Mutations in SPG11, encoding spatacsin, are a major cause of spastic paraplegia with thin corpus callosum.

Autosomal recessive hereditary spastic paraplegia (ARHSP) with thin corpus callosum (TCC) is a common and clinically distinct form of familial spastic paraplegia that is linked to the SPG11 locus on chromosome 15 in most affected families. We analyzed 12 ARHSP-TCC families, refined the SPG11 candidate interval and identified ten mutations in a previously unidentified gene expressed ubiquitously in the nervous system but most prominently in the cerebellum, cerebral cortex, hippocampus and pineal gland. The mutations were either nonsense or insertions and deletions leading to a frameshift, suggesting a loss-of-function mechanism. The identification of the function of the gene will provide insight into the mechanisms leading to the degeneration of the corticospinal tract and other brain structures in this frequent form of ARHSP.

Natalizumab for the prevention of post-partum relapses in women with multiple sclerosis.

OBJECTIVE: Our aim was to evaluate the impact of early redosing of natalizumab after delivery on the risk of post-partum relapses in six women with very active multiple sclerosis (MS). METHODS: We undertook a retrospective analysis of data collected prospectively in the Lyon MS Cohort. RESULTS: The annualized relapse rate (ARR) in the year before natalizumab treatment was 4.2 ±0.4, which decreased to 0.4 ±0.6 during the treatment period. The mean time between natalizumab withdrawal and onset of pregnancy was 9 months; one pregnancy was exposed to one infusion. The ARR between natalizumab withdrawal and onset of pregnancy was 1.8 ±0.7. Six relapses occurred before onset of pregnancy and seven during pregnancy. Natalizumab was restarted 7.8 days after delivery (between day 2 and 8 for five patients and on day 23 for one). Only one patient, who had restarted natalizumab 2 days after delivery, had a relapse 2 weeks later. The others five patients were relapse free after a mean of 14.2 ±9.1 months of follow-up. CONCLUSION: Despite a high risk of post-partum relapses, early redosing of natalizumab led to a complete disappearance of disease activity in all but one patient. These data suggest that natalizumab could be a good candidate for preventing early post-partum relapses.

Tissue remodeling in periplaque regions of multiple sclerosis spinal cord lesions.

Our knowledge of multiple sclerosis (MS) neuropathology has benefited from a number of studies that provided an in-depth description of plaques and, more recently, diffuse alterations of the normal-appearing white or grey matter. However, there have been few studies focusing on the periplaque regions surrounding demyelinated plaques, notably in MS spinal cords. In this context, the present study aimed to analyze the molecular immunopathology of periplaque demyelinated lesions (PDLs) in the spinal cord of patients with a progressive form of MS. To achieve this goal, the neuropathological features of PDLs were analyzed in postmortem tissues derived from the cervical spinal cord of 21 patients with primary or secondary progressive MS. We found that PDLs covered unexpectedly large areas of incomplete demyelination and were characterized by the superimposition of pro- and anti-inflammatory molecular signatures. Accordingly, macrophages/microglia accumulated in PDLs but exhibited a poor phagocytic activity toward myelin debris. Interestingly, while genes of the oligodendrocyte lineage were consistently down-regulated in PDLs, astrocyte-related molecules such as aquaporin 4, connexin 43 and the glutamate transporter EAAT1, were significantly upregulated in PDLs at the mRNA and protein levels. Overall, our work indicates that in the spinal cord of patients with a progressive form of MS, a tissue remodeling process that is temporally remote from plaque development takes place in PDLs. We propose that in spinal cord PDLs, this process is supported by subtle alterations of astrocyte functions and by low-grade inflammatory events that drive a slowly progressive loss of myelin and a failure of remyelination.

Randomized trial of oral teriflunomide for relapsing multiple sclerosis.

