Natalizumab therapy for multiple sclerosis

The novel HS-mimetic, Tet-29, regulates immune cell trafficking across barriers of the CNS during inflammation

BACKGROUND

Disruption of the extracellular matrix at the blood-brain barrier (BBB) underpins neuroinflammation in multiple sclerosis (MS). The degradation of extracellular matrix components, such as heparan sulfate (HS) proteoglycans, can be prevented by treatment with HS-mimetics through their ability to inhibit the enzyme heparanase. The heparanase-inhibiting ability of our small dendrimer HS-mimetics has been investigated in various cancers but their efficacy in neuroinflammatory models has not been evaluated. This study investigates the use of a novel HS-mimetic, Tet-29, in an animal model of MS.

METHODS

Neuroinflammation was induced in mice by experimental autoimmune encephalomyelitis, a murine model of MS. In addition, the BBB and choroid plexus were modelled in vitro using transmigration assays, and migration of immune cells in vivo and in vitro was quantified by flow cytometry.

RESULTS

We found that Tet-29 significantly reduced lymphocyte accumulation in the central nervous system which, in turn, decreased disease severity in experimental autoimmune encephalomyelitis. The disease-modifying effect of Tet-29 was associated with a rescue of BBB integrity, as well as inhibition of activated lymphocyte migration across the BBB and choroid plexus in transwell models. In contrast, Tet-29 did not significantly impair in vivo or in vitro steady state-trafficking under homeostatic conditions.

CONCLUSIONS

Together these results suggest that Tet-29 modulates, rather than abolishes, trafficking across central nervous system barriers.

Endothelial Cell Insulin Signaling Regulates CXCR4 (C-X-C Motif Chemokine Receptor 4) and Limits Leukocyte Adhesion to Endothelium

BACKGROUND

An activated, proinflammatory endothelium is a key feature in the development of complications of obesity and type 2 diabetes and can be caused by insulin resistance in endothelial cells.

METHODS

We analyzed primary human endothelial cells by RNA sequencing to discover novel insulin-regulated genes and used endothelial cell culture and animal models to characterize signaling through CXCR4 (C-X-C motif chemokine receptor 4) in endothelial cells.

RESULTS

CXCR4 was one of the genes most potently regulated by insulin, and this was mediated by PI3K (phosphatidylinositol 3-kinase), likely through FoxO1, which bound to the CXCR4 promoter. CXCR4 mRNA in CD31+ cells was 77% higher in mice with diet-induced obesity compared with lean controls and 37% higher in db/db mice than db/+ controls, consistent with upregulation of CXCR4 in endothelial cell insulin resistance. SDF-1 (stromal cell-derived factor-1)-the ligand for CXCR4-increased leukocyte adhesion to cultured endothelial cells. This effect was lost after deletion of CXCR4 by gene editing while 80% of the increase was prevented by treatment of endothelial cells with insulin. In vivo microscopy of mesenteric venules showed an increase in leukocyte rolling after intravenous injection of SDF-1, but most of this response was prevented in transgenic mice with endothelial overexpression of IRS-1 (insulin receptor substrate-1).

CONCLUSIONS

Endothelial cell insulin signaling limits leukocyte/endothelial cell interaction induced by SDF-1 through downregulation of CXCR4. Improving insulin signaling in endothelial cells or inhibiting endothelial CXCR4 may reduce immune cell recruitment to the vascular wall or tissue parenchyma in insulin resistance and thereby help prevent several vascular complications.

Multiple Sclerosis: Focus on Extracellular and Artificial Vesicles, Nanoparticles as Potential Therapeutic Approaches

Multiple sclerosis (MS) is an autoimmune disease of the Central Nervous System, characterized by an inflammatory process leading to the destruction of myelin with neuronal death and neurodegeneration. In MS, lymphocytes cross the blood-brain barrier, creating inflammatory demyelinated plaques located primarily in the white matter. MS potential treatments involve various mechanisms of action on immune cells, immunosuppression, inhibition of the passage through the blood-brain barrier, and immunotolerance. Bio-nanotechnology represents a promising approach to improve the treatment of autoimmune diseases by its ability to affect the immune responses. The use of nanotechnology has been actively investigated for the development of new MS therapies. In this review, we summarize the results of the studies on natural and artificial vesicles and nanoparticles, and take a look to the future clinical perspectives for their application in the MS therapy.

