Overlapping and distinct mechanisms of action of multiple sclerosis therapies

Vaccine Considerations for Multiple Sclerosis in the COVID-19 Era

People with multiple sclerosis (MS) are at risk for infections that can result in amplification of baseline symptoms and possibly trigger clinical relapses. Vaccination can prevent infection through the activation of humoral and cellular immune responses. This is particularly pertinent in the era of emerging novel vaccines against severe acute respiratory syndrome coronavirus 2, the virus that causes coronavirus disease 2019 (COVID-19). MS disease-modifying therapies (DMTs), which affect the immune system, may impact immune responses to COVID-19 vaccines in people with MS. The objective of this article is to provide information on immune system responses to vaccinations and review previous studies of vaccine responses in people with MS to support the safety and importance of receiving currently available and emerging COVID-19 vaccines. Immunological studies have shown that coordinated interactions between T and B lymphocytes of the adaptive immune system are key to successful generation of immunological memory and production of neutralizing antibodies following recognition of vaccine antigens by innate immune cells. CD4+ T cells are essential to facilitate CD8+ T cell and B cell activation, while B cells drive and sustain T cell memory. Data suggest that some classes of DMT, including type 1 interferons and glatiramer acetate, may not significantly impair the response to vaccination. DMTs-such as sphingosine-1-phosphate receptor modulators, which sequester lymphocytes from circulation; alemtuzumab; and anti-CD20 therapies, which rely on depleting populations of immune cells-have been shown to attenuate responses to conventional vaccines. Currently, three COVID-19 vaccines have been granted emergency use authorization in the USA on the basis of promising interim findings of ongoing trials. Because analyses of these vaccines in people with MS are not available, decisions regarding COVID-19 vaccination and DMT choice should be informed by data and expert consensus, and personalized with considerations for disease burden, risk of infection, and other factors.

Therapeutic Prospects of Cannabinoids in the Immunomodulation of Prevalent Autoimmune Diseases

Introduction: Cannabinoids such as ▵-9-THC and CBD can downregulate the immune response by modulating the endocannabinoid system. This modulation is relevant for the treatment of prevalent autoimmune diseases (ADs), such as multiple sclerosis (MS), systemic lupus erythematosus (SLE), diabetes mellitus type 1 (DMT1), and rheumatoid arthritis (RA). These conditions require new therapeutic options with fewer side effects for the control of the autoimmune response. Objective: to conduct a literature review of preclinical scientific evidence that supports further clinical investigations for the use of cannabinoids (natural or synthetic) as potential immunomodulators of the immune response in ADs. Methodology: A systematic search was carried out in different databases using different MeSH terms, such as Cannabis sativa L., cannabinoids, immunomodulation, and ADs. Initially, 677 journal articles were found. After filtering by publication date (from 2000 to 2020 for SLE, DMT1, and RA; and 2010 to 2020 for MS) and removing the duplicate items, 200 articles were selected and analyzed by title and summary associated with the use of cannabinoids as immunomodulatory treatment for those diseases. Results: Evidence of the immunomodulatory effect of cannabinoids in the diseases previously mentioned, but SLE that did not meet the search criteria, was summarized from 24 journal articles. CBD was found to be one of the main modulators of the immune response. This molecule decreased the number of Th1 and Th17 proinflammatory cells and the production of the proinflammatory cytokines, interleukin (IL)-1, IL-12, IL-17, interferon (IFN)-γ, and tumor necrosis factor alpha, in mouse models of MS and DMT1. Additionally, new synthetic cannabinoid-like molecules, with agonist or antagonist activity on CB1, CB2, TRPV1, PPAR-α, and PPAR-γ receptors, have shown anti-inflammatory properties in MS, DMT1, and RA. Conclusion: Data from experimental animal models of AD showed that natural and synthetic cannabinoids downregulate inflammatory responses mediated by immune cells responsible for AD chronicity and progression. Although synthetic cannabinoid-like molecules were evaluated in just two clinical trials, they corroborated the potential use of cannabinoids to treat some ADs. Notwithstanding, new cannabinoid-based approaches are required to provide alternative treatments to patients affected by the large group of ADs.