BACKGROUND: Teriflunomide is a new oral disease-modifying therapy for relapsing forms of multiple sclerosis. METHODS: We concluded a randomized trial involving 1088 patients with multiple sclerosis, 18 to 55 years of age, with a score of 0 to 5.5 on the Expanded Disability Status Scale and at least one relapse in the previous year or at least two relapses in the previous 2 years. Patients were randomly assigned (in a 1:1:1 ratio) to placebo, 7 mg of teriflunomide, or 14 mg of teriflunomide once daily for 108 weeks. The primary end point was the annualized relapse rate, and the key secondary end point was confirmed progression of disability for at least 12 weeks. RESULTS: Teriflunomide reduced the annualized relapse rate (0.54 for placebo vs. 0.37 for teriflunomide at either 7 or 14 mg), with relative risk reductions of 31.2% and 31.5%, respectively (P<0.001 for both comparisons with placebo). The proportion of patients with confirmed disability progression was 27.3% with placebo, 21.7% with teriflunomide at 7 mg (P=0.08), and 20.2% with teriflunomide at 14 mg (P=0.03). Both teriflunomide doses were superior to placebo on a range of end points measured by magnetic resonance imaging (MRI). Diarrhea, nausea, and hair thinning were more common with teriflunomide than with placebo. The incidence of elevated alanine aminotransferase levels (≥1 times the upper limit of the normal range) was higher with teriflunomide at 7 mg and 14 mg (54.0% and 57.3%, respectively) than with placebo (35.9%); the incidence of levels that were at least 3 times the upper limit of the normal range was similar in the lower- and higher-dose teriflunomide groups and the placebo group (6.3%, 6.7%, and 6.7%, respectively). Serious infections were reported in 1.6%, 2.5%, and 2.2% of patients in the three groups, respectively. No deaths occurred. CONCLUSIONS: Teriflunomide significantly reduced relapse rates, disability progression (at the higher dose), and MRI evidence of disease activity, as compared with placebo. (Funded by Sanofi-Aventis; TEMSO ClinicalTrials.gov number, NCT00134563.).

Teriflunomide versus subcutaneous interferon beta-1a in patients with relapsing multiple sclerosis: a randomised, controlled phase 3 trial.

BACKGROUND: In previous studies, teriflunomide significantly reduced the annualised relapse rate (ARR) and disability progression. OBJECTIVE: This phase 3, rater-blinded study (NCT00883337) compared teriflunomide with interferon-beta-1a (IFNß-1a). METHODS: Patients with relapsing multiple sclerosis were randomised (1:1:1) to oral teriflunomide 7-or 14 mg, or subcutaneous IFNß-1a 44 µg. The primary composite endpoint was time to failure, defined as first occurrence of confirmed relapse or permanent treatment discontinuation for any cause. Secondary endpoints included ARR, Fatigue Impact Scale (FIS) and Treatment Satisfaction Questionnaire for Medication (TSQM). The study was completed 48 weeks after the last patient was randomised. RESULTS: Some 324 patients were randomised (IFNß-1a: 104; teriflunomide 7 mg: 109; teriflunomide 14 mg: 111). No difference in time to failure was observed. There was no difference in ARR between teriflunomide 14 mg and IFNß-1a, but ARR was significantly higher with teriflunomide 7 mg. FIS scores indicated more frequent fatigue with IFNß-1a, though differences were only significant with teriflunomide 7 mg. TSQM scores were significantly higher with teriflunomide. There were no unexpected safety findings. CONCLUSION: Effects on time to failure were comparable between teriflunomide and IFNß-1a. There was no difference between teriflunomide 14 mg and IFNß-1a on ARR, though ARR was higher with teriflunomide 7 mg. The teriflunomide safety profile was consistent with previous studies.

Multiple sclerosis registries in Europe - results of a systematic survey.

BACKGROUND: Identification of MS registries and databases that are currently in use in Europe as well as a detailed knowledge of their content and structure is important in order to facilitate comprehensive analysis and comparison of data. METHODS: National MS registries or databases were identified by literature search, from the results of the MS Barometer 2011 and by asking 33 national MS societies. A standardized questionnaire was developed and sent to the registries' leaders, followed by telephone interviews with them. RESULTS: Twenty registries were identified, with 13 completing the questionnaire and seven being interviewed by telephone. These registries differed widely for objectives, structure, collected data, and for patients and centres included. Despite this heterogeneity, common objectives of the registries were epidemiology (n=10), long-term therapy outcome (n=8), healthcare research (n=9) and support/basis for clinical trials (n=8). While physician-based outcome measures (EDSS) are used in all registries, data from patients' perspectives were only collected in six registries. CONCLUSIONS: The detailed information on a large number of national MS registries in Europe is a prerequisite to facilitating harmonized integration of existing data from MS registries and databases, as well as comprehensive analyses and comparison across European populations.

