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Objective Our objective was to test whether natalizumab, an antibody against very late activating antigen (VLA)-4, interferes with central nervous system immune surveillance as assessed by leukocyte cell numbers and cellular phenotypes in cerebrospinal fluid (CSF) and peripheral blood. Methods Cell numbers and cellular phenotypes in CSF and peripheral blood were analyzed in multiple sclerosis (MS) patients treated with natalizumab, untreated MS patients, and patients with other neurological disease (OND). JC virus DNA in the CSF and peripheral blood was quantified by kinetic polymerase chain reaction. Results CSF leukocyte counts, CD4+ and CD8+ T cells, CD19+ B cells, and CD138+ plasma cells were significantly lower in natalizumab-treated MS patients compared with OND patients and untreated MS patients. JC virus DNA was not detected in CSF or peripheral blood from natalizumab-treated patients. Six months after cessation of natalizumab therapy, low lymphocyte counts in the CSF persisted. The patient with the highest total leukocyte and CD4+ and CD8+T-cell counts in the CSF experienced a clinical relapse. Interpretation These data suggest that natalizumab treatment results in a prolonged decrease of lymphocytes in the CSF and are consistent with the hypothesis that natalizumab impairs immune surveillance of the central nervous system. Ann Neurol 2006;59:743–747

The polymorphism in the human prion protein gene at codon 129 (PRNP 129) determines susceptibility to prion disease, and has been associated with early onset and a more severe course of other neurodegenerative disorders. Here, we tested the hypothesis that PRNP is a disease-modifying gene in clinical Wilson disease with a neurological phenotype. Allele frequencies in patients with clinical Wilson disease were not different from those of a healthy German control population, and PRNP 129 genotypes did not result in different serum copper, serum ceruloplasmin, or copper in 24-h urine concentrations. PRNP 129 methionine homozygosity, however, led to significantly more severe neurological symptoms in elderly patients, particularly tremor, supporting the notion that PRNP 129 homozygosity contributes to neuronal vulnerability.

Importance Most patients with relapsing-remitting (RR) multiple sclerosis (MS) who receive approved disease-modifying therapies experience breakthrough disease and accumulate neurologic disability. High-dose immunosuppressive therapy (HDIT) with autologous hematopoietic cell transplant (HCT) may, in contrast, induce sustained remissions in early MS. Objective To evaluate the safety, efficacy, and durability of MS disease stabilization through 3 years after HDIT/HCT. Design, setting, and participants Hematopoietic Cell Transplantation for Relapsing-Remitting Multiple Sclerosis (HALT-MS) is an ongoing, multicenter, single-arm, phase 2 clinical trial of HDIT/HCT for patients with RRMS who experienced relapses with loss of neurologic function while receiving disease-modifying therapies during the 18 months before enrolling. Participants are evaluated through 5 years after HCT. This report is a prespecified, 3-year interim analysis of the trial. Thirty-six patients with RRMS from referral centers were screened; 25 were enrolled. Interventions Autologous peripheral blood stem cell grafts were CD34+ selected; the participants then received high-dose treatment with carmustine, etoposide, cytarabine, and melphalan as well as rabbit antithymocyte globulin before autologous HCT. Main outcomes and measures The primary end point of HALT-MS is event-free survival defined as survival without death or disease activity from any one of the following outcomes: (1) confirmed loss of neurologic function, (2) clinical relapse, or (3) new lesions observed on magnetic resonance imaging. Toxic effects are reported using National Cancer Institute Common Terminology Criteria for Adverse Events. Results Grafts were collected from 25 patients, and 24 of these individuals received HDIT/HCT. The median follow-up period was 186 weeks (interquartile range, 176-250) weeks). Overall event-free survival was 78.4% (90% CI, 60.1%-89.0%) at 3 years. Progression-free survival and clinical relapse-free survival were 90.9% (90% CI, 73.7%-97.1%) and 86.3% (90% CI, 68.1%-94.5%), respectively, at 3 years. Adverse events were consistent with expected toxic effects associated with HDIT/HCT, and no acute treatment-related neurologic adverse events were observed. Improvements were noted in neurologic disability, quality-of-life, and functional scores. Conclusions and relevance At 3 years, HDIT/HCT without maintenance therapy was effective for inducing sustained remission of active RRMS and was associated with improvements in neurologic function. Treatment was associated with few serious early complications or unexpected adverse events.

Background: As new therapies emerge which increase the risk of autoimmune disease it is increasingly important to understand the incidence of autoimmune disease in multiple sclerosis (MS). Objective: The purpose of this review is to estimate the incidence and prevalence of comorbid autoimmune disease in MS. Methods: The PUBMED, EMBASE, SCOPUS and Web of Knowledge databases, conference proceedings, and reference lists of retrieved articles were searched, and abstracts were independently screened by two reviewers. The data were abstracted by one reviewer using a standardized data collection form, and the findings were verified by a second reviewer. We assessed quality of the included studies using a standardized approach and conducted meta-analyses of population-based studies. Results: Sixty-one articles met the inclusion criteria. We observed substantial heterogeneity with respect to the populations studied, methods of ascertaining comorbidity, and reporting of findings. Based solely on population-based studies, the most prevalent autoimmune comorbidities were psoriasis (7.74%) and thyroid disease (6.44%). Our findings also suggest an increased risk of inflammatory bowel disease, likely uveitis and possibly pemphigoid. Conclusion: Fewer than half of the studies identified were of high quality. Population-based studies that report age, sex and ethnicity-specific estimates of incidence and prevalence are needed in jurisdictions worldwide.

Multiple Sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS) which affects over 2.5 million people worldwide. Although MS has been extensively studied, many challenges still remain in regards to treatment, diagnosis, and prognosis. Typically, prognosis and individual responses to treatment are evaluated by clinical tests such the expanded disability status scale (EDSS), magnetic resonance imaging (MRI), and presence of oligoclonal bands (OCB) in the cerebrospinal fluid (CSF). However, none of these measures correlate strongly with treatment efficacy or disease progression across heterogeneous patient populations and subtypes of MS. Numerous studies over the past decades have attempted to identify sensitive and specific biomarkers for diagnosis, prognosis, and treatment efficacy of MS. The objective of this article is to review and discuss the current literature on body fluid biomarkers in MS, including research on potential biomarker candidates in the areas of microRNA, messenger RNA, lipids, and proteins.

Therapeutic monoclonal antibodies (mAbs) are a relatively novel class of drugs that has substantially advanced immunotherapy for patients with multiple sclerosis. The advantage of these agents is that they bind specifically and exclusively to predetermined proteins or cells. Natalizumab was the first mAb in neurology to obtain approval. It is also considered one of the most potent options for annualized relapse rate reduction among available therapeutic options. Alemtuzumab is currently also approved in several countries. Several mAbs have been tested in clinical studies in multiple sclerosis. Here, we review the history of drug development of therapeutic mAbs and their classification. Furthermore, we outline the putative mechanisms of action, clinical evidence and safety of approved mAbs and those in different stages of clinical development in multiple sclerosis and neuromyelitis optica.

