 0.99). Central lesions occurred in similar frequency in MS with VRF (8.3%, 9/108) and non-MS with VRF (16.3%, 7/43, p = 0.15). CONCLUSION: Peripheral pons lesion location is a good discriminator of MS from vascular lesions.

Distinct influence of different vascular risk factors on white matter brain lesions in multiple sclerosis.

OBJECTIVE: To determine if vascular risk factor (VRF), that is, smoking, arterial hypertension (HT), dyslipidaemia and diabetes, have an effect on multiple sclerosis (MS) pathology as measured by MS typical brain lesions, we have compared brain MRIs from patients with MS with and without VRF age-matched and sex-matched. METHODS: Brain MRIs from five centres were scored for the presence of Dawson's fingers (DF) and juxtacortical lesions (JCL). A regression model was built to predict the effect of each individual VRF on DF and JCL, considering age and disease duration. RESULTS: 92 MS cases without VRF and 106 MS with one or more VRF (80 ever-smokers, 43 hypertensives, 25 dyslipidaemics and 10 diabetics) were included. Ever-smoking associated with a higher burden of DF (Exp(B)=1.29, 95% CI 1.10 to 1.51, p<0.01) and JCL (Exp(B)=1.38, 95% CI 1.21 to 1.57, p<0.01). No other VRF had an impact on DF. Dyslipidaemia associated with increased JCL (Exp(B)=1.30, 95% CI 1.10 to 1.56, p<0.01) but HT did not associate with any of the outcomes. CONCLUSIONS: Individual VRF appear to affect MS-specific lesions differently. An increase in MS lesions was mainly seen in smokers; however, this VRF is most likely to be present from onset of MS, and other VRF effects may be partly mitigated by treatment. Our findings support that treating VRF and cessation of smoking may be important in the management of MS.

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease: practical considerations.

The field of central nervous system (CNS) inflammatory diseases has recently broadened to include a new condition associated with pathogenic serum antibodies against myelin oligodendrocyte glycoprotein (MOG). This is distinct from multiple sclerosis (MS) and aquaporin-4 (AQP4) antibody neuromyelitis optica spectrum disorders (NMOSD). MOG antibody-associated disease phenotypes are varied and range from classical neuromyelitis optica to acute demyelinating encephalomyelitis and cortical encephalitis. The diagnosis depends on using a reliable, specific and sensitive assay of the antibody. Clinical and imaging features of MOG-associated syndromes overlap with AQP4 antibody NMOSD but can be usually distinguished from MS: in particular, the silent lesions typical of MS that progressively increase lesion volume are rare in MOG antibody disease. The disease can relapse but medium-term immunosuppression appears to be protective. Permanent disability, particularly severe ambulatory and visual disability, is less frequent than in AQP4 antibody NMOSD and usually results from the onset attack. However, sphincter and sexual dysfunction after a transverse myelitis is common. Here we review the practical aspects of diagnosing and managing a patient with MOG antibody-associated disease.

Distinct brain imaging characteristics of autoantibody-mediated CNS conditions and multiple sclerosis.

