Humoral autoimmunity in multiple sclerosis

The Use of Kappa Free Light Chains to Diagnose Multiple Sclerosis

Background: The positive implications of using free light chains in diagnosing multiple sclerosis have increasingly gained considerable interest in medical research and the scientific community. It is often presumed that free light chains, particularly kappa and lambda free light chains, are of practical use and are associated with a higher probability of obtaining positive results compared to oligoclonal bands. The primary purpose of the current paper was to conduct a systematic review to assess the up-to-date methods for diagnosing multiple sclerosis using kappa and lambda free light chains. Method: An organized literature search was performed across four electronic sources, including Google Scholar, Web of Science, Embase, and MEDLINE. The sources analyzed in this systematic review and meta-analysis comprise randomized clinical trials, prospective cohort studies, retrospective studies, controlled clinical trials, and systematic reviews. Results: The review contains 116 reports that includes 1204 participants. The final selection includes a vast array of preexisting literature concerning the study topic: 35 randomized clinical trials, 21 prospective cohort studies, 19 retrospective studies, 22 controlled clinical trials, and 13 systematic reviews. Discussion: The incorporated literature sources provided integral insights into the benefits of free light chain diagnostics for multiple sclerosis. It was also evident that the use of free light chains in the diagnosis of clinically isolated syndrome (CIS) and multiple sclerosis is relatively fast and inexpensive in comparison to other conventional state-of-the-art diagnostic methods, e.g., using oligoclonal bands (OCBs).

Experimental laboratory biomarkers in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a chronic autoimmune disorder of the central nervous system; the cause of this condition remains unknown. Researchers have analyzed different biomarkers related to MS. Here, experimental laboratory biomarkers for MS are identified and analyzed.

METHODS

The current study examined articles investigating biomarkers for MS. Records were obtained from the PubMed, LILACS, and EBSCO databases using an identical search strategy and terms that included "multiple sclerosis," "MS," and "biomarkers." In the current review, we also focus on lesser known biomarkers that have not yet been established for use in clinical practice.

RESULTS

Previous studies have explored molecular substances that may help diagnose MS and manage its adverse effects. Commonly studied factors include neurofilaments, sCD163, CXCL13, NEO, NF‑L, OPN, B cells, T cells, and integrin-binding proteins.

CONCLUSIONS

Interactions between environmental and genetic factors have been implicated in the development of MS. Previous investigations have identified a wide range of biomarkers that can be used for diagnosis and disease management. These molecules and their associated studies provide vital insight and data to help primary physicians improve clinical and health outcomes for MS patients.

FasL regulatory B-cells during Mycobacterium tuberculosis infection and TB disease

Tuberculosis (TB) disease remains a major health crisis. Infection with Mycobacterium tuberculosis (M.tb) cause a range of diseases ranging from latent infection to active TB disease. This active state of the disease is characterised by the formation of granulomas (a physical barrier in the lung), a structure thought to protect the host by controlling the infection through preventing the growth of the bacilli. Subsequently, the surviving bacteria become inactive and in most cases, TB reactivation is prevented by the immune response of the host. B-cells perform numerous immunological functions beyond antibody production to positively regulate the response to pathogenic assault. A subgroup of B-cells with regulatory functions express death-inducing ligands, such as Fas ligand (FasL). Expression and interaction of the Fas receptor-ligand promotes the induction of apoptosis and the induction of T-cell tolerance. Here, we focus on the significance of B-cells by addressing their FasL phenotype and regulatory functions during TB, with reference to disease in humans, non-human primates and mice.

Experimental Models of Neuroimmunological Disorders: A Review

Immune-mediated inflammatory diseases of the central nervous system (CNS) are a group of neurological disorders in which inflammation and/or demyelination are induced by cellular and humoral immune responses specific to CNS antigens. They include diseases such as multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), acute disseminated encephalomyelitis (ADEM) and anti-NMDA receptor encephalitis (NMDAR encephalitis). Over the years, many in vivo and in vitro models were used to study clinical, pathological, physiological and immunological features of these neuroimmunological disorders. Nevertheless, there are important aspects of human diseases that are not fully reproduced in the experimental models due to their technical limitations. In this review, we describe the preclinical models of neuroimmune disorders, and how they contributed to the understanding of these disorders and explore potential treatments. We also describe the purpose and limitation of each one, as well as the recent advances in this field.

Impact of B cells to the pathophysiology of multiple sclerosis

Introduction

Multiple sclerosis (MS) is a chronic autoimmune disorder that affects the central nervous system and compromises the health and well-being of millions of people worldwide. B cells have been linked to MS and its progression. This review aimed to determine the role of B cells in MS development.

Methods

Articles used in this review were obtained from PubMed, LILACS, and EBSCO. The search terms and phrases included “multiple sclerosis,” “MS,” “B-Cells,” “pathogenesis,” and “development.” Original research studies and articles on MS and B cells published between 2007 and 2018 were included.

Results

Results from the selected articles showed a significant connection between B cell groups and MS. B cells act as a significant source of plasma cells, which generate antibodies while also regulating autoimmune processes and T cell production. In addition, B cells regulate the release of molecules that affect the proinflammatory actions of other immune cells.

Discussion

B cells play key roles in immune system functioning and MS. The findings of this review illustrate the complex nature of B cell actions, their effects on the autoimmune system, and the method by which they contribute to MS pathogenesis.

Conclusion

Previous research implicates biological, genetic, and environmental factors in MS pathogenesis. This review suggests that B cells contribute to MS development and advancement by influencing and regulating autoimmune processes such as T cell production and APC activity.

