Dimethyl fumarate-induced lymphopenia in MS due to differential T-cell subset apoptosis

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.

Characterization of lymphopenia in patients with MS treated with dimethyl fumarate and fingolimod

Objective:

Lymphopenia is a common occurrence of disease-modifying therapies (DMTs) for relapsing-remitting MS (RRMS). The aim of this study was to dissect the prevalence of various lymphocyte subsets in patients with RRMS treated with 2 DMTs commonly associated with lymphopenia, dimethyl fumarate (DMF), and fingolimod (FTY).

Methods:

Multicolor flow cytometry and multiplex assays were used to identify up to 50 lymphocyte subpopulations and to examine the expression of multiple cytokines in selected patients. We compared patients untreated (NT) or treated with FTY or DMF who did (DMF-L) or did not (DMF-N) develop lymphopenia.

Results:

All FTY patients developed lymphopenia in both T-cell and B-cell compartments. CD41 T cells were more affected by this treatment than CD81 cells. In the B-cell compartment, the CD271IgD2 subpopulation was reduced. T cells but not B cells were significantly reduced in DMF-L. However, within the B cells, CD271 cells were significantly lower. Both CD41 and CD81 subpopulations were reduced in DMF-L. Within the remaining CD41 and CD81 compartments, there was an expansion of the naive subpopulation and a reduction of the effector memory subpopulation. Unactivated lymphocyte from DMF-L patients had significantly higher levels of interferon-γ, interleukin (IL)-12, IL-2, IL-4, IL-6, and IL-1β compared with DMF-N. In plasma, TNFβ was significantly higher in DMF-N and DMF-L compared with NT, whereas CCL17 was significantly higher in DMF-L compared with NT and DMF-N.

Conclusions:

This study shows that different treatments can target different lymphocyte compartments and suggests that lymphopenia can induce compensatory mechanisms to maintain immune homeostasis.

Predictors of hematological abnormalities in multiple sclerosis patients treated with fingolimod and dimethyl fumarate and impact of treatment switch on lymphocyte and leukocyte count

BACKGROUND

There is limited data regarding the predictors of hematological abnormalities in multiple sclerosis (MS) patients treated with dimethyl fumarate (DMF) or fingolimod (FNG), and the impact of treatment switch on lymphocyte and leukocyte count METHODS: We identified 405 patients on DMF and 300 patients on FNG (treatment duration: at least 12 month) within a large prospective study of MS patients conducted at the Partners MS Center, Brigham and Women's Hospital (CLIMB study) between Jan 2011 to Feb 2016. Patients had complete blood counts with differentials at baseline and every 6 months while on treatment. Most participants had a clinical visit with complete neurologic examinations every 6 months and brain MRI scan every 12 months. T cell subset profile was available for subgroup of patients (n = 116).

RESULTS

In the FNG group, the risk of developing lymphopenia grade 4 (< 200) was higher in female patients (p = 0.0117) and those who were previously treated with natalizumab (p = 0.0116), while the risk of lymphopenia grade 3b+4 (< 350) was higher in female patients (p = 0.0009). DMF treated patients with lower baseline lymphocyte count had a higher chance of developing lymphopenia grade 2 (< 800) (p < 0.0001) or 2+3 (< 500) (p < 0.0001). We examined the effect of treatment switch between DMF and FNG. No significant recovery in lymphocyte and leukocyte count was observed after treatment switches. Reduced dosing of FNG in patients with lymphopenia led to increase in lymphocyte count but also increased disease activity in 25% of patients.

CONCLUSION

Female sex and prior exposure to natalizumab increased the probability of lymphopenia on FNG, while low absolute lymphocyte count was associated with increased risk of lymphopenia on DMF. Parallel switch did not lead to recovery from hematological abnormalities. Long-term studies with larger number of patients are required to confirm our findings and to establish guidelines for prediction and management of hematological abnormalities.

Relapse outcomes, safety, and treatment patterns in patients diagnosed with relapsing-remitting multiple sclerosis and initiated on subcutaneous interferon β-1a or dimethyl fumarate: a real-world study

OBJECTIVE

To estimate real-world treatment patterns, safety, and relapse outcomes of subcutaneous (sc) interferon (IFN) β-1a (Rebif) vs dimethyl fumarate (DMF; Tecfidera), to treat relapsing-remitting multiple sclerosis (RRMS).

METHODS

A US retrospective chart review of 450 randomly selected adults newly diagnosed with RRMS who received sc IFN β-1a (n = 143) or DMF (n = 307) was conducted. Patients were either (a) treatment-naïve, initiating first-line treatment with sc IFN β-1a or DMF, or (b) previously treated, switching to sc IFN β-1a or DMF. Two years' follow-up data were captured. Patient characteristics, persistence, and adverse events between treatment groups were compared using t-tests or Chi-square tests. Kaplan-Meier curves with log-rank tests and Cox proportional hazards models were used to compare time to, and risk of non-persistence. Annualized Relapse Rates (ARR) were calculated using a robust variance Poisson model adjusting for covariates. Propensity scores were used to address possible selection bias.