A single T cell epitope drives the neutralizing anti-drug antibody response to natalizumab in multiple sclerosis patients

Natalizumab (NZM), a humanized monoclonal IgG4 antibody to α4 integrins, is used to treat patients with relapsing-remitting multiple sclerosis (MS)^1,2, but in about 6% of the cases persistent neutralizing anti-drug antibodies (ADAs) are induced leading to therapy discontinuation^3,4. To understand the basis of the ADA response and the mechanism of ADA-mediated neutralization, we performed an in-depth analysis of the B and T cell responses in two patients. By characterizing a large panel of NZM-specific monoclonal antibodies, we found that, in both patients, the response was polyclonal and targeted different epitopes of the NZM idiotype. The neutralizing activity was acquired through somatic mutations and correlated with a slow dissociation rate, a finding that was supported by structural data. Interestingly, in both patients, the analysis of the CD4⁺ T cell response, combined with mass spectrometry-based peptidomics, revealed a single immunodominant T cell epitope spanning the FR2-CDR2 region of the NZM light chain. Moreover, a CDR2-modified version of NZM was not recognized by T cells, while retaining binding to α4 integrins. Collectively, our integrated analysis identifies the basis of T-B collaboration that leads to ADA-mediated therapeutic resistance and delineates an approach to design novel deimmunized antibodies for autoimmune disease and cancer treatment.

Advances in preventing adverse events during monoclonal antibody management of multiple sclerosis

INTRODUCTION

Decades of pharmacological research in Multiple Sclerosis (MS) led to the development of therapeutic Monoclonal Antibodies (MAbs) with many different mechanisms of action (MoA), potentially able to improve disability outcome but also determining a more complex management of patients. Areas covered: When clinicians select MS treatments, they should consider adverse events (AEs) on individual basis to minimize patients' risks. Some AEs are common and can be easily handled, but rare complications should also be taken into account. The aim of this review is to summarize existing evidence and provide practical recommendations for the management of therapeutic MAbs in MS. Expert opinion: The introduction of MAbs revolutionized MS treatment with an improvement in effectiveness. Unfortunately, this has been coupled with a more complex array of AEs needing a tighter surveillance strategy. A close interaction between general practitioners, neurologists, and other specialists is the key for a safer use of such effective drugs.

Natalizumab induced cutaneous sarcoidosis-like reaction

We present a case of a drug-induced sarcoidosis -like reaction (DISR) occurring following initiation of Natalizumab for multiple sclerosis. The reaction was purely cutaneous, and disappeared following drug withdrawal. We highlight this case to the practicing neurologists, with warning to be wary of a new rash on immunomodulatory therapies.

Gray matter atrophy in multiple sclerosis despite clinical and lesion stability during natalizumab treatment

BACKGROUND

Brain volume loss is an important surrogate marker for assessing disability in MS; however, contribution of gray and white matter to the whole brain volume loss needs further examination in the context of specific MS treatment.

OBJECTIVES

To examine whole and segmented gray, white, thalamic, and corpus callosum volume loss in stable patients receiving natalizumab for 2-5 years.

METHODS

This was a retrospective study of 20 patients undergoing treatment with natalizumab for 24-68 months. Whole brain volume loss was determined with SIENA. Gray and white matter segmentation was done using FAST. Thalamic and corpus callosum volumes were determined using Freesurfer. T1 relaxation values of chronic hypointense lesions (black holes) were determined using a quantitative, in-house developed method to assess lesion evolution.