Bcells and their regulatory functions during Tuberculosis: Latency and active disease

Tuberculosis (TB) is a global epidemic with devastating consequences. Emerging evidence suggests that B-cells have the ability to modulate the immune response and understanding these roles during Mycobacterium tuberculosis (M.tb) infection can help to find new strategies to treat TB. The immune system of individuals with pulmonary TB form granulomas in the lung which controls the infection by inhibiting the M.tb growth and acts as a physical barrier. Thereafter, surviving M.tb become dormant and in most cases the host's immunity prevents TB reactivation. B-cells execute several immunological functions and are regarded as protective regulators of immune responses by antibody and cytokine production, as well as presenting antigen. Some of these B-cells, or regulatory B-cells, have been shown to express death-inducing ligands, such as Fas ligand (FasL). This expression and binding to the Fas receptor leads to apoptosis, a major immune regulation mechanism, in addition to the ability to induce T-cell tolerance. Here, I discuss the relevance of B-cells, in particular their non-humoral functions by addressing their regulatory properties during M.tb infection.

Completing the Immunological Fingerprint by Refractory Proteins: Autoantibody Screening via an Improved Immunoblotting Technique

PURPOSE

Identifying autoantigens of serological autoantibodies requires expensive methods, such as protein microarrays or IP+MS. Thus, sera are commonly pre-screened for interesting immunopatterns via immunocytochemistry/immunohistochemistry. However, distinguishing immunopatterns can be difficult and intracellular antigens are less accessible. Therefore, a simple and cheap immunoblot screening able to distinguish immunopatterns and to detect refractory proteins is presented.

EXPERIMENTAL DESIGN

Five steps of immunoblotting-based autoantigen screening are revised: (1) choice of protein source, (2) protein extraction, (3) protein separation, (4) protein transfer, (5) antigen detection. Thereafter, 52 patients' sera with chronic inflammatory demyelinating polyneuropathy (CIDP) and 45 controls were screened.

RESULTS

The protein source impacts the detected antigen set. Steps 2-4 can be adapted for refractory proteins. Furthermore, longitudinal cutting of protein lanes saves ≥75% of time and material and allows for exact comparison of band patterns. As the latter are individually specific and temporarily constant, we call them "immunological fingerprints". In a proof-of-principle, a 155 kDa immunoband was detected with two anti-neurofascin-155-positive CIDP sera and two further immunobands (120/220 kDa) specific to a subgroup of 3-6 of 52 CIDP patients.

CONCLUSIONS AND CLINICAL RELEVANCE

Adapted immunoblotting is a cheap and simple method for accurate serum screening including refractory and intracellular antigens.

Relevance of Helicobacter pylori infection in Egyptian multiple sclerosis patients

Background

Multiple sclerosis (MS) is an autoimmune demyelinating disorder. The etiology of MS remains unknown exactly. Helicobacter pylori heat shock proteins were suggested as a potential trigger of immune system causing MS.

Objectives

The aim of this study was to assess the level of anti-Helicobacter pylori heat shock proteins 60 (Hp hsp60) antibodies at patients of MS and to correlate it with various epidemiological and clinical data.

Subjects and methods

This study design was a cross-sectional case control one. A total of 65 patients with multiple sclerosis diagnosed according to 2010 revised McDonald criteria and other 65 age- and sex-matched healthy controls were included in this study. All participants were subjected to full history taking, complete neurological examination including Expanded Disability Status Scale (EDSS) for the patients, measurement of serum level of anti-Hp hsp60 IgG using ELISA technique, and MRI brain for all the patients, being a goldstone for inclusion in the study.

Results

There was statistically significant high level of anti-Hp hsp60 IgG at MS patients especially secondary progressive multiple sclerosis (SPMS) patients. Moreover, a positive statistically significant correlation was found between it and age of patients, duration of illness, and EDSS.

Conclusion

We conclude that hsp60 of Hp may be a useful biomarker for attesting course progression in MS.

The Persisting Significance of Oligoclonal Bands in the Dawning Era of Kappa Free Light Chains for the Diagnosis of Multiple Sclerosis

The latest revision of the McDonald criteria of 2017 considers the evidence of an intrathecal immunoglobulin (IgG) synthesis as a diagnostic criterion for dissemination in time in multiple sclerosis. While the detection of oligoclonal bands is considered as the gold standard, determination of kappa free light chains might be a promising tool as a less technically demanding and cost saving method. However, data on the direct comparison between kappa free light chains and oligoclonal bands are limited and no study to date has used the highly sensitive method of polyacrylamide gels with consecutive silver staining for the demonstration of oligoclonal bands. Furthermore, the impact of the revised McDonald criteria of 2017 on the role of kappa free light chains as a biomarker has not been investigated. Nephelometry was used to determine kappa free light chains in cerebrospinal fluid (CSF) and serum from 149 patients with their first demyelinating event between 2010 and 2015. Clinical data, kappa free light chains, and oligoclonal band status were compared at the time of initial diagnosis and after follow-up to identify converters from clinically isolated syndrome to multiple sclerosis. An elevated kappa free light chain index (>5.9) was found in 79/83 patients (95%) with multiple sclerosis diagnosed at baseline, slightly less frequent than oligoclonal bands (98.8%). 18/25 (72%) patients who converted from clinically isolated syndrome to multiple sclerosis showed an elevated kappa free light chain index compared to 20/25 (80%) patients with positive oligoclonal bands. In patients with stable clinically isolated syndrome 7/41 (17%) displayed an elevated kappa free light chain index against 11/41 (27%) oligoclonal band positive patients. Only two patients with stable clinically isolated syndrome showed an elevated kappa free light chain index but were oligoclonal bands negative. In conclusion, determination of the kappa free light chain index is a promising diagnostic approach to assess intrathecal immunoglobulin synthesis in multiple sclerosis. Nevertheless, oligoclonal bands are highly prevalent in multiple sclerosis and can detect an intrathecal synthesis of IgG even when the kappa free light chain index is below the threshold. We consider sequential use of both methods as reasonable.

