Publications by authors named "Nicholas Schwab"

60 Publications

MCAM/CD146 Signaling PLCγ1 Leads to Activation of β-Integrins in Memory T-Cells Resulting in Increased Brain Infiltration.

Front Immunol 2020 14;11:599936. Epub 2020 Dec 14.

Department of Anesthesiology, Intensive Care and Pain Medicine, University of Münster, Münster, Germany.

Multiple sclerosis is a chronic auto-inflammatory disease of the central nervous system affecting patients worldwide. Neuroinflammation in multiple sclerosis is mainly driven by peripheral immune cells which invade the central nervous system and cause neurodegenerative inflammation. To enter the target tissue, immune cells have to overcome the endothelium and transmigrate into the tissue. Numerous molecules mediate this process and, as they determine the tissue invasiveness of immune cells, display great therapeutic potential. Melanoma cell adhesion molecule (MCAM) is a membrane-anchored glycoprotein expressed by a subset of T-cells and MCAM+ T-cells have been shown to contribute to neuroinflammation in multiple sclerosis. The role of the MCAM molecule for brain invasion, however, remained largely unknown. In order to investigate the role of the MCAM molecule on T-cells, we used different and assays, including flow chambers, biochemistry and microscopy experiments of the mouse brain. We demonstrate that MCAM directly mediates adhesion and that the engagement of MCAM induces intracellular signaling leading to β1-integrin activation on human T-cells. Furthermore, we show that MCAM engagement triggers the phosphorylation of PLCγ1 which is required for integrin activation and thus amplification of the cellular adhesive potential. To confirm the physiological relevance of our findings , we demonstrate that MCAM plays an important role in T-cell recruitment into the mouse brain. In conclusion, our data demonstrate that MCAM expressed on T-cells acts as an adhesion molecule and a signaling receptor that may trigger β1-integrin activation PLCγ1 upon engagement.
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http://dx.doi.org/10.3389/fimmu.2020.599936DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7767877PMC
December 2020

Sunlight exposure exerts immunomodulatory effects to reduce multiple sclerosis severity.

Proc Natl Acad Sci U S A 2021 Jan;118(1)

Department of Neurology with Institute of Translational Neurology, University of Muenster, 48149 Muenster, Germany;

Multiple sclerosis (MS) disease risk is associated with reduced sun-exposure. This study assessed the relationship between measures of sun exposure (vitamin D [vitD], latitude) and MS severity in the setting of two multicenter cohort studies ( = 946, = 990). Additionally, effect-modification by medication and photosensitivity-associated variants was assessed. High serum vitD was associated with a reduced MS severity score (MSSS), reduced risk for relapses, and lower disability accumulation over time. Low latitude was associated with higher vitD, lower MSSS, fewer gadolinium-enhancing lesions, and lower disability accumulation. The association of latitude with disability was lacking in IFN-β-treated patients. In carriers of :rs1805008(T), who reported increased sensitivity toward sunlight, lower latitude was associated with higher MRI activity, whereas for noncarriers there was less MRI activity at lower latitudes. In a further exploratory approach, the effect of ultraviolet (UV)-phototherapy on the transcriptome of immune cells of MS patients was assessed using samples from an earlier study. Phototherapy induced a vitD and type I IFN signature that was most apparent in monocytes but that could also be detected in B and T cells. In summary, our study suggests beneficial effects of sun exposure on established MS, as demonstrated by a correlative network between the three factors: Latitude, vitD, and disease severity. However, sun exposure might be detrimental for photosensitive patients. Furthermore, a direct induction of type I IFNs through sun exposure could be another mechanism of UV-mediated immune-modulation in MS.
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http://dx.doi.org/10.1073/pnas.2018457118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7817192PMC
January 2021

High anti-JCPyV serum titers coincide with high CSF cell counts in RRMS patients.

Mult Scler 2020 Nov 5:1352458520970103. Epub 2020 Nov 5.

Department of Neurology with Institute of Translational Neurology, University of Münster, Münster, Germany.