Alemtuzumab for patients with relapsing multiple sclerosis after disease-modifying therapy: a randomised controlled phase 3 trial.

BACKGROUND: The anti-CD52 monoclonal antibody alemtuzumab reduces disease activity in previously untreated patients with relapsing-remitting multiple sclerosis. We aimed to assess efficacy and safety of alemtuzumab compared with interferon beta 1a in patients who have relapsed despite first-line treatment. METHODS: In our 2 year, rater-masked, randomised controlled phase 3 trial, we enrolled adults aged 18-55 years with relapsing-remitting multiple sclerosis and at least one relapse on interferon beta or glatiramer. Eligible participants were randomly allocated in a 1:2:2 ratio by an interactive voice response system, stratified by site, to receive subcutaneous interferon beta 1a 44 µg, intravenous alemtuzumab 12 mg per day, or intravenous alemtuzumab 24 mg per day. Interferon beta 1a was given three-times per week and alemtuzumab was given once per day for 5 days at baseline and for 3 days at 12 months. The 24 mg per day group was discontinued to aid recruitment, but data are included for safety assessments. Coprimary endpoints were relapse rate and time to 6 month sustained accumulation of disability, comparing alemtuzumab 12 mg and interferon beta 1a in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT00548405. FINDINGS: 202 (87%) of 231 patients randomly allocated interferon beta 1a and 426 (98%) of 436 patients randomly allocated alemtuzumab 12 mg were included in the primary analyses. 104 (51%) patients in the interferon beta 1a group relapsed (201 events) compared with 147 (35%) patients in the alemtuzumab group (236 events; rate ratio 0·51 [95% CI 0·39-0·65]; p<0·0001), corresponding to a 49·4% improvement with alemtuzumab. 94 (47%) patients in the interferon beta 1a group were relapse-free at 2 years compared with 278 (65%) patients in the alemtuzumab group (p<0·0001). 40 (20%) patients in the interferon beta 1a group had sustained accumulation of disability compared with 54 (13%) in the alemtuzumab group (hazard ratio 0·58 [95% CI 0·38-0·87]; p=0·008), corresponding to a 42% improvement in the alemtuzumab group. For 435 patients allocated alemtuzumab 12 mg, 393 (90%) had infusion-associated reactions, 334 (77%) had infections (compared with 134 [66%] of 202 patients in the interferon beta 1a group) that were mostly mild-moderate with none fatal, 69 (16%) had thyroid disorders, and three (1%) had immune thrombocytopenia. INTERPRETATION: For patients with first-line treatment-refractory relapsing-remitting multiple sclerosis, alemtuzumab could be used to reduce relapse rates and sustained accumulation of disability. Suitable risk management strategies allow for early identification of alemtuzumab's main adverse effect of secondary autoimmunity. FUNDING: Genzyme (Sanofi) and Bayer Schering Pharma.

Alemtuzumab versus interferon beta 1a as first-line treatment for patients with relapsing-remitting multiple sclerosis: a randomised controlled phase 3 trial.