Brain imaging characteristics of MOG antibody disease are largely unknown and it is unclear whether they differ from those of multiple sclerosis and AQP4 antibody disease. The aim of this study was to identify brain imaging discriminators between those three inflammatory central nervous system diseases in adults and children to support diagnostic decisions, drive antibody testing and generate disease mechanism hypotheses. Clinical brain scans of 83 patients with brain lesions (67 in the training and 16 in the validation cohort, 65 adults and 18 children) with MOG antibody (n = 26), AQP4 antibody disease (n = 26) and multiple sclerosis (n = 31) recruited from Oxford neuromyelitis optica and multiple sclerosis clinical services were retrospectively and anonymously scored on a set of 29 predefined magnetic resonance imaging features by two independent raters. Principal component analysis was used to perform an overview of patients without a priori knowledge of the diagnosis. Orthogonal partial least squares discriminant analysis was used to build models separating diagnostic groups and identify best classifiers, which were then tested on an independent cohort set. Adults and children with MOG antibody disease frequently had fluffy brainstem lesions, often located in pons and/or adjacent to fourth ventricle. Children across all conditions showed more frequent bilateral, large, brainstem and deep grey matter lesions. MOG antibody disease spontaneously separated from multiple sclerosis but overlapped with AQP4 antibody disease. Multiple sclerosis was discriminated from MOG antibody disease and from AQP4 antibody disease with high predictive values, while MOG antibody disease could not be accurately discriminated from AQP4 antibody disease. Best classifiers between MOG antibody disease and multiple sclerosis were similar in adults and children, and included ovoid lesions adjacent to the body of lateral ventricles, Dawson's fingers, T1 hypointense lesions (multiple sclerosis), fluffy lesions and three lesions or less (MOG antibody). In the validation cohort patients with antibody-mediated conditions were differentiated from multiple sclerosis with high accuracy. Both antibody-mediated conditions can be clearly separated from multiple sclerosis on conventional brain imaging, both in adults and children. The overlap between MOG antibody oligodendrocytopathy and AQP4 antibody astrocytopathy suggests that the primary immune target is not the main substrate for brain lesion characteristics. This is also supported by the clear distinction between multiple sclerosis and MOG antibody disease both considered primary demyelinating conditions. We identify discriminatory features, which may be useful in classifying atypical multiple sclerosis, seronegative neuromyelitis optica spectrum disorders and relapsing acute disseminated encephalomyelitis, and characterizing cohorts for antibody discovery.

Clinical presentation and prognosis in MOG-antibody disease: a UK study.

See de Seze (doi:10.1093/brain/awx292) for a scientific commentary on this article. A condition associated with an autoantibody against MOG has been recently recognized as a new inflammatory disease of the central nervous system, but the disease course and disability outcomes are largely unknown. In this study we investigated clinical characteristics of MOG-antibody disease on a large cohort of patients from the UK. We obtained demographic and clinical data on 252 UK patients positive for serum immunoglobulin G1 MOG antibodies as tested by the Autoimmune Neurology Group in Oxford. Disability outcomes and disease course were analysed in more detail in a cohort followed in the Neuromyelitis Optica Oxford Service (n = 75), and this included an incident cohort who were diagnosed at disease onset (n = 44). MOG-antibody disease affects females (57%) slightly more often than males, shows no ethnic bias and typically presents with isolated optic neuritis (55%, bilateral in almost half), transverse myelitis (18%) or acute disseminated encephalomyelitis-like presentations (18%). In the total Oxford cohort after a median disease duration of 28 months, 47% of patients were left with permanent disability in at least one of the following: 16% patients had visual acuity ≤6/36 in at least one eye, mobility was limited in 7% (i.e. Expanded Disability Status Scale ≥ 4.0), 5% had Expanded Disability Status Scale ≥ 6.0, 28% had permanent bladder issues, 20% had bowel dysfunction, and 21% of males had erectile dysfunction. Transverse myelitis at onset was a significant predictor of long-term disability. In the incident cohort 36% relapsed after median disease duration of 16 months. The annualized relapse rate was 0.2. Immunosuppression longer than 3 months following the onset attack was associated with a lower risk of a second relapse. MOG-antibody disease has a moderate relapse risk, which might be mitigated by medium term immunosuppression at onset. Permanent disability occurs in about half of patients and more often involves sphincter and erectile functions than vision or mobility.

Brain lesion distribution criteria distinguish MS from AQP4-antibody NMOSD and MOG-antibody disease.

