The evidence for a role of B cells in multiple sclerosis

Extensive grey matter pathology in the cerebellum in multiple sclerosis is linked to inflammation in the subarachnoid space

AIMS

Multiple sclerosis (MS) is a progressive inflammatory neurological disease affecting myelin, neurons and glia. Demyelination and neurodegeneration of cortical grey matter contribute to a more severe disease, and inflammation of the forebrain meninges associates with pathology of the underlying neocortical grey matter, particularly in deep sulci. We assessed the extent of meningeal inflammation of the cerebellum, another structure with a deeply folded anatomy, to better understand the association between subarachnoid inflammation and grey matter pathology in progressive MS.

METHODS

We examined demyelinating and neuronal pathology in the context of meningeal inflammation in cerebellar tissue blocks from a cohort of 27 progressive MS cases previously characterized on the basis of the absence/presence of lymphoid-like aggregates in the forebrain meninges, in comparison with 11 non-neurological controls.

RESULTS

Demyelination and meningeal inflammation of the cerebellum was greatest in those cases previously characterized as harbouring lymphoid-like structures in the forebrain regions. Meningeal inflammation was mild to moderate in cerebellar tissue blocks, and no lymphoid-like structures were seen. Quantification of meningeal macrophages, CD4+, CD8+ T lymphocytes, B cells and plasma cells revealed that the density of meningeal macrophages associated with microglial activation in the grey matter, and the extent of grey matter demyelination correlated with the density of macrophages and plasma cells in the overlying meninges, and activated microglia of the parenchyma.

CONCLUSIONS

These data suggest that chronic inflammation is widespread throughout the subarachnoid space and contributes to a more severe subpial demyelinating pathology in the cerebellum.

Natalizumab analogon therapy is effective in a B cell-dependent multiple sclerosis model

AIMS

Natalizumab is a humanized monoclonal antibody specific for CD49d receptors of integrins. It inhibits the entry of inflammatory cells into the central nervous system and is approved for the treatment of relapsing-remitting multiple sclerosis (MS). Several lines of evidence indicate an involvement of B cells and plasma cells in MS pathogenesis. However, treatment with the natalizumab analogon PS/2 immunoglobulin G (IgG) has so far only been investigated in T cell-mediated animal models of MS. Due to the importance of B lineage cells in the pathogenesis of MS, the objective of the present study has thus been to analyse the effects of PS/2 IgG in a mouse model of MS with T and B cell cooperation (OSE mice).

METHODS

OSE mice were treated with the natalizumab analogon PS/2 IgG either at disease onset or after peak of disease. Treatment was also performed with PS/2 F(ab')2 fragments.

RESULTS

PS/2 IgG treatment improved the clinical outcome and decreased spinal cord demyelination and immune cell infiltration if given early in the disease course. Treatment increased blood leukocytes and resulted in a partial internalization of CD49d in T and B cells. The therapeutic effects of PS/2 IgG injections were independent of the Fc fragment as F(ab')2 injections were equally beneficial. In contrast, PS/2 IgG was not effective when given late in the disease course.

CONCLUSIONS

Results indicate that natalizumab may also be beneficial in MS with B cell-driven immunopathogenesis.

Involvement of the janus kinase/signal transducer and activator of transcription signaling pathway in multiple sclerosis and the animal model of experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) and its animal model of experimental autoimmune encephalomyelitis (EAE) are characterized by focal inflammatory infiltrates into the central nervous system, demyelinating lesions, axonal damage, and abundant production of cytokines that activate immune cells and damage neurons and oligodendrocytes, including interleukin-12 (IL-12), IL-6, IL-17, IL-21, IL-23, granulocyte macrophage-colony stimulating factor, and interferon-gamma. The Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signaling pathway mediates the biological activities of these cytokines and is essential for the development and regulation of immune responses. Dysregulation of the JAK/STAT pathway contributes to numerous autoimmune diseases, including MS/EAE. The JAK/STAT pathway is aberrantly activated in MS/EAE because of excessive production of cytokines, loss of expression of negative regulators such as suppressors of cytokine signaling proteins, and significant enrichment of genes encoding components of the JAK/STAT pathway, including STAT3. Specific JAK/STAT inhibitors have been used in numerous preclinical models of MS and demonstrate beneficial effects on the clinical course of disease and attenuation of innate and adaptive immune responses. In addition, other drugs such as statins, glatiramer acetate, laquinimod, and fumarates have beneficial effects that involve inhibition of the JAK/STAT pathway. We conclude by discussing the feasibility of the JAK/STAT pathway as a target for neuroinflammatory diseases.

Conversion from clinically isolated syndrome to multiple sclerosis: A large multicentre study

Background and objective:

We explored which clinical and biochemical variables predict conversion from clinically isolated syndrome (CIS) to clinically definite multiple sclerosis (CDMS) in a large international cohort.

Methods:

Thirty-three centres provided serum samples from 1047 CIS cases with at least two years’ follow-up. Age, sex, clinical presentation, T2-hyperintense lesions, cerebrospinal fluid (CSF) oligoclonal bands (OCBs), CSF IgG index, CSF cell count, serum 25-hydroxyvitamin D3 (25-OH-D), cotinine and IgG titres against Epstein-Barr nuclear antigen 1 (EBNA-1) and cytomegalovirus were tested for association with risk of CDMS.

Results:

At median follow-up of 4.31 years, 623 CIS cases converted to CDMS. Predictors of conversion in multivariable analyses were OCB (HR = 2.18, 95% CI = 1.71–2.77, p < 0.001), number of T2 lesions (two to nine lesions vs 0/1 lesions: HR = 1.97, 95% CI = 1.52–2.55, p < 0.001; >9 lesions vs 0/1 lesions: HR = 2.74, 95% CI = 2.04–3.68, p < 0.001) and age at CIS (HR per year inversely increase = 0.98, 95% CI = 0.98–0.99, p < 0.001). Lower 25-OH-D levels were associated with CDMS in univariable analysis, but this was attenuated in the multivariable model. OCB positivity was associated with higher EBNA-1 IgG titres.