Molecular control of B-cell homeostasis in health and malignancy

Altered B-cell homeostasis underlies a wide range of pathologies, from cancers to autoimmunity and immunodeficiency. The molecular safeguards against those disorders, which also allow effective immune responses, are therefore particularly critical. Here, we review recent findings detailing the fine control of B-cell homeostasis, during B-cell development, maturation in the periphery and during activation and differentiation into antibody-producing cells.

Contribution of the Degeneration of the Neuro-Axonal Unit to the Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating, autoimmune disease of the central nervous system. In recent years, it has become more evident that neurodegeneration, including neuronal damage and axonal injury, underlies permanent disability in MS. This manuscript reviews some of the mechanisms that could be responsible for neurodegeneration and axonal damage in MS and highlights the potential role that dysfunctional heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) and antibodies to hnRNP A1 may play in MS pathogenesis.

Experimental Models of Autoimmune Demyelinating Diseases in Nonhuman Primates

Human idiopathic inflammatory demyelinating diseases (IIDD) are a heterogeneous group of autoimmune inflammatory and demyelinating disorders of the central nervous system (CNS). These include multiple sclerosis (MS), the most common chronic IIDD, but also rarer disorders such as acute disseminated encephalomyelitis (ADEM) and neuromyelitis optica (NMO). Great efforts have been made to understand the pathophysiology of MS, leading to the development of a few effective treatments. Nonetheless, IIDD still require a better understanding of the causes and underlying mechanisms to implement more effective therapies and diagnostic methods. Experimental autoimmune encephalomyelitis (EAE) is a commonly used animal model to study the pathophysiology of IIDD. EAE is principally induced through immunization with myelin antigens combined with immune-activating adjuvants. Nonhuman primates (NHP), the phylogenetically closest relatives of humans, challenged by similar microorganisms as other primates may recapitulate comparable immune responses to that of humans. In this review, the authors describe EAE models in 3 NHP species: rhesus macaques ( Macaca mulatta), cynomolgus macaques ( Macaca fascicularis), and common marmosets ( Callithrix jacchus), evaluating their respective contribution to the understanding of human IIDD. EAE in NHP is a heterogeneous disease, including acute monophasic and chronic polyphasic forms. This diversity makes it a versatile model to use in translational research. This clinical variability also creates an opportunity to explore multiple facets of immune-mediated mechanisms of neuro-inflammation and demyelination as well as intrinsic protective mechanisms. Here, the authors review current insights into the pathogenesis and immunopathological mechanisms implicated in the development of EAE in NHP.

Anticeramide antibody and butyrylcholinesterase in peripheral neuropathies

Ceramide is a glycosphingolipid, a component of nerve and non neuronal cell membrane and plays a role in maintaining the integrity of neuronal tissue. Butyrylcholinesterase (BChE) is a multifunctional enzyme, its involvement in neurodegenerative diseases has been well established. Anticeramide antibody (Ab-Cer) and enzyme BChE have been implicated in peripheral neuropathies. The present study investigates whether there is an association between Ab-Cer and BChE activities and peripheral neuropathies. Patients included: human immunodeficiency virus associated peripheral neuropathy (HIV-PN, n=39), paucibacillary leprosy (PB-L, n=36), multibacillary leprosy (MB-L, n=52), diabetic neuropathy (DN, n=22), demyelinating sensory motor polyneuropathy (DSMN, n=13) and chronic inflammatory demyelinating polyneuropathy (CIDP, n=10). Plasma Ab-Cer was measured by indirect enzyme linked immune assay (ELISA) and BChE activity in plasma was measured by colorimetric method. Ab-Cer levels were significantly elevated in MB-L and DN as compared to healthy subjects (HS). BChE levels were significantly higher in MB-L and DN as well as in HIV and HIV-PN. There is no significant difference in either Ab-Cer or BChE levels in DSMN and CIDP. Elevated plasma Ab-Cer and BChE levels may be considered significant in the pathogenesis of neuropathies. The variation in concurrent involvement of both the molecules in the neuropathies of the study, suggest their unique involvement in neurodegenerative pathways.

Effects of in vivo and in vitro administration of neuro-Behcet's disease IgG

Antibodies directed against membrane antigens of neuronal axonal processes (neuropil) have been recently identified in neuro-Behcet's disease (NBD) patients. To delineate the potential pathogenic action of these antibodies, pooled sera from seven NBD patients with neuropil antibodies and seven healthy controls were divided into purified IgG and IgG-depleted serum (IgG-DS) fractions and each fraction was administered into lateral ventricles of rats. NBD IgG-injected rats showed reduced locomotor activity in the open field test as compared to NBD IgG-DS, healthy control IgG, healthy control IgG-DS and PBS injected rats (n = 10 for each group). There were no significant differences among treatment groups by means of anxiety-like behaviors (assessed by elevated plus maze test) and learning/memory functions (assessed by passive avoidance test). Administration of NBD IgG on cultured SH-SY5Y neuroblastoma cells induced significantly increased cell death and apoptosis (as measured by nucleosome levels in the supernatants) as compared to other treatment groups. Our results suggest that IgGs isolated from sera of neuropil antibody-positive NBD patients have a neurotoxic action, which is presumably mediated by apoptotic mechanisms. Motor deficits frequently observed in NBD patients might at least partially be caused by the pathogenic action of anti-neuronal IgG.