Background Aseptic meningitis associated with herpes simplex virus type 2 often has a relapsing-remitting clinical phenotype. Factors that lead to disease activation and reactivation are currently incompletely understood. Case presentation We describe the case of a 49-year-old Caucasian man who developed recurrent episodes of herpes simplex virus type 2-associated aseptic meningitis in the setting of heat exposure and bicycling. This case is compelling in that substantial data were available to the examining physicians on the amount of physical exercise and heat exposure. Strenuous physical activities or heat exposure in isolation did not cause re-occurrence of clinical signs and symptoms. Conclusions This case illustrates that the dual activation of mechanical and temperature receptors in dorsal root ganglia may lead to the recurrent reactivation and afferent dissemination of latent herpes simplex virus type 2 in some patients.

'Statins' are 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors - oral cholesterol-lowering drugs that are used to treat hypercholesterolaemia. It is widely accepted that statins have anti-inflammatory effects that are independent of their ability to lower cholesterol. Animal studies and observational clinical studies have indicated that statins might also be effective in treating certain neurological diseases - in particular, multiple sclerosis, Alzheimer's disease and ischaemic stroke. At present, however, results from ongoing prospective, randomized clinical trials are not available.

The disease-modifying agents currently used in the treatment of multiple sclerosis (MS) are not completely effective and are associated with adverse effects and high costs. Thus, alternative treatment options are highly desirable. HMG-CoA reductase inhibitors (statins), widely prescribed as cholesterol-lowering agents, may be a future treatment option for MS--either in an add-on therapy regimen or alone--as they have been shown to exhibit potent immunomodulatory effects. Several recent reports have demonstrated that HMG-CoA reductase inhibitors prevent and reverse chronic and relapsing experimental autoimmune encephalomyelitis, an animal model of MS. Furthermore, in vitro experiments with human immune cells have shown an immunomodulatory mode of action of HMG-CoA reductase inhibitors that is comparable to that of interferon-beta, an established treatment for MS. An open-label clinical trial assessing simvastatin treatment in patients with MS revealed a significant decrease in the number and volume of new lesions, as assessed using magnetic resonance imaging, and a favourable safety profile. A large multicentre, placebo-controlled phase II clinical trial assessing atorvastatin in patients with a clinically isolated syndrome (i.e. a single clinical event that is indicative of demyelination, and that predisposes to the development MS) has recently been initiated. However, prospective placebo-controlled trials of HMG-CoA reductase inhibitors in definite MS are difficult to perform because of ethical and financial issues. Furthermore, overly optimistic reports in the popular media, as well as the often uncontrolled access to HMG-CoA reductase inhibitors by patients with MS, complicate the evaluation of HMG-CoA reductase inhibitors as a realistic future treatment option for MS.

Multiple sclerosis (MS) is a CNS-demyelinating disease characterised by relapsing and chronic neurological impairment. While traditionally CNS autoantigen-specific CD4(+) T cells have been considered the culprits in the initial phase of the disease, recent observations have altered this concept. It is now recognised that other T lymphocyte subclasses can initiate CNS demyelination. In addition, other cell types and molecules may play an important role in MS pathogenesis. There is overwhelming evidence that MS is a dynamic process, in which recurrent episodes of blood-brain barrier disruption and CNS inflammation play a crucial role in early disease stages, leading eventually to the largely irreversible changes of demyelination, gliosis and axonal degeneration. These observations may have important therapeutic implications. Within the last ten years, several medications have been approved for MS treatment. These agents, all of which are given parenterally, are only partially effective and are often associated with adverse effects and potential toxicities. The number and different types of medications used for MS are likely to increase in the near future, as several novel therapies are currently tested in clinical trials. 3-hydroxy-3-methyglutaryl coenzyme A reductase inhibitors, 'statins', are cholesterol-lowering drugs that are given orally, are safe and have biological effects independent of their cholesterol-reducing properties. Recent reports have shown that statins have anti-inflammatory and neuroprotective properties that may be beneficial in the treatment of MS. This article will outline experimental evidence that suggests potential clinical benefits of statins for MS patients.

Multiple sclerosis is a central nervous system inflammatory demyelinating disease that is thought to have an autoimmune pathogenesis. Recent results indicate that 'statins', 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, which are the most commonly used oral cholesterol-lowering drugs, have immunomodulatory properties. In this article we will review those findings that indicate that statins may be beneficial in the treatment of multiple sclerosis, neurodegenerative disease, and ischemic stroke.It was reported that statin treatment could either inhibit or reverse chronic and relapsing experimental autoimmune encephalomyelitis, a model of multiple sclerosis. Several immunomodulatory properties of statins may account for their beneficial clinical effect: Statins decreased the migration of leukocytes into the central nervous system, inhibited MHC class II and costimulatory signals required for activation of proinflammatory T cells, induced a T(H)2 phenotype in T cells, and decreased the expression of inflammatory mediators in the central nervous system, including nitric oxide and tumor necrosis factor alpha. It was also demonstrated that statin use significantly reduced beta-amyloid secretion in the cerebrospinal fluid of experimental animals. Clinically, there is emerging evidence that statins have beneficial effects in patients with multiple sclerosis, Alzheimer's disease, and ischemic stroke.In-vitro studies have indicated that statins may have anti-inflammatory properties. Results from in-vivo animal models suggest that statins may be beneficial in treatment of different central nervous system conditions. Larger scale, randomized, double-blind trials are needed to validate the role of statins as a treatment of inflammatory central nervous system diseases.

Statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are approved for cholesterol reduction, may also be beneficial in the treatment of inflammatory diseases. Atorvastatin (Lipitor) was tested in chronic and relapsing experimental autoimmune encephalomyelitis, a CD4(+) Th1-mediated central nervous system (CNS) demyelinating disease model of multiple sclerosis. Here we show that oral atorvastatin prevented or reversed chronic and relapsing paralysis. Atorvastatin induced STAT6 phosphorylation and secretion of Th2 cytokines (interleukin (IL)-4, IL-5 and IL-10) and transforming growth factor (TGF)-beta. Conversely, STAT4 phosphorylation was inhibited and secretion of Th1 cytokines (IL-2, IL-12, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha) was suppressed. Atorvastatin promoted differentiation of Th0 cells into Th2 cells. In adoptive transfer, these Th2 cells protected recipient mice from EAE induction. Atorvastatin reduced CNS infiltration and major histocompatibility complex (MHC) class II expression. Treatment of microglia inhibited IFN-gamma-inducible transcription at multiple MHC class II transactivator (CIITA) promoters and suppressed class II upregulation. Atorvastatin suppressed IFN-gamma-inducible expression of CD40, CD80 and CD86 co-stimulatory molecules. l-Mevalonate, the product of HMG-CoA reductase, reversed atorvastatin's effects on antigen-presenting cells (APC) and T cells. Atorvastatin treatment of either APC or T cells suppressed antigen-specific T-cell activation. Thus, atorvastatin has pleiotropic immunomodulatory effects involving both APC and T-cell compartments. Statins may be beneficial for multiple sclerosis and other Th1-mediated autoimmune diseases.

