Interferon-beta therapy in multiple sclerosis: evidence for a clinically relevant dose response

Recent progress in epidemiology, clinical features, and therapy of multiple sclerosis in China

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system characterized by inflammation, demyelination, and neurodegeneration. It mainly affects young adults, imposing a heavy burden on families and society. The epidemiology, clinical features, and management of MS are distinct among different countries. Although MS is a rare disease in China, there are 1.4 billion people in China, so the total number of MS patients is not small. Because of the lack of specific diagnostic biomarkers for MS, there is a high misdiagnosis rate in China, as in other regions. Due to different genetic backgrounds, the clinical manifestations of MS in Chinese are different from those in the West. Herein, this review aims to summarize the disease comprehensively, including clinical profile and the status of disease-modifying therapies in China based on published population-based observation and cohort studies, and also to compare with data from other countries and regions, thus providing help to develop diagnostic guideline and the novel therapeutic drugs. Meanwhile, we also discuss the problems and challenges we face, specifically for the diagnosis and treatment of MS in the middle- and low-income countries.

Intranasal Delivery: Effects on the Neuroimmune Axes and Treatment of Neuroinflammation

This review highlights the pre-clinical and clinical work performed to use intranasal delivery of various compounds from growth factors to stem cells to reduce neuroimmune interactions. We introduce the concept of intranasal (IN) delivery and the variations of this delivery method based on the model used (i.e., rodents, non-human primates, and humans). We summarize the literature available on IN delivery of growth factors, vitamins and metabolites, cytokines, immunosuppressants, exosomes, and lastly stem cells. We focus on the improvement of neuroimmune interactions, such as the activation of resident central nervous system (CNS) immune cells, expression or release of cytokines, and detrimental effects of signaling processes. We highlight common diseases that are linked to dysregulations in neuroimmune interactions, such as Alzheimer's disease, Parkinson's disease, stroke, multiple sclerosis, and traumatic brain injury.

Type I interferon signals control Theiler's virus infection site, cellular infiltration and T cell stimulation in the CNS

Theiler's murine encephalomyelitis virus (TMEV) establishes a persistent infection in the central nervous system (CNS). To examine the role of type I interferon (IFN-I)-mediated signals in TMEV infection, mice lacking a subunit of the type I IFN receptor (IFN-IR KO mice) were utilized. In contrast to wild type mice, IFN-IR KO mice developed rapid fatal encephalitis accompanied with greater viral load and infiltration of immune cells to the CNS. The proportion of virus-specific CD4(+) and CD8(+) T cell responses in the CNS was significantly lower in IFN-IR KO mice during the early stage of infection. Levels of IFN-γ and IL-17 produced by isolated primed CD4(+) T cells in response to DCs from TMEV-infected IFN-IR KO mice were also lower than those stimulated by DCs from TMEV-infected wild type control mice. The less efficient stimulation of virus-specific T cells by virus-infected antigen-presenting cells is attributable in part to the low level expression of activation markers on TMEV-infected cells from IFN-IR KO mice. However, due to high levels of cellular infiltration and viral loads in the CNS, the overall numbers of virus-specific T cells are higher in IFN-IR KO mice during the later stage of viral infection. These results suggest that IFN-I-mediated signals play important roles in controlling cellular infiltration to the CNS and shaping local T cell immune responses.

[Subcutaneous interferon-beta-1a in the treatment of multiple sclerosis]