RESULTS

Over a mean of 36.6 months, median percent brain volume change (PBVC) was -2.0% (IQR 0.99-2.99). There was decline in gray (p = 0.001) but not white matter (p = 0.6), and thalamic (p = 0.01) but not corpus callosum volume (p = 0.09). Gray matter loss correlated with PBVC (Spearman's r = 0.64, p = 0.003) but not white matter (Spearman's r = 0.42, p = 0.07). Age significantly influenced whole brain volume loss (p = 0.010, multivariate regression), but disease duration and baseline T2 lesion volume did not. There was no change in T1 relaxation values of lesions or T2 lesion volume over time. All patients remained clinically stable.

CONCLUSIONS

These results demonstrate that brain volume loss in MS is primarily driven by gray matter changes and may be independent of clinically effective treatment.

[Monitoring of blood parameters under course-modified MS therapy : Substance-specific relevance and current recommendations for action]

With the approval of various substances for the immunotherapy of multiple sclerosis (MS), treatment possibilities have improved significantly over the last few years. Indeed, the choice of individually tailored preparations and treatment monitoring for the treating doctor is becoming increasingly more complex. This is particularly applicable for monitoring for a treatment-induced compromise of the immune system. The following article by members of the German Multiple Sclerosis Skills Network (KKNMS) and the task force "Provision Structures and Therapeutics" summarizes the practical recommendations for approved immunotherapy for mild to moderate and for (highly) active courses of MS. The focus is on elucidating the substance-specific relevance of particular laboratory parameters with regard to the mechanism of action and the side effects profile. To enable appropriate action to be taken in clinical practice, any blood work changes that can be expected, in addition to any undesirable laboratory findings and their causes and relevance, should be elucidated.

Natalizumab treatment of multiple sclerosis: new insights

Natalizumab is a monoclonal antibody directed against the α4 chain of the very late activating antigen 4 and α4β7 integrins, present on the leukocytes surface, used as monotherapy for the treatment of relapsing-remitting multiple sclerosis. It substantially reduces relapse rate and the accumulation of disability, but its use is associated with a very adverse event, that is the development of progressive multifocal leukoencephalopathy, a fatal demyelinating disease of the CNS, due to the lytic replication of the human polyomavirus JC. The main focus of the review is to describe the newest insights on natalizumab, its current use in the clinical practice, the natalizumab-treated patients' management and the risk stratification related to the progressive multifocal leukoencephalopathy development.

Natalizumab-Related Progressive Multifocal Leukoencephalopathy-Immune Reconstitution Inflammatory Syndrome: A Case Report Highlighting Clinical and MRI Features

Multiple sclerosis (MS) patients treated with natalizumab often face the uncommon but severe complication of developing progressive multifocal leukoencephalopathy (PML). PML may be further complicated by immune reconstitution inflammatory syndrome (IRIS) after the removal of the drug. Since both PML and IRIS are associated with high morbidity and mortality rates, early clinical and radiological diagnosis of these complications is of paramount importance. Here, we report a case of an adult male patient who was diagnosed with PML after receiving natalizumab therapy for 6 years for the treatment of MS. Upon cessation of natalizumab, he presented with a paradoxical worsening of clinical and radiological findings consistent with an inflammatory brain injury due to IRIS. He was treated with high dose corticosteroid therapy followed by a gradual improvement in clinical and imaging findings. This article illustrates the magnetic resonance imaging (MRI) features of natalizumab-associated PML-IRIS, along with a brief overview of its clinical features, complications and management strategies.