IFN-τ, a novel type I IFN that possesses immunomodulatory properties, lacks toxicity normally associated with other type I IFNs. We examined the effects of oral IFN-τ alone and in combination with oral glatiramer acetate in experimental allergic encephalomyelitis (EAE). By comparison of oral administration of IFN-α, -β, and -τ to myelin basic protein-specific TCR-transgenic mice, we demonstrate these type I IFNs promote secretion of the Th2 cytokine IL-10 with similar efficiency. Whereas IFN-α and -β induced IFN-γ secretion, a Th1 cytokine, IFN-τ did not. Oral IFN-τ alone suppressed EAE. When suboptimal doses were administered orally in combination to wild-type mice, IFN-τ and glatiramer acetate had a synergistic beneficial effect in suppression of EAE. This combination was associated with TGF-β secretion and enhanced IL-10 production. Thus, IFN-τ is a potential candidate for use as a single agent or in combination therapy for multiple sclerosis.

BACKGROUND Pharmacotherapy for relapsing-remitting multiple sclerosis (MS) advanced with the demonstration that interferon beta and glatiramer acetate improve the clinical course of this disease. Mitoxantrone is the first drug approved by the Food and Drug Administration for treatment of secondary progressive MS. Despite this progress, the agents presently available are only partially effective, are difficult to administer, and may have significant side effects. Several orally administered immunomodulatory agents are presently being evaluated for treatment of MS. One class of drugs, HMG CoA inhibitors (statins), is safe and well-tolerated and could become another mainstay of MS therapy. REVIEW SUMMARY This article reviews the clinical evidence for approved MS therapies and discusses their mechanisms of action. Furthermore, the clinical and laboratory data suggesting a potential role for statins in MS therapy are discussed. CONCLUSIONS Although treatment with interferon beta, glatiramer acetate, and mitoxantrone, the approved therapies, provide important treatment options for patients with relapsing-remitting MS and secondary progressive MS, the potential benefits of other medications, including statins, should be explored in controlled clinical trials.

Multiple Sclerosis is the most common disease in young adults affecting the central nervous system. Disease may progress with acute attacks (relapsing MS) or continuously (progressive MS). Glucocorticosteroids are used in the treatment of acute attacks. The aim of this study was to analyse characteristics of patients with MS, and their influence on current treatment patterns of relapses with glucocorticosteroids.In 2001, the German National MS Society initiated the German MS-Registry. Patients with relapsing MS were included (n = 5106) from this registry. Logistic regression models were used to detect trends over time. The likelihood of administration of steroids is modelled in dependence of calendar year and in dependence to confounders in treatment conditions. The sample size allows that odds ratios can be detected with a power of 90% (alpha = 0.05).Administration of glucocorticosteroids was influenced by EDSS (P< 0.0001), age (P< 0.0001) and disease duration (P< 0.0001). Therapy administration in an outpatient setting was more likely in patients with higher EDSS (P< 0.0001) and longer disease duration (P< 0.0001). The utilization of glucocorticosteroids increased with higher EDSS for all relapsing patients. Interestingly, all overutilization of glucocorticosteroids decreased over time and was accompanied by a steadily increased administration of emergent therapeutics. Although there are about 70% of registered patients with relapsing MS on immune-modulatory treatment, almost 60% of them received glucocorticosteroids for treatment of relapses.Treatment patterns with glucocorticosteroids in patients with MS are influenced mainly by EDSS and disease duration. The decline in the utilization of glucocorticosteroids is accompanied by an increase in natalizumab treatment.

Doesnatalizumabtherapybenefitpatientswithmultiplesclerosis (MS)?Theobviousanswer isyes.Natalizumabwasapprovedfor patientswithrelapsingformsofMSbyregulatoryagenciesbased on the results of 2phase3 clinical trials that showedsubstantial benefitswithregardtoclinicalandparaclinicaloutcomes.1,2Post hocanalysessuggestthatmanywhoadheretonatalizumabtherapyhaveahigh likelihoodofbeingdisease free formanyyears.3 Basedontheseefficacydata,patientsshouldperhapsbetreated withnatalizumab indefinitelyoruntil theyseemtohave transitioned to secondary progressiveMS. However, shortly after its initial approval, itwasdeterminedthatnatalizumabuse isassociatedwithprogressivemultifocalencephalopathy(PML),anopportunistic infectionofthecentralnervoussystemthat iscaused by the humanpolyomavirus JohnCunninghamvirus (JCV). It isunclearwhynatalizumab increases the riskofPML,but itsmechanismofantagonizingα4 integrin–mediatedcellmigration likelydiminishes immunesurveillanceof thebrainandspinalcord.Whiledebatablylow,thisriskiscauseforconcernamong physiciansandatvarious times for somepatientsbasedontheir risktolerance.Almostsince its approval, attemptshavebeen made to determine whether discontinuationofnatalizumabissafe, inwhomtheagentshould bediscontinued,andhow.Althoughthepathogenicevents leading tonatalizumab-associatedPML remain opaque, the following3 factorsareassociatedwith theoverall riskof this infection: apositiveserostatusforanti–JCVantibodies, theutilizationof immunosuppressantsbeforeinitiatingnatalizumabuse,andthedurationofnatalizumabtherapy (aloneor incombination).4 If all 3 risk factorsarepresent, the riskofnatalizumab-associatedPML is approximately 1 in 90,which seemsunacceptably high given that PML is associatedwith ahighmorbidity andmortality and that alternative therapiesexist.Thedevelopmentof anassay to identifypatientswhoarepositive for JCVandthe identification of theotherknownrisk factors representamajorplus for initiating therapy, butwhenapatient becomespositive for JCVorhas beenonanatalizumabregimenforasubstantial amountof time anddesires to stop therapy, the path is less clear. Consequently,neurologistshavebeen investigatinghowto transition patients who want to cease natalizumab to other therapies.5,6Thegoalofa treatmentchange is2-fold,namely, to lowertheriskofPMLandtopreventMSdiseasereactivation.The riskofPMListhoughttobeabsentornegligibleforanyoftheother approvedtherapies,whereas it remainselevatedat least foraperiodafternatalizumab isdiscontinued.7Theriskofdisease reactivation is high, and it occurswithin 3 to 6months after the last natalizumabdose is administered.8 Related article page 954 Figure. PatientsWithMultiple Sclerosis Experience aMeaningful Reduction in Disease Activity During Natalizumab Therapy

Background: Para-dichlorobenzene (PDCB) is an active ingredient of mothballs, deodorizers and fumigants. Due to the easy availability of this chemical, there is a considerable risk for accidental or intentional toxic exposure. Recently, multiple cases of PDCB toxicity due to mothball ingestion were reported. PDCB toxicity can affect multiple organ systems including liver, kidneys, skin, lung and the central nervous system (CNS). CNS toxicity often results in leukoencephalopathy and heterogeneous neurological manifestations. Objectives: The objective of this study was to illustrate the clinical presentation, imaging findings, diagnosis and management of PDCB toxicity. Methods: We carried out a literature review of the pharmacological and toxicological properties of PDCB. Conclusions: PDCB and other aromatic hydrocarbons are capable of CNS tissue damage and in promoting functional neurological decline. While very little is currently known about prevalence of PDCB addiction, it cannot be ruled out that its illicit use among young people is under-recognized. The number of cases of PDCB toxicity might also rise due to the increasing industrial and domestic use of this chemical.