BACKGROUND: The anti-CD52 monoclonal antibody alemtuzumab reduced disease activity in a phase 2 trial of previously untreated patients with relapsing-remitting multiple sclerosis. We aimed to assess efficacy and safety of first-line alemtuzumab compared with interferon beta 1a in a phase 3 trial. METHODS: In our 2 year, rater-masked, randomised controlled phase 3 trial, we enrolled adults aged 18-50 years with previously untreated relapsing-remitting multiple sclerosis. Eligible participants were randomly allocated in a 2:1 ratio by an interactive voice response system, stratified by site, to receive intravenous alemtuzumab 12 mg per day or subcutaneous interferon beta 1a 44 µg. Interferon beta 1a was given three-times per week and alemtuzumab was given once per day for 5 days at baseline and once per day for 3 days at 12 months. Coprimary endpoints were relapse rate and time to 6 month sustained accumulation of disability in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT00530348. FINDINGS: 187 (96%) of 195 patients randomly allocated interferon beta 1a and 376 (97%) of 386 patients randomly allocated alemtuzumab were included in the primary analyses. 75 (40%) patients in the interferon beta 1a group relapsed (122 events) compared with 82 (22%) patients in the alemtuzumab group (119 events; rate ratio 0·45 [95% CI 0·32-0·63]; p<0.0001), corresponding to a 54·9% improvement with alemtuzumab. Based on Kaplan-Meier estimates, 59% of patients in the interferon beta 1a group were relapse-free at 2 years compared with 78% of patients in the alemtuzumab group (p<0·0001). 20 (11%) of patients in the interferon beta 1a group had sustained accumulation of disability compared with 30 (8%) in the alemtuzumab group (hazard ratio 0·70 [95% CI 0·40-1·23]; p=0·22). 338 (90%) of patients in the alemtuzumab group had infusion-associated reactions; 12 (3%) of which were regarded as serious. Infections, predominantly of mild or moderate severity, occurred in 253 (67%) patients treated with alemtuzumab versus 85 (45%) patients treated with interferon beta 1a. 62 (16%) patients treated with alemtuzumab had herpes infections (predominantly cutaneous) compared with three (2%) patients treated with interferon beta 1a. By 24 months, 68 (18%) patients in the alemtuzumab group had thyroid-associated adverse events compared with 12 (6%) in the interferon beta 1a group, and three (1%) had immune thrombocytopenia compared with none in the interferon beta 1a group. Two patients in the alemtuzumab group developed thyroid papillary carcinoma. INTERPRETATION: Alemtuzumab's consistent safety profile and benefit in terms of reductions of relapse support its use for patients with previously untreated relapsing-remitting multiple sclerosis; however, benefit in terms of disability endpoints noted in previous trials was not observed here. FUNDING: Genzyme (Sanofi) and Bayer Schering Pharma.

Persistent visual impairment in multiple sclerosis: prevalence, mechanisms and resulting disability.

OBJECTIVE: The objective of this article is to evaluate in multiple sclerosis (MS) patients the prevalence of persistent complaints of visual disturbances and the mechanisms and resulting functional disability of persistent visual complaints (PVCs). METHODS: Firstly, the prevalence of PVCs was calculated in 303 MS patients. MS-related data of patients with or without PVCs were compared. Secondly, 70 patients with PVCs performed an extensive neuro-ophthalmologic assessment and a vision-related quality of life questionnaire, the National Eye Institute Visual Functionary Questionnaire (NEI-VFQ-25). RESULTS: PVCs were reported in 105 MS patients (34.6%). Patients with PVCs had more frequently primary progressive MS (30.5% vs 13.6%) and more neuro-ophthalmologic relapses (1.97 vs 1.36) than patients without PVCs. In the mechanisms/disability study, an afferent visual and an ocular-motor pathways dysfunction were respectively diagnosed in 41 and 59 patients, mostly related to bilateral optic neuropathy and bilateral internuclear ophthalmoplegia. The NEI-VFQ 25 score was poor and significantly correlated with the number of impaired neuro-ophthalmologic tests. CONCLUSION: Our study emphasizes the high prevalence of PVC in MS patients. Regarding the nature of neuro-ophthalmologic deficit, our results suggest that persistent optic neuropathy, as part of the progressive evolution of the disease, is not rare. We also demonstrate that isolated ocular motor dysfunctions induce visual disability in daily life.

Magnetic resonance imaging outcomes from a phase III trial of teriflunomide.

OBJECTIVE: The purpose of this study was to determine the effects of oral teriflunomide on multiple sclerosis (MS) pathology inferred by magnetic resonance imaging (MRI). METHODS: Patients (n=1088) with relapsing MS were randomized to once-daily teriflunomide 7 mg or 14 mg, or placebo, for 108 weeks. MRI was recorded at baseline, 24, 48, 72 and 108 weeks. Annualized relapse rate and confirmed progression of disability (sustained ≥12 weeks) were the primary and key secondary outcomes. The principal MRI outcome was change in total lesion volume. RESULTS: After 108 weeks, increase in total lesion volume was 67.4% (p=0.0003) and 39.4% (p=0.0317) lower in the 14 and 7 mg dose groups versus placebo. Other measures favoring teriflunomide were accumulated enhanced lesions, combined unique activity, T2-hyperintense and T1-hypointense component lesion volumes, white matter volume, and a composite MRI score; all were significant for teriflunomide 14 mg and most significant for 7 mg versus placebo. CONCLUSIONS: Teriflunomide provided benefits on brain MRI activity across multiple measures, with a dose effect evident on several markers. These effects were also consistent across selected subgroups of the study population. These findings complement clinical data showing significant teriflunomide-related reductions in relapse rate and disease progression, and demonstrate containment of MRI-defined disease progression.