Serum malondialdehyde as a lipid peroxidation marker in multiple sclerosis patients and its relation to disease characteristics

Introduction Oxidative stress has been suggested to play a key role in pathogenesis of multiple sclerosis (MS), but clinical data on oxidative stress markers in MS patients and their influence on clinical and radiologic characteristics of the disease are inconsistent. The aim of this study is to assess the serum levels of malondialdehyde (MDA) as a measure of lipid peroxidation in MS patients and its relation to disease characteristics. Methods This case control study included 120 patients with clinically definite relapsing remitting multiple sclerosis (RRMS) compared to 120 age and sex -matched healthy controls. MDA levels were measured using thiobarbituric acid reactive substances (TBARS) assay. Results MDA levels are significantly higher in patients with MS than those in control (P<0.001) especially during relapse, MDA levels are higher in patients taking no disease modifying therapy (DMT) than those taking interferon (IFN-β). MDA levels significantly correlate with expanded disability status scale (EDSS) (P<0.001). Conclusions The results of this study can provide evidence about the incrimination of oxidative stress in MS pathogenesis and disease disability and support the use of antioxidants as a new target of treatment that focuses on neutralizing free radicals and increases antioxidant capacity.

Impact of short-term cycle ergometer training on quality of life, cognition and depressive symptomatology in multiple sclerosis patients: a pilot study

In this pilot study, we investigate whether a routine cycle ergometry training programme has therapeutic potential in individuals with multiple sclerosis (MS) by improving quality of life (QOL) and depressive symptomatology, while ameliorating cognitive disturbances. Healthy volunteers and MS patients cycled for 30 min at 65-75% age-predicted maximal heart rate on a recumbent ergometer, with this session repeated twice a week for 8 weeks. QOL, depressive symptomatology and cognitive function were assessed pre- and post-exercise using the MS Quality of Life-54 (MSQOL-54) questionnaire, 16-item Quick Inventory of Depressive Symptomatology (QIDS-SR₁₆) questionnaire and the Cambridge Neuropsychological Test Automated Battery (CANTAB), respectively. We determined that QOL was lower in MS patients, compared to healthy subjects, with a reduction in physical and mental health summary scores observed. Exercise improved both physical and mental health scores in MS patients. In support of this, exercise was shown to reduce depressive symptomatology in MS patients. Exercise was also associated with an improvement in visual sustained attention, executive function/cognitive flexibility and hippocampal-dependent visuospatial memory in patients. Overall, this study identifies a short-term exercise programme that improves physical and mental health, while reducing depressive symptomatology and cognitive dysfunction in MS.

Interferon-β regulates dendritic cell activation and migration in experimental autoimmune encephalomyelitis

CD11c⁺ dendritic cells (DCs) exert a critical role as antigen-presenting cells in regulating pathogenic T cells in multiple sclerosis (MS). To determine whether the therapeutic benefit of interferon-β (IFN-β) treatment for MS is in part influenced by IFN regulation of DC function, we examined the immunophenotype of DCs derived from IFN-β^+/+ and IFN-β^-/- mice using a myelin oligodendrocyte glycoprotein (MOG) peptide-induced mouse model of MS, experimental autoimmune encephalomyelitis (EAE). Our earlier work identified that IFN-β^-/- mice exhibit earlier onset and more rapid progression of neurological impairment compared with IFN-β^+/+ mice. In this study we show that lipopolysaccharide-/MOG peptide-stimulated IFN-β^-/- DCs secrete cytokines associated with pathological T helper type 17 rather than regulatory T-cell polarization and exhibit increased CD80 and MHCII expression when compared with stimulated IFN-β^+/+ DCs. IFN-β^-/- DCs from mice immunized to develop EAE induce greater proliferation of MOG-transgenic CD4⁺ T cells and promote interleukin-17 production by these T cells. Adoptive transfer of MOG peptide-primed IFN-β^-/- DCs into IFN-β^+/+ and IFN-β^-/- mice immunized to develop EAE resulted in their rapid migration into the central nervous system of recipient mice, before onset of disease, which we attribute to failed signal transducer and activator of transcription 1-mediated inhibition of CCR7. Taken together, our data support immunoregulatory roles for IFN-β in the activation and migration of DCs during EAE.