IMPORTANCE: Neuromyelitis optica spectrum disorders (NMOSD) can present with very similar clinical features to multiple sclerosis (MS), but the international diagnostic imaging criteria for MS are not necessarily helpful in distinguishing these two diseases. OBJECTIVE: This multicentre study tested previously reported criteria of '(1) at least 1 lesion adjacent to the body of the lateral ventricle and in the inferior temporal lobe; or (2) the presence of a subcortical U-fibre lesion or (3) a Dawson's finger-type lesion' in an independent cohort of relapsing-remitting multiple sclerosis (RRMS) and AQP4-ab NMOSD patients and also assessed their value in myelin oligodendrocyte glycoprotein (MOG)-ab positive and ab-negative NMOSD. DESIGN: Brain MRI scans were anonymised and scored on the criteria by 2 of 3 independent raters. In case of disagreement, the final opinion was made by the third rater. PARTICIPANTS: 112 patients with NMOSD (31 AQP4-ab-positive, 21 MOG-ab-positive, 16 ab-negative) or MS (44) were selected from 3 centres (Oxford, Strasbourg and Liverpool) for the presence of brain lesions. RESULTS: MRI brain lesion distribution criteria were able to distinguish RRMS with a sensitivity of 90.9% and with a specificity of 87.1% against AQP4-ab NMOSD, 95.2% against MOG-ab NMOSD and 87.5% in the heterogenous ab-negative NMOSD cohort. Over the whole NMOSD group, the specificity was 89.7%. CONCLUSIONS: This study suggests that the brain MRI criteria for differentiating RRMS from NMOSD are sensitive and specific for all phenotypes.

Chronic neuropathic pain severity is determined by lesion level in aquaporin 4-antibody-positive myelitis.

IMPORTANCE: Chronic, intractable neuropathic pain is a common and debilitating consequence of neuromyelitis optica spectrum disorder (NMOSD) myelitis, with no satisfactory treatment; few studies have yet to explore its aetiology. OBJECTIVE: To establish if myelitis-associated chronic pain in NMOSD is related to the craniocaudal location of spinal cord lesions. METHOD: (1) Retrospective cohort of 76 aquaporin 4-antibody (AQP4-Ab)-positive patients from Oxford and Liverpool's national NMOSD clinics, assessing current pain and craniocaudal location of cord lesion contemporary to pain onset. (2) Focused prospective study of 26 AQP4-Ab-positive Oxford patients, a subset of the retrospective cohort, assessing current craniocaudal lesion location and current pain. RESULTS: Patients with isolated thoracic cord myelitis at the time of pain onset were significantly more disabled and suffered more pain. Cervical and thoracic lesions that persisted from pain onset to 'out of relapse' follow-up (current MRI) had highly significant (p<0.01) opposing effects on pain scores (std. ß=-0.46 and 0.48, respectively). Lesion length, total lesion burden and number of transverse myelitis relapses did not correlate with pain. CONCLUSIONS: Persistent, caudally located (ie, thoracic) cord lesions in AQP4-Ab-positive patients associate with high postmyelitis chronic pain scores, irrespective of number of myelitis relapses, lesion length and lesion burden. Although disability correlated with pain in isolation, it became an insignificant predictor of pain when analysed alongside craniocaudal location of lesions.

Overlapping CNS inflammatory diseases: differentiating features of NMO and MS.

Neuromyelitis optica (NMO) has long been considered as a variant of multiple sclerosis (MS) rather than a distinct disease. This concept changed with the discovery of serum antibodies (Ab) against aquaporin-4 (AQP4), which unequivocally differentiate NMO from MS. Patients who test positive for AQP4-Abs and present with optic neuritis (ON) and transverse myelitis (TM) are diagnosed with NMO and those who show an incomplete phenotype with isolated ON or longitudinally extensive TM (LETM) or less commonly brain/brainstem disease are referred to as NMO spectrum disorders (NMOSD). However, many patients, who have overlapping features of both NMO and MS, test negative for AQP4-Abs and may be difficult to definitively diagnose. This raises important practical issues, since NMO and MS respond differently to immunomodulatory treatment and have different prognoses. Here we review distinct features of AQP4-positive NMO and MS, which might then be useful in the diagnosis of antibody-negative overlap syndromes. We identify discriminators, which are related to demographic data (non-white origin, very late onset), clinical features (limited recovery from ON, bilateral ON, intractable nausea, progressive course of disability), laboratory results (cerebrospinal fluid (CSF) pleocytosis with eosinophils and/or neutrophils, oligoclonal bands, glial fibrillary acidic protein in the CSF) and imaging (LETM, LETM with T1 hypointensity, periependymal brainstem lesions, perivenous white matter lesions, Dawson's fingers, curved or S-shaped U-fibre juxtacortical lesions). We review the value of these discriminators and discuss the compelling need for new diagnostic markers in these two autoimmune demyelinating diseases of the central nervous system.