Summary Monoclonal antibodies (mAbs) are used as therapeutics in a number of disciplines in medicine, such as oncology, rheumatology, gastroenterology, dermatology and transplant rejection prevention. Since the introduction and reintroduction of the anti-alpha4-integrin mAb natalizumab in 2004 and 2006, mAbs have gained relevance in the treatment of multiple sclerosis (MS). At present, numerous mAbs have been tested in clinical trials in relapsing–remitting MS, and in progressive forms of MS. One of the agents that might soon be approved for very active forms of relapsing–remitting MS is alemtuzumab, a humanized mAb against CD52. This review provides insights into clinical studies with the mAbs natalizumab, alemtuzumab, daclizumab, rituximab, ocrelizumab and ofatumumab.

Neuromyelitis optica (NMO, Devic's syndrome) is a clinical syndrome characterized by optic neuritis and (mostly longitudinally extensive) myelitis. If untreated, NMO usually takes a relapsing course and often results in blindness and tetra- or paraparesis. The discovery of autoantibodies to aquaporin-4, the most abundant water channel in the CNS, in 70-80% of patients with NMO (termed NMO-IgG or AQP4-Ab) and subsequent investigations into the pathogenic impact of this new reactivity have led to the recognition of NMO as an autoimmune condition and as a disease entity in its own right, distinct from classic multiple sclerosis. Here, we comprehensively review the current knowledge on the role of NMO-IgG/AQP4-Ab, B cells, T cells, and the innate immune system in the pathogenesis of NMO.

Accurate clinical course descriptions (phenotypes) of multiple sclerosis (MS) are important for communication, prognostication, design and recruitment of clinical trials, and treatment decision-making. Standardized descriptions published in 1996 based on a survey of international MS experts provided purely clinical phenotypes based on data and consensus at that time, but imaging and biological correlates were lacking. Increased understanding of MS and its pathology, coupled with general concern that the original descriptors may not adequately reflect more recently identified clinical aspects of the disease, prompted a re-examination of MS disease phenotypes by the International Advisory Committee on Clinical Trials of MS. While imaging and biological markers that might provide objective criteria for separating clinical phenotypes are lacking, we propose refined descriptors that include consideration of disease activity (based on clinical relapse rate and imaging findings) and disease progression. Strategies for future research to better define phenotypes are also outlined.

Malignant gliomas (MGs), lethal human central nervous system (CNS) neoplasms, contain tumor infiltrating lymphocytes (TIL). Although MHC class II molecules are frequently detected on MG cells, suggesting that they may be capable of antigen (Ag) presentation to CD4(+) T cells, deficiencies in CD4(+) T-cell activation are associated with these nonimmunogenic tumors. We evaluated regulation of the MHC class II transactivator (CIITA), the key intermediate that controls class II expression, in MG cells and tested whether MG cells could process native Ag. After interferon-gamma (IFN-gamma) stimulation, MG cells upregulated CIITA and class II molecules. IFN-gamma-inducible CIITA expression in MG cells, as well as primary human astrocytes, was directed by two CIITA promoters, pIV, the promoter for IFN-gamma-inducible CIITA expression in nonprofessional antigen-presenting cells (APC), and pIII, the promoter that directs constitutive CIITA expression in B cells. Both pIII and pIV directed CIITA transcription in vivo in MGs and ex vivo in IFN-gamma-activated primary MG cultures. We also demonstrate for the first time that MG cells can process native Ag for presentation to CD4(+) MHC class II-restricted Th1 cells, indicating that MG cells can serve as nonprofessional APC. CIITA may be a key target to modulate MHC class II expression, which could augment immunogenicity, Ag presentation, and CD4(+) T-cell activation in MG therapy.

Summary Inflammatory disorders of the peripheral nervous system (PNS) and central nervous system (CNS) are common, and contribute substantially to physical and emotional disability of affected individuals. Often, the afflicted are young and in their active years. In the past, physicians and scientists often had very little to offer in terms of diagnostic precision and therapeutic effectiveness. During the past two decades, both of these relative shortcomings have clearly improved. Some of the recent developments in clinical neuroimmunology are illustrated in this special edition of Clinical and Experimental Immunology.

Combinations of new medications or existing therapies are gaining momentum over monotherapy to treat central nervous system (CNS) demyelinating diseases including multiple sclerosis (MS). Recent studies established that statins (HMG-CoA reductase inhibitors) are effective in experimental autoimmune encephalomyelitis (EAE), an MS model and are promising candidates for future MS medication. Another drug, rolipram (phosphodiesterase-4 inhibitor) ameliorates the clinical severity of EAE via induction of various anti-inflammatory and neuroprotective activities. In this study, we tested whether combining the suboptimal doses of these drugs can suppress the severity of EAE. Prophylactic studies revealed that combined treatment with suboptimal doses of statins perform better than their individually administered optimal doses in EAE as evidenced by delayed clinical scores, reduced disease severity, and rapid recovery. Importantly, combination therapy suppressed the progression of disease in an established EAE case via attenuation of inflammation, axonal loss and demyelination. Combination treatment attenuated inflammatory TH1 and TH17 immune responses and induced TH2-biased immunity in the peripheral and CNS as revealed by serological, quantitative, and immunosorbant assay-based analyses. Moreover, the expansion of T regulatory (CD25+/Foxp3+) cells and self-immune tolerance was apparent in the CNS. These effects of combined drugs were reduced or minimal with either drug alone in this setting. In conclusion, our findings demonstrate that the combination of these drugs suppresses EAE severity and provides neuroprotection thereby suggesting that this pharmacological approach could be a better future therapeutic strategy to treat MS patients.

Previous reports by our group and by others have shown that in vitro treatment of T cells derived from healthy, normal subjects with interferon β-1b (IFN-β1b) reduces metalloproteinase (metalloproteinase type 9 [MMP-9]) activity with a consequent reduction in lymphocyte migration. In this study, we used a Boyden chamber assay to assess the migratory capacity of T cells derived from multiple sclerosis patients who either did or did not receive IFN-β1b. Lymphocytes derived from patients treated for less than 2 years with IFN-β migrated at a low rate that was indistinguishable from that of cells isolated from healthy donors. However, longer term treatment with IFN (>3.5 years) was associated with a reversion of the migration to a high level that did not differ statistically from that of cells isolated from untreated multiple sclerosis patients. For both high-migratory groups, migration could be reduced to control levels after the exogenous addition of TIMP-1, a relatively specific inhibitor of the MMP-9, implicating this protease in the process of T-cell migration. Our findings suggest that one of the mechanisms by which IFN-β exerts its action is by reducing MMP-9 activity and thus the entry of inflammatory cells into the nervous system and, as such, MMPs may constitute potential therapeutic targets in inflammatory diseases such as multiple sclerosis.