Conclusions:

We validated MRI lesion load, OCB and age at CIS as the strongest independent predictors of conversion to CDMS in this multicentre setting. A role for vitamin D is suggested but requires further investigation.

[A study of the relation between the sCD40-sCD40L system and the course of multiple sclerosis]

AIM

To determine the relationship between the level of soluble CD40 and CD40L (sCD40, sCD40L) and key characteristics of the course of multiple sclerosis.

MATERIAL AND METHODS

A comparative cross-sectional study covered 80 patients with multiple sclerosis diagnosed according to 2005 McDonald criteria. Enzyme immunoassay method was applied to measure the concentration of sCD40 and sCD40L in venous blood serum.

RESULTS

No significant changes in sCDL or sСD levels were found during acute MS periods in comparison to remission periods. The positive correlation between the frequency of exacerbations and the level of sCDL was shown.

CONCLUSION

No evidence for the association between indexes of activity of the sCD40-sCD40L system in blood and both exacerbation of MS, severity and rate of neurological impairment in this disease was demonstrated.

Cell-based modulation of autoimmune responses in multiple sclerosis and experimental autoimmmune encephalomyelitis: therapeutic implications

Multiple sclerosis (MS) is a prototypic autoimmune inflammatory disorder of the central nervous system (CNS). MS pathogenesis is a complex phenomenon that is influenced by genetic and environmental factors that lead to the dysregulation of immune homeostasis and tolerance. It has been shown that pathogenic T lymphocyte subsets, such as T helper 1 (Th1) and Th17 cells, play a crucial role in the autoimmune cascade influencing disease initiation, progression and subsequent tissue damage during MS. On the other hand, several mechanisms have been described in both patients and animal models of MS with the potential to modulate myelin-specific autoimmune responses and to facilitate amelioration of disease pathology. To this end, regulatory T cells (Tregs) are considered to be a powerful cell subset not only in the maintenance of homeostasis but also in the re-establishment of tolerance. Along these lines, other cell subsets such as dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), γδ T cells and natural killer (NK) cells have been shown to regulate the autoimmune response in the CNS under certain circumstances. This review will attempt to summarize the relevant knowledge of the regulatory mechanisms exerted by immune cells in MS that could hold the promise for the design of novel therapeutic strategies.

Retinoic acid enhances the levels of IL-10 in TLR-stimulated B cells from patients with relapsing-remitting multiple sclerosis

We have explored the beneficial effects of retinoic acid (RA) on B cells from multiple sclerosis (MS) patients. When co-stimulated via the toll-like receptors (TLRs) TLR9 and RP105, MS B cells secreted less of the anti-inflammatory cytokine interleukin 10 (IL-10) compared to B cells from healthy controls. Importantly, RA enhanced the secretion of IL-10 by MS-derived B cells without affecting the levels of the pro-inflammatory cytokine TNF-α. RA revealed the same ability to induce IL-10 as did interferon-β-1b (IFN-β-1b), and B-cells from patients treated with glatiramer acetate or IFN-β-1b still displayed the beneficial effects of RA on the IL-10/TNF-α ratio.

Human interferon regulatory factor 5 homologous epitopes of Epstein-Barr virus and Mycobacterium avium subsp. paratuberculosis induce a specific humoral and cellular immune response in multiple sclerosis patients

BACKGROUND

A large number of reports indicate the association of Epstein-Barr virus (EBV), and Mycobacterium avium subsp. paratuberculosis (MAP) with multiple sclerosis (MS).

OBJECTIVE

To gain a better understanding of the role of these two pathogens, we investigated the host response induced by selected antigenic peptides.

METHODS

We examined both humoral and cell-mediated responses against peptides deriving from EBV tegument protein BOLF1, the MAP_4027 and the human interferon regulatory factor 5 (IRF5424-434) homolog in several MS patients and healthy controls (HCs).

RESULTS

Antibodies against these peptides were highly prevalent in MS patients compared to HCs. Concerning MS patients, BOLF1305-320, MAP_402718-32 and IRF5424-434 peptides were able to induce mainly Th1-related cytokines secretion, whereas Th2-related cytokines were down-regulated. Flow cytometry analyses performed on a subset of MS patients highlighted that these peptides were capable of inducing the release of pro-inflammatory cytokines: IFN-γ and TNF-α by CD4(+) and CD8(+) T lymphocytes, and IL-6 and TNF-α by CD14(+) monocyte cells.

CONCLUSION

Our data demonstrated that both EBV and MAP epitopes elicit a consistent humoral response in MS patients compared to HCs, and that the aforementioned peptides are able to induce a T-cell-mediated response that is MS correlated.

A new risk variant for multiple sclerosis at the immunoglobulin heavy chain locus associates with intrathecal IgG, IgM index and oligoclonal bands

Background:

Recent findings have shown a correlation between the intrathecal IgG index and variants at the immunoglobulin heavy chain (IGHC) locus in patients with multiple sclerosis (MS).

Objectives:

The objective of this paper is to analyse the association of the locus with MS susceptibility and its relationship with intrathecal immunoglobulin (Ig) parameters.

Methods:

We genotyped the rs11621145 variant, located at the IGHC locus, in 2726 patients with MS and 2133 healthy controls. Associations of intrathecal IgG and IgM indexes with rs11621145 were analysed by linear regression analysis in 538 MS patients.