Rapamycin Augments Immunomodulatory Properties of Bone Marrow-Derived Mesenchymal Stem Cells in Experimental Autoimmune Encephalomyelitis

The immunomodulatory and anti-inflammatory properties of bone marrow-derived mesenchymal stem cells (BM-MSCs) have been considered as an appropriate candidate for treatment of autoimmune diseases. Previous studies have revealed that treatment with BM-MSCs may modulate immune responses and alleviate the symptoms in experimental autoimmune encephalomyelitis (EAE) mice, an animal model of multiple sclerosis. Therefore, the present study was designed to examine immunomodulatory effects of BM-MSCs in the treatment of myelin oligodendrocyte glycoprotein (MOG) 35-55-induced EAE in C57BL/6 mice. MSCs were obtained from the bone marrow of C57BL mice, cultured with DMEM/F12, and characterized with flow cytometry for the presence of cell surface markers for BM-MSCs. Following three passages, BM-MSCs were injected intraperitoneally into EAE mice alone or in combination with rapamycin. Immunological and histopathological effects of BM-MSCs and addition of rapamycin to BM-MSCs were evaluated. The results demonstrated that adding rapamycin to BM-MSCs transplantation in EAE mice significantly reduced inflammation infiltration and demyelination, enhanced the immunomodulatory functions, and inhibited progress of neurological impairments compared to BM-MSC transplantation and control groups. The immunological effects of rapamycin and BM-MSC treatments were associated with the inhibition of the Ag-specific lymphocyte proliferation, CD8+ cytolytic activity, and the Th1-type cytokine (gamma-interferon (IFN-γ)) and the increase of Th-2 cytokine (interleukin-4 (IL-4) and IL-10) production. Addition of rapamycin to BM-MSCs was able to ameliorate neurological deficits and provide neuroprotective effects in EAE. This suggests the potential of rapamycin and BM-MSC combined therapy to play neuroprotective roles in the treatment of neuroinflammatory disorders.

Further understanding of the immunopathology of multiple sclerosis: impact on future treatments

INTRODUCTION

The understanding of the immunopathogenesis of multiple sclerosis (MS) has expanded with more research into T-cell subtypes, cytokine contributors, B-cell participation, mitochondrial dysfunction, and more. Treatment options have rapidly expanded with three relatively recent oral therapy alternatives entering the arena.

AREAS COVERED

In the following review, we discuss current mechanisms of immune dysregulation in MS, how they relate to current treatments, and the impact these findings will have on the future of therapy. Expert commentary: The efficacy of these medications and understanding their mechanisms of actions validates the immunopathogenic mechanisms thought to underlie MS. Further research has exposed new targets, while new promising therapies have shed light on new aspects into the pathophysiology of MS.

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.

IFNAR signaling directly modulates T lymphocyte activity, resulting in milder experimental autoimmune encephalomyelitis development

Although interferon-β is used as first-line therapy for multiple sclerosis, the cell type-specific activity of type I interferons in multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis, remains obscure. In this study, we have elucidated the in vivo immunomodulatory role of type I interferon signaling in T cells during experimental autoimmune encephalomyelitis by use of a novel transgenic mouse, carrying a cd2-ifnar1 transgene on a interferon-α/β receptor 1 null genetic background, thus allowing expression of the interferon-α/β receptor 1 and hence, a functional type I interferon receptor exclusively on T cells. These transgenic mice exhibited milder experimental autoimmune encephalomyelitis with reduced T cell infiltration, demyelination, and axonal damage in the central nervous system. It is noteworthy that interferon-β administration in transgenic mice generated a more pronounced, protective effect against experimental autoimmune encephalomyelitis compared with untreated littermates. In vivo studies demonstrated that before experimental autoimmune encephalomyelitis onset, endogenous type I interferon receptor signaling in T cells led to impaired T-helper 17 responses, with a reduced fraction of CCR6(+) CD4(+) T cells in the periphery. At the acute phase, an increased proportion of interleukin-10- and interferon-γ-producing CD4(+) T cells was detected in the periphery of the transgenic mice, accompanied by up-regulation of the interferon-γ-induced gene Irgm1 in peripheral T cells. Together, these results reveal a hitherto unknown T cell-associated protective role of type I interferon in experimental autoimmune encephalomyelitis that may provide valuable clues for designing novel therapeutic strategies for multiple sclerosis.