Acute disseminated encephalomyelitis is considered a monophasic, inflammatory demyelinating disorder of the central nervous system. A temporal relationship usually exists between the onset of neurologic symptoms and an infection or a vaccination. A viral exanthem facilitates the diagnosis. Some heterogeneity exists with regard to etiology and clinical course of this disease. Immunosuppression is considered the treatment of choice.

JO N 2 95 6 II trial in relapsing-remitting MS (RRMS) [6–9]. At present, the duration of the treatment effect, its effect on progression of disability, and types of adverse events associated with this drug that may occur remain elusive [10]. We report an 18-year old righthanded Caucasian male who was diagnosed with RRMS in 2001 at the age of 12 years by a neurologist in private practice. At that time, the patient experienced 3–4 relapses per year, and treatment was initiated with interferon-beta 1a (Rebif®) s.c. tiw, initially 22 μg followed by 44 μg for two years. Due to lack of clinical efficacy immunosuppression with mitoxantrone was initiated in 2003, with a dose of 12 mg/m2 i.v. every 12 weeks. A total of 4 infusions were applied without any effect on relapse rate. His neurologist then changed therapy to interferon-beta 1a (Avonex®) 30 μg i.m. once weekly in 2004 without any tangible effect. In 2006, the patient first presented to our out-patient clinic with a severe relapse, characterized primarily by cerebellar ataxia. At this time, the Expanded Disability Status Scale (EDSS) score was 5.0. Two courses of intravenous methylprednisolone (IVMP) did not result in any clinical benefit. Consequently, six courses of plasma exchange (PE) were initiated resulting in a clinical improvement to an EDSS of 2.5. Treatment with interferon-beta 1a was terminated, and therapy with natalizumab 300 mg i.v. q month was initiated. The patient received a total of 6 infusions. Unfortunately, two clinical relapses occurred during this time, the second one characterized by a large brainstem lesion and a worsening to an EDSS of 7.0. The patient did not respond to IVMP. Again, clinical improvement was seen after six courses of PE, and his clinical status improved to an EDSS of 5.0. Because natalizumab treatment did Verena I. Leussink Helmar C. Lehmann Gerd Meyer zu Horste Hans-Peter Hartung Olaf Stuve Bernd C. Kieseier

For 2 decades, it has been a high priority to develop effective therapies for patients with relapsing-remitting multiple sclerosis (RRMS). This effort has been tremendously successful, and there are currently 13 anti-inflammatory agents approved for the treatment of RRMS. These treatments vary in mechanism of action, route and frequency of administration, side-effect profiles, and efficacy. The availability of this palette of treatments creates the opportunity to control disease activity in most people with RRMS. They also demand a new level of sophistication from neurologists using these agents to treat RRMS.

Interferon beta (IFN-β) has been shown in several clinical trials to have efficacy in MS. Its mechanism of action, however, remains unclear. In this review, several biological activities of IFN-β are highlighted, including its inhibitory effects on proliferation of leukocytes and antigen presentation. Furthermore, IFN-β may modulate the profile of cytokine production toward that of the anti-inflammatory phenotype, and this appears to occur in the systemic circulation and within the CNS. Finally, IFN-β can reduce T-cell migration by inhibiting the activity of T-cell matrix metalloproteinases. These activities are likely to act in concert to account for the mechanism of IFN-β in MS.

Summary Background Laboratory evidence has shown that cannabinoids might have a neuroprotective action. We investigated whether oral dronabinol (Δ9-tetrahydrocannabinol) might slow the course of progressive multiple sclerosis. Methods In this multicentre, parallel, randomised, double-blind, placebo-controlled study, we recruited patients aged 18–65 years with primary or secondary progressive multiple sclerosis from 27 UK neurology or rehabilitation departments. Patients were randomly assigned (2:1) to receive dronabinol or placebo for 36 months; randomisation was by stochastic minimisation, using a computer-generated randomisation sequence, balanced according to expanded disability status scale (EDSS) score, centre, and disease type. Maximum dose was 28 mg per day, titrated against bodyweight and adverse effects. Primary outcomes were EDSS score progression (masked assessor, time to progression of ≥1 point from a baseline score of 4·0–5·0 or ≥0·5 points from a baseline score of ≥5·5, confirmed after 6 months) and change from baseline in the physical impact subscale of the 29-item multiple sclerosis impact scale (MSIS-29-PHYS). All patients who received at least one dose of study drug were included in the intention-to-treat analyses. This trial is registered as an International Standard Randomised Controlled Trial (ISRCTN 62942668). Findings Of the 498 patients randomly assigned to a treatment group, 329 received at least one dose of dronabinol and 164 received at least one dose of placebo (five did not receive the allocated intervention). 145 patients in the dronabinol group had EDSS score progression (0·24 first progression events per patient-year; crude rate) compared with 73 in the placebo group (0·23 first progression events per patient-year; crude rate); HR for prespecified primary analysis was 0·92 (95% CI 0·68–1·23; p=0·57). Mean yearly change in MSIS-29-PHYS score was 0·62 points (SD 3·29) in the dronabinol group versus 1·03 points (3·74) in the placebo group. Primary analysis with a multilevel model gave an estimated between-group difference (dronabinol–placebo) of −0·9 points (95% CI −2·0 to 0·2). We noted no serious safety concerns (114 [35%] patients in the dronabinol group had at least one serious adverse event, compared with 46 [28%] in the placebo group). Interpretation Our results show that dronabinol has no overall effect on the progression of multiple sclerosis in the progressive phase. The findings have implications for the design of future studies of progressive multiple sclerosis, because lower than expected progression rates might have affected our ability to detect clinical change. Funding UK Medical Research Council, National Institute for Health Research Efficacy and Mechanism Evaluation programme, Multiple Sclerosis Society, and Multiple Sclerosis Trust.

Multiple sclerosis (MS) is thought to be a CD4+ T cell mediated autoimmune demyelinating disease of the central nervous system (CNS) that is rarely diagnosed during infancy. Cellular and molecular mechanisms that confer disease resistance in this age group are unknown. We tested the hypothesis that a differential composition of immune cells within the CNS modulates age-associated susceptibility to CNS autoimmune disease. C57BL/6 mice younger than eight weeks were resistant to experimental autoimmune encephalomyelitis (EAE) following active immunization with myelin oligodendrocyte glycoprotein (MOG) peptide (p) 35–55. Neonates also developed milder EAE after transfer of adult encephalitogenic T cells primed by adult or neonate antigen presenting cells (APC). There was a significant increase in CD45+ hematopoietic immune cells and CD45+ high side scatter granulocytes in the CNS of adults, but not in neonates. Within the CD45+ immune cell compartment of adults, the accumulation of CD4+ T cells, Gr-1+ and Gr-1- monocytes and CD11c+ dendritic cells (DC) was identified. A significantly greater percentage of CD19+ B cells in the adult CNS expressed MHC II than neonate CNS B cells. Only in the adult CNS could IFNγ transcripts be detected 10 days post immunization for EAE. IFNγ is highly expressed by adult donor CD4+ T cells that are adoptively transferred but not by transferred neonate donor cells. In contrast, IL-17 transcripts could not be detected in adult or neonate CNS in this EAE model, and neither adult nor neonate donor CD4+ T cells expressed IL-17 at the time of adoptive transfer.