Results:

We found that rs11621145 showed statistically significant evidence for association with susceptibility to MS (odds ratio = 0.69, p = 1.053E-09), though validation of this result in additional cohorts would be desirable. We confirmed the association between the IgG index and the rs11621145 ( p = 6.85E-07, Beta = 0.207). Furthermore, rs11621145 was inversely correlated with IgM index ( p = 7.24E-04, Beta = -0.277), and therefore marks a decreased likelihood of presenting IgM oligoclonal bands (odds ratio = 0.38, p = 2.35E-06).

Conclusions:

Our results suggest that the polymorphism of the IGHC locus could be altering the switching of the Ig isotype in B cells and it may be interfering with T-dependent and T-independent antibody responses.

Meningeal inflammation and demyelination in a patient clinically diagnosed with acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS) are both CNS inflammatory demyelinating diseases with overlapping clinical features. A case is reported of a 51-year-old female who presented with headache, progressive aphasia and hemiparesis without preceding infection or vaccination. Brain MRI revealed multiple, often confluent, subcortical white matter lesions without enhancement, affecting predominantly the left cerebral hemisphere. CSF examination failed to reveal oligoclonal bands. Brain biopsy revealed both pathological features of ADEM and findings are consistent with the early stage of MS, including meningeal B and T lymphocytic infiltration, perivenular demyelination, subpial demyelination and discrete confluent plaque-like foci of demyelination. Steroid treatment resulted in remarkable clinical and radiological improvement and there has been no recurrence in six years of follow-up. This case highlights the difficulties in differentiating between ADEM and the first attack of MS and further suggests that ADEM and the early stage of MS, and its tumefactive variant, may have a common underlying pathologic mechanism, which may have a therapeutic implication in treating these diseases.

Endothelin-1 overexpression exacerbate experimental allergic encephalomyelitis

BACKGROUND

Multiple sclerosis (MS) is a CNS inflammatory demyelinating disorder. T helper 1 (Th1) and T helper 17 (Th17) cells are important in MS immunopathogenesis. Level of endothelin-1 (ET-1), a potent vasoconstrictor, is increased in sera of MS patients. We studied the role of ET-1 in experimental allergic encephalomyelitis (EAE), a MS animal model.

METHODS

EAE is induced in transgenic mice overexpressing endothelial ET-1 (TET-1), transgenic mice overexpressing astrocytic ET-1 (GET-1) and non-transgenic (NTg) mice by immunization with myelin oligodendrocyte glycoprotein (MOG)35-55 peptide. EAE scores, spinal cord histology, serum proinflammatory cytokines levels, and proinflammatory cytokines production from splenocytes of ET-1 transgenic and NTg mice with EAE were studied.

RESULTS

ET-1 transgenic mice developed more severe EAE than NTg with increased inflammation and demyelination in spinal cord. The mean maximum EAE scores for GET-1, TET-1 and NTg mice with EAE were 4.84, 4.31 and 4.05 respectively (p<0.05). Serum levels of IL-6, IL-17A, IFN-γ and TNF-α were higher in ET-1 transgenic than NTg mice with EAE (p<0.05) while serum IL-4 levels were similar. mRNA levels of IL-6, IL-17A, IFN-γ and TNF-α from cultured splenocytes were higher in ET-1-transgenic than NTg mice with EAE (p<0.05) while IL-4 mRNA levels were similar. Consistently, levels of IL-6, IL-17A, IFN-γ and TNF-α in culture media of splenocytes were higher in ET-1 transgenic than NTg mice with EAE (p<0.05) while IL-4 levels were similar.

CONCLUSIONS

Mice with endothelial or astrocytic ET-1 overexpression developed more severe EAE with increased splenic lymphocyte production of Th1 and Th17 proinflammatory cytokines.

Higher incidence of Epstein-Barr virus-induced lymphocyte transformation in multiple sclerosis

OBJECTIVES

Epstein-Barr virus (EBV) infection is associated with multiple sclerosis (MS), and EBV may transform lymphoblastoid cell lines more frequently in MS patients than controls, but it is not clear whether this reflects a higher viral load or an enhanced ability to reactivate EBV.

MATERIAL AND METHODS

MS patients and controls were examined for their B-cell subsets and during 16 weeks for spontaneous lymphocyte transforming events.

RESULTS

MS patients had normal distribution of B-cell subsets, but a significantly higher incidence of B-cell transforming events, which occurred with kinetics similar to controls.

CONCLUSIONS

The higher incidence suggests an increased frequency of latent EBV-infected B cells in MS.

HHV-6-positivity in diseases with demyelination

BACKGROUND

The triggering agent of multiple sclerosis is still unknown and many viruses, including human herpesvirus-6 (HHV-6), are under suspicion. In earlier study we found patients who had HHV-6 reactive OCBs in their CSF. We wanted to investigate whether HHV-6 has an active role in diseases with demyelination.

OBJECTIVE

To analyze the HHV-6-reactive cases in detail and investigate the possible independent role of HHV-6 in the development of central nervous system involvements with demyelination.

STUDY DESIGN

We studied serum and CSF samples that were collected over a period of one year, from all patients who had oligoclonal bands (OCB) in cerebrospinal fluid (CSF) and were examined in the Department of Neurology, University Central Hospital of Helsinki, Finland. Clinical evaluation was accomplished blinded of HHV-6 analysis and follow-up time was two years. All patients underwent MRI of the head and clinically indicated CSF analysis.

RESULTS

The 17 patients with HHV-6-reactive OCBs were significantly younger and had significantly more IgG-OCBs in comparison to patients without HHV-6-reactive OCBs. Initial diagnoses in patients with HHV-6-reactive OCBs remained the same during the follow-up time.

CONCLUSION

Patients with HHV-6-positive OCBs appear to form a separable group. In progressive neurological diseases HHV-6 may have a role in long-term infection with demyelination.