Background: Progressive multifocal leukoencephalopathy (PML) can in rare cases occur in natalizumab-treated patients with high serum anti-JCPyV antibodies, hypothetically due to excessive blockade of immune cell migration.

Objective: Immune cell recruitment to the central nervous system (CNS) was assessed in relapsing-remitting multiple sclerosis (RRMS) patients stratified by low versus high anti-JCPyV antibody titers as indicator for PML risk.

Methods: Cerebrospinal fluid (CSF) cell counts of 145 RRMS patients were quantified by flow cytometry. Generalized linear models were employed to assess influence of age, sex, disease duration, Expanded Disability Status Scale (EDSS), clinical/radiological activity, current steroid or natalizumab treatment, as well as anti-JCPyV serology on CSF cell subset counts.

Results: While clinical/radiological activity was associated with increased CD4, natural killer (NK), B and plasma cell counts, natalizumab therapy reduced all subpopulations except monocytes. With and without natalizumab therapy, patients with high anti-JCPyV serum titers presented with increased CSF T-cell counts compared to patients with low anti-JCPyV serum titers. In contrast, PML patients assessed before ( = 2) or at diagnosis ( = 5) presented with comparably low CD8 and B-cell counts, which increased after plasma exchange ( = 4).

Conclusion: High anti-JCPyV indices, which could be indicative of increased viral activity, are associated with elevated immune cell recruitment to the CNS. Its excessive impairment in conjunction with viral activity could predispose for PML development.
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http://dx.doi.org/10.1177/1352458520970103DOI Listing
November 2020

Next-Generation Neuroimmunology: New Technologies to Understand Central Nervous System Autoimmunity.

Trends Immunol 2020 04 5;41(4):341-354. Epub 2020 Mar 5.

Department of Neurology with Institute of Translational Neurology, University Hospital Münster, University of Münster, Münster, Germany. Electronic address:

Understanding neuroimmunological disorders is essential for developing new diagnostic and therapeutic strategies. Rodent models have provided valuable insights, but are sometimes equated with their human counterparts. Here, we summarize how novel technologies may enable an improved human-focused view of immune mechanisms. Recent studies have applied these new technologies to the brain parenchyma, its surrounding cerebrospinal fluid, and peripheral immune compartments. Therapeutic interventions have also facilitated translational understanding in a reverse way. However, with improved technology, access to patient samples remains a rate-limiting step in translational research. We anticipate that next-generation neuroimmunology is likely to integrate, in the immediate future, diverse technical tools for optimal diagnosis, prognosis, and treatment of neuroimmunological disorders.
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http://dx.doi.org/10.1016/j.it.2020.02.005DOI Listing
April 2020

CD8 T cell-mediated endotheliopathy is a targetable mechanism of neuro-inflammation in Susac syndrome.

Nat Commun 2019 12 18;10(1):5779. Epub 2019 Dec 18.

Centre de Physiopathologie Toulouse-Purpan (CPTP), Université de Toulouse, CNRS, Inserm, UPS, CHU Purpan - BP 3028 - 31024, Toulouse Cedex 3, Toulouse, France.

Neuroinflammation is often associated with blood-brain-barrier dysfunction, which contributes to neurological tissue damage. Here, we reveal the pathophysiology of Susac syndrome (SuS), an enigmatic neuroinflammatory disease with central nervous system (CNS) endotheliopathy. By investigating immune cells from the blood, cerebrospinal fluid, and CNS of SuS patients, we demonstrate oligoclonal expansion of terminally differentiated activated cytotoxic CD8 T cells (CTLs). Neuropathological data derived from both SuS patients and a newly-developed transgenic mouse model recapitulating the disease indicate that CTLs adhere to CNS microvessels in distinct areas and polarize granzyme B, which most likely results in the observed endothelial cell injury and microhemorrhages. Blocking T-cell adhesion by anti-α4 integrin-intervention ameliorates the disease in the preclinical model. Similarly, disease severity decreases in four SuS patients treated with natalizumab along with other therapy. Our study identifies CD8 T-cell-mediated endotheliopathy as a key disease mechanism in SuS and highlights therapeutic opportunities.
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http://dx.doi.org/10.1038/s41467-019-13593-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6920411PMC
December 2019

Ineffective treatment of PML with pembrolizumab: Exhausted memory T-cell subsets as a clue?