Diagnostic Performance of Cortical Lesions and the Central Vein Sign in Multiple Sclerosis.

Importance: Multiple sclerosis (MS) misdiagnosis remains an important issue in clinical practice. Objective: To quantify the performance of cortical lesions (CLs) and central vein sign (CVS) in distinguishing MS from other conditions showing brain lesions on magnetic resonance imaging (MRI). Design, Setting, and Participants: This was a retrospective, cross-sectional multicenter study, with clinical and MRI data acquired between January 2010 and May 2020. Centralized MRI analysis was conducted between July 2020 and December 2022 by 2 raters blinded to participants' diagnosis. Participants were recruited from 14 European centers and from a multicenter pan-European cohort. Eligible participants had a diagnosis of MS, clinically isolated syndrome (CIS), or non-MS conditions; availability of a brain 3-T MRI scan with at least 1 sequence suitable for CL and CVS assessment; presence of T2-hyperintense white matter lesions (WMLs). A total of 1051 individuals were included with either MS/CIS (n = 599; 386 [64.4%] female; mean [SD] age, 41.5 [12.3] years) or non-MS conditions (including other neuroinflammatory disorders, cerebrovascular disease, migraine, and incidental WMLs in healthy control individuals; n = 452; 302 [66.8%] female; mean [SD] age, 49.2 [14.5] years). Five individuals were excluded due to missing clinical or demographic information (n = 3) or unclear diagnosis (n = 2). Exposures: MS/CIS vs non-MS conditions. Main Outcomes and Measures: Area under the receiver operating characteristic curves (AUCs) were used to explore the diagnostic performance of CLs and the CVS in isolation and in combination; sensitivity, specificity, and accuracy were calculated for various cutoffs. The diagnostic importance of CLs and CVS compared to conventional MRI features (ie, presence of infratentorial, periventricular, and juxtacortical WMLs) was ranked with a random forest model. Results: The presence of CLs and the previously proposed 40% CVS rule had a sensitivity, specificity, and accuracy for MS of 59.0% (95% CI, 55.1-62.8), 93.6% (95% CI, 91.4-95.6), and 73.9% (95% CI, 71.6-76.3) and 78.7% (95% CI, 75.5-82.0), 86.0% (95% CI, 82.1-89.5), and 81.5% (95% CI, 78.9-83.7), respectively. The diagnostic performance of the CVS (AUC, 0.89 [95% CI, 0.86-0.91]) was superior to that of CLs (AUC, 0.77 [95% CI, 0.75-0.80]; P < .001), and was increased when combining the 2 imaging markers (AUC, 0.92 [95% CI, 0.90-0.94]; P = .04); in the random forest model, both CVS and CLs outperformed the presence of infratentorial, periventricular, and juxtacortical WMLs in supporting MS differential diagnosis. Conclusions and Relevance: The findings in this study suggest that CVS and CLs may be valuable tools to increase the accuracy of MS diagnosis.

Elucidating distinct clinico-radiologic signatures in the borderland between neuromyelitis optica and multiple sclerosis.