Serum Gelatinases Levels in Multiple Sclerosis Patients during 21 Months of Natalizumab Therapy

Background. Natalizumab is a highly effective treatment approved for multiple sclerosis (MS). The opening of the blood-brain barrier mediated by matrix metalloproteinases (MMPs) is considered a crucial step in MS pathogenesis. Our goal was to verify the utility of serum levels of active MMP-2 and MMP-9 as biomarkers in twenty MS patients treated with Natalizumab. Methods. Serum levels of active MMP-2 and MMP-9 and of specific tissue inhibitors TIMP-1 and TIMP-2 were determined before treatment and for 21 months of therapy. Results. Serum levels of active MMP-2 and MMP-9 and of TIMP-1 and TIMP-2 did not differ during the treatment. The ratio between MMP-9 and MMP-2 was increased at the 15th month compared with the 3rd, 6th, and 9th months, greater at the 18th month than at the 3rd and 6th months, and higher at the 21st than at the 3rd and 6th months. Discussion. Our data indicate that an imbalance between active MMP-9 and active MMP-2 can occur in MS patients after 15 months of Natalizumab therapy; however, they do not support the use of serum active MMP-2 and active MMP-9 and TIMP-1 and TIMP-2 levels as biomarkers for monitoring therapeutic response to Natalizumab.

A longitudinal uncontrolled study of cerebral gray matter volume in patients receiving natalizumab for multiple sclerosis

OBJECTIVE

Brain atrophy in multiple sclerosis (MS) selectively affects gray matter (GM), which is highly relevant to disability and cognitive impairment. We assessed cerebral GM volume (GMV) during one year of natalizumab therapy.

DESIGN/METHODS

Patients with relapsing-remitting (n = 18) or progressive (n = 2) MS had MRI ∼1 year apart during natalizumab treatment. At baseline, patients were on natalizumab for (mean ± SD) 16.6 ± 10.9 months with age 38.5 ± 7.4 and disease duration 9.7 ± 4.3 years.

RESULTS

At baseline, GMV was 664.0 ± 56.4 ml, Expanded Disability Status Scale (EDSS) score was 2.3 ± 2.0, timed 25-foot walk (T25FW) was 6.1±3.4 s; two patients (10%) had gadolinium (Gd)-enhancing lesions. At follow-up, GMV was 663.9 ± 60.2 mL; EDSS was 2.6 ± 2.1 and T25FW was 5.9 ± 2.9 s. One patient had a mild clinical relapse during the observation period (0.052 annualized relapse rate for the entire cohort). No patients had Gd-enhancing lesions at follow-up. Linear mixed-effect models showed no significant change in annualized GMV [estimated mean change per year 0.338 mL, 95% confidence interval -9.66, 10.34, p = 0.94)], GM fraction (p = 0.92), whole brain parenchymal fraction (p = 0.64), T2 lesion load (p = 0.64), EDSS (p = 0.26) or T25FW (p = 0.79).

CONCLUSIONS

This pilot study shows no GM atrophy during one year of natalizumab MS therapy. We also did not detect any loss of whole brain volume or progression of cerebral T2 hyperintense lesion volume during the observation period. These MRI results paralleled the lack of clinical worsening.

Dengue fever in patients with multiple sclerosis taking fingolimod or natalizumab

Dengue fever is the most prevalent mosquito-borne viral illness in humans. There may be different clinical manifestations of the disease, from mild symptoms to hemorrhagic forms of dengue fever and even neurological complications of this viral infection. Blood cells are usually affected, and thrombocytopenia is the hallmark of the disease. This paper presents 15 cases of dengue fever in patients with multiple sclerosis (MS) taking fingolimod or natalizumab. There were no complications of dengue fever or worse outcomes of MS in these patients, and only four of them needed short-term treatment withdrawal due to lymphopenia.