Neurol Neuroimmunol Neuroinflamm 2019 11 9;6(6):e627. Epub 2019 Oct 9.

From the Department of Neurology with Institute of Translational Neurology, University of Muenster, Germany.

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http://dx.doi.org/10.1212/NXI.0000000000000627DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6812729PMC
November 2019

Human CCR5high effector memory cells perform CNS parenchymal immune surveillance via GZMK-mediated transendothelial diapedesis.

Brain 2019 11;142(11):3411-3427

Department of Neurology with Institute of Translational Neurology, University Hospital Münster, University of Münster, Münster, Germany.

Although the CNS is immune privileged, continuous search for pathogens and tumours by immune cells within the CNS is indispensable. Thus, distinct immune-cell populations also cross the blood-brain barrier independently of inflammation/under homeostatic conditions. It was previously shown that effector memory T cells populate healthy CNS parenchyma in humans and, independently, that CCR5-expressing lymphocytes as well as CCR5 ligands are enriched in the CNS of patients with multiple sclerosis. Apart from the recently described CD8+ CNS tissue-resident memory T cells, we identified a population of CD4+CCR5high effector memory cells as brain parenchyma-surveilling cells. These cells used their high levels of VLA-4 to arrest on scattered VCAM1, their open-conformation LFA-1 to crawl preferentially against the flow in search for sites permissive for extravasation, and their stored granzyme K (GZMK) to induce local ICAM1 aggregation and perform trans-, rather than paracellular diapedesis through unstimulated primary brain microvascular endothelial cells. This study included peripheral blood mononuclear cell samples from 175 healthy donors, 29 patients infected with HIV, with neurological symptoms in terms of cognitive impairment, 73 patients with relapsing-remitting multiple sclerosis in remission, either 1-4 weeks before (n = 29), or 18-60 months after the initiation of natalizumab therapy (n = 44), as well as white matter brain tissue of three patients suffering from epilepsy. We here provide ex vivo evidence that CCR5highGZMK+CD4+ effector memory T cells are involved in CNS immune surveillance during homeostasis, but could also play a role in CNS pathology. Among CD4+ T cells, this subset was found to dominate the CNS of patients without neurological inflammation ex vivo. The reduction in peripheral blood of HIV-positive patients with neurological symptoms correlated to their CD4 count as a measure of disease progression. Their peripheral enrichment in multiple sclerosis patients and specific peripheral entrapment through the CNS infiltration inhibiting drug natalizumab additionally suggests a contribution to CNS autoimmune pathology. Our transcriptome analysis revealed a migratory phenotype sharing many features with tissue-resident memory and Th17.1 cells, most notably the transcription factor eomesodermin. Knowledge on this cell subset should enable future studies to find ways to strengthen the host defence against CNS-resident pathogens and brain tumours or to prevent CNS autoimmunity.
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http://dx.doi.org/10.1093/brain/awz301DOI Listing
November 2019

Prospective validation of the PML risk biomarker l-selectin and influence of natalizumab extended intervals.

Neurology 2019 09 22;93(12):550-554. Epub 2019 Aug 22.

From the Department of Neurology with Institute of Translational Neurology (N.S., T.S.-H., P.O., L.K., C.C.G., S.G.M., H.W.), University of Münster, Münster, Germany; CRC-SEP-Neurosciences Department (B.P., F.B., L.S., J.C., D. Biotti, D. Brassat), CHU Toulouse, Toulouse, France; CPTP-INSERM U1043-CNRS U5282-Université Toulouse III (B.P., F.B., L.S., D. Brassat), Toulouse, France; APHM (C.L.-F.), Hôpital de la Timone, Pôle de Neurosciences Cliniques, Marseille, France; CHU of Nice (G.M.), Nice, France; CHU Montpied, Neurology, Clermont-Ferrand, France (P.C.); APHM (J.P.), Hôpital de la Timone, Pôle de Neurosciences Cliniques, Service de Neurologie, CRCSEP Marseille, France; Institute of Clinical Neuroimmunology (I.M.), Ludwig-Maximilians University, Munich, Germany; Department of Neurology (S.W.), Clinics Osnabrück, Osnabrück, Germany; and Department of Neurology (F.G.), Innsbruck Medical University, Innsbruck, Austria.