During the last 10 years recombinant interferon-beta-1a administered subcutaneously has been the subject of several clinical trials in relapsing remitting multiple sclerosis (RRMS), in secondary progressive MS (SPMS), as well as in clinically isolated syndromes. All of them met the criteria of evidence level class I. Consistent evidence for moderate immunomodulatory effects on clinical parameters of disease activity was gained, and even higher efficacy of IFN-beta-1a sc. on MRI activity of multiple sclerosis was proven. Indirect evidence confirmed the hypothesis of a dose-response curve for IFN-beta-1a formulations in MS. The higher efficacy of IFN-beta-1a 44 microg sc. TIW, however, also includes more adverse events such as injection site reactions, flu-like symptoms and a moderate immunogenicity. Current evidence does not allow a recommendation of IFN-beta-1a sc. as most effective first line therapy, because also the individual patient's choice in the route of administration and long-term effects of neutralizing antibodies to IFN-beta-1a sc. must be taken into account. In the long-term, IFN-beta-1a showed a beneficial safety-tolerability profile with 50 % of patients sticking to the initial immunomodulatory treatment. There were no teratogenic effects, IFN-beta-1a sc. did not enhance depressive symptoms. Data on inhibition of the progression of disease, however, remained inconclusive. Probable beneficial effects of IFN-beta-1a sc. on cognitive function or "chronic fatigue" have not been investigated yet.

A novel modification of a flow cytometric assay of phosphorylated STAT1 in whole blood lymphocytes for rapid detection of interferon-α signal in vivo

Phosphorylation of signal transducer and activator of transcription factor 1 (STAT1) is a key response in the type I interferon (IFN) signal cascade. We developed a novel flow cytometric assay for phosphotyrosine-STAT1 (p-STAT1) to rapidly monitor in vivo IFN signaling. Mouse blood stimulated with mouse IFN-alpha was hemolyzed with lysis buffer in place of lymphocyte purification, permeabilized with methanol, and stained with an Alexa Fluor 488-conjugated anti-p-STAT1 antibody. The cells were also stained with phycoerythrin (PE)-conjugated anti-CD45 antibody for eliminating debris (CD45-negative) from leukocytes (CD45-positive), and with PE covalently linked to cyanin 5-conjugated anti-Gr-1 antibody for separating lymphocytes (Gr-1-negative) and granulocytes (Gr-1-positive). When whole blood was treated with IFN-alpha, the Alexa Fluor 488 intensity of lymphocytes increased, reaching a peak within 1 h, and this increase was statistically significant at IFN-alpha concentrations of 100 U/mL and higher. When IFN-alpha was administered intravenously to mice, the Alexa Fluor 488 intensity of blood lymphocytes was increased, reaching a peak in 1 h and returning to baseline at 18 h, and this increase was dose-dependent, with statistically significant increases seen at doses of 1,000 U/body and higher. The kinetics and dose-responses of p-STAT1 levels in the spleen, lung, and liver were similar to those in blood lymphocytes. This new flow cytometric assay of p-STAT1 in peripheral blood leukocytes will be useful for examining IFN-alpha signaling and for monitoring tissue response to IFN-alpha in vivo.

Diretrizes para o tratamento da esclerosa mútipla com drogas imunomoduladoras

O tratamento de pacientes com esclerose múltipla (EM) com imunomoduladores e, mais recentemente, com imunossupressores, modificou o curso natural da doença nos últimos anos. As conclusões e recomendações elaboradas por inúmeros autores a partir de estudos multicêntricos, obrigam-nos a rever e atualizar conceitos, propondo modificações aos órgãos governamentais para aprimorar a assistência aos portadores de EM, objetivo principal deste trabalho. Assim, o Departamento Científico de Neuroimunologia da Academia Brasileira de Neurologia julgou oportuno atualizar as recomendações quanto aos critérios de diagnóstico, classificação das formas evolutivas da EM, criação dos centros de referência e uso de imunomoduladores.

Innate immune response induced by Theiler's murine encephalomyelitis virus infection

Although the causative agents of human multiple sclerosis (MS) are not known, it is suspected that a viral infection may be associated with the initiation of the disease. Several viral disease models in mice have been studied to understand the pathogenesis of demeylination. In particular, Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD) has been extensively studied as a relevant model. Various cytokines and chemokines are produced upon viral infection by different cell types, including antigen-presenting cells (APCs) such as macrophages; dendritic cells (DCs); and glial cells, such as astrocytes, microglia, and oligoden-drocytes. The upregulation of the corresponding molecules are also found in MS and are likely to play an important role in the protection and/or pathogenesis of chronic inflammatory demyelinating disease. In this review, the type of cells and molecules, gene-activation mechanisms as well as their potential roles in protection and pathogenesis will be discussed.