Whereas the number of treatment options in relapsing-remitting multiple sclerosis (RRMS) is growing constantly, alternatives are rare in the case of secondary-progressive multiple sclerosis (SPMS). Besides mitoxantrone in North America and Europe, interferon beta-1b and beta-1a are approved for treatment in Europe. Glucocorticosteroids, azathioprine, intravenous immunoglobulins (IVIG) and cyclophosphamide (CYC), although not approved, are commonly utilized in SPMS. Currently monoclonal antibodies (mab), and masitinib are under examination for treatment for SPMS. Hematopoietic stem cell transplantation and immunoablative stem cell transplantation are therapies with the aim of reconstitution of the immune system. This review gives information on the different therapeutics and the trials that tested them. Pathophysiological considerations are presented in view of efficacy of the therapeutics. In addition, therapeutics that showed no efficacy in trials or with unacceptable side effects are topics of this review.

Background Neuromyelitis optica (NMO) is an autoimmune disease of the central nervous system in which aberrant antibody responses to the astrocytic water channel aquaporin 4 have been described. Experimental evidence is emerging that NMO is partly driven by the proinflammatory cytokine interleukin 6 (IL-6), which propagates the survival of disease-specific B cell subclasses, and deviates CD4 + T helper cell differentiation toward IL-17-producing T helper 17 cells. Tocilizumab is a recombinant humanized monoclonal antibody against the IL-6 receptor approved for treatment of rheumatoid arthritis. Objectives To study clinical and paraclinical effects of tocilizumab in a patient with NMO. Design Case report. Setting Academic neurology department. Patient A patient with highly active aquaporin 4–seropositive NMO who failed numerous immunosuppressive interventions, including high-dose corticosteroids, mitoxantrone, plasma exchange (PE), rituximab (anti-CD20), and alemtuzumab (anti-CD52), before receiving tocilizumab. Main Outcome Measures Clinical disability, magnetic resonance imaging, cytokines and transcription factors levels in the cerebrospinal fluid, and peripheral blood mononuclear cells. Results A patient who continued to accumulate neurological disability and magnetic resonance imaging activity while receiving numerous immunoactive therapies stabilized, and eventually improved clinically and on magnetic resonance metrics after treatment initiation with tocilizumab. Treatment and clinical response correlated with a significant reduction of IL-6 levels in the CSF as well as a diminished expression of signal transducer and activator of transcription 3. Conclusions Tocilizumab might be effective in NMO, here in a patient not responding to leukocyte depletion. Our findings further support data that implicate IL-6 as a critical molecule in the immunopathogenesis of NMO, and a critical role for T cells in the pathogenesis of this disorder.

Abstract 962 Most patients with relapsing-remitting multiple sclerosis (RRMS) do not achieve a sustained remission after disease-modifying therapy. A phase II clinical trial of high-dose immunochemotherapy (HDIT; BCNU, etoposide, ara-C, melphalan and antithymocyte globulin) and autologous hematopoietic cell transplantation (HCT) was conducted in patients with highly active RRMS who had failed conventional therapy to assess if a high rate of sustained remission could be induced. Eligibility required an EDSS of 3.0 (moderate disability, fully ambulatory) to 5.5(severe disability, ambulatory only 100 meters without aids) and >2 relapses on treatment in previous 18 months. Treatment-failure was defined as a composite endpoint including 1) mortality 2) relapse 3) new MRI lesions or 4) disability increase >0.5 EDSS points. Adverse events (AE) were recorded according to NCI-CTCAE v3.0. 25 patients at a median age of 38(27-53) years were treated with G-CSF to mobilize the autograft; prednisone was given at the same time to prevent MS flares. The autograft was CD34-selected (Baxter, Isolex). One patient withdrew after mobilization secondary to HIT/pulmonary embolus. 24 patients had HDIT/HCT according to protocol. Median follow-up was 131 (52, 282) weeks. After initially stabilizing, one patient died from progressive loss of neurological function at 32 months. No patient had delayed recovery of blood counts. In the 1st year after HDIT, there were 42 grade 3 and 6 grade 4 non-hematopoietic AE. Grade 4 AE included: one suicide attempt (with 3 grade 4 AE); hyperuricemia; hypokalemia; and elevated ALT. In the 2ndyear, there were 13 grade 3 and 1 grade 4 non-hematopoietic AE. The 1-year and 2-year probabilities of event-free survival (i.e. without treatment-failure) were 95.8% (90% CI: 80.2%-99.2%) and 82.8% (90% CI: 65.0%-92.0%), respectively. Progression-free and relapse-free survival at 1 year were 100% (90% CI: 100%-100%) and 95.8% (90% CI: 80.2%-99.2%) and at 2 years were 91.7% (90% CI: 75.7%-97.3%) and 91.7% (90% CI: 75.7%-97.3%), respectively. The probability of freedom from disease activity detected by brain MRI was 95.8% (90% CI: 80.2%-99.2%) at both year 1 and 2. In comparison, a randomized clinical trial of placebo vs natalizumab (Havrdova E et al, Lancet Neurology, 2009) showed that 7% and 37% of RRMS patients were free of disease activity (i.e. progression, relapse and MRI) at 2 years, respectively. T2-weighted MRI scans measure disease burden from MS. T2 lesion volume was significantly reduced by 6 months and was sustained at 2 years (Table 1). T1 lesion volume was increased at 1 year. There was a significant loss of brain volume at 6 months but stabilized after this time point. Flow cytometry of peripheral blood was done at baseline and at 1, 2, 6 and 12 months. There was near complete depletion of naïve CD4 and CD8 T cells (CD45RA+) at 1 month. Memory CD4 and CD8 T cells (CD45RO+) were not completely eliminated from the blood after in vivo depletion from HDIT. Within 2 months of transplant, there was rapid expansion of memory CD8 T cells. The numbers of CD4 naïve and memory T cells were not recovered at 1 year. CD4 and CD8 recent thymic emigrants (CD45RA+, CD31+) were increased at 1 year compared to the nadir at 1 month but did not completely recover. Recovery of naïve and memory B cells was complete between months 6 and 12. HDIT/HCT for highly active RRMS resulted in profound immunosuppression and induced a high rate of sustained remissions at 2 years. The small increase in T1-weighted lesion volume in the absence of persistent brain inflammation may have resulted from damage due to previous brain injury. No further loss in brain volume was observed after 6 months. Follow-up is planned through 5 years. Table 1: Brain MRI: Changes after HDIT/HCT as compared to baseline* or screening**. Disclosures: No relevant conflicts of interest to declare.