Gene expression profiling of the response to interferon beta in Epstein-Barr-transformed and primary B cells of patients with multiple sclerosis

The effects of interferon-beta (IFN-β), one of the key immunotherapies used in multiple sclerosis (MS), on peripheral blood leukocytes and T cells have been extensively studied. B cells are a less abundant leukocyte type, and accordingly less is known about the B cell-specific response to IFN-β. To identify gene expression changes and pathways induced by IFN-β in B cells, we studied the in vitro response of human Epstein Barr-transformed B cells (lymphoblast cell lines-LCLs), and validated our results in primary B cells. LCLs were derived from an MS patient repository. Whole genome expression analysis identified 115 genes that were more than two-fold differentially up-regulated following IFN-β exposure, with over 50 previously unrecognized as IFN-β response genes. Pathways analysis demonstrated that IFN-β affected LCLs in a similar manner to other cell types by activating known IFN-β canonical pathways. Additionally, IFN-β increased the expression of innate immune response genes, while down-regulating many B cell receptor pathway genes and genes involved in adaptive immune responses. Novel response genes identified herein, NEXN, DDX60L, IGFBP4, and HAPLN3, B cell receptor pathway genes, CD79B and SYK, and lymphocyte activation genes, LAG3 and IL27RA, were validated as IFN-β response genes in primary B cells. In this study new IFN-β response genes were identified in B cells, with possible implications to B cell-specific functions. The study's results emphasize the applicability of LCLs for studies of human B cell drug response. The usage of LCLs from patient-based repositories may facilitate future studies of drug response in MS and other immune-mediated disorders with a B cell component.

Semaforin Sema4D in the immune system in multiple sclerosis

The expression of class IV semaforin Sema4D and its CD72 receptor on lymphocytes was studied in patients with multiple sclerosis. The disease was associated with an increase in Sema4D level on intact T lymphocytes and with its more intense shedding from the membrane of activated cell. Multiple sclerosis was also associated with a decrease of CD72 receptor expression by B lymphocytes. Possible contribution of Sema4D to the disease development via the direct effects in the CNS and the immunomodulatory effect, specifically, B cell activity regulation, was discussed.

High frequency of antiphospholipid antibodies in relapse of multiple sclerosis: a possible indicator of inflammatory-thrombotic processes

The exact prevalence and pathogenic role of antiphospholipid antibodies (aPL) in multiple sclerosis (MS) remain unclear. This observational laboratory-blinded study evaluated the rate of aPL positivity in healthy controls and MS patients in different disease phases to recognize their frequency and possible pathogenic meaning. Reactivity for anti-cardiolipin, anti-β2 glycoprotein I, anti-prothrombin, anti-annexin V (IgG and IgM) was studied by enzyme immunoassays in 60 healthy controls and 100 consecutive MS patients [58 relapsing-remitting (RR) patients in remission, 26 RR patients in relapse, and 16 secondary progressive patients]. The overall rate of positivity for at least one aPL was significantly higher in MS patients compared to controls (32 % vs. 7 %, respectively, p < 0.0001), and in relapsing phase compared to those remitting or secondary progressive (53.8, 20.7 and 37.5 %, respectively, p = 0.002). In the single aPL analysis, the rate of positivity was significantly higher in MS patients compared to controls for anti-prothrombin IgM (7 % vs. 0, p = 0.05), and in relapsing phase compared to remitting and secondary progressive phases for anti-β2 glycoprotein I IgM (26.9, 1.7, 6.3 %, respectively, p < 0.0001), anti-prothrombin IgM (15.4, 3.4, 6.3 %, respectively, p = 0.05) and IgG (19.2, 5.2, 0 %, respectively, p = 0.05). We showed a significant aPL increase in MS patients compared to healthy controls, particularly during disease relapse which was also associated with significantly higher values of anti-β2 glycoprotein I and anti-prothrombin. These data suggest that antiphospholipid antibody occurrence in multiple sclerosis could be related to modification of structure and function of proteins involved in the inflammatory-thrombotic processes during disease re-activation.

Transcriptomic profile reveals gender-specific molecular mechanisms driving multiple sclerosis progression

Background

Although the most common clinical presentation of multiple sclerosis (MS) is the so called Relapsing-Remitting MS (RRMS), the molecular mechanisms responsible for its progression are currently unknown. To tackle this problem, a whole-genome gene expression analysis has been performed on RRMS patients.

Results

The comparative analysis of the Affymetrix Human Gene 1.0 ST microarray data from peripheral blood leucocytes obtained from 25 patients in remission and relapse and 25 healthy subjects has revealed 174 genes altered in both remission and relapse, a high proportion of them showing what we have called “mirror pattern”: they are upregulated in remission and downregulated in relapse or vice versa. The coexpression analysis of these genes has shown that they are organized in three female-specific and one male-specific modules.

Conclusions

The interpretation of the modules of the coexpression network suggests that Epstein-Barr virus (EBV) reactivation of B cells happens in MS relapses; however, qPCR expression data of the viral genes supports that hypothesis only in female patients, reinforcing the notion that different molecular processes drive disease progression in females and males. Besides, we propose that the “primed” state showed by neutrophils in women is an endogenous control mechanism triggered to keep EBV reactivation under control through vitamin B12 physiology. Finally, our results also point towards an important sex-specific role of non-coding RNA in MS.

Pertussis toxin modulates microglia and T cell profile to protect experimental autoimmune encephalomyelitis

Pertussis toxin (PTx) has various effects in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). This study was designed to explore the protective effects of PTx of different doses and subunits. EAE model was induced with myelin oligodendrocyte glycoprotein (MOG35-55, 200 ug) plus complete Freund's adjuvant in 6-7 week-old female C57BL/6 mice. PTx reduced clinical deficits of EAE by 91.3%. This reduction in clinical deficits was achieved by attenuating demyelination by 75.5%. Furthermore, PTx reduced the lymphocyte infiltration, deactivated microglia activation and changed T cell profile by increasing T helper (type 1 and 2) and T regulatory cells.