Epstein-Barr Virus Specific Antibody Response in Multiple Sclerosis Patients during 21 Months of Natalizumab Treatment

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system. Natalizumab, a humanized anti-α4 integrin monoclonal antibody, is a highly effective treatment approved for MS. An association between MS and an exposure to Epstein-Barr Virus (EBV) sustained by the levels of antiviral capsid antigen (VCA) and anti-Epstein-Barr nuclear antigen-1 (EBNA-1) IgG has been described. Our goal was to verify the utility of EBV-specific IgG as a marker in Natalizumab treated MS. Twenty patients (17 female and 3 male) in treatment with Natalizumab were enrolled. Serum levels of anti-VCA and anti-EBNA-1 IgG were determined and expressed as arbitrary units (AU) before treatment and every three months for 21 months of therapy. Anti-VCA IgG levels were increased at the 15th month (235410 ± 196712 AU) comparing with the 3rd (98146 ± 47145 AU) and the 6th (109866 ± 52270 AU) months of therapy (p < 0.05). No significant differences were found for serum anti-EBNA-1 IgG levels. Our data indicate that a transient, self-limited, EBV reactivation can occur in MS during Natalizumab therapy but our results do not support the use of serum EBV-specific antibody levels as biomarkers for monitoring therapeutic response to Natalizumab in the course of MS.

Hexosylceramides as intrathecal markers of worsening disability in multiple sclerosis

BACKGROUND

Sphingolipids are important components of neurons and the myelin sheath whose levels are altered in multiple sclerosis (MS).

OBJECTIVES

We aimed to determine if cerebrospinal fluid (CSF) sphingolipids can be used as markers of MS disease progression.

METHODS

Using liquid chromatography tandem mass spectrometry, we analysed sphingolipids in CSF from 134 individuals. The MS group included 65 patients divided into 41 relapsing-remitting MS (RRMS) and 24 progressive MS (ProgMS). In addition, a group of 13 early MS/clinically isolated syndrome (EarlyMS) and two control groups consisting of 38 individuals with other neurological diseases (OND) and 18 OND with signs of inflammation (iOND) were analysed. A follow-up study included 17 additional RRMS patients sampled at two time points 4.7±1.7 years apart.

RESULTS

Levels of sphingomyelin (SM)- and hexosylceramide (HexCer)-derived sphingolipids increased in the CSF of patients with MS independently of the fatty acid chain length in RRMS (p<0.05). Levels of palmitic acid (16:0)-containing HexCer (HexCer16:0) increased significantly in ProgMS compared with the OND (p<0.001), iOND (p<0.05) and EarlyMS (p<0.01) groups and correlated with Expanded Disability Status Scale in RRMS in both studies (p=0.048; p=0.027).

CONCLUSION

HexCer16:0 is a promising candidate marker of disease progression in MS, especially in RRMS.

The role of glycosylation in IBD

A number of genetic and immunological studies give impetus for investigating the role of glycosylation in IBD. Experimental mouse models have helped to delineate the role of glycosylation in intestinal mucins and to explore the putative pathogenic role of glycosylation in colitis. These experiments have been extended to human studies investigating the glycosylation patterns of intestinal mucins as well as levels of glycans of serum glycoproteins and expression of glycan receptors. These early human studies have generated interesting hypotheses regarding the pathogenic role of glycans in IBD, but have generally been restricted to fairly small underpowered studies. Decreased glycosylation has been observed in the intestinal mucus of patients with IBD, suggesting that a defective inner mucus layer might lead to increased bacterial contact with the epithelium, potentially triggering inflammation. In sera, decreased galactosylation of IgG has been suggested as a diagnostic marker for IBD. Advances in glycoprofiling technology make it technically feasible and affordable to perform high-throughput glycan pattern analyses and to build on previous work investigating a much wider range of glycan parameters in large numbers of patients.

Pregnancy and fetal outcomes following natalizumab exposure in pregnancy. A prospective, controlled observational study

BACKGROUND

Safety data on first-trimester natalizumab exposure are scarce, as natalizumab is usually withdrawn three months before pregnancy.

OBJECTIVE

The objective of this paper is to investigate the fetal safety of exposure to natalizumab (Tysabri(®)) during the first trimester of pregnancy using disease-matched (DM) and healthy control (HC) comparison groups.