A genome-scale DNA repair RNAi screen identifies SPG48 as a novel gene associated with hereditary spastic paraplegia.

DNA repair is essential to maintain genome integrity, and genes with roles in DNA repair are frequently mutated in a variety of human diseases. Repair via homologous recombination typically restores the original DNA sequence without introducing mutations, and a number of genes that are required for homologous recombination DNA double-strand break repair (HR-DSBR) have been identified. However, a systematic analysis of this important DNA repair pathway in mammalian cells has not been reported. Here, we describe a genome-scale endoribonuclease-prepared short interfering RNA (esiRNA) screen for genes involved in DNA double strand break repair. We report 61 genes that influenced the frequency of HR-DSBR and characterize in detail one of the genes that decreased the frequency of HR-DSBR. We show that the gene KIAA0415 encodes a putative helicase that interacts with SPG11 and SPG15, two proteins mutated in hereditary spastic paraplegia (HSP). We identify mutations in HSP patients, discovering KIAA0415/SPG48 as a novel HSP-associated gene, and show that a KIAA0415/SPG48 mutant cell line is more sensitive to DNA damaging drugs. We present the first genome-scale survey of HR-DSBR in mammalian cells providing a dataset that should accelerate the discovery of novel genes with roles in DNA repair and associated medical conditions. The discovery that proteins forming a novel protein complex are required for efficient HR-DSBR and are mutated in patients suffering from HSP suggests a link between HSP and DNA repair.

Increased risk of multiple sclerosis relapse after in vitro fertilisation.

BACKGROUND: Exogenous sexual steroids together with pregnancy have been shown to influence the risk of relapses in multiple sclerosis (MS). Treatments used during assisted reproductive techniques may consequently influence the short term evolution of MS by modifying the hormonal status of the patient. The objective of this study was to determine if there was an increased risk of developing exacerbations in women with MS after in vitro fertilisation (IVF). METHODS: MS and IVF data were either automatically extracted from 13 French university hospital databases or obtained from referring neurologists. After matching databases, patient clinical files were systematically reviewed to collect information about MS and the treatments used for IVF. The association between IVF and the occurrence of MS relapses was analysed in detail using univariate and multivariate statistical tests. FINDINGS: During the 11 year study period, 32 women with MS had undergone 70 IVF treatments, 48 using gonadotrophin releasing hormone (GnRH) agonists and 19 using GnRH antagonists. A significant increase in the annualised relapse rate (ARR) was observed during the 3 month period following IVF (mean ARR 1.60, median ARR 0) compared with the same period just before IVF (mean ARR 0.80, median ARR 0) and to a control period 1 year before IVF (mean ARR 0.68, median ARR 0). The significant increase in relapses was associated with the use of GnRH agonists (Wilcoxon paired test, p=0.025) as well as IVF failure (Wilcoxon paired test, p=0.019). INTERPRETATION: An increased relapse rate was observed in this study after IVF in patients with MS and may be partly related both to IVF failure and the use of GnRH agonists.

Long-term follow-up of a phase 2 study of oral teriflunomide in relapsing multiple sclerosis: safety and efficacy results up to 8.5 years.

