Tjalf Ziemssen

Stroke-Induced Immunodepression Experimental Evidence and Clinical Relevance

Stroke affects the normally well-balanced interplay of the 2 supersystems: the nervous and the immune system. Recent research elucidated some of the involved signals and mechanisms and, importantly, was able to demonstrate that brain-immune interactions are highly relevant for functional outcome after stroke. Immunodepression after stroke increases the susceptibility to infection, the most relevant complication in stroke patients. However, immunodepression after stroke may also have beneficial effects, for example, by suppressing autoaggressive responses during lesion-induced exposure of central nervous system-specific antigens to the immune system. Thus, before immunomodulatory therapy can be applied to stroke patients, we need to understand better the interaction of brain and immune system after focal cerebral ischemia. Until then, anticipating an important consequence of stroke-induced immunodepression, bacterial infection, preventive antibiotic strategies have been proposed. In mouse experiments, preventive antibiotic treatment dramatically improves mortality and outcome. Results of clinical studies on this issue are contradictory at present, and larger trials are needed to settle the question whether (and which) stroke patients should be preventively treated. Nevertheless, clinical evidence is emerging demonstrating that stroke-induced immunodepression in humans not only exists, but has very similar features to those characterized in rodent experiments.

Identifying prodromal Parkinson's disease: pre-motor disorders in Parkinson's disease.

Increasing recognition that Parkinsons disease (PD) may start outside of the substantia nigra has led to a rapidly expanding effort to define prodromal stages of PD, before motor signs permit classical diagnosis. Many of these efforts center around the identification of clinical non‐motor symptoms and signs of disease. There is now direct evidence that olfaction, rapid eye movement (REM) sleep behavior disorder (RBD), constipation, and depression can be present in prodromal PD. In addition, there is suggestive evidence that visual changes, other autonomic symptoms, and subtle cognitive changes may also be present at prodromal stages. A critical issue in utility of these prodromal markers will be assessment of sensitivity, specificity, and positive and negative predictive values. Although these have yet to be fully defined, olfactory deficits, some visual changes, and autonomic symptoms occur in the majority of PD patients at diagnosis, suggesting good potential sensitivity. However, with the exception of RBD and perhaps some specific autonomic measures, specificity, and positive predictive value of these markers may be insufficient to be used alone as identifiers of prodromal disease. The evidence for the utility of olfaction, RBD, autonomic markers, visual changes, mood disorders, and cognitive loss as markers of prodromal PD and the potential sensitivity and specificity of these markers are summarized.

The activation status of neuroantigen-specific T cells in the target organ determines the clinical outcome of autoimmune encephalomyelitis

The clinical picture of experimental autoimmune encephalomyelitis (EAE) is critically dependent on the nature of the target autoantigen and the genetic background of the experimental animals. Potentially lethal EAE is mediated by myelin basic protein (MBP)–specific T cells in Lewis rats, whereas transfer of S100β- or myelin oligodendrocyte glycoprotein (MOG)–specific T cells causes intense inflammatory response in the central nervous system (CNS) with minimal disease. However, in Dark Agouti rats, the pathogenicity of MOG-specific T cells resembles the one of MBP-specific T cells in the Lewis rat. Using retrovirally transduced green fluorescent T cells, we now report that differential disease activity reflects different levels of autoreactive effector T cell activation in their target tissue. Irrespective of their pathogenicity, the migratory activity, gene expression patterns, and immigration of green fluorescent protein+ T cells into the CNS were similar. However, exclusively highly pathogenic T cells were significantly reactivated within the CNS. Without local effector T cell activation, production of monocyte chemoattractants was insufficient to initiate and propagate a full inflammatory response. Low-level reactivation of weakly pathogenic T cells was not due to anergy because these cells could be activated by specific antigen in situ as well as after isolation ex vivo.

Multiple sclerosis beyond EDSS: depression and fatigue

Depression and fatigue are common symptoms of multiple sclerosis and are the primary determinants of impaired quality of life in this demyelinating neurological disease. The twelve-month prevalence of major depression in patients with multiple sclerosis is around 15%. Untreated depression is associated with suicidal ideation, impaired cognitive function and poor adherence to immunomodulatory treatment. For these reasons, systematic screening and management of depressive symptoms is recommended for all patients with multiple sclerosis. There is some evidence that interferon-beta treatment may exacerbate depressive symptoms and a switch to glatiramer acetate can be envisaged in patients treated with an interferon-beta in whom depressive symptoms become an issue. Fatigue is present in over three-quarters of patients with multiple sclerosis. It is considered the most debilitating symptom of the disease and is a major reason for work absenteeism. There is growing evidence that immunomodulatory treatments, in particular glatiramer acetate, improve fatigue symptoms in patients with multiple sclerosis.