METHODS

A total of 101 German women with RRMS exposed to natalizumab during the first trimester of pregnancy were identified. Birth outcomes in the exposed group were compared to a DM group (N = 78) with or without exposure to other disease-modifying drugs, and an HC group (N = 97).

RESULTS

A total of 77, 69 and 92 live births occurred in the Exposed, DM and HC groups, respectively. The rates of major malformations (p = 0.67), low birth weight (<2500 grams) (p = 1.0) and premature birth (p = 0.37) did not differ among groups. Higher miscarriage rates (p = 0.002) and lower birth weights (p = 0.001) occurred among the Exposed and DM groups, as compared to the HC; however, there was no significant difference between the Exposed and DM groups.

CONCLUSION

Exposure to natalizumab in early pregnancy does not appear to increase the risk of adverse pregnancy outcomes in comparison to a DM group not exposed to natalizumab.

The efficacy and safety of daclizumab and its potential role in the treatment of multiple sclerosis

Daclizumab is a humanized monoclonal antibody of the immunoglobulin G1 (IgG1) isotype that binds to the α-subunit (CD25) of the high-affinity interleukin-2 (IL-2) receptor expressed on activated T cells and CD4+CD25+FoxP3+ regulatory T cells. Based on the assumption that it would block the activation and expansion of autoreactive T cells that are central to the immune pathogenesis of multiple sclerosis (MS), daclizumab was tested in several small open-label clinical trials in MS and demonstrated a profound inhibition of inflammatory disease activity. Surprisingly, accompanying mechanistic studies revealed that the most important biological effect of daclizumab was rather a dramatic expansion and activation of immunoregulatory CD56(bright) natural-killer (NK) cells that correlated with treatment response, while there was no or only minor effect on peripheral T-cell activation and function. These CD56(bright) NK cells were able to gain access to the central nervous system in MS and kill autologous activated T cells. Additional and relatively large phase IIb clinical trials showed that daclizumab, as add-on or monotherapy in relapsing-remitting (RR) MS, was highly effective in reducing relapse rate, disability progression, and the number and volume of gadolinium-enhancing, T1 and T2 lesions on brain magnetic resonance imaging (MRI), and reproduced the expansion of CD56(bright) NK cells as a biomarker for daclizumab activity. Daclizumab is generally very well tolerated and has shown a favorable adverse event (AE) profile in transplant recipients. However, several potentially serious and newly emerging AEs (mainly infections, skin reactions, elevated liver function tests and autoimmune phenomena in several body organs) may require strict safety monitoring programs in future clinical practice and place daclizumab together with other new and highly effective MS drugs as a second-line therapy. Ongoing phase III clinical trials in RRMS are expected to provide definite information on the efficacy and safety of daclizumab and to determine its place in the fast-growing armamentarium of MS therapies.

Normal outcome of pregnancy with ongoing treatment with natalizumab

BACKGROUND

Treatment of multiple sclerosis (MS) with natalizumab during pregnancy is not recommended due to potential risks for the foetus. Despite strong advice accidental pregnancies occur.

CASE

A 32-year old woman with MS since the age of 26 was treated with natalizumab since January 2008. Treatment was stopped April 2011 due to pregnancy plans, but was restarted following an MS relapse. The patient was thoroughly informed about potential foetal risks, but nevertheless she one year later disclosed that she was pregnant in gestational week 15. Treatment was continued, since the first trimester had passed. The pregnancy course was normal and a healthy daughter was born at full gestational term.

CONCLUSIONS

This is the second known case where natalizumab treatment continued throughout the whole gestational period.