Fingolimod for the treatment of relapsing multiple sclerosis

Fingolimod 0.5 mg (Gilenya(™), Novartis Pharmaceuticals Corporation, FL, USA) is the first once-daily oral therapy approved for relapsing forms of multiple sclerosis (MS) in the USA and for rapidly evolving severe MS or highly active disease despite IFN-β treatment in Europe. An extensive clinical development program has established fingolimod as an effective therapy that reduces relapses by approximately half compared with placebo or intramuscular IFN-β1a. Over 2 years of postmarketing experience in >63,000 MS patients (with >73,000 patient-years of exposure) across the world has contributed to a well-characterized safety profile for fingolimod, and its side effects are manageable through patient monitoring. This article discusses the unique mechanisms of action of fingolimod in the immune and nervous systems, the key data underlying its efficacy and safety profile and perspectives on the role of fingolimod in current and future treatment strategies for MS.

Regulatory B cells, helminths, and multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease affecting the central nervous system. Autoimmunity appears to play a key role in both susceptibility to MS and development of disease, and pathogenesis has been linked to defects in distinct regulatory cell subsets. B cells are known for their capacity to produce antibodies. Recent advances in B cell biology, however, have demonstrated that regulatory B cells, a functional subset of B cells, contribute to tolerance development. Regulatory B cells were originally described in mouse autoimmunity and inflammation models where they dampen inflammation, but have also been found in several helminth infection models. We recently demonstrated that helminth-infected MS patients show a significantly lower clinical and radiological disease activity. Parasite-driven protection was associated with regulatory T cell induction and secretion of suppressive cytokines such as IL-10 and TGF-β. In addition, helminth infections in MS patients induced regulatory B cell populations producing high levels of IL-10, dampening harmful immune responses through a mechanism mediated, at least in part, by the ICOS-B/RP-1 pathway. More importantly, production of IL-10 by B cells in this study was restricted to helminth-infected individuals exclusively.The first part of this chapter will detail the criteria used in this study for selection of helminth-infected MS patients, MS patients without infection, and patients infected with Trypanosoma cruzi. Methods for isolation of peripheral blood CD19(+) cells and in particular for their stimulation with heat-inactivated Staphylococcus aureus Cowan strain, CDw32L cells, and CD40 antibody will also be described in detail. Finally, we will illustrate the procedures used to analyze phenotypic surface markers on these cells and characterize them in terms of IL-4, IL-6, IL-10, TNF-α, lymphotoxin, and TGF-β secretion.

Biomarkers for multiple sclerosis

Magnetic resonance imaging has been shown to be a powerful tool for diagnosing multiple sclerosis (MS) and evaluating surrogate markers of the disease activity. However, biomarkers may provide more accurate information regarding ongoing immune responses leading to demyelination and treatment effects in MS patients. Although serum biomarkers are easily accessible, they do not provide clear-cut results, whereas cerebrospinal fluid (CSF) biomarkers provide unequivocal information, although samples cannot be repeatedly obtained. For diagnosis, the presence of oligoclonal IgG bands remains important. In addition, measuring the levels of adhesion molecules, matrix metalloproteinase-9 and complement regulator factor H in the serum and evaluating the proportion of Th1/Th2 cells in the blood may be clinically feasible for monitoring the disease activity. In CSF samples, increased IL-8, IL-12, IL-17, CCL3, CCL5 and CXCL10 levels indicate active disease, and the flow cytometry findings of CSF cells can be used to detect increases in Th1 and CD4(+)CD25(+) cells during relapse. Biomarkers closely linked to the disease activity may be informative of the pathogenesis of MS, while those associated with tissue damage or repair may be targets of new treatment strategies. Establishing the latter will be a primary point of research in the near future.

Demyelination in multiple sclerosis

This review, focused on demyelination in multiple sclerosis, is divided in two parts. The first part addresses the many and not exclusive mechanisms leading to demyelination in the central nervous system. Although the hypothesis that a primary oligodendrocyte or myelin injury induces a secondary immune response in the central nervous system is still a matter of debate, most recent advances underline the influence of a primary immune response against myelin antigen(s), with a diversity of potential targets. Whereas multiple sclerosis was long considered as a T cell-mediated disease, the role of B lymphocytes is now increasingly recognized, and the influence of antibodies on tissue damage actively investigated. The second part of the review describes the axonal consequences of demyelination. Segmental demyelination results in conduction block or slowing of conduction through adaptative responses, notably related to modifications in the distribution of voltage gated sodium channels along the denuded axon. If demyelination persists, these changes, as well as the loss of trophic and metabolic support, will lead to irreversible axonal damage and loss. In this respect, favouring early myelin repair, during a window of time when axonal damage is still reversible, might pave the way for neuroprotection.

Increased B cell and cytotoxic NK cell proportions and increased T cell responsiveness in blood of natalizumab-treated multiple sclerosis patients

Background

Changes in the blood lymphocyte composition probably both mediate and reflect the effects of natalizumab treatment in multiple sclerosis, with implications for treatment benefits and risks.

Methods

A broad panel of markers for lymphocyte populations, including states of activation and co-stimulation, as well as functional T cell responses to recall antigens and mitogens, were assessed by flow cytometry in 40 patients with relapsing multiple sclerosis before and after one-year natalizumab treatment.

Results

Absolute numbers of all major lymphocyte populations increased after treatment, most markedly for NK and B cells. The fraction of both memory and presumed regulatory B cell subsets increased, as did CD3^-CD56^dim cytotoxic NK cells, whereas CD3^-CD56^bright regulatory NK cells decreased. The increase in cell numbers was further associated with a restored T cell responsiveness to recall antigens and mitogens in functional assays.

