Immunosuppression followed by immunomodulation

Multiple sclerosis and the role of immune cells

Multiple sclerosis (MS) is a complex disease with many different immune cells involved in its pathogenesis, and in particular T cells as the most recognized cell type. Recently, the innate immune system has also been researched for its effect on the disease. Hence, cells of the immune system play vital roles in either ameliorating or exacerbating the disease. The genetic and environmental factors, as well as the etiology and pathogenesis are of utmost importance for the development of MS. An insight into the roles play by T cells, B cells, natural killer cells, and dendritic cells in MS and the animal model experimental autoimmune encephalomyelitis, will be presented. Understanding the mechanisms of action for current therapeutic modalities should help developing new therapeutic tools to treat this disease and other autoimmune diseases.

A one year follow-up study of natural killer and dendritic cells activities in multiple sclerosis patients receiving glatiramer acetate (GA)

Background

Multiple sclerosis (MS) is a chronic inflammatory, demyelinating and neurodegenerative disease. It is thought to be mediated by CD4⁺ Th1/Th17 cells. More recently, cells of the innate immune system such as dendritic cells (DCs) and natural killer (NK) cells have been in focus. Glatiramer acetate (GA) is an approved drug for treating MS patients.

Methodology/Principal Findings

In the current study we examined the activities of NK and DCs in nine relapsing remitting MS patients for up to one year after initiation of GA treatment. We observed that NK cells isolated from most of these patients have increased cytotoxic activity against K562 cells. Further analysis showed that the same NK cells lysed both autologous immature (i) and mature (m) DCs. In most patients this increased activity was correlated with increased NK cell activating cytotoxicity receptors such as NKp30, NKp44, NKp46 and NKG2D, and reduced expression of the inhibitory molecule CD158 on the surface of these NK cells. The expression of HLA-DR was increased on iDCs and mDCs in the majority of the patients, but no consistency was observed for the expression of HLA-I or HLA-E. Also, the co-stimulatory receptors CD80, CD83 or CD86 expression was down-regulated on iDCs and mDCs in most cases. Further, the expression of CCR6 was increased on mDCs at later time points of therapy (between 32–48 weeks).

Conclusions/Significance

Our results are the first showing the effects of GA treatment on NK cells in MS patients, which may impact future use of this and other drugs to treat this disease.

Treatment update in multiple sclerosis

Multiple sclerosis is the most common cause of disability in young people in the Western world. Reduced life expectancy and worsening quality of life due to increasing disability later in the disease course have significant personal and societal costs. Changes in treatment strategies and newly available treatments hope to improve the outlook for our often young patients. This paper details currently available treatments and some that are expected to reach the market shortly.

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.

Principles of a new treatment algorithm in multiple sclerosis

We are entering a new era in the management of patients with multiple sclerosis (MS). The first oral treatment (fingolimod) has now gained US FDA approval, addressing an unmet need for patients with MS who wish to avoid parenteral administration. A second agent (cladribine) is currently being considered for approval. With the arrival of these oral agents, a key question is where they may fit into the existing MS treatment algorithm. This article aims to help answer this question by analyzing the trial data for the new oral therapies, as well as for existing MS treatments, by applying practical clinical experience, and through consideration of our increased understanding of how to define treatment success in MS. This article also provides a speculative look at what the treatment algorithm may look like in 5 years, with the availability of new data, greater experience and, potentially, other novel agents.

A critical appraisal of treatment decisions in multiple sclerosis--old versus new

Interferon β and glatiramer acetate have been available for the treatment of multiple sclerosis (MS) for over a decade and their efficacy and safety are well established. These agents have detectable effects on the immune system, but have not been associated with a breakdown of immune surveillance. Novel MS therapies have been approved, or are awaiting approval, that differ from established immunotherapies with regard to their mechanisms of action, modes of administration, adverse-effect profiles and, possibly, the clinical and paraclinical benefits that they may provide for patients. Neurologists will soon be required to make complex treatment decisions with their patients on the basis of very limited clinical data and evidence. Under these circumstances, optimal assessment of risks and benefits will be challenging. In this Review, the anticipated benefits of novel therapies, including reduction in disease activity, possible prevention of disability, and improvement in quality of life, are outlined. In addition, the current acceptance of potential risks--including serious or even life-threatening adverse effects, the likelihood of which may rise with increased cumulative exposure to a particular agent--by patients with MS will be reviewed.