Is multiple sclerosis a disease that requires frequent beta interferon dosing?

The three currently available beta interferon products for the treatment of patients with relapsing-remitting multiple sclerosis (RRMS) are administered according to different regimens. Placebo-controlled clinical trials support the efficacy of both alternate-day interferon beta-1b (Betaferon) and once-a-week interferon beta-1a (Avonex), but benefits to patients are probably dependent on the regimen used. Once-weekly administration, perceived to have fewer adverse events and greater convenience, may improve compliance, whereas frequent administration might enhance efficacy. However, more frequent administration is also associated with an increase in neutralising antibody (NAb) production, relative to once weekly treatment. The issue of NAbs is complex, and their clinical relevance, if any, has yet to be fully assessed. Pharmacological evidence suggests that the effects of beta interferon on a number of biological markers is maximised when administered every 48 hours. This might arise as a result of sustained activity in the intracellular molecular signalling pathways regulating beta interferon-induced gene expression. Some evidence suggests that the increase in biological effect at higher more frequent doses is mirrored by improvements in clinical and MRI outcome measures. Two recent comparative studies demonstrated significantly better clinical and magnetic resonance imaging outcomes in patients with RRMS receiving alternate-day high-dose interferon beta-1b (250 micro g subcutaneously) or three-times-weekly high-dose interferon beta-1a compared to those receiving once weekly low-dose interferon beta-1a (30 micro g intramuscularly). Despite some methodological drawbacks, these studies indicate that the benefits of high-dose frequently administered beta interferon on relapse rate are seen soon after beginning treatment. Therefore, it seems appropriate to begin the treatment of RRMS with this dosing regimen.

Disease-modifying therapy in MS: a critical review of the literature

The use of so-called evidence-based medicine represents a structured way in which to critically assess the medical literature with the goal of defining the value of different therapeutic interventions and, ultimately, improving both physician decision-making and patient outcome. This is not a consensus-based process of the type that has often been employed previously in the development of treatment guidelines. Rather, these assessments involve a series of structured steps. Initially, the specific clinical questions to be answered are defined and the evidence is assembled following a structured literature search. Then, the individual studies are classified as to the quality of the evidence provided, and, finally, using a set of pre-specified rules, this evidence is translated into specific recommendations and conclusions. In this manner, evidence-based medicine can be a very powerful tool for practicing physicians and, consequently, it is important that they become familiar with the fundamentals of this analytical approach. It is the purpose of this manuscript, therefore, to provide an overview of this process using examples from two recently completed assessments on disease-modifying therapies in multiple sclerosis.

Intranasal administration of interferon beta bypasses the blood–brain barrier to target the central nervous system and cervical lymph nodes: a non-invasive treatment strategy for multiple sclerosis

Intranasal (i.n.) administration of IFN beta-1b was examined as a route for targeted delivery to the rat central nervous system (CNS). Intranasal administration resulted in significant delivery throughout the CNS and cervical lymph nodes with low delivery to peripheral organs. At similar blood levels, intravenous (i.v.) administration of IFN beta-1b yielded 88-98% lower CNS levels and 100-1650% greater peripheral organ levels compared to intranasal. Autoradiography confirmed much greater delivery to the CNS with intranasal administration. Intranasally administered IFN beta-1b reached the brain intact and produced tyrosine phosphorylation of IFN receptor in the CNS. Intranasal administration offers a non-invasive method of drug delivery for multiple sclerosis (MS) that bypasses the blood-brain barrier (BBB) and directly targets the CNS and lymph nodes.