BACKGROUND: Teriflunomide, an oral disease-modifying therapy in development for patients with relapsing forms of multiple sclerosis (RMS), was well tolerated and effective in reducing magnetic resonance imaging (MRI) lesions in 179 RMS patients in a phase 2 36-week, placebo-controlled study. METHODS: A total of 147 patients who completed the core study entered an open-label extension. Teriflunomide patients continued their assigned dose, and placebo patients were re-allocated to teriflunomide, 7 mg/day or 14 mg/day. An interim analysis was performed at a cut-off on January 8 2010. RESULTS: The mean and median duration of study treatment, including both the core and extension phase, from baseline to the interim cut-off, was 5.6 years (standard deviation: 2.7 years) and 7.1 years (range: 0.05-8.5 years), respectively. Of 147 patients, 62 (42.2%) discontinued (19% due to treatment-emergent adverse events (TEAEs)). The most common TEAEs were mild infections, fatigue, sensory disturbances and diarrhoea. No serious opportunistic infections occurred, with no discontinuations due to infection. Asymptomatic alanine aminotransferase increases (≤3× upper limit of normal (ULN)) were common (7 mg, 64.2%; 14 mg, 62.1%); increases >3×ULN were similar across groups (7 mg, 12.3%; 14 mg, 12.1%). Mild decreases in neutrophil counts occurred; none led to discontinuation. The incidence of malignancies was comparable to that of the general population, and cases were not reminiscent of those observed in immunocompromised patients. Annualised relapse rates remained low, minimal disability progression was observed, with a dose-dependent benefit with teriflunomide 14 mg for several MRI parameters. CONCLUSION: Teriflunomide had a favourable safety profile for up to 8.5 years.

Pre-specified subgroup analyses of a placebo-controlled phase III trial (TEMSO) of oral teriflunomide in relapsing multiple sclerosis.

BACKGROUND: The Teriflunomide Multiple Sclerosis Oral (TEMSO) trial, a randomized, double-blind, placebo-controlled phase III study, demonstrated that teriflunomide significantly reduced annualized relapse rate (ARR), disease progression and magnetic resonance imaging (MRI) activity, with a favorable safety profile in relapsing multiple sclerosis (RMS) patients. OBJECTIVE: The purpose of this study was to report the effects of teriflunomide on ARR and disability progression in pre-specified subgroups. METHODS: RMS patients (n=1088) were randomized to placebo or teriflunomide, 7 mg or 14 mg, once daily, for 108 weeks. Subgroup analyses were performed for ARR and disability progression by baseline demographics (gender, race, age), disease characteristics (Expanded Disability Status Scale (EDSS) strata, relapse history, multiple sclerosis (MS) subtype), MRI parameters (gadolinium-enhancing lesions, total lesion volume) and prior use of MS drugs. A generalized estimating equation method and Cox regression model were used to assess consistency of the treatment effect across subgroups, utilizing a treatment-by-subgroup interaction test for each factor separately. RESULTS: Reductions in ARR and disability progression were consistent across subgroups in favor of teriflunomide, with no treatment-by-subgroup interaction test reaching statistical significance. CONCLUSION: The positive effects of teriflunomide were demonstrated consistently across subgroups in TEMSO.

Tyrosine kinase 2 variant influences T lymphocyte polarization and multiple sclerosis susceptibility.

The tyrosine kinase 2 variant rs34536443 has been established as a genetic risk factor for multiple sclerosis in a variety of populations. However, the functional effect of this variant on disease pathogenesis remains unclear. This study replicated the genetic association of tyrosine kinase 2 with multiple sclerosis in a cohort of 1366 French patients and 1802 controls. Furthermore, we assessed the functional consequences of this polymorphism on human T lymphocytes by comparing the reactivity and cytokine profile of T lymphocytes isolated from individuals expressing the protective TYK2(GC) genotype with the disease-associated TYK2(GG) genotype. Our results demonstrate that the protective C allele infers decreased tyrosine kinase 2 activity, and this reduction of activity is associated with a shift in the cytokine profile favouring the secretion of Th2 cytokines. These findings suggest that the rs34536443 variant effect on multiple sclerosis susceptibility might be mediated by deviating T lymphocyte differentiation toward a Th2 phenotype. This impact of tyrosine kinase 2 on effector differentiation is likely to be of wider importance because other autoimmune diseases also have been associated with polymorphisms within tyrosine kinase 2. The modulation of tyrosine kinase 2 activity might therefore represent a new therapeutic approach for the treatment of autoimmune diseases.

[New therapies in multiple sclerosis]. / Actualités thérapeutiques dans la sclérose en plaques.