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http://dx.doi.org/10.1212/WNL.0000000000008135DOI Listing
September 2019

Extensive immune reconstitution inflammatory syndrome in Fingolimod-associated PML: a case report with 7 Tesla MRI data.

BMC Neurol 2019 Aug 9;19(1):190. Epub 2019 Aug 9.

Department of Neurology, Alfried Krupp von Bohlen und Halbach Hospital, Alfried-Krupp-Str. 21, 45117, Essen, Germany.

Background: Progressive multifocal leukoencephalopathy (PML) is a rare complication of patients treated with fingolimod.

Case Presentation: Routine MRI eventually led to diagnosis of asymptomatic early PML that remained stable after discontinuation of fingolimod. As blood lymphocyte counts normalized, signs of immune reconstitution inflammatory syndrome (IRIS) and renewed MS activity developed. Both, advanced laboratory and ultrahigh field MRI findings elucidated differences between PML and MS.

Conclusions: In our case, early discontinuation of fingolimod yielded a good outcome, lymphocyte counts reflected immune system activity, and paraclinical findings helped to differentiate between PML-IRIS and MS.
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http://dx.doi.org/10.1186/s12883-019-1407-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6688281PMC
August 2019

Teriflunomide treatment for multiple sclerosis modulates T cell mitochondrial respiration with affinity-dependent effects.

Sci Transl Med 2019 05;11(490)

University Hospital Münster, Department of Neurology with Institute of Translational Neurology, 48149 Münster, Germany.

Interference with immune cell proliferation represents a successful treatment strategy in T cell-mediated autoimmune diseases such as rheumatoid arthritis and multiple sclerosis (MS). One prominent example is pharmacological inhibition of dihydroorotate dehydrogenase (DHODH), which mediates de novo pyrimidine synthesis in actively proliferating T and B lymphocytes. Within the TERIDYNAMIC clinical study, we observed that the DHODH inhibitor teriflunomide caused selective changes in T cell subset composition and T cell receptor repertoire diversity in patients with relapsing-remitting MS (RRMS). In a preclinical antigen-specific setup, DHODH inhibition preferentially suppressed the proliferation of high-affinity T cells. Mechanistically, DHODH inhibition interferes with oxidative phosphorylation (OXPHOS) and aerobic glycolysis in activated T cells via functional inhibition of complex III of the respiratory chain. The affinity-dependent effects of DHODH inhibition were closely linked to differences in T cell metabolism. High-affinity T cells preferentially use OXPHOS during early activation, which explains their increased susceptibility toward DHODH inhibition. In a mouse model of MS, DHODH inhibitory treatment resulted in preferential inhibition of high-affinity autoreactive T cell clones. Compared to T cells from healthy controls, T cells from patients with RRMS exhibited increased OXPHOS and glycolysis, which were reduced with teriflunomide treatment. Together, these data point to a mechanism of action where DHODH inhibition corrects metabolic disturbances in T cells, which primarily affects profoundly metabolically active high-affinity T cell clones. Hence, DHODH inhibition may promote recovery of an altered T cell receptor repertoire in autoimmunity.
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http://dx.doi.org/10.1126/scitranslmed.aao5563DOI Listing
May 2019

Risks and risk management in modern multiple sclerosis immunotherapeutic treatment.

Ther Adv Neurol Disord 2019 1;12:1756286419836571. Epub 2019 Apr 1.

Department of Neurology with Institute of Translational Neurology, University of Münster, Building A1, Albert Schweitzer Campus 1, 48149 Münster, Germany.