Circulating levels of interleukin-35 in patients with multiple sclerosis: evaluation of the influences of FOXP3 gene polymorphism and treatment program

The regulatory T (Treg) cells play a major role in the control of the autoimmunity and inflammation, and IL-35 has been described as an immunosuppressive cytokine that is mainly produced by CD4(+)FOXP3(+) Treg cells. The aim of this study was to evaluate the serum levels of IL-35 and a single nucleotide polymorphism (SNP), rs3761548, in FOXP3 gene in patients with multiple sclerosis. The blood samples were collected from 140 multiple sclerosis (MS) patients (including 51 untreated and 89 treated patients) and 140 healthy subjects as a control group. The serum levels of IL-35 were measured by ELISA. The DNA was analyzed for SNP rs3761548 in FOXP3 gene using SSP-PCR. There was no significant difference between untreated MS patients and control group regarding the mean serum levels of IL-35, although this parameter was higher in untreated patients. However, the mean serum level of IL-35 in treated MS patients was significantly higher than that in the control group (P < 0.008). The mean serum levels of IL-35 in patients who were treated with interferon-β, methylprednisolone, or with the both interferon-β and methylprednisolone were significantly higher than that in the healthy group (P < 0.01, P < 0.01, and P < 0.2, respectively). The frequencies of AA and AC genotypes at rs3761548 in the FOXP3 gene were significantly higher in MS group as compared with healthy subjects (P < 0.05). The frequency of CC genotype at rs3761548 was significantly lower in the MS group in comparison with healthy control subjects (P < 0.001). Moreover, the frequency of A allele was significantly higher whereas the frequency of C allele was significantly lower in MS patients in comparison to healthy subjects (P < 0.001). The mean serum level of IL-35 was significantly lower in MS patients or healthy subjects with AA genotype as compared with those with CC genotype at rs3761548 in FOXP3 gene (P < 0.01 and P < 0.001, respectively). These results showed higher serum levels of IL-35 in treated MS patients representing that the benefit effects of treatment may in part performed through the upregulation of the IL-35 production. The SNP rs3761548 may influence the susceptibility to MS disease and the serum levels of IL-35.

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

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

Alteration of prolyl oligopeptidase and activated α-2-macroglobulin in multiple sclerosis subtypes and in the clinically isolated syndrome

Prolyl oligopeptidase (PREP) has been considered as a drug target for the treatment of neurodegenerative diseases. In plasma, PREP has been found altered in several disorders of the central nervous system including multiple sclerosis (MS). Oxidative stress and the levels of an endogenous plasma PREP inhibitor have been proposed to decrease PREP activity in MS. In this work, we measured the circulating levels of PREP in patients suffering of relapsing remitting (RR), secondary progressive (SP), primary progressive (PP) MS, and in subjects with clinically isolated syndrome (CIS). We found a significantly lower PREP activity in plasma of RRMS as well as in PPMS patients and a trend to reduced activity in subjects diagnosed with CIS, compared to controls. No signs of oxidative inactivation of PREP, and no correlation with the endogenous PREP inhibitor, identified as activated α-2-macroglobulin (α2M*), were observed in any of the patients studied. However, a significant decrease of α2M* was recorded in MS. In cell cultures, we found that PREP specifically stimulates immune active cells possibly by modifying the levels of fibrinogen β, thymosin β4, and collagen. Our results open new lines of research on the role of PREP and α2M* in MS, aiming to relate them to the diagnosis and prognosis of this devastating disease.