Conclusions

Our data confirms that natalizumab treatment increases the number of lymphocytes in blood, likely mirroring the expression of VLA-4 being highest on NK and B cells. This finding supports reduction of lymphocyte extravasation as a main mode of action, although the differential effects on subpopulation composition suggests that cell-signalling may also be affected. The systemic increase in T cell responsiveness reflects the increase in numbers, and while augmenting anti-infectious responses systemically, localized responses may become correspondingly decreased.

Activation of MSRV-type endogenous retroviruses during infectious mononucleosis and Epstein-Barr virus latency: the missing link with multiple sclerosis?

The etiology of multiple sclerosis (MS) is still unclear. The immuno-pathogenic phenomena leading to neurodegeneration are thought to be triggered by environmental (viral?) factors operating on predisposing genetic backgrounds. Among the proposed co-factors are the Epstein Barr virus (EBV), and the potentially neuropathogenic HERV-W/MSRV/Syncytin-1 endogenous retroviruses. The ascertained links between EBV and MS are history of late primary infection, possibly leading to infectious mononucleosis (IM), and high titers of pre-onset IgG against EBV nuclear antigens (anti-EBNA IgG). During MS, there is no evidence of MS-specific EBV expression, while a continuous expression of HERV-Ws occurs, paralleling disease behaviour. We found repeatedly extracellular HERV-W/MSRV and MSRV-specific mRNA sequences in MS patients (in blood, spinal fluid, and brain samples), and MRSV presence/load strikingly paralleled MS stages and active/remission phases. Aim of the study was to verify whether HERV-W might be activated in vivo, in hospitalized young adults with IM symptoms, that were analyzed with respect to expression of HERV-W/MSRV transcripts and proteins. Healthy controls were either EBV-negative or latently EBV-infected with/without high titers of anti-EBNA-1 IgG. The results show that activation of HERV-W/MSRV occurs in blood mononuclear cells of IM patients (2Log10 increase of MSRV-type env mRNA accumulation with respect to EBV-negative controls). When healthy controls are stratified for previous EBV infection (high and low, or no anti-EBNA-1 IgG titers), a direct correlation occurs with MSRV mRNA accumulation. Flow cytometry data show increased percentages of cells exposing surface HERV-Wenv protein, that occur differently in specific cell subsets, and in acute disease and past infection. Thus, the data indicate that the two main links between EBV and MS (IM and high anti-EBNA-1-IgG titers) are paralleled by activation of the potentially neuropathogenic HERV-W/MSRV. These novel findings suggest HERV-W/MSRV activation as the missing link between EBV and MS, and may open new avenues of intervention.

The potential role of T cell migration and chemotaxis as targets of glucocorticoids in multiple sclerosis and experimental autoimmune encephalomyelitis

Glucocorticoids (GCs) are the most commonly prescribed drugs for the treatment of acute disease bouts in multiple sclerosis (MS) patients. While T lymphocytes were shown to be essential targets of GC therapy, at least in animal models of MS, the mechanisms by which GCs modulate T cell function are less clear. Until now, apoptosis induction and repression of pro-inflammatory cytokines in T cells have been considered the most critical mechanisms in ameliorating disease symptoms. However, this notion is being challenged by increasing evidence that the control of T cell migration and chemotaxis by GCs might be even more important for the treatment of neuroinflammatory diseases. In this review we aim to provide an overview of how GCs impact the morphological alterations that T cells undergo during activation and migration as well as the influences that GCs have on the directed movement of T cells under the influence of chemokines. A deeper understanding of these processes should not only help to advance our understanding of how GCs exert their beneficial effects in MS therapy but may reveal future strategies to intervene in the pathogenesis of neuroinflammatory diseases.

The effects of teriflunomide on lymphocyte subpopulations in human peripheral blood mononuclear cells in vitro

Teriflunomide is an inhibitor of dihydro-orotate dehydrogenase (DHODH), and is hypothesized to ameliorate multiple sclerosis by reducing proliferation of stimulated lymphocytes. We investigated teriflunomide's effects on proliferation, activation, survival, and function of stimulated human peripheral blood mononuclear cell subsets in vitro. Teriflunomide had little/no impact on lymphocyte activation but exerted significant dose-dependent inhibition of T- and B-cell proliferation, which was uridine-reversible (DHODH-dependent). Viability analyses showed no teriflunomide-associated cytotoxicity. Teriflunomide significantly decreased release of several pro-inflammatory cytokines from activated monocytes in a DHODH-independent fashion. In conclusion, teriflunomide acts on multiple immune cell types and processes via DHODH-dependent and independent mechanisms.

MicroRNAs and multiple sclerosis: from physiopathology toward therapy

INTRODUCTION

MicroRNAs (miRNAs) are an emerging group of small noncoding RNAs that regulate gene expression posttranscriptionally, by targeting messenger RNAs (mRNAs) for translational repression or degradation. They have roles in multiple facets of immunity, from regulation of cell development to activation and function in immune responses. Recent evidence underlines an involvement of miRNAs in the pathogenesis of autoimmune diseases as well as multiple sclerosis (MS).

AREAS COVERED

In this review, the current knowledge of miRNA biogenesis, diverse roles of miRNAs in different cells that could be involved in the process of the disease, and their potential therapeutic applications are summarized. The authors searched MEDLINE and Science direct databases.

EXPERT OPINION

The miRNAs in central nervous system lesions and peripheral blood are potential biomarkers for diagnostic and prognostic use. Also, miRNA mimics, small-molecule inhibitors of specific miRNAs, and antisense oligonucleotides could be therapeutic weapons that facilitate us to combat the disease.

