Treatment response to dimethyl fumarate is characterized by disproportionate CD8+ T cell reduction in MS

B cell depletion with anti-CD20 promotes neuroprotection in a BAFF-dependent manner in mice and humans

Anti-CD20 therapy to deplete B cells is highly efficacious in preventing new white matter lesions in patients with relapsing-remitting multiple sclerosis (RRMS), but its protective capacity against gray matter injury and axonal damage is unclear. In a passive experimental autoimmune encephalomyelitis (EAE) model whereby TH17 cells promote brain leptomeningeal immune cell aggregates, we found that anti-CD20 treatment effectively spared myelin content and prevented myeloid cell activation, oxidative damage, and mitochondrial stress in the subpial gray matter. Anti-CD20 treatment increased B cell survival factor (BAFF) in the serum, cerebrospinal fluid, and leptomeninges of mice with EAE. Although anti-CD20 prevented gray matter demyelination, axonal loss, and neuronal atrophy, co-treatment with anti-BAFF abrogated these benefits. Consistent with the murine studies, we observed that elevated BAFF concentrations after anti-CD20 treatment in patients with RRMS were associated with better clinical outcomes. Moreover, BAFF promoted survival of human neurons in vitro. Together, our data demonstrate that BAFF exerts beneficial functions in MS and EAE in the context of anti-CD20 treatment.

Multiple faces of multiple sclerosis in the era of highly efficient treatment modalities: Lymphopenia and switching treatment options challenges daily practice

The expanded treatment landscape in relapsing-remitting multiple sclerosis (MS) has resulted in highly effective treatment options and complexity in managing disease- or drug-related events during disease progression. Proper decision-making requires thorough knowledge of the immunobiology of MS itself and an understanding of the main principles behind the mechanisms that lead to secondary autoimmunity affecting organs other than the central nervous system as well as opportunistic infections. The immune system is highly adapted to both environmental and disease-modifying agents. Immune reconstitution following cell depletion or cell entrapment therapies eliminates pathogenic aspects of the disease but can also lead to distorted immune responses with harmful effects. Atypical relapses occur with second-line treatments or after their discontinuation and require appropriate clinical decisions. Lymphopenia is a result of the mechanism of action of many drugs used to treat MS. However, persistent lymphopenia and cell-specific lymphopenia could result in disease exacerbation, secondary autoimmunity, or the emergence of opportunistic infections. Clinicians treating patients with MS should be aware of the multiple faces of MS under novel, efficient treatment modalities and understand the intricate brain-immune cell interactions in the context of an altered immune system. MS relapses and disease progression still occur despite the current treatment modalities and are mediated either by failure to control effector mechanisms inherent to MS pathophysiology or by new drug-related mechanisms. The multiple faces of MS due to the highly adapted immune system of patients impose the need for appropriate switching therapies that safeguard disease remission and further clinical improvement.

Post-vaccination SARS-Cov-2 T-cell receptor repertoires in patients with multiple sclerosis and related disorders

BACKGROUND

Attenuation in post-vaccination SARS-CoV-2 humoral responses has been demonstrated in people treated with either anti-CD20 therapies or sphingosine-1-phosphate (S1P) receptor modulators. In the setting of disease modifying therapy (DMT) use, humoral response may not correlate with effective immunity, and analysis of vaccine-mediated SARS-CoV-2-specific memory T-cell responses is crucial. While vaccination in patients treated with anti-CD20 agents leads to deficient antibody production, emerging data from live cell assays suggests intact T-cell responses to vaccination. We evaluated post-vaccination SARS-CoV-2 T-cell receptor (TCR) repertoires in DMT-treated patients using the ImmunoSeqR assay, an assay that does not require live cells.

METHODS

Adults 18-80 years old without prior COVID-19, with neuroimmune conditions, who had been vaccinated with two doses of Pfizer-BioNTech or Moderna mRNA vaccines at least 3 weeks and up to 6 months prior, were recruited. Whole blood was obtained for immunosequencing, and matched serum was obtained for humoral analysis. Immunosequencing of the CDR3 regions of human TCRβ chains was completed using the immunoSEQR Assay (Adaptive Biotechnologies). TCR sequences were mapped across a set of TCR sequences reactive to SARS-CoV-2. Clonal diversity (breadth) and frequency (depth) of TCRs specific to SARS-CoV-2 spike protein were calculated and relationships with clinical variables were assessed.

RESULTS

Forty patients were recruited into the study, aged 25-77, and 27 female. 37 had MS, 2 had neuromyelitis optica spectrum disorder (NMOSD), and 1 had hypophysitis. Subjects treated with anti-CD20 agents and S1P receptor modulators had severely attenuated humoral responses, but SARS-CoV-2-spike-specific TCR clonal depth and breadth were robust across all treatment classes except S1P modulators. No spike-specific or non-spike-specific SARS-CoV-2-associated TCRs were found in those treated with S1P modulators (p = 0.002 for both breadth and depth). Subjects treated with fumarates exhibited somewhat lower spike TCR breadth than subjects treated with other or no DMTs (median 2.27 × 10^-5 for fumarates and 4.96 × 10^-5 for all others, p = 0.008), but no statistically significant difference was demonstrated with spike TCR depth. No other significant associations with DMT type were found. We found no significant correlations between depth or breadth and age, duration of treatment, type of vaccination, or time interval since vaccination.

CONCLUSION

This is the first study to characterize post-vaccination SARS-CoV-2 TCR repertoires in DMT-treated individuals. We demonstrated a dichotomous response to SARS-CoV-2 vaccination in anti-CD20-treated patients, with severely attenuated humoral response but intact TCR depth and breadth. It is unclear to what degree each arm of the adaptive immune system impacts post-vaccine immunity, both from the standpoint of incidence of post-vaccine infections and that of infection severity, and further clinical studies are necessary. S1P modulator-treated subjects exhibited both severely attenuated humoral responses and absent spike-specific TCR depth and breadth, information which is crucial for counseling of patients on these agents. Our methodology can be used in larger studies to determine the benefit of repeated vaccination doses, including those that are modified to better target modern or seasonal variants, without the use of live cell assays.

Immune cell subpopulations and serum neurofilament light chain are associated with increased risk of disease worsening in multiple sclerosis

Changes is lymphocyte subpopulations in peripheral blood have been proposed as biomarkers for evaluation of disease activity in multiple sclerosis (MS). Serum neurofilament light chain (sNfL) is a biomarker reflecting neuro-axonal injury in MS that could be used to monitor disease activity, response to drugs and to prognosticate disease course. Here we show a moderate correlation between sNfL and lymphocyte cell subpopulations, and our data furthermore suggest that sNfL and specific immune cell subpopulations together could predict future disease worsening in MS.