Interferon-β in the treatment of relapsing–remitting multiple sclerosis

The role of interferon-beta as a disease-modifying drug (DMD) for the treatment of relapsing-remitting multiple sclerosis (RRMS) is now well established, and its efficacy has been demonstrated unequivocally in large-scale clinical trials. However, current evidence suggests that in order to increase the benefit of therapy, use of an effective drug and dosing regimen should be commenced early in the course of the disease, a finding that places new emphasis on the need for early diagnosis. Indeed, it is now known that MS lesions often develop at a subclinical level and that axonal damage occurs even in the very early stages of the disease. Moreover, such damage may be irreversible, and there is strong evidence to suggest that efficacy lost as a consequence of delay in the onset of treatment or the use of a suboptimal drug regimen cannot be regained. At present, the choice of interferon-beta is complicated by the availability of 3 different products, each with a different dosing regimen. Although the optimal interferon-beta dosing regimen for RRMS has been the focus of much discussion, the issues of dose, and particularly dosing frequency, have not been satisfactorily addressed in clinical trials until recently. Over the last 2 years, however, 3 comparative studies of interferon-beta products have been conducted. The results obtained from these recent trials underline the importance of both dose and dosing frequency and indicate that for improved efficacy in RRMS, interferon-beta therapy should be administered frequently at the highest tolerable, and thus most effective, dose.

Dendritic cells mediate NK cell help for Th1 and CTL responses: two-signal requirement for the induction of NK cell helper function

Early stages of viral infections are associated with local recruitment and activation of dendritic cells (DC) and NK cells. Although activated DC and NK cells are known to support each other's functions, it is less clear whether their local interaction in infected tissues can modulate the subsequent ability of migrating DC to induce T cell responses in draining lymph nodes. In this study, we report that NK cells are capable of inducing stable type 1-polarized "effector/memory" DC (DC1) that act as carriers of NK cell-derived helper signals for the development of type 1 immune responses. NK cell-induced DC1 show a strongly elevated ability to produce IL-12p70 after subsequent CD40 ligand stimulation. NK-induced DC1 prime naive CD4+ Th cells for high levels of IFN-gamma, but low IL-4 production, and demonstrate a strongly enhanced ability to induce Ag-specific CD8+ T cell responses. Resting NK cells display stringent activation requirements to perform this novel, DC-mediated, "helper" function. Although their interaction with K562 cells results in effective target cell killing, the induction of DC1 requires a second NK cell-activating signal. Such costimulatory signal can be provided by type I IFNs, common mediators of antiviral responses. Therefore, in addition to their cytolytic function, NK cells also have immunoregulatory activity, induced under more stringent conditions. The currently demonstrated helper activity of NK cells may support the development of Th1- and CTL-dominated type 1 immunity against intracellular pathogens and may have implications for cancer immunotherapy.

A comparison of the biologic activity of two recombinant IFN-beta preparations used in the treatment of relapsing-remitting multiple sclerosis

Recent clinical trials with interferon-beta (IFN-beta) in relapsing-remitting multiple sclerosis (RRMS) have clearly demonstrated that the IFN-beta dosing regimen affects the clinical efficacy, thereby highlighting the importance of determining the relative biologic activities of the IFN-beta products currently available. Although studies have been published that examine the biologic activities of the two structurally different forms of recombinant IFN-beta, IFN-beta1a (Rebif), Serono, Geneva, Switzerland) and IFN-beta1b (Betaseron)/Betaferon), Berlex [Montville, NJ]/Schering [Berlin, Germany]), there have been few direct comparative studies. Therefore, to obtain a more accurate estimate of the relative biologic activities of Rebif and Betaseron, this study examined the antiviral activities of these two products within the same assay system and against the same natural human IFN-beta standard. Whereas the manufacturers' information suggests that the bioactivity of Betaseron is only about 8.7-fold less than that of Rebif, the results of the present direct, comparative study show that Rebif has an antiviral activity 14 times greater than that of Betaseron. This may have important clinical implications, because on the basis of the results reported here, Rebif at 44 microg t.i.w. is approximately double the maximal licensed weekly dose for Betaseron.