Autoantibodies to heterogeneous nuclear ribonuclear protein A1 (hnRNPA1) cause altered 'ribostasis' and neurodegeneration; the legacy of HAM/TSP as a model of progressive multiple sclerosis

Several years following its discovery in 1980, infection with human T-lymphotropic virus type 1 (HTLV-1) was shown to cause HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), a disease biologically similar to progressive forms of multiple sclerosis (MS). In this manuscript, we review some of the clinical, pathological, and immunological similarities between HAM/TSP and MS with an emphasis on how autoantibodies to an RNA binding protein, heterogeneous nuclear ribonuclear protein A1 (hnRNP A1), might contribute to neurodegeneration in immune mediated diseases of the central nervous system.

Environmental Factors and Their Regulation of Immunity in Multiple Sclerosis

In multiple sclerosis (MS), environmental factors and genetic traits cooperate in the induction of the chronic activation of immune cells to produce the brain pathology. Epidemiology has focused on different environmental risk factors but certainly virus infection, smoking, vitamin D levels, and sunlight exposure are the most relevant. What is certainly less clear is the way in which these external factors are able to induce and sustain the internal pathology process of the disease. Epigenetics has been recently focused on trying to shed light on this aspect. As a matter of fact epigenetic changes are highly sensitive to environmental factors that therefore may influence the susceptibility to the disease by acting through epigenetic modifications. In this chapter we discuss the most relevant environmental factors and how they may affect the immune response in MS. Finally, we discuss the possible role of the microbiota in inducing autoimmunity in MS.

B Cells in the Multiple Sclerosis Central Nervous System: Trafficking and Contribution to CNS-Compartmentalized Inflammation

Clinical trial results of peripheral B cell depletion indicate abnormal proinflammatory B cell properties, and particularly antibody-independent functions, contribute to relapsing MS disease activity. However, potential roles of B cells in progressive forms of disease continue to be debated. Prior work indicates that presence of B cells is fostered within the inflamed MS central nervous system (CNS) environment, and that B cell-rich immune cell collections may be present within the meninges of patients. A potential association is reported between such meningeal immune cell collections and the subpial pattern of cortical injury that is now considered important in progressive disease. Elucidating the characteristics of B cells that populate the MS CNS, how they traffic into the CNS and how they may contribute to progressive forms of the disease has become of considerable interest. Here, we will review characteristics of human B cells identified within distinct CNS subcompartments of patients with MS, including the cerebrospinal fluid, parenchymal lesions, and meninges, as well as the relationship between B cell populations identified in these subcompartments and the periphery. We will further describe the different barriers of the CNS and the possible mechanisms of migration of B cells across these barriers. Finally, we will consider the range of human B cell responses (including potential for antibody production, cytokine secretion, and antigen presentation) that may contribute to propagating inflammation and injury cascades thought to underlie MS progression.

Investigating the Antigen Specificity of Multiple Sclerosis Central Nervous System-Derived Immunoglobulins

The central nervous system (CNS) of patients with multiple sclerosis (MS) is the site where disease pathology is evident. Damaged CNS tissue is commonly associated with immune cell infiltration. This infiltrate often includes B cells that are found in multiple locations throughout the CNS, including the cerebrospinal fluid (CSF), parenchyma, and the meninges, frequently forming tertiary lymphoid structures in the latter. Several groups, including our own, have shown that B cells from distinct locations within the MS CNS are clonally related and display the characteristics of an antigen-driven response. However, the antigen(s) driving this response have yet to be conclusively defined. To explore the antigen specificity of the MS B cell response, we produced recombinant human immunoglobulin (rIgG) from a series of expanded B cell clones that we isolated from the CNS tissue of six MS brains. The specificity of these MS-derived rIgG and control rIgG derived from non-MS tissues was then examined using multiple methodologies that included testing individual candidate antigens, screening with high-throughput antigen arrays and evaluating binding to CNS-derived cell lines. We report that while several MS-derived rIgG recognized particular antigens, including neurofilament light and a protocadherin isoform, none were unique to MS, as non-MS-derived rIgG used as controls invariably displayed similar binding specificities. We conclude that while MS CNS resident B cells display the characteristics of an antigen-driven B cell response, the antigen(s) driving this response remain at large.

Changes in Blood B Cell-Activating Factor (BAFF) Levels in Multiple Sclerosis: A Sign of Treatment Outcome

Multiple sclerosis (MS) is mediated primarily by autoreactive T cells. However, evidence suggesting the involvement of humoral immunity in brain diseases has increased interest in the role of B cells and their products during MS pathogenesis. The major survival factor for B cells, BAFF has been shown to play a role in several autoimmune conditions. Elevated BAFF levels have been reported in MS animal model and during MS relapse in patients. Moreover, disease-modifying treatments (DMT) reportedly influence blood BAFF levels in MS patients, but the significance of these changes remains unclear. The present study addresses how blood BAFF levels are associated with the clinical course of relapsing-remitting MS and the effectiveness of DMT and short-term steroid treatment. During a prospective longitudinal follow-up of 2.3 years, BAFF was measured in the blood of 170 MS patients in the stable phase and within 186 relapses. BAFF levels were significantly higher in MS patients compared to healthy controls. However, stable MS patients without relapses exhibited significantly higher BAFF levels than relapsing patients. Treatment with interferon-β and immunosuppressants raised BAFF blood levels. Interestingly, a similar effect was not seen in patients treated with glatiramer acetate. Short-term treatment with high doses of intravenous methylprednisolone did not significantly alter plasma BAFF levels in 65% of relapsing-remitting MS patients. BAFF were correlated weakly but significantly with monocyte and basophil counts, but not with other blood cell types (neutrophils, lymphocytes, or eosinophils) or inflammatory biomarkers. To our knowledge, this is the first report demonstrating that higher blood BAFF levels may reflect a more stable and effective MS treatment outcome. These results challenge hypotheses suggesting that elevated blood BAFF levels are associated with more severe disease presentation and could explain the recent failure of pharmaceutical trials targeting BAFF with soluble receptor for MS treatment.