Treating multiple sclerosis with monoclonal antibodies: a 2013 update

The third part of this in-depth review series on the treatment of multiple sclerosis (MS) with monoclonal antibodies covers the years 2010-2012. The natalizumab section gives a progressive multifocal leukoencephalopathy update, focusing on clinically relevant aspects. Furthermore, it outlines problems around natalizumab cessation and current evidence on therapeutic strategies thereafter. Finally, it reviews evidence on Janus-faced modes of natalizumab action besides anti-inflammatory effects, including proinflammatory effects. The section on alemtuzumab critically analyzes recent Phase III results and discusses which patients might be best suited for alemtuzumab treatment, and reviews the long-term immunological impact of this anti-CD52 antibody. The daclizumab section critically summarizes results from the Phase IIb SELECT/SELECTION trial and introduces the Phase III program. The section on anti-CD20 antibodies reviews Phase II results on ocrelizumab and ofatumumab, and discusses current perspectives of these antibodies for MS therapy. Promising recent Phase II results on the anti-IL-17A antibody secukinumab (AIN457) are outlined and a short update on tabalumab (LY2127399) is given. Other highlighted antibodies currently being tested in MS patients include GNbAC1, BIIB033, MOR103 and MEDI-551. Finally, the authors give an update on the role monoclonal antibodies could play in the therapeutic armamentarium for MS in the medium term.

Interactions of serum cholesterol with anti-herpesvirus responses affect disease progression in clinically isolated syndromes

OBJECTIVES

To investigate whether anti-herpesvirus antibodies are associated with serum cholesterol profiles in clinically isolated syndromes (CIS).

METHODS

Pre-treatment serum samples from 118 high-risk CIS patients were analyzed for IgG antibodies against cytomegalovirus (anti-CMV), Epstein Barr virus (EBV) viral capsid antigen (VCA) and EBV nuclear antigen-1 (EBNA-1). A lipid profile consisting of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) was obtained. Clinical and MRI assessments were obtained at baseline, 6, 12, and 24 months after start of interferon-beta treatment.

RESULTS

The study included 118 CIS patients (77 females, 41 males, 65.3% female; mean age: 28.1±SD 8.1 years). Anti-EBV EBNA-1 antibody levels were associated with LDL-C (p=0.009) and TC (p=0.008) levels. Anti-CMV positivity status was associated with reduced time to relapse (p=0.006) and the greater number of relapses (p=0.009) in patients with high HDL-C. Anti-EBV VCA antibody levels were associated with greater number of new T2 lesions (p=0.002) and with increased brain atrophy (p<0.001) in patients with high LDL-C.

CONCLUSIONS

Our results indicate that higher levels of anti-EBV EBNA-1 antibodies are associated with higher LDL-C and TC levels. Anti-CMV positive individuals have greater disease progression in the presence of higher HDL-C levels. Individuals with higher levels of anti-EBV VCA antibodies have greater progression on MRI measures in the presence of higher LDL-C.

Drugs in clinical development for multiple sclerosis: focusing on anti-CD20 antibodies

INTRODUCTION

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS), traditionally considered to be an autoimmune disease. Despite the standard of care for patients with MS is significantly improved in recent years, there is still room for improvement in terms of effectiveness and also compliance.

AREAS COVERED

The continuous improvements of our understanding of the pathophysiological changes that occur in MS have translated into many novel therapeutic agents at different stages of development. A number of therapies for MS are in advanced development and likely to be available soon. Along with these, we have also seen the appearance of a group of drugs considered together as a consequence of their similar design: the monoclonal antibodies (mAbs). Here, the focus will be on reviewing results that have emerged from a better clarification of MS pathogenesis to clinical trials of different anti-CD20 mAbs.

EXPERT OPINION

The decision to switch established patients from well-known drugs to either new formulations or new agents will be made on balancing efficacy and tolerability of the existing treatments. Safety seems increasingly likely to become a key factor.

Cytometric profiling in various clinical forms of multiple sclerosis with respect to CD21+, CD32+, and CD35+ B and T cells

Background

We aimed to evaluate the frequency of various types of B and T cells expressing CD21, CD32, and CD35 in multiple sclerosis (MS) clinical courses.

Methods

Peripheral blood mononuclear cell from 30 MS patients (17 relapsing remitting [RRMS], six secondary progressive [SPMS], and seven primary progressive MS [PPMS]) and 18 healthy subjects were analyzed. All patients were in acute attack. Healthy controls were matched for age and gender ratio. The frequencies of various subsets of B and T cells were determined using flow cytometry.

Results

The frequency of CD4⁺T cells was lower in MS patients compared to control subjects (41.14 ± 9.45% vs. 46.88 ± 6.98%, respectively, P < 0.05). The CD32⁺ fraction of CD4⁺T cells and the CD21⁺ fraction of CD8⁺T cells were higher in MS patients (2.85 ± 3.72% vs. 1.06 ± 0.62% for CD32⁺CD4⁺T cells, 2.71 ± 1.86% vs. 1.16 ± 0.99% for CD21⁺CD8⁺T cells in MS patients and control subjects, respectively, P < 0.05). After dividing subjects by type of MS course, higher values of these two T cell subsets were found in SPMS patients compared to control subjects (P < 0.05). Further, RRMS patients had lower levels of CD32⁺CD4⁺T cells than SPMS patients and also they had lower levels of CD32⁺CD8⁺T cells than PPMS patients (P < 0.05). However, neither the expression of CD35 on T cells nor the various B cell subsets were statistically different between the compared groups.

Conclusions

Our findings demonstrate that T cell subsets expressing CD21 and CD32 may differ with respect to the presence or clinical forms of MS disease. By contrast, CD35⁺T cells and different subsets of B cells are not altered in various MS clinical courses.