BACKGROUND: Separating antibody-negative neuromyelitis optica spectrum disorders (NMOSD) from multiple sclerosis (MS) in borderline cases is extremely challenging due to lack of biomarkers. Elucidating different pathologies within the likely heterogenous antibody-negative NMOSD/MS overlap syndrome is, therefore, a major unmet need which would help avoid disability from inappropriate treatment. OBJECTIVE: In this study we aimed to identify distinct subgroups within the antibody-negative NMOSD/MS overlap syndrome. METHODS: Twenty-five relapsing antibody-negative patients with NMOSD features underwent a prospective brain and spinal cord MRI. Subgroups were identified by an unsupervised algorithm based on pre-selected NMOSD/MS discriminators. RESULTS: Four subgroups were identified. Patients from Group 1 termed "MS-like" (n = 6) often had central vein sign and cortical lesions (83% and 67%, respectively). All patients from Group 2 ("spinal MS-like", 8) had short-segment myelitis and no MS-like brain lesions. Group 3 ("classic NMO-like", 6) had high percentage of bilateral optic neuritis and longitudinally extensive transverse myelitis (LETM, 80% and 60%, respectively) and normal brain appearance (100%). Group 4 ("NMO-like with brain involvement", 5) typically had a history of NMOSD-like brain lesions and LETM. When compared with other groups, Group 4 had significantly decreased fractional anisotropy in non-lesioned tracts (0.46 vs. 0.49, p = 0.003) and decreased thalamus volume (0.84 vs. 0.98, p = 0.04). CONCLUSIONS: NMOSD/MS cohort contains distinct subgroups likely corresponding to different pathologies and requiring tailored treatment. We propose that non-conventional MRI might help optimise diagnosis in these challenging patients.

Towards imaging criteria that best differentiate MS from NMOSD and MOGAD: Large multi-ethnic population and different clinical scenarios.

BACKGROUND: The "1/3″ brain magnetic resonance imaging (MRI) criteria including 1) a lesion adjacent to the lateral ventricle and in the inferior temporal lobe, or 2) a juxtacortical lesion, or 3) a Dawson finger-type lesion were shown to distinguish multiple sclerosis (MS) from antibody-mediated conditions. In this large multicentre study, we aimed to assess how the criteria perform 1) in different onset phenotypes, 2) distinct ethnic groups, 3) when the absence of myelin oligodendrocyte glycoprotein antibody (MOG-Ab)-associated disease (MOGAD)-typical fluffy infratentorial (FIT) lesions and longitudinally extensive transverse myelitis (LETM) lesions are added as features ("2/4″ and 3/5″ criteria, respectively). METHODS: 577 patients with MS (n = 332), aquaporin-4 antibody (AQP4-Ab) neuromyelitis optica spectrum disorder (NMOSD) (n = 196) and MOGAD (n = 49) were recruited from 6 international centres (Buenos Aires, Sao Paolo, Maracaibo, Goyang, Oxford and Milan). Imaging scans were obtained at disease onset or relapse. RESULTS: Adding the absence of FIT lesions increased the specificity of the "1/3″ criteria vs. AQP4-Ab NMOSD from 84.7% to 87.2% and vs. MOGAD from 85.7% to 93.9% without compromising their sensitivity (86%). In particular, for those presenting with brain/brainstem attacks "2/4″ had significantly higher specificity than "1/3″ (85% vs. 80% against AQP4-Ab NMOSD, 88.9% vs. 72.2% against MOGAD). Positive predictive values of the "1/3″ criteria for MS were lowest for Asian patients (84.8 vs. 99.1% for White) but were significantly increased by adding further criteria (94.1% for "3/5″). CONCLUSION: The "1/3″ criteria perform well in discriminating MS from NMOSD and MOGAD regardless of ethnic background and clinical scenario. Adding the absence of FIT lesions increases the specificity in those presenting with brain/brainstem symptoms.

Immune regulation of multiple sclerosis by transdermally applied myelin peptides.