Chronic Cerebrospinal Venous Insufficiency in Multiple Sclerosis: A Failed Concept

In 2009 Paolo Zamboni et al. implicated that chronic cerebral venous congestion lead to the development of multiple sclerosis. In this review, we examined the role of chronic cerbrospinal venous insufficiency in multiple sclerosis and the proposed therapy entailing venous angioplasty and stenting of extracranial veins with available evidence to date.

Animal models of Multiple Sclerosis

Multiple Sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) which involves a complex interaction between immune system and neural cells. Animal modeling has been critical for addressing MS pathogenesis. The three most characterized animal models of MS are (1) the experimental autoimmune/allergic encephalomyelitis (EAE); (2) the virally-induced chronic demyelinating disease, known as Theiler׳s murine encephalomyelitis virus (TMEV) infection and (3) the toxin-induced demyelination. All these models, in a complementary way, have allowed to reach a good knowledge of the pathogenesis of MS. Specifically, EAE is the model which better reflects the autoimmune pathogenesis of MS and is extremely useful to study potential experimental treatments. Furthermore, both TMEV and toxin-induced demyelination models are suitable for characterizing the role of the axonal injury/repair and the remyelination process in MS. In conclusion, animal models, despite their limitations, remain the most useful instrument for implementing the study of MS.

Complement C1q-C3-associated synaptic changes in multiple sclerosis hippocampus

OBJECTIVE

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system, leading to memory impairment in up to 65% of patients. Memory dysfunction in MS has been associated with loss of synapses in the hippocampus, but its molecular basis is unknown. Accumulating evidence suggests that components of the complement system, C1q and C3, can mediate elimination of synapses.

METHODS

To investigate the involvement of complement in synaptic changes in MS, gene and protein expression and localization of C1q and C3 were analyzed in relation to neuropathological changes in myelinated and demyelinated hippocampi from postmortem MS brains. Findings were compared to hippocampi of Alzheimer disease (AD) and non-neurological controls.

RESULTS

C1q expression and C3 activation were increased in myelinated and demyelinated MS hippocampi, mainly in the CA3/2 and CA1 subfields, which also showed a marked decrease in synaptic density and increased neuronal staining for the mitochondrial heat shock protein 70 (mtHSP70) stress marker. Neurons were the major source of C1q mRNA. C1q protein and activated C3 localized at synapses within human leukocyte antigen-positive cell processes and lysosomes, suggesting engulfment of complement-tagged synapses by microglia. A significant association (p < 0.0001) between the density of C1q and synaptophysin-positive synapses or mtHSP70 was seen in myelinated MS hippocampi, further pointing toward a link between the complement pathway and synaptic changes. In contrast to AD, MS hippocampi were consistently negative for the terminal complement activation complex C5b9.

INTERPRETATION

These data support a role for the C1q-C3 complement axis in synaptic alterations in the MS hippocampus.

Multiple sclerosis-a quiet revolution

Multiple sclerosis (MS) has been thought to be a complex and indecipherable disease, and poorly understood with regards to aetiology. Here, we suggest an emphatically positive view of progress over several decades in the understanding and treatment of MS, particularly focusing on advances made within the past 20 years. As with virtually all complex disorders, MS is caused by the interaction of genetic and environmental factors. In recent years, formidable biochemical, bioinformatic, epidemiological and neuroimaging tools have been brought to bear on research into the causes of MS. While susceptibility to the disease is now relatively well accounted for, disease course is not and remains a salient challenge. In the therapeutic realm, numerous agents have become available, reflecting the fact that the disease can be attacked successfully at many levels and using varied strategies. Tailoring therapies to individuals, risk mitigation and selection of first-line as compared with second-line medications remain to be completed. In our view, the MS landscape has been comprehensively and irreversibly transformed by this progress. Here we focus on MS therapeutics-the most meaningful outcome of research efforts.

Differential roles of microglia and monocytes in the inflamed central nervous system

Phagocytic monocyte-derived macrophages associate with the nodes of Ranvier and initiate demyelination while microglia clear debris and display a suppressed metabolic gene signature in EAE.

In the human disorder multiple sclerosis (MS) and in the model experimental autoimmune encephalomyelitis (EAE), macrophages predominate in demyelinated areas and their numbers correlate to tissue damage. Macrophages may be derived from infiltrating monocytes or resident microglia, yet are indistinguishable by light microscopy and surface phenotype. It is axiomatic that T cell–mediated macrophage activation is critical for inflammatory demyelination in EAE, yet the precise details by which tissue injury takes place remain poorly understood. In the present study, we addressed the cellular basis of autoimmune demyelination by discriminating microglial versus monocyte origins of effector macrophages. Using serial block-face scanning electron microscopy (SBF-SEM), we show that monocyte-derived macrophages associate with nodes of Ranvier and initiate demyelination, whereas microglia appear to clear debris. Gene expression profiles confirm that monocyte-derived macrophages are highly phagocytic and inflammatory, whereas those arising from microglia demonstrate an unexpected signature of globally suppressed cellular metabolism at disease onset. Distinguishing tissue-resident macrophages from infiltrating monocytes will point toward new strategies to treat disease and promote repair in diverse inflammatory pathologies in varied organs.