Background and purpose Multiple sclerosis (MS) patients discontinuing natalizumab are at risk of rebound of disease activity. Methods In the present multi-center, open-label, non-randomized, prospective, pilot study, we tested whether treatment with glatiramer acetate (GA) is safe and effective after natalizumab in MS patients. The study was performed at academic tertiary medical centers. Forty active relapsing–remitting MS patients who never failed GA therapy and who discontinued natalizumab after 12–18 months of therapy were enrolled. GA was initiated 4 weeks after the last dose of natalizumab. Results 62.5% of patients were relapse-free 12 months after GA initiation. Annualized relapse rate and time to relapse were significantly lower than before natalizumab. Notably, the frequency of relapses was significantly lower amongst those patients who had experienced ≤2 relapses the year before initiation of natalizumab therapy, compared with patients who had had three or more relapses. No evidence of rebound was observed in magnetic resonance imaging scans. Furthermore, Expanded Disability Status Scale and Multiple Sclerosis Functional Composite were stable in our patients, again suggesting that 12 months of post-natalizumab–GA therapy is not associated with clinical deterioration. Conclusions Following discontinuation of natalizumab, 12 months of therapy with GA is safe and well tolerated in MS patients. GA can reduce the risk of early reactivation/rebound of disease activity in this setting.

Diagnosis of multiple sclerosis (MS) requires the exclusion of other possible diagnoses. For this reason, the cerebrospinal fluid (CSF) should be routinely analysed in patients with a first clinical event suggestive of MS. CSF analysis is no longer mandatory for diagnosis of relapsing-remitting MS, as long as MRI diagnostic criteria are fulfilled. However, caution is required in diagnosing MS in patients with negative MRI findings or in the absence of CSF analysis, as CSF investigation is useful to eliminate other causes of disease. The detection of oligoclonal IgG bands in CSF has potential prognostic value and is helpful for clinical decision-making. In addition, CSF analysis is important for research into the pathogenesis of MS. Pathophysiological and neurodegenerative findings of inflammation in MS have been derived from CSF investigations. Novel CSF biomarkers, though not yet validated, have been identified for diagnosis of MS and for ascertaining disease activity, prognosis and response to treatment, and are likely to increase in number with modern detection techniques. In this Review, we summarize CSF findings that shed light on the differential diagnosis of MS, and highlight the potential of novel biomarkers for this disease that could advance understanding of its pathophysiology. © 2013 Macmillan Publishers Limited. All rights reserved.

Background: Multiple sclerosis (MS) patients discontinuing natalizumab treatment are at risk of disease reactivation. No clinical or surrogate parameters exist to identify patients at risk of post-natalizumab MS reactivation. Objective: To determine the role of natalizumab-induced lymphocytosis and of Akt polymorphisms in disease reactivation after natalizumab discontinuation. Methods: Peripheral leukocyte count and composition were monitored in 93 MS patients during natalizumab treatment, and in 56 of these subjects who discontinued the treatment. Genetic variants of the anti-apoptotic protein Akt were determined in all subjects because natalizumab modulates the apoptotic pathway and lymphocyte survival is regulated by the apoptotic cascade. Results: Natalizumab-induced peripheral lymphocytosis protected from post-natalizumab MS reactivation. Subjects who relapsed or had magnetic resonance imaging (MRI) worsening after treatment cessation, in fact, had milder peripheral lymphocyte increases during the treatment, largely caused by less marked T cell increase. Furthermore, subjects carrying a variant of the gene coding for Akt associated with reduced anti-apoptotic efficiency (rs2498804T) had lower lymphocytosis and higher risk of disease reactivation. Conclusion: This study identified one functionally meaningful genetic variant within the Akt signaling pathway that is associated with both lymphocyte count and composition alterations during natalizumab treatment, and with the risk of disease reactivation after natalizumab discontinuation.

In multiple sclerosis (MS), the influx of activated T lymphocytes into the brain parenchyma leads to the subsequent damage of oligodendrocytes, the cells that produce central nervous system (CNS) myelin. We report here that interferon beta-1b (IFNbeta-1b), a drug shown to be efficacious in the treatment of patients with MS, decreases the in vitro migration of activated T lymphocytes through fibronectin (FN), a major component of the basement membrane that surrounds cerebral endothelium. At 1,000 IU/ml, IFNbeta-1b reduced the migratory rate to that of unactivated T cells. In contrast, IFNgamma at 1,000 IU/ml, which caused a similar decrease (25%) in the proliferation rate of T lymphocytes as IFNbeta-1b, did not affect migration. All T-lymphocyte subsets and natural killer (NK) cells were demonstrated by flow cytometry to be equally affected by IFNbeta-1b treatment. 125I-Western blot analyses revealed that IFNbeta-1b treatment resulted in a marked reduction of the ability of T cells to cleave FN. The substrate-degrading capability of T lymphocytes was shown to be due predominantly to the activity of a 92-kd matrix metalloproteinase, MMP-9, whose levels were decreased by IFNbeta-1b. We suggest that the clinical benefits of IFNbeta-1b treatment in MS patients may be in part a result of the ability of this drug to significantly decrease MMP-9 activity, leading to a reduction of T-lymphocyte infiltration into the CNS.

Laquinimod is an orally available quinoline 3-carboxamide derivative drug studied in phase II and III clinical trials for relapsing-remitting multiple sclerosis (RRMS), systemic lupus erythematosus, and Crohn disease. Laquinimod has shown promise in RRMS clinical trials,1,2 and identifying the mechanism underlying its disease-modifying effects could help target it to the patient population where it would be most effective. Studies in experimental autoimmune encephalomyelitis (EAE) models of multiple sclerosis (MS) have suggested that the drug may ameliorate disease by modulating innate and adaptive immune responses, for example via effects on macrophages/monocytes, dendritic cells (DCs), and T-helper (Th) cells.3–5 However, its key effector mechanisms and the cellular targets by which the drug ameliorates disease are still not fully resolved. The article by Varrin-Doyer et al.6 in this issue of Neurology ® Neuroimmunology & Neuroinflammation sheds new light on this question and provides important insights that could be relevant for the treatment of MS. In elegant experiments, Varrin-Doyer et al. provide convincing evidence that treatment with laquinimod strongly ameliorates disease in 2 models of recombinant myelin oligodendrocyte glycoprotein (MOG)–induced EAE and spontaneous EAE in mice transgenic for a T-cell receptor specific for MOG35-55 peptide and a MOG-specific immunoglobulin H chain knock-in (2D2 × Th mice). In both of these models, the authors show that laquinimod treatment prevented the development of T-follicular-helper (Tfh) cells and decreased the production of MOG-specific immunoglobulin G antibodies. Interestingly, in a spontaneous model of EAE, associated with the formation of meningeal follicle-like structures that are populated by B and T cells,7 laquinimod therapy reduced the number and the size of these cellular aggregates.