Implications of immunometabolism for smouldering MS pathology and therapy

Clinical symptom worsening in patients with multiple sclerosis (MS) is driven by inflammation compartmentalized within the CNS, which results in chronic neuronal damage owing to insufficient repair mechanisms. The term 'smouldering inflammation' summarizes the biological aspects underlying this chronic, non-relapsing and immune-mediated mechanism of disease progression. Smouldering inflammation is likely to be shaped and sustained by local factors in the CNS that account for the persistence of this inflammatory response and explain why current treatments for MS do not sufficiently target this process. Local factors that affect the metabolic properties of glial cells and neurons include cytokines, pH value, lactate levels and nutrient availability. This Review summarizes current knowledge of the local inflammatory microenvironment in smouldering inflammation and how it interacts with the metabolism of tissue-resident immune cells, thereby promoting inflammatory niches within the CNS. The discussion highlights environmental and lifestyle factors that are increasingly recognized as capable of altering immune cell metabolism and potentially responsible for smouldering pathology in the CNS. Currently approved MS therapies that target metabolic pathways are also discussed, along with their potential for preventing the processes that contribute to smouldering inflammation and thereby to progressive neurodegenerative damage in MS.

Beyond Antioxidation: Keap1-Nrf2 in the Development and Effector Functions of Adaptive Immune Cells

Ubiquitously expressed in mammalian cells, the Kelch-like ECH-associated protein 1 (Keap1)-NF erythroid 2-related factor 2 (Nrf2) complex forms the evolutionarily conserved antioxidation system to tackle oxidative stress caused by reactive oxygen species. Reactive oxygen species, generated as byproducts of cellular metabolism, were identified as essential second messengers for T cell signaling, activation, and effector responses. Apart from its traditional role as an antioxidant, a growing body of evidence indicates that Nrf2, tightly regulated by Keap1, modulates immune responses and regulates cellular metabolism. Newer functions of Keap1 and Nrf2 in immune cell activation and function, as well as their role in inflammatory diseases such as sepsis, inflammatory bowel disease, and multiple sclerosis, are emerging. In this review, we highlight recent findings about the influence of Keap1 and Nrf2 in the development and effector functions of adaptive immune cells, that is, T cells and B cells, and discuss the knowledge gaps in our understanding. We also summarize the research potential and targetability of Nrf2 for treating immune pathologies.

Repurposing MS immunotherapies for CIDP and other autoimmune neuropathies: unfulfilled promise or efficient strategy?

Despite advances in the treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and other common autoimmune neuropathies (AN), still-many patients with these diseases do not respond satisfactorily to the available treatments. Repurposing of disease-modifying therapies (DMTs) from other autoimmune conditions, particularly multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), is a promising strategy that may accelerate the establishment of novel treatment choices for AN. This approach appears attractive due to homologies in the pathogenesis of these diseases and the extensive post-marketing experience that has been gathered from treating MS and NMOSD patients. The idea is also strengthened by a number of studies that explored the efficacy of DMTs in animal models of AN but also in some CIDP patients. We here review the available preclinical and clinical data of approved MS therapeutics in terms of their applicability to AN, especially CIDP. Promising therapeutic approaches appear to be B cell-directed and complement-targeting strategies, such as anti-CD20/anti-CD19 agents, Bruton's tyrosine kinase inhibitors and anti-C5 agents, as they exert their effects in the periphery. This is a major advantage because, in contrast to MS, their action in the periphery is sufficient to exert significant immunomodulation.

MRI and laboratory monitoring of disease-modifying therapy efficacy and risks

PURPOSE OF REVIEW

Increasingly, therapeutic strategy in multiple sclerosis (MS) is informed by imaging and laboratory biomarkers, in addition to traditional clinical factors. Here, we review aspects of monitoring the efficacy and risks of disease-modifying therapy (DMT) with both conventional and emerging MRI and laboratory measures.

RECENT FINDINGS

The adoption of consensus-driven, stable MRI acquisition protocols and artificial intelligence-based, quantitative image analysis is heralding an era of precision monitoring of DMT efficacy. New MRI measures of compartmentalized inflammation, neuro-degeneration and repair complement traditional metrics but require validation before use in individual patients. Laboratory markers of brain cellular injury, such as neurofilament light, are robust outcomes in DMT efficacy trials; their use in clinical practice is being refined. DMT-specific laboratory monitoring for safety is critical and may include lymphocytes, immunoglobulins, autoimmunity surveillance, John Cunningham virus serology and COVID-19 vaccination seroresponse.

SUMMARY

A biomarker-enhanced monitoring strategy has immediate clinical application, with growing evidence of long-term reductions in disability accrual when both clinically symptomatic and asymptomatic inflammatory activity is fully suppressed; and amelioration of the risks associated with therapy. Emerging MRI and blood-based measures will also become important tools for monitoring agents that target the innate immune system and promote neuro-repair.

Immunological effects of dimethyl fumarate treatment in blood and CSF of patients with primary progressive MS

Dimethyl fumarate is an efficient therapy used widely in patients with relapsing-remitting multiple sclerosis (RRMS). However, lacking effect of treatment has recently been reported in patients with primary progressive MS (PPMS) (Højsgaard Chow et al., 2021). In order to further analyze the immunological treatment response we investigated the systemic and intrathecal immunological effects of dimethyl fumarate (DMF) treatment in 50 patients with PPMS who participated in a 48-week randomized controlled trial with dimethyl fumarate vs placebo. We found substantial systemic immunomodulatory effects of DMF treatment comparable with those observed in patients with RRMS. However, intrathecal effects were limited and restricted to CD4⁺ T cells presumably resulting in higher concentrations of intrathecal IL-7.

Dimethyl fumarate treatment restrains the antioxidative capacity of T cells to control autoimmunity

Dimethyl fumarate, an approved treatment for relapsing-remitting multiple sclerosis, exerts pleiotropic effects on immune cells as well as CNS resident cells.

Here, we show that dimethyl fumarate exerts a profound alteration of the metabolic profile of human CD4⁺ as well as CD8⁺ T cells and restricts their antioxidative capacities by decreasing intracellular levels of the reactive oxygen species scavenger glutathione. This causes an increase in mitochondrial reactive oxygen species levels accompanied by an enhanced mitochondrial stress response, ultimately leading to impaired mitochondrial function. Enhanced mitochondrial reactive oxygen species levels not only result in enhanced T-cell apoptosis in vitro as well as in dimethyl fumarate-treated patients, but are key for the well-known immunomodulatory effects of dimethyl fumarate both in vitro and in an animal model of multiple sclerosis, i.e. experimental autoimmune encephalomyelitis. Indeed, dimethyl fumarate immune-modulatory effects on T cells were completely abrogated by pharmacological interference of mitochondrial reactive oxygen species production.

These data shed new light on dimethyl fumarate as bona fide immune-metabolic drug that targets the intracellular stress response in activated T cells, thereby restricting mitochondrial function and energetic capacity, providing novel insight into the role of oxidative stress in modulating cellular immune responses and T cell-mediated autoimmunity.