Cerebrospinal fluid immunoglobulin kappa light chain in clinically isolated syndrome and multiple sclerosis

Background

Oligoclonal bands (OCB) are the most widely used CSF test to support the diagnosis of MS and to predict conversion of clinically isolated syndrome (CIS) to multiple sclerosis (MS). Since OCB tests are based on non-quantitative and difficult to standardise techniques, measurement of immunoglobulin kappa free light chains (KFLC) may represent an easier to use quantitative test.

Methods

KFLC were measured in CSF and serum of 211 patients using ELISA. These include patients without any inflammatory central nervous system reaction (NIND, n = 77), MS (n = 20), viral CNS infections (V-CNS-I, n = 10), neuroborreliosis (NB, n = 17) and other bacterial CNS infections (B-CNS-I, n = 10). Furthermore a cohort of 77 patients with CIS, including 39 patients that remained CIS over follow-up of two years (CIS-CIS) and 38 patients that developed MS over the same follow-up time (CIS-MS).

Results

CSF-serum ratio of KFLC (Q KFLC) was elevated in all patients with MS, 86.8% of patients with CIS-MS and 61.5% of patients with CIS-CIS. It was significantly elevated in CIS with presence of OCB (p<0.001). Q KFLC significantly correlated with other CSF variables such as CSF leukocyte count (p<0.001, R = 0.46), CSF CXCL13 levels (p<0.001, R = 0.64) and also intrathecal IgG synthesis (p<0.001, R = 0.74) as determined by nephelometry and quotient diagram. OCB were detected in 66.7% of CIS-CIS and in 92.1% of CIS-MS.

Conclusions

Although the measurement of CSF KFLC is a rapid and quantitative easy to standardize tool, it is almost equal but not superior to OCB with regard to diagnostic sensitivity and specificity in patients with early MS.

Maternal neurofascin-specific autoantibodies bind to structures of the fetal nervous system during pregnancy, but have no long term effect on development in the rat

Neurofascin was recently reported as a target for axopathic autoantibodies in patients with multiple sclerosis (MS), a response that will exacerbate axonal pathology and disease severity in an animal model of multiple sclerosis. As transplacental transfer of maternal autoantibodies can permanently damage the developing nervous system we investigated whether intrauterine exposure to this neurofascin-specific response had any detrimental effect on white matter tract development. To address this question we intravenously injected pregnant rats with either a pathogenic anti-neurofascin monoclonal antibody or an appropriate isotype control on days 15 and 18 of pregnancy, respectively, to mimic the physiological concentration of maternal antibodies in the circulation of the fetus towards the end of pregnancy. Pups were monitored daily with respect to litter size, birth weight, growth and motor development. Histological studies were performed on E20 embryos and pups sacrificed on days 2, 10, 21, 32 and 45 days post partum. Results: Immunohistochemistry for light and confocal microscopy confirmed passively transferred anti-neurofascin antibody had crossed the placenta to bind to distinct structures in the developing cortex and cerebellum. However, this did not result in any significant differences in litter size, birth weight, or general physical development between litters from control mothers or those treated with the neurofascin-specific antibody. Histological analysis also failed to identify any neuronal or white matter tract abnormalities induced by the neurofascin-specific antibody. Conclusions: We show that transplacental transfer of circulating anti-neurofascin antibodies can occur and targets specific structures in the CNS of the developing fetus. However, this did not result in any pre- or post-natal abnormalities in the offspring of the treated mothers. These results assure that even if anti-neurofascin responses are detected in pregnant women with multiple sclerosis these are unlikely to have a negative effect on their children.

Pediatric multiple sclerosis: current concepts and consensus definitions

Multiple sclerosis (MS), a chronic inflammatory autoimmune disease of the central nervous system (CNS) commonly diagnosed in adults, is being recognized increasingly in children. An estimated 1.7%-5.6% of all patients with MS have clinical symptoms before reaching the age of 18 years. In comparison with adults, the diagnosis of MS in children can be more difficult, being dismissed or misdiagnosed as other clinical disorders. Although adults and children share basic aspects of the disorder, children have distinctive clinical features, neuroimaging, laboratory, and courses of the disease. The 2010 McDonald criteria have simplified the requirements for establishing the diagnosis of MS and have been proposed to be applicable for the diagnosis of pediatric MS, mainly in children 12 years and older. This paper describes the distinctive features of common pediatric demyelinating disorders, including MS, and summarizes the most recent advances based on the available literature.

Type I interferons: beneficial in Th1 and detrimental in Th17 autoimmunity

In relapsing remitting multiple sclerosis (RRMS), type I interferon (IFN) is considered immuno-modulatory, and recombinant forms of IFN-β are the most prescribed treatment for this disease. However, within the RRMS population, 30-50% of MS patients are nonresponsive to this treatment, and it consistently worsens neuromyelitis optica (NMO), a disease once considered to be a form of RRMS. In contrast to RRMS, type I IFNs have been shown to have properties that drive the inflammatory pathologies in many other autoimmune diseases. These diseases include Sjögren's syndrome, system lupus erythematosus (SLE), neuromyelitis optica (NMO), rheumatoid arthritis (RA) and psoriasis. Historically, autoimmune diseases were thought to be driven by a TH1 response to auto-antigens. However, since the discovery of the TH17 in experimental autoimmune encephalomyelitis (EAE), it is now generally thought that TH17 plays an important role in MS and all other autoimmune diseases. In this article, we will discuss recent clinical and basic research advances in the field of autoimmunity and argue that IFN-β and other type I IFNs are immuno-modulatory in diseases driven predominantly by TH1 but in contrast are inflammatory in diseases that have a predominant Th17 response.