Due to the autoimmune nature of multiple sclerosis (MS), the current disease modifying treatments aim at reducing the immune system activity or at interfering with it. Immune modulators from the interferon Beta and glatiramer acetate families are widely used as first line treatments. They often prove sufficient for moderately active forms of the disease. For more active forms, powerful immunosuppressants such as mitoxantrone or a monoclonal antibody (natalizumab), selective inhibitor of the T cell adhesion molecule on the cerebral endothelium, are used. Several new promising oral medications should be added to this therapeutic arsenal shortly. Most of the times, these various treatments are already effective for preventing relapses. However, they remain rather ineffective for progression which is the second clinical constituent of the disease. Improvements are urgently needed in this area.

Meningeal T cells associate with diffuse axonal loss in multiple sclerosis spinal cords.

OBJECTIVE: A link between diffuse axonal loss and diffuse inflammation has been established in the brain of patients with progressive multiple sclerosis (MS). In the present paper, we sought to determine whether such a link could be similarly demonstrated in the spinal cord of patients with progressive MS. METHODS: A neuropathological quantitative assessment of inflammation and axonal loss was performed in the cervical spinal cord of 18 patients with progressive MS and 5 control subjects. RESULTS: As previously reported, we found a mean 25% decrease of axonal density in the normal-appearing white matter (NAWM) of MS versus control spinal cords. T-cell perivascular infiltrates were rare, but a robust diffuse inflammation was observed in both the normal-appearing parenchyma and the meninges. The extent of diffuse axonal loss in the NAWM correlated with both the density of major histocompatibility complex (MHC) class II(+) microglia in the NAWM and, surprisingly, the density of CD3(+) T cells in the meninges. Interestingly, close interactions between T cells and MHC class II(+) macrophages were observed in the meninges of spinal cords from MS patients. INTERPRETATION: Recent studies assigned a major role to meningeal B-cell follicles in the pathophysiology of secondary progressive MS. The present work also emphasizes the link between meningeal inflammation and parenchymal lesions and points to a specific role exerted by both meningeal T cells and activated microglia in diffuse axonal loss in the spinal cord.

Oligodendrocytes are damaged by neuromyelitis optica immunoglobulin G via astrocyte injury.

Devic's neuromyelitis optica is an inflammatory demyelinating disorder normally restricted to the optic nerves and spinal cord. Since the identification of a specific autoantibody directed against aquaporin 4, neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody, neuromyelitis optica has been considered an entity distinct from multiple sclerosis. Recent findings indicate that the neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody has a pathogenic role through complement-dependent astrocyte toxicity. However, the link with demyelination remains elusive. Autoantibodies can act as receptor agonists/antagonists or alter antigen density in their target cells. We hypothesized that the neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody impairs astrocytic function and secondarily leads to demyelination. Rat astrocytes and oligodendrocytes from primary cultures and rat optic nerves were exposed long-term (24 h) to immunoglobulin G in the absence of complement. Immunoglobulin G was purified from the serum of patients with neuromyelitis optica who were either neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody positive or negative, as well as from healthy controls. Flow cytometry analysis showed a reduction of membrane aquaporin 4 and glutamate transporter type 1 on astrocytes following contact with immunoglobulin G purified from neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody positive serum only. The activity of glutamine synthetase, an astrocyte enzyme converting glutamate into glutamine, decreased in parallel, indicating astrocyte dysfunction. Treatment also reduced oligodendrocytic cell processes and approximately 30% oligodendrocytes died. This deleterious effect was confirmed ex vivo; exposed optic nerves showed reduction of myelin basic protein. Immunoglobulin G from neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody seronegative patients and from healthy controls had no similar effect. Neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody did not directly injure oligodendrocytes cultured without astrocytes. A toxic bystander effect of astrocytes damaged by neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody on oligodendrocytes was identified. Progressive accumulation of glutamate in the culture medium of neuromyelitis optica-immunoglobulin G/aquaporin 4-antibody-treated glial cells supported the hypothesis of a glutamate-mediated excitotoxic death of oligodendrocytes in our models. Moreover, co-treatment of glial cultures with neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody and d+2-amino-5-phosphonopentanoic acid, a competitive antagonist at the N-methyl-d-aspartate/glutamate receptor, partially protected oligodendrocytes. Co-immunolabelling of oligodendrocyte markers and neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody showed that astrocytic positive processes were in close contact with oligodendrocytes and myelin in rat optic nerves and spinal cord, but far less so in other parts of the central nervous system. This suggests a bystander effect of neuromyelitis optica-immunoglobulin G-damaged astrocytes on oligodendrocytes in the nervous tissues affected by neuromyelitis optica. In conclusion, in these cell culture models we found a direct, complement-independent effect of neuromyelitis optica-immunoglobulin G/aquaporin 4 antibody on astrocytes, with secondary damage to oligodendrocytes possibly resulting from glutamate-mediated excitotoxicity. These mechanisms could add to the complement-induced damage, particularly the demyelination, seen in vivo.