OBJECTIVE: Antigen-specific therapy targeting selective inhibition of autoreactive responses holds promise for controlling multiple sclerosis (MS) without disturbing homeostasis of the whole immune system. Key autoantigens in MS include myelin proteins, such as myelin basic protein (MBP), proteolipid protein (PLP), and myelin oligodendrocyte glycoprotein (MOG). In this study, we examined the effect of transdermal therapy with myelin peptides on immune responses in the skin, lymph nodes, and peripheral blood immune cells of MS patients. METHODS: In a 1-year placebo-controlled study, 30 patients with relapsing-remitting MS were treated transdermally with a mixture of 3 myelin peptides: MBP85-99, PLP139-151, and MOG35-55, or placebo. The phenotype of immune cells in the skin was assessed using immunohistochemistry. Cell populations in lymph nodes were analyzed using flow cytometry. In peripheral blood immune cells, cytokine production was measured by enzyme-linked immunosorbent assay, and myelin-specific proliferation was examined by carboxyfluorescein succinimidyl ester-based assay. RESULTS: We found that myelin peptides applied transdermally to MS patients activated dendritic Langerhans cells in the skin at the site of immunization and induced a unique population of granular dendritic cells in local lymph nodes. In the periphery, transdermal immunization with myelin peptides resulted in the generation of type 1, interleukin-10-producing regulatory T cells, suppression of specific autoreactive proliferative responses, and suppression of interferon-γ and transforming growth factor-ß production. INTERPRETATION: We demonstrate for the first time the immunoregulatory potential of transdermal immunization with myelin peptides in MS patients.

Classifying the antibody-negative NMO syndromes: Clinical, imaging, and metabolomic modeling.

OBJECTIVE: To determine whether unsupervised principal component analysis (PCA) of comprehensive clinico-radiologic data can identify phenotypic subgroups within antibody-negative patients with overlapping features of multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSDs), and to validate the phenotypic classifications using high-resolution nuclear magnetic resonance (NMR) plasma metabolomics with inference to underlying pathologies. METHODS: Forty-one antibody-negative patients were recruited from the Oxford NMO Service. Thirty-six clinico-radiologic parameters, focusing on features known to distinguish NMOSD and MS, were collected to build an unbiased PCA model identifying phenotypic subgroups within antibody-negative patients. Metabolomics data from patients with relapsing-remitting MS (RRMS) (n = 34) and antibody-positive NMOSD (Ab-NMOSD) (aquaporin-4 antibody n = 54, myelin oligodendrocyte glycoprotein antibody n = 20) were used to identify discriminatory plasma metabolites separating RRMS and Ab-NMOSD. RESULTS: PCA of the 36 clinico-radiologic parameters revealed 3 phenotypic subgroups within antibody-negative patients: an MS-like subgroup, an NMOSD-like subgroup, and a low brain lesion subgroup. Supervised multivariate analysis of metabolomics data from patients with RRMS and Ab-NMOSD identified myoinositol and formate as the most discriminatory metabolites (both higher in RRMS). Within antibody-negative patients, myoinositol and formate were significantly higher in the MS-like vs NMOSD-like subgroup; myoinositol (mean [SD], 0.0023 [0.0002] vs 0.0019 [0.0003] arbitrary units [AU]; p = 0.041); formate (0.0027 [0.0006] vs 0.0019 [0.0006] AU; p = 0.010) (AU). CONCLUSIONS: PCA identifies 3 phenotypic subgroups within antibody-negative patients and that the metabolite discriminators of RRMS and Ab-NMOSD suggest that these groupings have some pathogenic meaning. Thus, the identified clinico-radiologic discriminators may provide useful diagnostic clues when seeing antibody-negative patients in the clinic.

Overcoming failure to repair demyelination in EAE: gamma-secretase inhibition of Notch signaling.

In multiple sclerosis (MS), myelin destroyed by the immune attack is not effectively repaired by oligodendrocytes (OLs) and MS foci eventually undergo glial scarring. Although oligodendrocyte precursor cells (OPCs) are normally recruited to the lesion areas, they fail to mature and remyelinate the damaged fibers. Activation of the Notch pathway has been shown to inhibit OPC differentiation and to hamper their ability to produce myelin during CNS development. We have recently shown that inhibition of gamma-secretase within the CNS of SJL/J mice with experimental autoimmune encephalomyelitis (EAE) blocks Notch pathway activation in OLs, promotes remyelination, reduces axonal damage and significantly enhances clinical recovery from the disease. Our results suggest that inhibiting the non-myelin permissive environment maintained by Notch pathways within the mature CNS offers a new strategy for treating autoimmune demyelination, including MS.