Autoantibodies to Non-myelin Antigens as Contributors to the Pathogenesis of Multiple Sclerosis

For years, investigators have sought to prove that myelin antigens are the primary targets of autoimmunity in multiple sclerosis (MS). Recent experiments have begun to challenge this assumption, particularly when studying the neurodegenerative phase of MS. T-lymphocyte responses to myelin antigens have been extensively studied, and are likely early contributors to the pathogenesis of MS. Antibodies to myelin antigens have a much more inconstant association with the pathogenesis of MS. Recent studies indicate that antibodies to non-myelin antigens such as neurofilaments, neurofascin, RNA binding proteins and potassium channels may contribute to the pathogenesis of MS. The purpose of this review is to analyze recent studies that examine the role that autoantibodies to non-myelin antigens might play in the pathogenesis of MS.

Exacerbation of experimental autoimmune encephalomyelitis by passive transfer of IgG antibodies from a multiple sclerosis patient responsive to immunoadsorption

The pathogenic role of antibodies in multiple sclerosis (MS) is still controversial. We transferred to mice with experimental autoimmune encephalomyelitis (EAE), animal model of MS, IgG antibodies purified from a MS patient presenting a dramatic clinical improvement during relapse after selective IgG removal with immunoadsorption. Passive transfer of patient's IgG exacerbated motor paralysis and increased mouse central nervous system (CNS) inflammation and demyelination. Binding of patient's IgG was demonstrated in mouse CNS, with a diffuse staining of white matter oligodendrocytes. These data support a growing body of evidence that antibodies can play an important role in the pathobiology of MS.

Pathogenic mechanisms of neurodegeneration based on the phenotypic expression of progressive forms of immune-mediated neurologic disease

Considering there are no treatments for progressive forms of multiple sclerosis (MS), a comprehensive understanding of the role of neurodegeneration in the pathogenesis of MS should lead to novel therapeutic strategies to treat it. Many studies have implicated viral triggers as a cause of MS, yet no single virus has been exclusively shown to cause MS. Given this, human and animal viral models of MS are used to study its pathogenesis. One example is human T-lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Importantly, HAM/TSP is similar clinically, pathologically, and immunologically to progressive MS. Interestingly, both MS and HAM/TSP patients were found to make antibodies to heterogeneous nuclear ribonucleoprotein (hnRNP) A1, an RNA-binding protein overexpressed in neurons. Anti-hnRNP A1 antibodies reduced neuronal firing and caused neurodegeneration in neuronal cell lines, suggesting the autoantibodies are pathogenic. Further, microarray analyses of neurons exposed to anti-hnRNP A1 antibodies revealed novel pathways of neurodegeneration related to alterations of RNA levels of the spinal paraplegia genes (SPGs). Mutations in SPGs cause hereditary spastic paraparesis, genetic disorders clinically indistinguishable from progressive MS and HAM/TSP. Thus, there is a strong association between involvement of SPGs in neurodegeneration and the clinical phenotype of progressive MS and HAM/TSP patients, who commonly develop spastic paraparesis. Taken together, these data begin to clarify mechanisms of neurodegeneration related to the clinical presentation of patients with chronic immune-mediated neurological disease of the central nervous system, which will give insights into the design of novel therapies to treat these neurological diseases.

Environmental factors and their regulation of immunity in multiple sclerosis

Epidemiological and clinical studies have shown that environmental factors such as infections, smoking and vitamin D are associated with the risk of developing multiple sclerosis (MS). Some of these factors also play a role in the MS disease course. We are currently beginning to understand how environmental factors may impact immune function in MS on a cellular and molecular level. Here we review epidemiological, clinical and basic immunological studies on the environmental factors, viral and parasitic infections, smoking, and vitamin D and relate epidemiological findings with their likely pathophysiology in MS.

Autoinflammatory grey matter lesions in humans: cortical encephalitis, clinical disorders, experimental models

PURPOSE OF REVIEW

In recent years, evidence has accumulated that grey matter abnormalities are common in many inflammatory central nervous system (CNS) disorders, such as multiple sclerosis (MS), which is by far the most frequent autoimmune-mediated CNS disease.

RECENT FINDINGS

A recent study described comprehensively the pathology of grey matter lesions in early MS. In this study, cortical demyelination together with inflammation was frequently observed in early MS cases. This study and others serve as a basis for a model of the development of cortical MS lesions in which several consecutive events may be involved. After the activation of T cells, which may open the blood-brain barrier, the humoral immune system may mediate the inflammatory process. The inflammation may become chronic through the involvement of activated glial cells and the persistence of immune cells in the meninges.Apart from MS, other grey matter CNS disorders exist in which antibodies against neuronal structures contribute to pathophysiological events such as in limbic encephalitis. Humoral and adaptive immunity mediates the pathophysiology of Rasmussen encephalitis.

SUMMARY

This review focuses on the difference between inflammatory grey matter and white matter lesions. New insights into inflammatory grey matter lesions in MS and other CNS inflammatory processes such as limbic encephalitis are discussed.