RESULTS

One hundred and twelve patients became non-persistent, most commonly due to an adverse event (n = 37). No difference was observed in time to overall non-persistence between sc IFN β-1a and DMF patients. Among treatment-naïve patients, those receiving DMF had 2.4-times the risk (HR = 2.439, 95% CI = 1.007-5.917, p = .0483) of experiencing a discontinuation than patients receiving sc IFN β-1a. Non-persistent patients receiving DMF had 2.3-times the risk (HR = 2.311, 95% CI = 1.350-3.958, p = .0023) of experiencing an adverse event at a given time point than patients prescribed sc IFN β-1a. No differences in relapse risk or ARR between sc IFN β-1a- and DMF-treated patients were observed.

CONCLUSIONS

sc IFN β-1a-treated patients had comparable persistence and relapse outcomes, and better safety outcomes vs DMF-treated patients across 2 years.

Dimethyl fumarate influences innate and adaptive immunity in multiple sclerosis

INTRODUCTION

The mode of action of dimethyl fumarate (DMF), an immunomodulatory treatment for relapsing-remitting multiple sclerosis (RRMS), has not yet been fully elucidated. While in-vitro experiments and animal studies suggest effects on immune cell survival, proliferation, migration and oxidative stress response, corresponding observations from human studies are lacking. This study aims to characterize ex-vivo and in-vivo effects in a cohort of DMF treated RRMS patients.

METHODS

Blood samples were collected from twenty well-characterized RRMS patients at baseline and after 3, 6 and 12 months of DMF treatment and an age- and gender-matched cohort of 20 healthy individuals at 0 and 3 months. Leukocyte subpopulations, immunoglobulin levels and cytokine secretion were measured. T cells were assessed for their levels of reactive oxygen species (ROS), metabolic status and their proliferative capacity. Levels of antioxidants were determined in serum by mass spectrometry. Responses of monocyte activation markers as well as NFkB and MAPK pathways to DMF were analysed.

RESULTS

Upon DMF treatment, all lymphocyte subpopulations dropped significantly over the course of 12 months with cytotoxic and effector T cells being affected most significantly. DMF induced cell death and inhibited proliferation of T cells in-vitro. Interestingly, this anti-proliferative effect decreased under treatment. In-vivo DMF treatment led to decreased T cell glycolysis and higher turn-over of antioxidants. In line with these results a significant increase of cytosolic ROS levels after 3 months treatment was detected in T cells. In-vitro DMF treatment reduced NFkB (p65) translocation to the nucleus and MAPK (p38) levels decreased upon stimulation with monomethyl fumarate (MMF) in-vitro and ex-vivo. Consequently, the expression of co-stimulatory molecules like CD40 and CD150 was decreased in antigen presenting cells both in-vitro and ex-vivo.

CONCLUSION

This study translates knowledge from in-vitro and animal studies on DMF into the clinical setting. Our data suggest that DMF not only alters lymphocyte composition, but also has profound effects on proliferation and induces oxidative stress in T cells. It also acts on innate immunity by reducing the activation status of antigen presenting cells (APCs) via NFkB and MAPK inactivation.

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.

Medical ozone promotes Nrf2 phosphorylation reducing oxidative stress and pro-inflammatory cytokines in multiple sclerosis patients

Oxidative stress and inflammation play key roles in the pathogenesis of Multiple sclerosis (MS). Different drugs have been used in the clinical practice, however, there is not a completely effective treatment. Due to its potential therapeutic action, medical ozone represents a promising approach for neurodegenerative disorders. The aim of the present study was to address the role of ozone therapy on the cellular redox state in MS patients. Ozone (20μg/ml) was administered three times per week during a month by rectal insufflation. The effect of ozone therapy on biomarkers of oxidative stress and inflammation was addressed by spectrophotometric and immunoenzymatic assays. Furthermore, we investigated the action of ozone on CK2 expression and Nrf2 phosphorylation by western blotting analysis. Medical ozone significantly improved (P < 0.05) the activity of antioxidant enzymes and increased the levels of cellular reduced glutathione. In accordance, a significant reduction (P < 0.05) of oxidative damage on lipids and proteins was observed in ozone-treated patients. As well, the levels of pro-inflammatory cytokines TNFα and IL-1β were lower after ozone treatment. Ozone therapy incremented the CK2 expression together with Nrf2 phosphorylation in mononuclear cells of MS patients. These findings suggest that ozone´s antioxidant and anti-inflammatory effects might be partially associated with an induction of Nrf2 phosphorylation and activation. These results provide new insights on the molecular events modulated by ozone, and pointed out ozone therapy as a potential therapeutic alternative for MS patients.