Effect of interferon beta-1a on B7.1 and B7.2 B-cell expression and its impact on T-cell proliferation

The effect of pharmacologically relevant doses of interferon (IFN) β-1a on B-cell expression of B7.1 and B7.2 was investigated. Culture of peripheral blood mononuclear cells with IFN β-1a 100 IU/mL decreased B-cell expression of B7.1 and increased B7.2 expression. Interleukin-10 in B cells was significantly enhanced by IFN β-1a. Anti-CD3 and anti-CD28 monoclonal antibody-mediated T-cell proliferations were partially suppressed in the presence of B cells pretreated with IFN β-1a. These data suggest that IFN β-1a and B cells can interact to play a beneficial role in the treatment of multiple sclerosis.

Randomized study combining interferon and glatiramer acetate in multiple sclerosis

OBJECTIVE

A double-blind, randomized, controlled study was undertaken to determine whether combined use of interferon β-1a (IFN) 30 μg intramuscularly weekly and glatiramer acetate (GA) 20 mg daily is more efficacious than either agent alone in relapsing-remitting multiple sclerosis.

METHODS

A total of 1,008 participants were randomized and followed until the last participant enrolled completed 3 years. The primary endpoint was reduction in annualized relapse rate utilizing a strict definition of relapse. Secondary outcomes included time to confirmed disability, Multiple Sclerosis Functional Composite (MSFC) score, and magnetic resonance imaging (MRI) metrics.

RESULTS

Combination IFN+GA was not superior to the better of the single agents (GA) in risk of relapse. Both the combination therapy and GA were significantly better than IFN in reducing the risk of relapse. The combination was not better than either agent alone in lessening confirmed Expanded Disability Status Scale progression or change in MSFC over 36 months. The combination was superior to either agent alone in reducing new lesion activity and accumulation of total lesion volumes. In a post hoc analysis, combination therapy resulted in a higher proportion of participants attaining disease activity-free status (DAFS) compared to either single arm, driven by the MRI results.

INTERPRETATION

Combining the 2 most commonly prescribed therapies for multiple sclerosis did not produce a significant clinical benefit over 3 years. An effect was seen on some MRI metrics. In a test of comparative efficacy, GA was superior to IFN in reducing the risk of exacerbation. The extension phase for CombiRx will address whether the observed differences in MRI and DAFS findings predict later clinical differences.

Interferon beta and glatiramer acetate therapy

Interferon beta and glatiramer acetate have been mainstays of treatment in relapsingremitting multiple sclerosis for two decades. Remarkable advances in our understanding of immune function and dysfunction as well as increasingly sophisticated clinical trial design have stemmed from efforts to better understand these drugs. In this chapter, we review the history of their development and elaborate on known and theorized mechanisms of action. We describe the pivotal clinical trials that have led to their widespread use. We evaluate the clinical use of the drugs including tolerability, side effects, and efficacy measures. Finally, we look to the future of interferon beta and glatiramer acetate in the context of an ever growing armamentarium of treatments for relapsing remitting multiple sclerosis.

Role of Natural Killer Cells in Multiple Sclerosis

Although the etiology of multiple sclerosis (MS) is not known, the consensus is that Th1 cells sensitized to myelin proteins in the periphery are recruited into the CNS and damage the myelin sheath. Natural killers (NK) are cells that spontaneously lyse tumor target cells and have immunoregulatory activity secreting multiple cytokines and chemokines, as well as interacting with cells of innate and adaptive immune systems. A great discovery in the field is the cloning of several inhibitory and activating receptors. Another important contribution is the discovery that these cells express many seven-transmembrane-spanning domain receptors which aid them in extravasations into injured tissues. Despite all this progress, the role of NK cells in autoimmune diseases including MS is still not quite clear. In this paper, I will summarize recent findings related to the effects of these cells in both MS and the animal model of experimental autoimmune encephalomyelitis (EAE). Hence, I will discuss the effects of drugs used to treat MS/EAE and then explain their effects on NK cells. These include anti-CD25 or daclizumab, interferon-β (IFN-β), natalizumab, glatiramer acetate (GA), and fingolimod (FTY720). Finally, I will explain the contribution of the recently discovered NK17/NK1 cells in MS disease.