Reviewing the Significance of Blood-Brain Barrier Disruption in Multiple Sclerosis Pathology and Treatment

The disruption of blood–brain barrier (BBB) for multiple sclerosis (MS) pathogenesis has a double effect: early on during the onset of the immune attack and later for the CNS self-sustained ‘inside-out’ demyelination and neurodegeneration processes. This review presents the characteristics of BBB malfunction in MS but mostly highlights current developments regarding the impairment of the neurovascular unit (NVU) and the metabolic and mitochondrial dysfunctions of the BBB’s endothelial cells. The hypoxic hypothesis is largely studied and agreed upon recently in the pathologic processes in MS. Hypoxia in MS might be produced per se by the NVU malfunction or secondary to mitochondria dysfunction. We present three different but related terms that denominate the ongoing neurodegenerative process in progressive forms of MS that are indirectly related to BBB disruption: progression independent of relapses, no evidence of disease activity and smoldering demyelination or silent progression. Dimethyl fumarate (DMF), modulators of S1P receptor, cladribine and laquinimode are DMTs that are able to cross the BBB and exhibit beneficial direct effects in the CNS with very different mechanisms of action, providing hope that a combined therapy might be effective in treating MS. Detailed mechanisms of action of these DMTs are described and also illustrated in dedicated images. With increasing knowledge about the involvement of BBB in MS pathology, BBB might become a therapeutic target in MS not only to make it impenetrable against activated immune cells but also to allow molecules that have a neuroprotective effect in reaching the cell target inside the CNS.

A retrospective analysis of changes in lymphocyte levels in patients with multiple sclerosis during and after Tecfidera® treatment

Background

There are currently no best practice recommendations for lymphocyte subset monitoring for patients with multiple sclerosis (pwMS) on disease-modifying therapies including Tecfidera® (dimethyl fumarate, DMF). However, there have been several cases of pwMS on DMF without severe lymphopenia who had high CD4:CD8 T cell ratios and went on to develop progressive multifocal leukoencephalopathy.

Objective

Our objective was to characterize the changes in immune profile during and after DMF treatment in pwMS.

Methods

A retrospective analysis of longitudinal data from 299 pwMS who have been treated with DMF at the Fraser Health Multiple Sclerosis Clinic in British Columbia, Canada. The blood test results were taken from January 1, 2013 to April 1, 2020.

Results

Our results suggest that CD8+ T cells had the highest proportional decrease compared to other lymphocyte subset populations and overall lymphocyte count in response to DMF treatment. CD56+ Natural Killer cells were similarly decreased in response to DMF treatment. CD4:CD8 T cell ratio was the measurement that had the highest rate of change in response to DMF initiation and discontinuation.

Conclusion

CD8+ T cell count and CD4:CD8 T cell ratio may be a more sensitive measurement of the immune landscape of patients with MS on DMF.

The CD8 T Cell-Epstein-Barr Virus-B Cell Trialogue: A Central Issue in Multiple Sclerosis Pathogenesis

The cause and the pathogenic mechanisms leading to multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system (CNS), are still under scrutiny. During the last decade, awareness has increased that multiple genetic and environmental factors act in concert to modulate MS risk. Likewise, the landscape of cells of the adaptive immune system that are believed to play a role in MS immunopathogenesis has expanded by including not only CD4 T helper cells but also cytotoxic CD8 T cells and B cells. Once the key cellular players are identified, the main challenge is to define precisely how they act and interact to induce neuroinflammation and the neurodegenerative cascade in MS. CD8 T cells have been implicated in MS pathogenesis since the 80's when it was shown that CD8 T cells predominate in MS brain lesions. Interest in the role of CD8 T cells in MS was revived in 2000 and the years thereafter by studies showing that CNS-recruited CD8 T cells are clonally expanded and have a memory effector phenotype indicating in situ antigen-driven reactivation. The association of certain MHC class I alleles with MS genetic risk implicates CD8 T cells in disease pathogenesis. Moreover, experimental studies have highlighted the detrimental effects of CD8 T cell activation on neural cells. While the antigens responsible for T cell recruitment and activation in the CNS remain elusive, the high efficacy of B-cell depleting drugs in MS and a growing number of studies implicate B cells and Epstein-Barr virus (EBV), a B-lymphotropic herpesvirus that is strongly associated with MS, in the activation of pathogenic T cells. This article reviews the results of human studies that have contributed to elucidate the role of CD8 T cells in MS immunopathogenesis, and discusses them in light of current understanding of autoreactivity, B-cell and EBV involvement in MS, and mechanism of action of different MS treatments. Based on the available evidences, an immunopathological model of MS is proposed that entails a persistent EBV infection of CNS-infiltrating B cells as the target of a dysregulated cytotoxic CD8 T cell response causing CNS tissue damage.

Low serum neurofilament light chain values identify optimal responders to dimethyl fumarate in multiple sclerosis treatment

Serum neurofilament light chains (sNfL) are biomarkers of disease activity in multiple sclerosis (MS), but their value to predict response to treatment, and their association with patient immunological profile, need to be further explored. We studied 80 relapsing–remitting MS patients initiating dimethyl fumarate (DMF) treatment. sNfL levels were explored at baseline and at 3, 6 and 12 months by single molecule array. Blood lymphocyte subsets were measured at baseline and at 6 months by flow cytometry. Patients were followed a year and classified as NEDA (no evidence of disease activity) or ODA (ongoing disease activity). NEDA patients had lower sNfL levels at baseline (p = 0.0001), and after three (p = 0.004) and six (p = 0.03) months of DMF treatment. Consequently, low baseline sNfL values (≤ 12 pg/ml) increased the probability of NEDA (OR 5.8; CI 1.82–15.6; p = 0.002, after correcting by disease activity in the previous year), and associated with significant reductions of central memory CD4+ T lymphocytes, interferon-gamma+ CD8+ T lymphocytes, Natural Killer T cells, and memory B cells upon DMF treatment, being the highest differences in memory B cells (p < 0.0001). This shows that low baseline sNfL values identify MS patients with higher probability of optimal response to DMF and of a reduction in effector immune cells.

Lower lymphocyte counts and older age are associated with reduced multiple sclerosis disease activity during dimethyl fumarate treatment

BACKGROUND

delayed-release dimethyl fumarate (DMF) is a disease modifying therapy for relapsing-remitting multiple sclerosis (MS) with antioxidant and anti-inflammatory properties. The drug causes lymphocyte count reduction, which can lead to lymphopenia development during treatment. This is an important safety issue, due to infectious risk, mainly progressive multifocal leukoencephalopathy (PML). If the lymphocyte count influences the response to treatment is still a matter of debate, as there are contrasting contrasting data in the literature. Considering this, we aimed to identify DMF induced lymphopenia risk factors and to evaluate lymphopenia impact on MS disease activity in a real world setting.