Siponimod for patients with relapsing-remitting multiple sclerosis (BOLD): an adaptive, dose-ranging, randomised, phase 2 study

BACKGROUND Siponimod is an oral selective modulator of sphingosine 1-phosphate receptor types 1 and type 5, with an elimination half-life leading to washout in 7 days. We aimed to determine the dose-response relation of siponimod in terms of its effects on brain MRI lesion activity and characterise safety and tolerability in patients with relapsing-remitting multiple sclerosis. METHODS In this double-blind, adaptive dose-ranging phase 2 study, we enrolled adults (aged 18-55 years) with relapsing-remitting multiple sclerosis at 73 medical centres in Europe and North America. We tested two patient cohorts sequentially, separated by an interim analysis at 3 months. We randomly allocated patients in cohort 1 (1:1:1:1) to receive once-daily siponimod 10 mg, 2 mg, or 0·5 mg, or placebo for 6 months. We randomly allocated patients in cohort 2 (4:4:1) to siponimod 1·25 mg, siponimod 0·25 mg, or placebo once-daily for 3 months. Randomisation was done with a central, automated system and patients and investigators were masked to treatment assignment. The primary endpoint was dose-response, assessed by percentage reduction in monthly number of combined unique active lesions at 3 months for siponimod versus placebo; this endpoint was analysed by a multiple comparison procedure with modelling techniques in all patients with at least one MRI scan up to 3 months. We assessed safety in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT00879658. FINDINGS Between March 30, 2009, and Oct 22, 2010, we recruited 188 patients into cohort 1 and 109 patients into cohort 2. We showed a dose-response relation (p=0·0001) across the five doses of siponimod, with reductions in combined unique active lesions at 3 months compared with placebo of 35% (95% CI 17-57) for siponimod 0·25 mg (51 patients included in the primary endpoint analysis), 50% (29-69) for siponimod 0·5 mg (43 patients), 66% (48-80) for siponimod 1·25 mg (42 patients), 72% (57-84) for siponimod 2 mg (45 patients), and 82% (70-90) for siponimod 10 mg (44 patients). In patients treated for 6 months, 37 (86%) of 43 patients who received siponimod 0·5 mg had adverse events (eight serious), as did 48 (98%) of 49 patients who received siponimod 2 mg (four serious), 48 (96%) of 50 patients who received siponimod 10 mg (three serious), and 36 (80%) of 45 controls (none serious). For individuals treated to 3 months, 38 (74%) of 51 patients who received siponimod 0·25 mg had adverse events (none serious), as did 29 (69%) of 42 patients who received siponimod 1·25 mg (two serious) and 13 (81%) of 16 controls (none serious). INTERPRETATION Therapeutic effects of siponimod on MRI lesion activity in model-based analyses and its tolerability in relapsing-remitting multiple sclerosis warrant investigation in a phase 3 trial. FUNDING Novartis Pharma AG.

Psychoneuroimmunology - Cross-talk between the immune and nervous systems

Psychoneuroimmunology is a relatively new field of study that investigates interactions between behaviour and the immune system, mediated by the endocrine and nervous systems. The immune and central nervous system (CNS) maintain extensive communication. On the one hand, the brain modulates the immune system by hardwiring sympathetic and parasympathetic nerves (autonomic nervous system) to lymphoid organs. On the other hand, neuroendocrine hormones such as corticotrophin-releasing hormone or substance P regulate cytokine balance. Vice versa, the immune system modulates brain activity including sleep and body temperature. Based on a close functional and anatomical link, the immune and nervous systems act in a highly reciprocal manner. From fever to stress, the influence of one system on the other has evolved in an intricate manner to help sense danger and to mount an appropriate adaptive response. Over recent decades, reasonable evidence has emerged that these brain-to-immune interactions are highly modulated by psychological factors which influence immunity and immune system-mediated disease.

Effector T-cell trafficking between the leptomeninges and the cerebrospinal fluid

In multiple sclerosis, brain-reactive T cells invade the central nervous system (CNS) and induce a self-destructive inflammatory process. T-cell infiltrates are not only found within the parenchyma and the meninges, but also in the cerebrospinal fluid (CSF) that bathes the entire CNS tissue. How the T cells reach the CSF, their functionality, and whether they traffic between the CSF and other CNS compartments remains hypothetical. Here we show that effector T cells enter the CSF from the leptomeninges during Lewis rat experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis. While moving through the three-dimensional leptomeningeal network of collagen fibres in a random Brownian walk, T cells were flushed from the surface by the flow of the CSF. The detached cells displayed significantly lower activation levels compared to T cells from the leptomeninges and CNS parenchyma. However, they did not represent a specialized non-pathogenic cellular sub-fraction, as their gene expression profile strongly resembled that of tissue-derived T cells and they fully retained their encephalitogenic potential. T-cell detachment from the leptomeninges was counteracted by integrins VLA-4 and LFA-1 binding to their respective ligands produced by resident macrophages. Chemokine signalling via CCR5/CXCR3 and antigenic stimulation of T cells in contact with the leptomeningeal macrophages enforced their adhesiveness. T cells floating in the CSF were able to reattach to the leptomeninges through steps reminiscent of vascular adhesion in CNS blood vessels, and invade the parenchyma. The molecular/cellular conditions for T-cell reattachment were the same as the requirements for detachment from the leptomeningeal milieu. Our data indicate that the leptomeninges represent a checkpoint at which activated T cells are licensed to enter the CNS parenchyma and non-activated T cells are preferentially released into the CSF, from where they can reach areas of antigen availability and tissue damage.