The synthetic cannabinoid R(+)WIN55,212-2 augments interferon-β expression via peroxisome proliferator-activated receptor-α

We have demonstrated that R(+)WIN55,212-2, a synthetic cannabinoid that possesses cannabimimetic properties, acts as a novel regulator of Toll-like receptor 3 (TLR3) signaling to interferon (IFN) regulatory factor 3 (IRF3) activation and IFN-β expression, and this is critical for manifesting its protective effects in a murine multiple sclerosis model. Here we investigated the role of peroxisome proliferator-activated receptor-α (PPARα) in mediating the effects of R(+)WIN55,212-2 on this pathway. Data herein demonstrate that the TLR3 agonist poly(I:C) promotes IFN-β expression and R(+)WIN55,212-2 enhances TLR3-induced IFN-β expression in a stereoselective manner via PPARα. R(+)WIN55,212-2 promotes increased transactivation and expression of PPARα. Using the PPARα antagonist GW6471, we demonstrate that R(+)WIN55,212-2 acts via PPARα to activate JNK, activator protein-1, and positive regulatory domain IV to transcriptionally regulate the IFN-β promoter. Furthermore, GW6471 ameliorated the protective effects of R(+)WIN55,212-2 during the initial phase of experimental autoimmune encephalomyelitis. Overall, these findings define PPARα as an important mediator in manifesting the effects of R(+)WIN55,212-2 on the signaling cascade regulating IFN-β expression. The study adds to our molecular appreciation of potential therapeutic effects of R(+)WIN55,212-2 in multiple sclerosis.

Clinical predictors of response to immunomodulators for multiple sclerosis

OBJECTIVES: To determine, based on clinical criteria, the proportion of multiple sclerosis (MS) patients responsive to immunomodulators (RI) and nonresponsive to immunomodulators (NRI), and to ascertain whether clinical and epidemiological data differs between RI and NRI patient groups. METHODS: Patients were assessed on rate of exarcerbations per year, for the period before and after commencement of treatment. The RI and NRI groups were compared for several clinical and epidemiological characteristics. DISCUSSION AND CONCLUSION: A total of 31.4% of the patients were nonresponders to the immunomodulatory treatment. The main predictors of immunomodulatory response were early diagnostic and commencement of therapy and high rate of annual exacerbations prior to treatment. Given the arsenal of medication options available for MS management, screening potential candidates for different therapeutic approaches are critical to optimize evolution of patients with the disease.

Sieving treatment biomarkers from blood gene-expression profiles: a pharmacogenomic update on two types of multiple sclerosis therapy

Interferon-β (IFN-β) and glatiramer acetate are routinely used to inhibit disease activity in multiple sclerosis, but their mechanisms of action are incompletely understood. Individual treatment responses vary and candidate molecular markers that predict them have yet to be established. Why some patients respond poorly to a certain treatment while others respond well is addressed by the pharmacogenomic approach, which postulates that the molecular response to treatment correlates with the clinical effects, and thus seeks biological markers to estimate prognosis, guide therapy, comprehend the drugs' mechanisms of action and offer insights into disease pathogenesis. A poor clinical response can be owing to genetic variants in drug receptors or signaling components, or the appearance of neutralizing antibodies that interfere with the drug's binding efficacy. Independently, such mechanisms could lead to inadequate, that is to say unchanged, molecular responses, or exceedingly increased or decreased changes. By means of DNA microarray studies, various research groups endeavour to establish a clinically relevant relationship between the biological response to these drugs and treatment effects. Molecular profiles obtained in this way differ in the pattern and number of modulated genes, suggesting the existence of an individual 'drug-response fingerprint'. To further unravel the underlying regulatory interaction structure of the genes responsive to these immunotherapies represents a daunting but inevitable task. In this article, we focus on longitudinal ex vivo transcriptomic studies in multiple sclerosis and its therapy. We will discuss recurrently reported biomarker candidates, emphasizing those of immunologically meaning, and review studies with network module outputs.