METHODS

a retrospective study on 135 MS patients receiving DMF with a mean treatment duration of 32.3±15.9 months was performed. Baseline and follow-up demographic, clinical, magnetic resonance imaging (MRI) and laboratory data were collected.

RESULTS

44 patients (32.6%) developed lymphopenia, with 11 (8.1%) grade 1, 23 (17.0%) grade 2 and 10 (7.4 %) grade 3. Older age and lower basal absolute lymphocyte count were found to be associated with lymphopenia development on a binary regression model (p<0.001 and p=0.009). When compared with non lymphopenic+lymphopenia grade 1 patients, those experiencing lymphopenia grade 2+3 had longer disease activity free survival (p<0.001), fewer clinical relapses (p=0.005) and lower MRI disease activity (p≤0.001). On Cox regression model, older age and lymphopenia grade 2+3 were found to be protective factors against disease activity (HR=0.966; 95% C.I.=0.942-0.992; p=0.009 for age; HR=0.137; 95% C.I.=0.043-0.439; p=0.001 for lymphopenia grade 2+3) and MRI disease activity (HR=0.968; 95% C.I.=0.941-0.997; p=0.030 for age; HR=0.142; 95% C.I.=0.034-0.591; p=0.007 for lymphopenia grade 2+3). Only lymphopenia grade 2+3 was found to be a predictor of clinical relapses (HR=0.970; 95% C.I.=0.936-1.005; p=0.095 for age; HR=0.115; 95% C.I.=0.016-0.854; p=0.034 for lymphopenia grade 2+3), with a protective effect.

CONCLUSION

older age and lower basal lymphocyte count were found to be associated with lymphopenia development. Lymphopenia grade 2+3 and older age could be protective against clinical and radiologic disease activity during DMF treatment.

Severe Relapses of Neuromyelitis Optica Spectrum Disorder During Treatment With Dimethyl Fumarate

ABSTRACT

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune demyelinating disease of the central nervous system, characterized by a specific antibody that selectively binds aquaporin-4 channel.This is a report of an NMOSD case, with severe attacks of optic neuritis and myelitis after initiate of dimethyl fumarate (DMF).We suggested that DMF could deteriorate the neuromyelitis optica (NMO) disease course, which results in serious morbidity and mortality in patients. Thus, initiation of DMF should be avoided before ruling out NMOSD in patients experiencing demyelinating attacks, especially in the case of recurrent optic neuritis or myelopathy and concurrency of other rheumatologic diseases.

Calming the (Cytokine) Storm: Dimethyl Fumarate as a Therapeutic Candidate for COVID-19

COVID-19 has rapidly spread worldwide and incidences of hospitalisation from respiratory distress are significant. While a vaccine is in the pipeline, there is urgency for therapeutic options to address the immune dysregulation, hyperinflammation and oxidative stress that can lead to death. Given the shared pathogenesis of severe cases of COVID-19 with aspects of multiple sclerosis and psoriasis, we propose dimethyl fumarate as a viable treatment option. Currently approved for multiple sclerosis and psoriasis, dimethyl fumarate is an immunomodulatory, anti-inflammatory and anti-oxidative drug that could be rapidly implemented into the clinic to calm the cytokine storm which drives severe COVID-19.

Dimethyl fumarate induced lymphopenia in multiple sclerosis: A review of the literature

Dimethyl fumarate (DMF) is a first line medication for multiple sclerosis. It has a favourable safety profile, however, there is concern regarding the occurrence of moderate-severe and sustained lymphopenia and the associated risk of progressive multifocal leukoencephalopathy. We carried out an extensive literature review to understand the molecular mechanisms underlying this adverse reaction. Dynamic changes in certain components of the immune system are likely to be important for the therapeutic effects of DMF, including depletion of memory T cells and decrease in activated T cells together with expansion of naïve T cells. Similar modifications were reported for the B cell components. CD8⁺ T cells are particularly susceptible to DMF-induced cell death, with marked reductions observed in lymphopenic subjects. The reasons underlying such increased sensitivity are not known, nor it is known how expansion of other lymphocyte subsets occurs. Understanding the molecular mechanisms underlying DMF action is challenging: in vivo DMF is rapidly metabolized to monomethyl fumarate (MMF), a less potent immunomodulator in vitro. Pharmacokinetics indicate that MMF is the main active species in vivo. However, the relative importance of DMF and MMF in toxicity remains unclear, with evidence presented in favour of either of the compounds as toxic species. Pharmacogenetic studies to identify genetic predictors of DMF-induced lymphopenia are limited, with inconclusive results. A role of the gut microbiome in the pharmacological effects of DMF is emerging. It is clear that further investigations are necessary to understand the mechanisms of DMF-induced lymphopenia and devise preventive strategies. Periodic monitoring of absolute lymphocyte counts, currently performed in clinical practise, allows for the early detection of lymphopenia as a risk-minimization strategy.

Dimethyl fumarate-induced lymphocyte count drop is related to clinical effectiveness in relapsing-remitting multiple sclerosis

BACKGROUND AND PURPOSE

Dimethyl fumarate (DMF) causes a mean lymphocyte count drop of approximately 30% in relapsing-remitting multiple sclerosis (RRMS) patients. The relationship between this reduction and DMF effectiveness is controversial. The objective was to investigate if the decrease in absolute lymphocyte count (ALC) from baseline during DMF treatment is associated with clinical and magnetic resonance imaging (MRI) disease activity. A secondary aim was to evaluate ALC variations over time in a real-life cohort of DMF-treated patients.

METHODS

Demographic, laboratory, clinical and MRI data were collected in this observational multicentre study, conducted on RRMS patients treated with DMF for at least 6 months. Multivariate Cox models were performed to evaluate the impact of 6-month ALC drop on time to no evidence of disease activity (NEDA-3) status loss. NEDA-3 is defined as absence of clinical relapses, MRI disease activity and confirmed disability progression.

RESULTS

In all, 476 patients (312 females, age at DMF start 38.4 ± 9.97 years) were analysed up to 5-year follow-up. A greater lymphocyte decrease was associated with a lower risk of NEDA-3 status loss (hazard ratio 0.87, P = 0.01). A worse outcome in patients with lower ALC drop (<11.5%), compared with higher tertiles (11.5%-40.5% and >40.5%), was observed (P = 0.008). The nadir of ALC drop (-33.6%) and 35% of grade III lymphopaenia cases occurred after 12 months of treatment.

CONCLUSION

A higher lymphocyte count drop at 6 months is related to better outcomes in DMF-treated patients. A careful ALC monitoring should be pursued up to 24 months of treatment.

Safety of dimethyl fumarate for multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

The safety profile of dimethyl fumarate (DMF) for multiple sclerosis (MS) is not fully understood.

OBJECTIVE

To systematically review the literature for adverse events (AE) associated with DMF for MS.