Activated B cells in the granulomas of nonhuman primates infected with Mycobacterium tuberculosis

In an attempt to contain Mycobacterium tuberculosis, host immune cells form a granuloma as a physical and immunological barrier. To date, the contribution of humoral immunity, including antibodies and specific functions of B cells, to M. tuberculosis infection in humans remains largely unknown. Recent studies in mice show that humoral immunity can alter M. tuberculosis infection outcomes. M. tuberculosis infection in cynomolgus macaques recapitulates essentially all aspects of human tuberculosis. As a first step toward understanding the importance of humoral immunity to control of M. tuberculosis infection in primates, we characterized the B-cell and plasma-cell populations in infected animals and found that B cells are present primarily in clusters within the granuloma. The B-cell clusters are in close proximity to peripheral node addressin-positive cells and contain cells positive for Ki-67, a proliferation marker. Granuloma B cells also express CXCR5 and have elevated HLA-DR expression. Tissues containing M. tuberculosis bacilli had higher levels of M. tuberculosis-specific IgG, compared with uninvolved tissue from the same monkeys. Plasma cells detected within the granuloma produced mycobacteria-specific antibodies. Together, these data demonstrate that B cells are present and actively secreting antibodies specific for M. tuberculosis antigens at the site of infection, including lung granulomas and thoracic lymph nodes. These antibodies likely have the capacity to modulate local control of infection in tissues.

Functional identification of pathogenic autoantibody responses in patients with multiple sclerosis

Pathological and clinical studies implicate antibody-dependent mechanisms in the immunopathogenesis of multiple sclerosis. We tested this hypothesis directly by investigating the ability of patient-derived immunoglobulins to mediate demyelination and axonal injury in vitro. Using a myelinating culture system, we developed a sensitive and reproducible bioassay to detect and quantify these effects and applied this to investigate the pathogenic potential of immunoglobulin G preparations obtained from patients with multiple sclerosis (n = 37), other neurological diseases (n = 10) and healthy control donors (n = 13). This identified complement-dependent demyelinating immunoglobulin G responses in approximately 30% of patients with multiple sclerosis, which in two cases was accompanied by significant complement-dependent antibody mediated axonal loss. No pathogenic immunoglobulin G responses were detected in patients with other neurological disease or healthy controls, indicating that the presence of these demyelinating/axopathic autoantibodies is specific for a subset of patients with multiple sclerosis. Immunofluorescence microscopy revealed immunoglobulin G preparations with demyelinating activity contained antibodies that specifically decorated the surface of myelinating oligodendrocytes and their contiguous myelin sheaths. No other binding was observed indicating that the response is restricted to autoantigens expressed by terminally differentiated myelinating oligodendrocytes. In conclusion, our study identifies axopathic and/or demyelinating autoantibody responses in a subset of patients with multiple sclerosis. This observation underlines the mechanistic heterogeneity of multiple sclerosis and provides a rational explanation why some patients benefit from antibody depleting treatments.

Anti-NMDA receptor encephalitis. The disorder, the diagnosis and the immunobiology

Anti-NMDAR encephalitis is a newly characterized syndrome with a progressive, predictable clinical course and the possibility of effective treatment. Accurate and timely diagnosis is critical to selection and implementation of treatments, and optimal patient outcomes. Outcomes are improved with early diagnosis via indirect immunofluorescence or cell-based assays, and the rapid and appropriate administration of immunosuppressant and anti-psychotic therapies. Three possible scenarios accounting for the immunopathogenesis of anti-NMDAR encephalitis are presented, with the most probable one being that of paraneoplastic autoimmunity. Future efforts in this disorder should focus on elucidating the mechanisms that contribute to initiation of this antibody response, as well as exploring the role of tumors, infectious triggers and immune-reactivation. Finally, accessible tools need to be developed that allow for reliable identification of specific antibody markers against synaptic proteins.

The perfect crime? CCSVI not leaving a trace in MS

BACKGROUND

Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease of the central nervous system, believed to be triggered by an autoimmune reaction to myelin. Recently, a fundamentally different pathomechanism termed 'chronic cerebrospinal venous insufficiency' (CCSVI) was proposed, provoking significant attention in the media and scientific community.

METHODS

Twenty MS patients (mean age 42.2 ± 13.3 years; median Extended Disability Status Scale 3.0, range 0-6.5) were compared with 20 healthy controls. Extra- and intracranial venous flow direction was assessed by colour-coded duplex sonography, and extracranial venous cross-sectional area (VCSA) of the internal jugular and vertebral veins (IJV/VV) was measured in B-mode to assess the five previously proposed CCSVI criteria. IJV-VCSA ≤ 0.3 cm(2) indicated 'stenosis,' and IJV-VCSA decrease from supine to upright position 'reverted postural control.' The sonographer, data analyser and statistician were blinded to the patient/control status of the participants.

RESULTS

No participant showed retrograde flow of cervical or intracranial veins. IJV-VCSA ≤ 0.3 cm(2) was found in 13 MS patients versus 16 controls (p=0.48). A decrease in IJV-VCSA from supine to upright position was observed in all participants, but this denotes a physiological finding. No MS patient and one control had undetectable IJV flow despite deep inspiration (p=0.49). Only one healthy control and no MS patients fulfilled at least two criteria for CCSVI.

CONCLUSIONS

This triple-blinded extra- and transcranial duplex sonographic assessment of cervical and cerebral veins does not provide supportive evidence for the presence of CCSVI in MS patients. The findings cast serious doubt on the concept of CCSVI in MS.

γδ T cells and multiple sclerosis: Friends, foes, or both?

Multiple sclerosis (MS) is a debilitating CNS disease characterized by demyelination and neuro-axonal loss. Though the exact etiology is still unknown, accumulated evidence points to the immune system being involved in the MS disease-process. Both ill-fated adaptive and innate immune responses can potentially contribute to the etiopathogenesis. We have been interested in deciphering how innate immunity might be involved; in particular, the role of γδ T cells. In this review, we discuss the current understanding about γδ T cells and describe the evidence implicating them in myelin injury, neurotoxicity, and immunoregulation in the development of MS.