In recent years, there has been a paradigm shift in the treatment of multiple sclerosis (MS) owing to the approval of a number of new drugs with very distinct mechanisms of action. All approved disease-modifying drugs primarily work directly on the immune system. However, the identification of an 'optimal choice' for individual patients with regard to treatment efficacy, treatment adherence and side-effect profile has become increasingly complex including conceptual as well as practical considerations. Similarly, there are peculiarities and specific requirements with regard to treatment monitoring, especially in relation to immunosuppression, the development of secondary immune-related complications, as well as the existence of drug-specific on- and off-target effects. Both classical immunosuppression and selective immune interventions generate a spectrum of potential therapy-related complications. This article provides a comprehensive overview of available immunotherapeutics for MS and their risks, detailing individual mechanisms of action and side-effect profiles. Furthermore, practical recommendations for patients treated with modern MS immunotherapeutics are provided.
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http://dx.doi.org/10.1177/1756286419836571DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444778PMC
April 2019

Natalizumab-associated progressive multifocal leukoencephalopathy in Germany.

Neurology 2019 05 5;92(19):e2232-e2239. Epub 2019 Apr 5.

From the Department Safety of Medicinal Products and Medical Devices (K.B., B.K.-S.), and Section Biostatistics (B.H.), Paul-Ehrlich-Institut, Federal Institute for Vaccines and Biomedicines, Langen; Clinic of Neurology with Institute of Translational Neurology (N.S.), University Hospital Muenster, University Muenster; Institute for Virology (O.A.), University of Duesseldorf, Medical Faculty, Duesseldorf; and Department of Neurology (C.W.), University Hospital Koeln, Germany.

Objective: To evaluate characteristics relevant to diagnosis of JC polyomavirus-associated progressive multifocal leukoencephalopathy (PML), and PML risk stratification in a large national cohort of patients with multiple sclerosis during therapy with natalizumab.

Methods: Analysis of 292 adverse drug reaction forms on suspected cases of PML reported to the German national competent authority until July 2017. Patients not fulfilling PML diagnostic criteria or with insufficient information available were excluded.

Results: Of the 142 confirmed patients with PML, 72.3% (95% confidence interval [CI] 64.4%-79.1%) were women, and the median age was 43 years (range 19-69). Of these patients, 7.7% (95% CI 4.3%-13.5%) were clinically asymptomatic at time of PML diagnosis. PML was fatal in 9.1% (95% CI 5.3%-15.1%) of the patients. Infratentorial lesions on imaging were reported in 40% (95% CI 32.0%-48.6%) of the patients. JC polyomavirus DNA in CSF was undetectable at time of first analysis in 23.8% (95% CI 17.3%-31.9%) of the patients. Three patients tested negative for anti-JC polyomavirus antibodies within 6 to 18 months before PML diagnosis, with seroconversion confirmed 5.5 months, 7 months (in a post hoc analysis only), or at time of PML diagnosis.

Conclusions: JC polyomavirus DNA detection in CSF has limited sensitivity in early PML, and clinical and imaging presentation may be atypical. Thus, critical revision of current PML diagnostic criteria is warranted. Negative anti-JC polyomavirus antibodies in sera do not preclude the later development of PML. This emphasizes the need for close and regular serologic, imaging, and clinical monitoring in patients treated with natalizumab.
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http://dx.doi.org/10.1212/WNL.0000000000007451DOI Listing
May 2019

VLA-2 blockade in vivo by vatelizumab induces CD4+FoxP3+ regulatory T cells.

Int Immunol 2019 05;31(6):407-412

Clinic of Neurology with Institute of Translational Neurology, University Hospital Münster, Münster, Germany.