Loss of nocturnal blood pressure fall in various extrapyramidal syndromes

Cardiovascular autonomic dysfunction has frequently been reported in some patients with extrapyramidal syndromes, especially multiple system atrophy (MSA) but also Parkinsons disease (PD). However, there are only few reports on the prevalence of cardiovascular autonomic dysfunction progressive in supranuclear palsy (PSP). Moreover, the relation of detailed cardiovascular testing and easy to assess 24‐hour ambulatory blood pressure (BP) is not known. Our study evaluates 24‐hour ambulatory BP monitoring in patients with PD, PSP, MSA, and corresponding controls (Con) and relates the findings to the results of comprehensive cardiovascular autonomic testing. Twenty‐three patients with PD, 25 patients with PSP, 25 patients with MSA, and 26 corresponding controls were studied by 24‐hour ambulatory BP monitoring (ABPM) in comparison to cardiovascular autonomic testing. Patients with PD, PSP, and MSA presented frequently with a pathological nocturnal BP regulation (no decrease or even an increase of nocturnal BP) in comparison to the control group (PD 48%, PSP 40%, MSA 68% vs. Con 8%). In MSA and PD patients, the frequent pathological BP increase during night was closely correlated to orthostatic hypotension. Since loss of nocturnal BP fall is frequent in patients with extrapyramidal syndromes, even if they are free of subjective autonomic dysfunction, we recommend 24‐hour ABPM as an easy to perform screening test, especially if detailed autonomic testing is not available. Pathological loss of nocturnal BP fall may account for increased cardiovascular mortality in extrapyramidal syndromes.

Effects of glatiramer acetate on fatigue and days of absence from work in first-time treated relapsing-remitting multiple sclerosis.

ObjectivesTreatment of multiple sclerosis patients with glatiramer acetate has been demonstrated a beneficial effect on disease activity. The objective of this prospective naturalistic study was to evaluate the impact of glatiramer acetate on fatigue and work absenteeism.Methods291 treatment-naïve patients with relapsing remitting multiple sclerosis were included and treated with glatiramer acetate for twelve months. Relapse rates, disability, fatigue symptoms, days of absence from work and adverse events were monitored. Fatigue was measured with the MFIS scale and with a visual analogue scale.ResultsTotal MFIS scores decreased by 7.6 ± 16.4 from 34.6 to 27.0 (p ≤ 0.001). Significant reductions were observed on all three subscales of the MFIS. Fatigue symptoms, assessed using a visual analogue scale, decreased by 1.04 ± 2.88 cm from 4.47 cm to 3.43 cm (p ≤ 0.001). The proportion of patients absent from work at least once was reduced by a factor of two from 65.1% to 30.1% (p ≤ 0.001). Tolerance to treatment was rated as very good or good in 78.3% of patients. Adverse effects, most frequently local injection site reactions, were reported in 15.1% of patients.ConclusionTreatment with glatiramer acetate was associated with a significant improvement in fatigue symptoms and a marked reduction in absence from work. Treatment was well-tolerated. Such benefits are of relevance to overall patient well-being.

Optimizing treatment success in multiple sclerosis

Despite important advances in the treatment of multiple sclerosis (MS) over recent years, the introduction of several disease-modifying therapies (DMTs), the burden of progressive disability and premature mortality associated with the condition remains substantial. This burden, together with the high healthcare and societal costs associated with MS, creates a compelling case for early treatment optimization with highly efficacious therapies. Often, patients receive several first-line therapies, while more recent and in part more effective treatments are still being introduced only after these have failed. However, with the availability of highly efficacious therapies, a novel treatment strategy has emerged, where the aim is to achieve no evidence of disease activity (NEDA). Achieving NEDA necessitates regular monitoring of relapses, disability and functionality. However, there is only a poor correlation between conventional magnetic resonance imaging measures like T2 hyperintense lesion burden and the level of clinical disability. Hence, MRI-based measures of brain atrophy have emerged in recent years potentially reflecting the magnitude of MS-related neuroaxonal damage. Currently available DMTs differ markedly in their effects on brain atrophy: some, such as fingolimod, have been shown to significantly slow brain volume loss, compared to placebo, whereas others have shown either no, inconsistent, or delayed effects. In addition to regular monitoring, treatment optimization also requires early intervention with efficacious therapies, because accumulating evidence shows that effective intervention during a limited period early in the course of MS is critical for maintaining neurological function and preventing subsequent disability. Together, the advent of new MS therapies and evolving management strategies offer exciting new opportunities to optimize treatment outcomes.