METHODS

We searched MEDLINE, EMBASE, CINAHL, Web of Science, CENTRAL, and clinicaltrials.gov for articles published from database inception to May/2019. Studies (observational and randomized controlled trials (RCTs)) reporting AEs, serious AEs (SAE), or discontinuation due to AEs were included. We summarized the proportion of DMF-exposed patients affected and calculated the risk ratios (RR) and number needed to treat for an additional harmful outcome (NNTH) and 95% confidence intervals (CI) for the DMF relative to placebo-exposed participants. RCT findings were pooled via meta-analyses.

RESULTS

Twenty-one observational studies, 4 RCTs, 1 RCT extension study, and 2 open-label studies were included, totalling 12,380 MS patients on DMF followed for an average of 19.8 months. Compared to placebo, DMF-exposed patients had a higher risk of grade III/IV lymphopenia (NNTH = 28.8;95%CI:20.2-50.5), pruritus (NNTH = 22.1;95%CI:14.0-52.3), flushing (NNTH = 3.7;95%CI:3.3-4.1), gastrointestinal related events (NNTH = 5.7;95%CI:3.5-15.7), nausea (NNTH = 23.4;95%CI:14.9-54.7), diarrhea (NNTH = 21.2;95%CI:13.6-47.6), and abdominal pain (NNTH = 19.2;95%CI:12.9-37.9). Patients discontinued DMF because of GI symptoms (498/5619;8.9%), lymphopenia (163/4003;4.1%), and flushing (173/4779;3.6%). From pooled analyses of 4 RCTs, AE risks were higher in the DMF versus placebo groups (RR = 1.37;95%CI:1.27-1.48), but SAEs were similar (RR = 1.01;95%CI:0.77-1.33).

CONCLUSION

Over the short-term, DMF was associated with a higher risk of AEs. The NNTH included 4 for flushing, 6 for gastrointestinal complaints, and 29 for severe or life-threatening (grade III/IV) lymphopenia. The longer-term safety of DMF, including consequences of lymphopenia remain unknown.

An evaluation of dimethyl fumarate for the treatment of relapsing remitting multiple sclerosis

INTRODUCTION

In recent years there has been a dramatic rise in available disease-modifying therapies for the treatment of relapsing multiple sclerosis (MS). Dimethyl fumarate (DMF) is an oral drug approved by the FDA for relapsing MS with unique immunomodulatory and cytoprotective effects.

AREAS COVERED

Herein, the authors provide the reader with a review of the literature obtained via a PubMed database search and provide their expert opinion on the use of DMF in clinical practice. The article details DMF's mechanism of action, long-term data on efficacy, tolerability and safety.

EXPERT OPINION

Since approval, growing experience with DMF in clinical practice demonstrates a combination of efficacy, ease of administration along with an acceptable safety profile. The authors believe that DMF is a valuable long-term treatment option in patients with relapsing MS. However, long-term follow up studies are needed to provide further data on progressive multifocal leukoencephalopathy (PML) risk stratification for MS patients on treatment with DMF. Indeed, despite the strong association with lymphopenia, not all patients with DMF associated PML experienced prolonged overall lymphopenia, suggesting that additional predictive metrics are still needed.

Impact of treatment on cellular immunophenotype in MS: A cross-sectional study

Objective

To establish cytometry profiles associated with disease stages and immunotherapy in MS.

Methods

Demographic/clinical data and peripheral blood samples were collected from 227 patients with MS and 82 sex- and age-matched healthy controls (HCs) enrolled in a cross-sectional study at 4 European MS centers (Spain, Italy, Germany, and Norway). Flow cytometry of isolated peripheral blood mononuclear cells was performed in each center using specifically prepared antibody-cocktail Lyotubes; data analysis was centralized at the Genoa center. Differences in immune cell subsets were assessed between groups of untreated patients with relapsing-remitting or progressive MS (RRMS or PMS) and HCs and between groups of patients with RRMS taking 6 commonly used disease-modifying drugs.

Results

In untreated patients with MS, significantly higher frequencies of Th17 cells in the RRMS population compared with HC and lower frequencies of B-memory/B-regulatory cells as well as higher percentages of B-mature cells in patients with PMS compared with HCs emerged. Overall, the greatest deviation in immunophenotype in MS was observed by treatment rather than disease course, with the strongest impact found in fingolimod-treated patients. Fingolimod induced a decrease in total CD4⁺ T cells and in B-mature and B-memory cells and increases in CD4⁺ and CD8⁺ T-regulatory and B-regulatory cells.

Conclusions

Our highly standardized, multisite cytomics data provide further understanding of treatment impact on MS immunophenotype and could pave the way toward monitoring immune cells to help clinical management of MS individuals.

IL-17+ CD8+ T cell suppression by dimethyl fumarate associates with clinical response in multiple sclerosis

IL-17-producing CD8⁺ (Tc17) cells are enriched in active lesions of patients with multiple sclerosis (MS), suggesting a role in the pathogenesis of autoimmunity. Here we show that amelioration of MS by dimethyl fumarate (DMF), a mechanistically elusive drug, associates with suppression of Tc17 cells. DMF treatment results in reduced frequency of Tc17, contrary to Th17 cells, and in a decreased ratio of the regulators RORC-to-TBX21, along with a shift towards cytotoxic T lymphocyte gene expression signature in CD8⁺ T cells from MS patients. Mechanistically, DMF potentiates the PI3K-AKT-FOXO1-T-BET pathway, thereby limiting IL-17 and RORγt expression as well as STAT5-signaling in a glutathione-dependent manner. This results in chromatin remodeling at the Il17 locus. Consequently, T-BET-deficiency in mice or inhibition of PI3K-AKT, STAT5 or reactive oxygen species prevents DMF-mediated Tc17 suppression. Overall, our data disclose a DMF-AKT-T-BET driven immune modulation and suggest putative therapy targets in MS and beyond.

Dimethyl fumarate (DMF) is a therapy for multiple sclerosis (MS) with undetermined mechanism of action. Here the authors find that clinical response to DMF associates with decrease in IL-17-producing CD8⁺ T cells (Tc17), delineate molecular pathways involved, and show that DMF suppresses Tc17 pathogenicity in a mouse model of MS.

Dimethyl fumarate therapy reduces memory T cells and the CNS migration potential in patients with multiple sclerosis

BACKGROUND

Dimethyl fumarate (DMF) is a disease-modifying therapy for patients with relapsing-remitting multiple sclerosis (RRMS). T cells are major contributors to the pathogenesis of RRMS, where they regulate the pathogenic immune response and participate in CNS lesion development.

OBJECTIVES

In this study we evaluate the therapeutic effects of DMF on T cell subpopulations, their CNS migration potential and effector functions.

METHODS

Blood and CSF from untreated and DMF-treated patients with RRMS and healthy donors were analyzed by flow cytometry.

RESULTS

DMF reduced the prevalence of circulating proinflammatory CD4+ and CD8+ memory T cells, whereas regulatory T cells were unaffected. Furthermore, DMF reduced the frequency of CD4+ T cells expressing CNS-homing markers. In coherence, we found a reduced recruitment of CD4+ but not CD8+ T cells to CSF. We also found that monomethyl fumarate dampened T cell proliferation and reduced the frequency of TNF-α, IL-17 and IFN-γ producing T cells.