Geographic variations of multiple sclerosis in France.

France is located in an area with a medium to high prevalence of multiple sclerosis, where its epidemiology is not well known. We estimated the national and regional prevalence of multiple sclerosis in France on 31 October 2004 and the incidence between 31 October 2003 and 31 October 2004 based on data from the main French health insurance system: the Caisse Nationale d'Assurance Maladie des Travailleurs Salariés. The Caisse Nationale d'Assurance Maladie des Travailleurs Salariés insures 87% of the French population. We analysed geographic variations in the prevalence and incidence of multiple sclerosis in France using the Bayesian approach. On the 31 October 2004, 49 417 people were registered with multiple sclerosis out of the 52 359 912 insured with the Caisse Nationale d'Assurance Maladie des Travailleurs Salariés. Among these, 4497 were new multiple sclerosis cases declared between 31 October 2003 and 31 October 2004. After standardization for age, total multiple sclerosis prevalence in France was 94.7 per 100,000 (94.3-95.1); 130.5 (129.8-131.2) in females and 54.8 (54.4-55.3) in males. The national incidence of multiple sclerosis between 31 October 2003 and 31 October 2004 was 7.5 per 100,000 (7.3-7.6); 10.4 (10.2-10.6) in females and 4.2 (4.0-4.3) in males. The prevalence and incidence of multiple sclerosis were higher in North-Eastern France, but there was no obvious North-South gradient. This study is the first performed among a representative population of France (87%) using the same method throughout. The Bayesian approach, which takes into account spatial heterogeneity among geographical units and spatial autocorrelation, did not confirm the existence of a prevalence gradient but only a higher prevalence of multiple sclerosis in North-Eastern France and a lower prevalence of multiple sclerosis in the Paris area and on the Mediterranean coast.

Natural history of multiple sclerosis with childhood onset.

BACKGROUND: The course and prognosis of childhood-onset multiple sclerosis have not been well described. METHODS: We used data from 13 adult neurology departments affiliated with the European Database for Multiple Sclerosis (EDMUS) network to identify a cohort of 394 patients who had multiple sclerosis with an onset at 16 years of age or younger and a comparison group of 1775 patients who had multiple sclerosis with an onset after 16 years of age. We determined the initial clinical features, the dates of disease onset, and the occurrence of outcomes, including relapse, conversion to secondary progression, and irreversible disability as measured by scores of 4 (limited walking ability but ability to walk more than 500 m without aid or rest), 6 (ability to walk with unilateral support no more than 100 m without rest), and 7 (ability to walk no more than 10 m without rest while using a wall or furniture for support) on the Kurtzke Disability Status Scale (range, 0 to 10; higher scores indicate more severe disability). RESULTS: For patients with childhood-onset multiple sclerosis, the estimated median time from onset to secondary progression was 28 years, and the median age at conversion to secondary progression was 41 years. The median times from onset to disability scores of 4, 6, and 7 were 20.0, 28.9, and 37.0 years, respectively, and the corresponding median ages were 34.6, 42.2, and 50.5 years. In comparison with patients with adult-onset disease, those with childhood-onset disease were more likely to be female than male (female:male ratio, 2.8 vs. 1.8), were more likely to have an exacerbating-remitting initial course (98% vs. 84%), took approximately 10 years longer to reach secondary progression and irreversible disability, and reached these landmarks at an age approximately 10 years younger (P<0.001 for all comparisons). CONCLUSIONS: Patients with childhood-onset multiple sclerosis take longer to reach states of irreversible disability but do so at a younger age than patients with adult-onset multiple sclerosis.