PSGL-1 and E/P-selectins are essential for T-cell rolling in inflamed CNS microvessels but dispensable for initiation of EAE

T-cell migration across the blood-brain barrier is a crucial step in the pathogenesis of EAE, an animal model for MS. Live cell imaging studies demonstrated that P-selectin glycoprotein ligand-1 (PSGL-1) and its endothelial ligands E- and P-selectin mediate the initial rolling of T cells in brain vessels during EAE. As functional absence of PSGL-1 or E/P-selectins does not result in ameliorated EAE, we speculated that T-cell entry into the spinal cord is independent of PSGL-1 and E/P-selectin. Performing intravital microscopy, we observed the interaction of WT or PSGL-1(-/-) proteolipid protein-specific T cells in inflamed spinal cord microvessels of WT or E/P-selectin(-/-) SJL/J mice during EAE. T-cell rolling but not T-cell capture was completely abrogated in the absence of either PSGL-1 or E- and P-selectin, resulting in a significantly reduced number of T cells able to firmly adhere in the inflamed spinal cord microvessels, but did not lead to reduced T-cell invasion into the CNS parenchyma. Thus, PSGL-1 interaction with E/P-selectin is essential for T-cell rolling in inflamed spinal cord microvessels during EAE. Taken together with previous observations, our findings show that T-cell rolling is not required for successful T-cell entry into the CNS and initiation of EAE.

Defining and scoring response to IFN-β in multiple sclerosis

The advent of a large number of new therapies for multiple sclerosis (MS) warrants the development of tools that enable selection of the best treatment option for each new patient with MS. Evidence from clinical trials clearly supports the efficacy of IFN-β for the treatment of MS, but few factors that predict a response to this drug in individual patients have emerged. This deficit might be due, at least in part, to the lack of a standardized definition of the clinical outcomes that signify improvement or worsening of the disease. MRI markers and clinical relapses have been the most widely studied short-term factors to predict long-term response to IFN-β, although the results are conflicting. Recently, integrated strategies combining MRI and clinical markers in scoring systems have provided a potentially useful approach for the management of patients with MS. In this Review, we focus on the many definitions of clinical response to IFN-β and explore the markers that can be used to predict this response. We also highlight advantages and limitations of the existing scoring systems in light of future expansion of these models to biological markers and to other classes of emerging therapies for MS.

Role of regulatory T cells in pathogenesis and biological therapy of multiple sclerosis

Multiple sclerosis (MS) is an inflammatory disease in which the myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms. It is caused by an autoimmune response to self-antigens in a genetically susceptible individual induced by unknown environmental factors. Principal cells of the immune system that drive the immunopathological processes are T cells, especially of T_H1 and T_H17 subsets. However, in recent years, it was disclosed that regulatory T cells took part in, too. Subsequently, there was endeavour to develop ways how to re-establish their physiological functions. In this review, we describe known mechanisms of action, efficacy, and side-effects of contemporary and emerging MS immunotherapeutical agents on Treg cells and other cells of the immune system involved in the immunopathogenesis of the disease. Furthermore, we discuss how laboratory immunology can offer physicians its help in the diagnosis process and decisions what kind of biological therapy should be used.

Roles of T helper 17 cells and interleukin-17 in neuroautoimmune diseases with emphasis on multiple sclerosis and Guillain-Barré syndrome as well as their animal models

The identification of T helper 17 (Th17) cells challenges the Th1/Th2 paradigm of the immune response and invites intensive exploration of their mechanisms and functions in the field of autoimmune diseases, host defense, allergy, etc. The collective data have shown that transforming growth factor-β (TGF-β), interleukin (IL)-6, IL-1β, IL-21, and IL-23 are involved in the differentiation program of Th17 cells. The transcription factors RORγT, STAT3, RORγ, RORα, and IRF4 exert regulatory effects on the development of Th17 cells. Among the Th17-related effector cytokines, such as IL-17, IL-17F, IL-21, and IL-22, IL-17 is regarded as a key cytokine to induce inflammatory responses. This review outlines the cytokines and transcription factors involved in the differentiation of Th17 cells and their effector functions, with specific focus on the roles of Th17 cells and IL-17 in neuroautoimmune diseases, especially in multiple sclerosis and Guillain-Barré syndrome, as well as in their animal models, experimental autoimmune encephalomyelitis and experimental autoimmune neuritis.