CONCLUSION

DMF influences the balance between proinflammatory and regulatory T cells, presumably favoring a less proinflammatory environment. DMF also reduces the CNS migratory potential of CD4+ T cells whereas CD8+ T cells are less affected. Altogether, our study suggests an anti-inflammatory effect of DMF mainly on the CD4+ T cell compartment.

Selective Brain Network and Cellular Responses Upon Dimethyl Fumarate Immunomodulation in Multiple Sclerosis

Background: Efficient personalized therapy paradigms are needed to modify the disease course and halt gray (GM) and white matter (WM) damage in patients with multiple sclerosis (MS). Presently, promising disease-modifying drugs show impressive efficiency, however, tailored markers of therapy responses are required. Here, we aimed to detect in a real-world setting patients with a more favorable brain network response and immune cell dynamics upon dimethyl fumarate (DMF) treatment. Methods: In a cohort of 78 MS patients we identified two thoroughly matched groups, based on age, disease duration, disability status and lesion volume, receiving DMF (n = 42) and NAT (n = 36) and followed them over 16 months. The rate of cortical atrophy and deep GM volumes were quantified. GM and WM network responses were characterized by brain modularization as a marker of regional and global structural alterations. In the DMF group, lymphocyte subsets were analyzed by flow cytometry and related to clinical and MRI parameters. Results: Sixty percent (25 patients) of the DMF and 36% (13 patients) of the NAT group had disease activity during the study period. The rate of cortical atrophy was higher in the DMF group (-2.4%) compared to NAT (-2.1%, p < 0.05) group. GM and WM network dynamics presented increased modularization in both groups. When dividing the DMF-treated cohort into patients free of disease activity (n = 17, DMF_R) and patients with disease activity (n = 25, DMF_NR) these groups differed significantly in CD8+ cell depletion counts (DMF_R: 197.7 ± 97.1/μl; DMF_NR: 298.4 ± 190.6/μl, p = 0.03) and also in cortical atrophy (DMF_R: -1.7%; DMF_NR: -3.2%, p = 0.01). DMF_R presented reduced longitudinal GM and WM modularization and less atrophy as markers of preserved structural global network integrity in comparison to DMF_NR and even NAT patients. Conclusions: NAT treatment contributes to a reduced rate of cortical atrophy compared to DMF therapy. However, patients under DMF treatment with a stronger CD8+ T cell depletion present a more favorable response in terms of cortical integrity and GM and WM network responses. Our findings may serve as basis for the development of personalized treatment paradigms.

Lymphocyte Count and Body Mass Index as Biomarkers of Early Treatment Response in a Multiple Sclerosis Dimethyl Fumarate-Treated Cohort

Introduction: In relapsing Multiple Sclerosis (RMS) patients treated with disease modifying drugs (DMDs), few data are available regarding the biomarkers of treatment response. We aimed to assess the predictive value of lymphocyte count (LC) and Body Mass Index (BMI) for treatment response in a real life setting of dimethyl fumarate (DMF) treated patients. Materials and Methods: We included in our observational analysis 338 patients who were prescribed DMF in an Italian MS Center. We collected clinical and demographic data at the beginning of DMF (T0), and assessed White Blood Cells (WBC) and LC at T0 and at 3 (T3), 6 (T6), 9 (T9), and 12 (T12) months. Gadolinium enhancing (Gd+), new T2 lesions and relapses within the first year of treatment (T12) were recorded in order to evaluate clinical activity at 12 months. Analysis of correlation was performed to correlate WBC, LC and BMI with clinical and radiological responses. We evaluated whether BMI or LC can predict treatment response by using multivariate logistic regression models at each follow-up. Results: Our cohort was followed up for a mean period of 19.8 ± 6.8 months. The mean BMI at baseline was 24.19 ± 4.48. The multivariate models gave as predictive factors for Gd+ lesions at T12, LC at T3 (OR = 1.003, 95% CI = 1.00-1.07; p = 0.046) and baseline BMI (OR = 0.71, 95% CI = 0.52-0.98; p = 0.037). Predictive factors for new T2 lesions at T12 were LC at T3 (OR = 1.01 95%CI = 1.00-1.95; p = 0.005) and baseline BMI (OR = 0.99, 95% CI = 0.98-1.00; p = 0.026). Conclusions: In our real life-experience, BMI and LC may be early biomarkers to predict treatment response during DMF.

Effect of dimethyl fumarate on lymphocytes in RRMS: Implications for clinical practice

OBJECTIVE

To assess functional changes in lymphocyte repertoire and subsequent clinical implications during delayed-release dimethyl fumarate (DMF) treatment in patients with multiple sclerosis.

METHODS

Using peripheral blood from several clinical trials of DMF, immune cell subsets were quantified using flow cytometry. For some patients, lymphocyte counts were assessed after DMF discontinuation. Incidence of adverse events, including serious and opportunistic infections, was assessed.

RESULTS

In DMF-treated patients, absolute lymphocyte counts (ALCs) demonstrated a pattern of decline followed by stabilization, which also was reflected in the global reduction in numbers of circulating functional lymphocyte subsets. The relative frequencies of circulating memory T- and B-cell populations declined and naive cells increased. No increased incidence of serious infection or malignancy was observed for patients treated with DMF, even when stratified by ALC or T-cell subset frequencies. For patients who discontinued DMF due to lymphopenia, ALCs increased after DMF discontinuation; recovery time varied by ALC level at discontinuation. T-cell subsets closely correlated with ALCs in both longitudinal and cross-sectional analyses.

CONCLUSIONS

DMF shifted the immunophenotype of circulating lymphocyte subsets. ALCs were closely correlated with CD4⁺ and CD8⁺ T-cell counts, indicating that lymphocyte subset monitoring is not required for safety vigilance. No increased risk of serious infection was observed in patients with low T-cell subset counts. Monitoring ALC remains the most effective way of identifying patients at risk of subsequently developing prolonged moderate to severe lymphopenia, a risk factor for progressive multifocal leukoencephalopathy in DMF-treated patients.

TRIAL REGISTRATION NUMBERS

EUDRA CT 2015-001973-42, NCT00168701, NCT00420212, NCT00451451, and NCT00835770.

Insight into the mechanism of action of dimethyl fumarate in multiple sclerosis

Dimethyl fumarate (DMF) is an oral, disease-modifying agent for the treatment of relapsing-remitting multiple sclerosis (RRMS). However, details regarding its mode of action are still emerging. It is believed that the mode of action of DMF involves both nuclear factor erythroid-derived 2-related factor (Nrf2)-dependent and independent pathways, which lead to an anti-inflammatory immune response due to type II myeloid cell and Th2 cell differentiation and neuroprotection. In this review, we will focus on the molecular and signaling effects of DMF that lead to changes in peripheral immune cell composition and function, alteration in CNS cell-specific functions, and effect on the blood-brain barrier.