Importance This dose-blinded extension of the phase 2 BOLD (BAF312 on MRI Lesion Given Once Daily) Study in relapsing-remitting multiple sclerosis provides evidence on disease activity and safety of a range of siponimod doses for up to 24 months. Objective To assess the safety and efficacy of siponimod for up to 24 months during the dose-blinded extension of the BOLD Study. Design, Setting, and Participants At extension baseline in a randomized clinical trial, patients taking siponimod continued at the originally assigned dose and patients taking placebo were rerandomized to the 5 siponimod doses. Initial treatment was titrated over 10 days. A total of 252 eligible patients were treated at specialized multiple sclerosis centers for this study conducted from August 30, 2010, through June 3, 2013. Interventions Siponimod at 10-mg, 2-mg, 1.25-mg, 0.5-mg, and 0.25-mg doses. Main Outcomes and Measures Safety assessment included blood tests, documentation of adverse events at regular scheduled visits and Holter monitoring; key efficacy measures were annualized relapse rate and magnetic resonance imaging lesion activity. Results Among the 252 eligible patients, the mean (SD) ages were 37.2 (8.4) years, 35.2 (9.1) years, 34.0 (7.6) years, 35.1 (9.2) years, and 36.8 (9.1) years in the 0.25-mg, 0.5-mg, 1.25-mg, 2-mg, and 10-mg groups. Of the 252 patients, 184 (73%) entered the extension and received siponimod (10 mg: n = 33; 2 mg: n = 29; 1.25 mg: n = 43; 0.5 mg: n = 29; and 0.25 mg: n = 50); 159 (86.4%) completed the dose-blinded extension. The incidence of adverse events was similar across treatment groups (10 mg: 87.9%; 2 mg: 89.7%; 1.25 mg: 88.4%; 0.5 mg: 96.6%; and 0.25 mg: 84.0%). Nine patients reported serious adverse events (2 mg: 3/29 [10.3%], 1.25 mg: 1/43 [2.3%], 0.5 mg: 4/29 [13.8%], and 0.25 mg: 1/50 [2.0%]; no serious adverse event was reported for more than 1 patient and no new safety signals occurred compared with the BOLD Study. Dose titration mitigated symptomatic bradycardic events. Reductions in mean (95% CI) gadolinium-enhancing T1 lesion counts from the last BOLD assessment were sustained in the 10-mg, 2-mg, 1.25-mg, and 0.5-mg dose groups (0 [0-0], 0.1 [0-1.9], 0.1 [0-2.6], and 0.1 [0-2.8] at month 24, respectively). At the 3 highest vs 2 lowest doses, the estimated new/newly enlarging T2 lesion counts (95% CIs) were lower during months 6 to 12 (0.5 [0.2-1.3], 0.4 [0.2-1.1], and 0.2 [0.1-0.6] vs 1.3 [0.6-2.8] and 1.4 [0.7-2.7]), months 12 to 18 (0.4 [0.1-1.1], 0.4 [0.1-1.3], and 0.4 [0.2-1.0] vs 1.0 [0.4-2.6] and 3.6 [1.7-7.6]), and months 18 to 24 (0 [0-not estimable], 0.9 [0.1-7.6], and 0.1 [0-1.7] vs 1.6 [0.3-7.7] and 2.0 [0.4-9.5]). Annualized relapse rates (95% CIs) up to month 24 were similarly lower for the 3 highest doses: 0.22 (0.12-0.40) for 10 mg, 0.20 (0.10-0.38) for 2 mg, and 0.14 (0.08-0.26) for 1.25 mg vs 0.33 (0.19-0.56) for 0.5 mg and 0.33 (0.21-0.50) for 0.25 mg. Conclusions and Relevance For up to 24 months of siponimod treatment, multiple sclerosis disease activity was low and there were no new safety signals; investigation in phase 3 trials is encouraged. Trial Registration clinicaltrials.gov Identifier:NCT01185821

BACKGROUND:Aquaporin 4 (AQP4) is considered a putative autoantigen in patients with Neuromyelitis optica (NMO), an autoinflammatory disorder of the central nervous system (CNS). HLA haplotype analyses of patients with NMO suggest a positive association with HLA-DRB1* 03:01. We previously showed that the human (h) AQP4 peptide 281-300 is the dominant immunogenic determinant of hAQP4 in the context of HLA-DRB1*03:01. This immunogenic peptide stimulates a strong Th1 and Th17 immune response. AQP4281-300-specific encephalitogenic CD4+ T cells should initiate CNS inflammation that results in a clinical phenotype in HLA-DRB1*03:01 transgenic mice. METHODS:Controlled study with humanized experimental animals. HLA-DRB1*03:01 transgenic mice were immunized with hAQP4281-300, or whole-length hAQP4 protein emulsified in complete Freund's adjuvant. Humoral immune responses to both antigens were assessed longitudinally. In vivo T cell frequencies were assessed by tetramer staining. Mice were followed clinically, and the anterior visual pathway was tested by pupillometry. CNS tissue was examined histologically post-mortem. Flow cytometry was utilized for MHC binding assays and to immunophenotype T cells, and T cell frequencies were determined by ELISpot assay. RESULTS:Immunization with hAQP4281-300 resulted in an in vivo expansion of antigen-specific CD4+ T cells, and an immunoglobulin isotype switch. HLA-DRB1*03:01 TG mice actively immunized with hAQP4281-300, or with whole-length hAQP4 protein were resistant to developing a neurological disease that resembles NMO. Experimental mice show no histological evidence of CNS inflammation, nor change in pupillary responses. Subsequent analysis reveals that a single amino acid substitution from aspartic acid in hAQP4 to glutamic acid in murine (m)AQP4 at position 290 prevents the recognition of hAQP4281-300 by the murine T cell receptor (TCR). CONCLUSION:Induction of a CNS inflammatory autoimmune disorder by active immunization of HLA-DRB1*03:01 TG mice with human hAQP4281-300 will be complex due to a single amino acid substitution. The pathogenic role of T cells in this disorder remains critical despite these observations.

Objective To identify linear determinants of human aquaporin 4 (hAQP4) in the context of HLA-DRB1*03:01. Design In this controlled study with humanized experimental animals, HLA-DRB1*03:01 transgenic mice were immunized with whole-protein hAQP4 emulsified in complete Freund adjuvant. To test T-cell responses, lymph node cells and splenocytes were cultured in vitro with synthetic peptides 20 amino acids long that overlap by 10 amino acids across the entirety of hAQP4. The frequency of interferon γ, interleukin (IL) 17, granulocyte-macrophage colony-stimulating factor, and IL-5–secreting CD4 + T cells was determined by the enzyme-linked immunosorbent sport assay. Quantitative immunofluorescence microscopy was performed to determine whether hAQP4 281-300 inhibits the binding of anti-hAQP4 recombinant antibody to surface full-length hAQP4. Setting Academic neuroimmunology laboratories. Subjects Humanized HLA-DRB1*03:01 +/+ H-2b −/− transgenic mice on a B10 background. Results Peptide hAQP4 281-300 generated a significantly (P H 1 and T H 17 immune response than any of the other linear peptides screened. This 20mer peptide contains 2 dominant immunogenic 15mer peptides. hAQP4 284-298 induced predominantly an IL-17 and granulocyte-macrophage colony-stimulating factor T H cell phenotype, whereas hAQP4 285-299 resulted in a higher frequency of T H 1 cells. hAQP4 281-300 did not interfere with recombinant AQP4 autoantibody binding. Conclusions hAQP4 281-330 is the dominant linear immunogenic determinant of hAQP4 in the context of HLA-DRB1*03:01. Within hAQP4 281-330 are 2 dominant immunogenic determinants that induce differential T H phenotypes. hAQP4 determinants identified in this study can serve as diagnostic biomarkers in patients with neuromyelitis optica and may facilitate the monitoring of treatment responses to pharmacotherapies.