Effects of vitamin D on immune disorders with special regard to asthma, COPD and autoimmune diseases: a short review

This paper reviews the recent data on the role of vitamin D (VD) in the genesis of various immunological disorders. It inhibits immune reactions in general, but it enhances the transcription of 'endogenous antibiotics' such as cathelicidin and defensins. VD inhibits the genesis of both Th1- and Th2-cell mediated diseases. The pleiotropic character VD-induced effects are due to the altered transcription of hundreds of genes. VD supplementation in most related studies reduced the prevalence of asthma. Th1-dependent autoimmune diseases (e.g., multiple sclerosis, Type 1 diabetes, Crohn's disease, rheumatoid arthritis and so on) are also inhibited by VD due to inhibition of antigen presentation, reduced polarization of Th0 cells to Th1 cells and reduced production of cytokines from the latter cells. VD seems to also be a useful adjunct in the prevention of allograft rejection. Last but not least, VD supplementation may be useful in the prevention or adjunct treatment of chronic obstructive pulmonary disease.

Increased thyroid autoimmunity among women with multiple sclerosis in the postpartum setting

Background:

Multiple sclerosis (MS) patients are predisposed to thyroid abnormalities, but the risk for pregnancy-related thyroid pathology among MS patients has not been evaluated.

Objectives:

The objectives of this research are to prospectively evaluate the prevalence of thyroid autoimmunity among MS patients in relation to pregnancy, and to investigate its impact on pregnancy outcome, postpartum depression and fatigue.

Methods:

Forty-six pregnant MS patients underwent repeat testing for serum thyroid antibodies (Abs), clinical evaluation and thyroid hormone measurement. Results were compared to 35 age-matched healthy mothers.

Results:

At six months postpartum 35.3% of MS patients presented elevated levels of thyroid Abs compared to 5.7% of controls, p = 0.01. Mean thyroid Ab concentrations among MS patients were significantly reduced during pregnancy and returned to maximal levels at six months postpartum. The proportion of individuals with postpartum thyroid dysfunction did not differ significantly between MS patients and healthy controls (3.4% vs 2.9%, p = 1.00). Elevated thyroid Ab levels did not increase the risk for adverse pregnancy outcome, fatigue or postpartum depression.

Conclusions:

Considering the tendency of MS mothers to develop thyroid autoimmunity postpartum and in association to treatments, we recommend screening MS patients for thyroid dysfunction (TSH) during early pregnancy and after delivery.

Dynamic cross-regulation of antigen-specific effector and regulatory T cell subpopulations and microglia in brain autoimmunity

Background

Multiple Sclerosis (MS) is considered a T-cell-mediated autoimmune disease with a prototypical oscillatory behavior, as evidenced by the presence of clinical relapses. Understanding the dynamics of immune cells governing the course of MS, therefore, has many implications for immunotherapy. Here, we used flow cytometry to analyze the time-dependent behavior of antigen-specific effector (T_eff) and regulatory (T_reg) T cells and microglia in mice model of MS, Experimental Autoimmune Encephalomyelitis (EAE), and compared the observations with a mathematical cross-regulation model of T-cell dynamics in autoimmune disease.

Results

We found that T_eff and T_reg cells specific to myelin olygodendrocyte glycoprotein (MOG) developed coupled oscillatory dynamics with a 4- to 5-day period and decreasing amplitude that was always higher for the T_eff populations, in agreement with the mathematical model. Microglia activation followed the oscillations of MOG-specific T_eff cells in the secondary lymphoid organs, but they were activated before MOG-specific T-cell peaks in the CNS. Finally, we assessed the role of B-cell depletion induced by anti-CD20 therapy in the dynamics of T cells in an EAE model with more severe disease after therapy. We observed that B-cell depletion decreases T_eff expansion, although its oscillatory behavior persists. However, the effect of B cell depletion was more significant in the T_reg population within the CNS, which matched with activation of microglia and worsening of the disease. Mathematical modeling of T-cell cross-regulation after anti-CD20 therapy suggests that B-cell depletion may influence the dynamics of T cells by fine-tuning their activation.

Conclusions

The oscillatory dynamics of T-cells have an intrinsic origin in the physiological regulation of the adaptive immune response, which influences both disease phenotype and response to immunotherapy.

Alemtuzumab: evidence for its potential in relapsing-remitting multiple sclerosis

Alemtuzumab (previously known as Campath^®) is a humanized monoclonal antibody directed against the CD52 antigen on mature lymphocytes that results in lymphopenia and subsequent modification of the immune repertoire. Here we explore evidence for its efficacy and safety in relapsing–remitting multiple sclerosis. One Phase II and two Phase III trials of alemtuzumab versus active comparator (interferon beta-1a) have been reported. Two of these rater-blinded randomized studies assessed clinical and radiological outcomes in treatment-naïve patients; one explored patients who had relapsed despite first-line therapy. Compared to interferon beta-1a, alemtuzumab reduced the relapse rate by 49%–74% (P < 0.0001), and in two studies it reduced the risk of sustained disability accumulation by 42%–71% (P < 0.01). In one study (Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis; CARE-MS1), there was no significant difference compared to interferon, perhaps reflecting the surprisingly low frequency of disability events in the comparator group. After alemtuzumab, the Expanded Disability Status Scale score improved by 0.14–1.2 points, culminating in a net advantage with alemtuzumab of 0.41–0.77 points over interferon in the CAMMS223 and CARE-MS2 trials (both P < 0.001). Radiological markers of new lesion formation and brain atrophy following alemtuzumab were significantly improved when compared to interferon in all studies. Adverse events were more common following alemtuzumab than interferon beta-1a (7.2–8.66 versus 4.9–5.7 events per person-year). While infusion reactions are the most common, autoimmunity is the most concerning; within Phase III studies, thyroid disorders (17%–18% versus 5%–6%) and immune thrombocytopenic purpura (1% versus 0%) were reported in patients taking alemtuzumab and interferon beta-1a, respectively. All patients responded to conventional therapy. One patient taking alemtuzumab in the Phase II study suffered a fatal intracranial hemorrhage following immune thrombocytopenic purpura, heralding assiduous monitoring of all patients thereafter. Alemtuzumab has been submitted for licensing in relapsing–remitting multiple sclerosis in the United States and Europe.