Fumaric acid ester-induced T-cell lymphopenia in the real-life treatment of psoriasis

Background

Fumaric acid esters (FAEs) are used to treat psoriasis and are known to cause lymphopenia in roughly 60% of the patients. Much remains to be elucidated about the biological effects of FAEs on lymphocytes.

Objective

To evaluate the influence of long‐term FAE (Fumaderm^®) treatment on peripheral blood CD4⁺ and CD8⁺ T cells, CD19⁺ B cells and CD56⁺ natural killer (NK) cells in psoriasis.

Methods

In this single‐centre retrospective observational subcohort study, we obtained leucocyte and lymphocyte subset counts before initiating FAE therapy in 371 psoriasis patients (mean age, 47.8 years; 63.3% males) and monitored them during treatment (mean treatment duration, 2.9 years). Multiparametric flow cytometry was used for immunophenotyping.

Results

FAEs significantly reduced the numbers of CD4⁺ T, CD8⁺ T, CD19⁺ B and CD56⁺NK cells. Among lymphocyte subsets, the mean percentage reduction from baseline was always highest for CD8⁺ T cells, with a peak of 55.7% after 2 years of therapy. The risk of T‐cell lymphopenia increased significantly with the age of the psoriasis patients at the time that FAE therapy was initiated. It was significantly decreased for the combination therapy with methotrexate and folic acid (vitamin B9) supplementation. Supporting evidence was found suggesting that T‐cell lymphopenia enhances the effectiveness of FAE therapy.

Conclusions

Monitoring distinct T‐cell subsets rather than just absolute lymphocyte counts may provide more meaningful insights into both the FAE treatment safety and efficacy. We therefore suggest optimizing pharmacovigilance by additionally monitoring CD4⁺ and CD8⁺ T‐cell counts at regular intervals, especially in patients of middle to older age. Thus, further prospective studies are needed to establish evidence‐based recommendations to guide dermatologists in the management of psoriasis patients who are taking FAEs and who develop low absolute T‐cell counts.

Dimethyl fumarate treatment induces lipid metabolism alterations that are linked to immunological changes

Objective

Identify metabolic changes produced by dimethyl fumarate (DMF) treatment and link them to immunological effects.

Methods

We enrolled 18 MS patients and obtained blood prior to DMF and 6 months postinitiation. We also enrolled 18 healthy controls for comparison. We performed global metabolomics on plasma and used weighted correlation network analysis (WGCNA) to identify modules of correlated metabolites. We identified modules that changed with treatment, followed by targeted metabolomics to corroborate changes identified in global analyses. We correlated changes in metabolite modules and individual metabolites with changes in immunological parameters.

Results

We identified alterations in lipid metabolism after DMF treatment – increases in two modules (phospholipids, lysophospholipids and plasmalogens) and reduction in one module (saturated and poly‐unsaturated fatty acids) eigen‐metabolite values (all P < 0.05). Change in the fatty acid module was greater in participants who developed lymphopenia and was strongly associated with both reduction in absolute lymphocyte counts (r = 0.65; P = 0.005) and change in CD8+ T cell subsets. We also noted significant correlation of change in lymphocyte counts with multiple fatty acid levels (measured by targeted or untargeted methods).

Interpretation

This study demonstrates that DMF treatment alters lipid metabolism and that changes in fatty acid levels are related to DMF‐induced immunological changes.

Dimethyl fumarate therapy suppresses B cell responses and follicular helper T cells in relapsing-remitting multiple sclerosis

Background:

Dimethyl fumarate (DMF) is a disease-modifying therapy used for patients with relapsing-remitting multiple sclerosis (RRMS). B cells are important contributors to the pathogenesis of RRMS, where they regulate the inflammatory immune responses and participate in development of lesions in the central nervous system (CNS). The impact of DMF on B cell subpopulations remains incompletely understood.

Objectives:

In this study, we evaluated the effects of DMF on B cell subpopulations and their effector functions.

Methods:

Blood from 21 DMF-treated and 18 untreated patients with RRMS was analyzed by flow cytometry.

Results:

We found that DMF reduces the frequency of circulating antigen–experienced B cells, a reduction likely related to a reduced frequency of follicular helper T (TFH) cells and an increased frequency of follicular regulatory T (TFR) cells. Studying the impact of monomethyl fumarate (MMF), the primary metabolite of DMF, on B cell effector function in vitro showed that MMF increased the frequency of transforming growth factor (TGF)-β-producing B cells and decreased the frequency of B cells secreting lymphotoxin (LT)-α, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and to a lesser extent IL-10.

Conclusion:

In summary, these data suggest an anti-inflammatory role of DMF and its metabolite MMF on the B cell compartment.

GFAPα IgG-associated encephalitis upon daclizumab treatment of MS

Objective

To describe a case of glial fibrillary acidic protein (GFAP)α immunoglobulin G (IgG)-associated encephalitis in a patient referred to us with MS on daclizumab treatment and to summarize characteristics of 5 additional recent German MS cases of serious encephalitis along with a previously published American case of CNS vasculitis associated with daclizumab.

Methods

Evaluation of cause, clinical symptoms, and treatment response.

Results

The 6 patients included 4 women and 2 men. The median age at onset was 38 years (range 32–51 years). Clinical presentation was marked by progressing neuropsychologic and/or neurologic deficits. Additional drug rash with eosinophilia was seen in 3 patients, whereas 2 patients showed a highly active demyelinating process. Examination of CSF samples detected pleocytosis, elevated total protein levels, and GFAPα IgG antibodies, which were not found in serum. In our case, we discovered autoimmune GFAP astrocytopathy associated with encephalitis as secondary autoimmunity, which was steroid responsive. Clinical outcome of other cases was marked by partial recovery in 4 patients and persistent foster care in 1 patient.

Conclusions

Our case of GFAPα IgG-associated encephalitis along with 12 other cases of serious inflammatory brain disorders following daclizumab treatment so far indicates that interfering with NK cells and Tregs by anti-CD25 antibody therapy can result in severe secondary CNS autoimmunity in man.

Reassessing B cell contributions in multiple sclerosis

There is growing recognition that B cell contributions to normal immune responses extend well beyond their potential to become antibody-producing cells, including roles at the innate-adaptive interface and their potential to modulate the responses of other immune cells such as T cells and myeloid cells. These B cell functions can have both pathogenic and protective effects in the context of central nervous system (CNS) inflammation. Here, we review recent advances in the field of multiple sclerosis (MS), which has traditionally been viewed as primarily a T cell-mediated disease, and we consider antibody-dependent and, particularly, emerging antibody-independent functions of B cells that may be relevant in both the peripheral and CNS disease compartments.

Dimethyl fumarate induces a persistent change in the composition of the innate and adaptive immune system in multiple sclerosis patients

The effects of dimethyl fumarate (DMF) on the immune system in multiple sclerosis (MS) are not completely elucidated. In this study, an extensive immunophenotypic analysis of innate and adaptive immune cells of DMF-treated MS patients was performed. Peripheral blood immune cell phenotypes were determined using flow cytometry in a follow-up study of 12 MS patients before, after 3 and 12 months of DMF treatment and a cross-sectional study of 25 untreated and 64 DMF-treated MS patients. Direct effects of DMF on B cells were analyzed in vitro. After 12 months of DMF treatment, percentages of monocytes, natural killer cells, naive T and B cells and transitional B cells increased. Percentages of (effector) memory T cells, (non) class-switched memory B cells and double negative B cells decreased together with CD4⁺ T cells expressing interferon-γ (IFN-γ), granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin-17 (IL-17). DMF treatment was fully effective as of 6 months and directly induced apoptosis and decreased expression of costimulatory CD40, antigen presentation molecule MHCII and B cell activating factor receptor (BAFFR) on B cells. DMF induced a persistent change of the immune system of MS patients, directly induced apoptosis and reduced expression of functional markers on B cells.

Emerging Understanding of the Mechanism of Action for Dimethyl Fumarate in the Treatment of Multiple Sclerosis

Dimethyl fumarate (DMF) is an effective treatment option for relapsing-remitting multiple sclerosis (MS), but its therapeutic mechanism of action has not been fully elucidated. A better understanding of its mechanism will allow for the development of assays to monitor its clinical efficacy and safety in patients, as well as guide the development of the next generation of therapies for MS. In order to build the foundation for determining its mechanism, we reviewed the manner in which DMF alters lymphocyte subsets in MS patients, its impact on clinical efficacy and safety, as well as its molecular effects in cellular and animal models. DMF decreases absolute lymphocyte counts, but does not affect all subsets uniformly. CD8⁺ T-cells are the most profoundly affected, but reduction also occurs in the CD4⁺ population, particularly within the pro-inflammatory T-helper Th1 and Th17 subsets, creating a bias toward more anti-inflammatory Th2 and regulatory subsets. Similarly, B-lymphocyte, myeloid, and natural killer populations are also shifted toward a more anti-inflammatory state. In vitro and animal models demonstrate a role for DMF within the central nervous system (CNS) in promoting neuronal survival in an Nrf2 pathway-dependent manner. However, the impact of DMF directly within the CNS of MS patients remains largely unknown.

Inhibition of Acute Graft-versus-Host Disease with Retention of Graft-versus-Tumor Effects by Dimethyl Fumarate

Acute graft-versus-host disease (aGVHD) remains a clinical challenge and a major source of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Dimethyl fumarate (DMF), an activator of Nrf2, has been shown to have anti-inflammatory and immunomodulatory properties without significant immunosuppression. We therefore hypothesized that DMF could be potentially harnessed for the treatment of aGVHD with retention of graft-versus-tumor effect. In this study, we showed that DMF significantly inhibited alloreactive T cell responses in vitro in mixed lymphocyte reaction assay. Administration of DMF significantly alleviated the severity, histological damage, and the overall mortality of aGVHD in an MHC-mismatched aGVHD model. DMF administration reduced the activation and effector function of donor T cells in vitro and in vivo. In addition, DMF treatment upregulated antioxidant enzymes heme oxygenase-1 and glutathione S-transferase-α1 expressions. Furthermore, DMF treatment markedly increased the frequencies of Treg cells. Depletion of CD25⁺ cells in DMF recipients aggravated aGVHD mortality compared with IgG control recipients. DMF could promote Treg cell differentiation in a dose dependent manner by upregulating TGF-β expression in vitro. Most importantly, DMF administration preserved graft-versus-leukemia effect after bone marrow transplantation. In conclusion, our findings demonstrated DMF as a promising agent for the prevention of aGVHD after allo-HSCT.

Immune response to vaccines is maintained in patients treated with dimethyl fumarate

Objectives:

To investigate the immune response to vaccinations in patients with relapsing forms of MS treated with delayed-release dimethyl fumarate (DMF) vs nonpegylated interferon (IFN).

Methods:

In this open-label, multicenter study, patients received 3 vaccinations: (1) tetanus-diphtheria toxoid (Td) to test T-cell–dependent recall response, (2) pneumococcal vaccine polyvalent to test T-cell–independent humoral response, and (3) meningococcal (groups A, C, W-135, and Y) oligosaccharide CRM₁₉₇ conjugate to test T-cell–dependent neoantigen response. Eligible patients were aged 18–55 years, diagnosed with relapsing-remitting MS (RRMS), and either treated for ≥6 months with an approved dose of DMF or for ≥3 months with an approved dose of nonpegylated IFN. Primary end point was the proportion of patients with ≥2-fold rise in antitetanus serum IgG levels from prevaccination to 4 weeks after vaccination.

Results:

Seventy-one patients (DMF treated, 38; IFN treated, 33) were enrolled. The mean age was 45.3 years (range 27–55); 86% were women. Responder rates (≥2-fold rise) to Td vaccination were comparable between DMF- and IFN-treated groups (68% vs 73%). Responder rates (≥2-fold rise) were also similar between DMF- and IFN-treated groups for diphtheria antitoxoid (58% vs 61%), pneumococcal serotype 3 (66% vs 79%), pneumococcal serotype 8 (95% vs 88%), and meningococcal serogroup C (53% vs 53%), all p > 0.05. In a post hoc analysis, no meaningful differences were observed between groups in the proportion of responders when stratified by age category or lymphocyte count.

Conclusions:

DMF-treated patients mount an immune response to recall, neoantigens, and T-cell–independent antigens, which was comparable with that of IFN-treated patients and provided adequate seroprotection.

ClinicalTrials.gov identifier:

NCT02097849.

Classification of evidence:

This study provides Class II evidence that patients with RRMS treated with DMF respond to vaccinations comparably with IFN-treated patients.

Infections in Patients Receiving Multiple Sclerosis Disease-Modifying Therapies

PURPOSE OF REVIEW

This paper will systemically review the risk of infections associated with current disease-modifying treatments and will discuss pre-treatment testing recommendations, infection monitoring strategies, and patient education.

RECENT FINDINGS

Aside from glatiramer acetate and interferon-beta therapies, all other multiple sclerosis treatments to various degrees impair immune surveillance and may predispose patients to the development of both community-acquired and opportunistic infections. Some of these infections are rarely seen in neurologic practice, and neurologists should be aware of how to monitor for these infections and how to educate patients about medication-specific risks. Of particular interest in this discussion is the risk of PML in association with the recently approved B cell depleting therapy, ocrelizumab, particularly when switching from natalizumab. The risk of infection in association with MS treatments has become one of the most important factors in the choice of therapy. Balance of the overall risk versus benefit should be continuously re-evaluated during treatment.