Integrin α2β1, also known as very late antigen (VLA)-2, is a collagen-binding molecule expressed constitutively on platelets. Vatelizumab, a monoclonal antibody targeting the α2 subunit (CD49b) of VLA-2, was recently investigated for its safety and efficacy during a Phase 2 clinical study in multiple sclerosis patients, as integrin-mediated collagen binding at the site of inflammation is central to a number of downstream pro-inflammatory events. In the course of this study, we could show that VLA-2 is expressed ex vivo on platelets, platelet-T-cell aggregates, as well as a small population of highly activated memory T cells. Even though the clinical trial did not meet its primary clinical end-point (reduction in the cumulative number of new contrast-enhancing lesions on magnetic resonance imaging (MRI)), we observed enhanced frequencies of regulatory T cells (TREG) following vatelizumab treatment. Elevated TREG frequencies might be explained by the inhibition of p38 mitogen-activated protein kinase (MAPK) signaling, which is critically involved in the polarization of T helper 17 (TH17) cells and is activated by the α2 integrin cytoplasmic domain. Our findings suggest that blockade of VLA-2 might be a way to safely shift the TH17/TREG balance by inducing TREGin vivo.
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http://dx.doi.org/10.1093/intimm/dxz018DOI Listing
May 2019

Dietary salt promotes ischemic brain injury and is associated with parenchymal migrasome formation.

PLoS One 2018 27;13(12):e0209871. Epub 2018 Dec 27.

Department of Neurology with Institute of Translational Neurology, University of Münster, Münster, Germany.

Sodium chloride promotes vascular fibrosis, arterial hypertension, pro-inflammatory immune cell polarization and endothelial dysfunction, all of which might influence outcomes following stroke. But despite enormous translational relevance, the functional importance of sodium chloride in the pathophysiology of acute ischemic stroke is still unclear. In the current study, we show that high-salt diet leads to significantly worse functional outcomes, increased infarct volumes, and a loss of astrocytes and cortical neurons in acute ischemic stroke. While analyzing the underlying pathologic processes, we identified the migrasome as a novel, sodium chloride-driven pathomechanism in acute ischemic stroke. The migrasome was previously described in vitro as a migrating organelle, which incorporates and dispatches cytosol of surrounding cells and plays a role in intercellular signaling, whereas a pathophysiological meaning has not been elaborated. We here confirm previously reported characteristics of the migrasome in vivo. Immunohistochemistry, electron microscopy and proteomic analyses further demonstrate that the migrasome incorporates and dispatches cytosol of surrounding neurons following stroke. The clinical relevance of these findings is emphasized by neuropathological examinations, which detected migrasome formation in infarcted brain parenchyma of human stroke patients. In summary, we demonstrate that high-salt diet aggravates stroke outcomes, and we characterize the migrasome as a novel mechanism in acute stroke pathophysiology.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0209871PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6307724PMC
May 2019

Blockade of MCAM/CD146 impedes CNS infiltration of T cells over the choroid plexus.

J Neuroinflammation 2018 Aug 22;15(1):236. Epub 2018 Aug 22.

Clinic of Neurology with Institute of Translational Neurology, University of Münster, Albert-Schweitzer-Campus-1, Building A01, 48149, Münster, Germany.

Background: Very late antigen 4 (VLA-4; integrin α4β1) is critical for transmigration of T helper (T) 1 cells into the central nervous system (CNS) under inflammatory conditions such as multiple sclerosis (MS). We have previously shown that VLA-4 and melanoma cell adhesion molecule (MCAM) are important for trans-endothelial migration of human T17 cells in vitro and here investigate their contribution to pathogenic CNS inflammation.

Methods: Antibody blockade of VLA-4 and MCAM is assessed in murine models of CNS inflammation in conjunction with conditional ablation of α4-integrin expression in T cells. Effects of VLA-4 and MCAM blockade on lymphocyte migration are further investigated in the human system via in vitro T cell transmigration assays.

Results: Compared to the broad effects of VLA-4 blockade on encephalitogenic T cell migration over endothelial barriers, MCAM blockade impeded encephalitogenic T cell migration in murine models of MS that especially depend on CNS migration across the choroid plexus (CP). In transgenic mice lacking T cell α4-integrin expression (CD4::Itga4), MCAM blockade delayed disease onset. Migration of MCAM-expressing T cells through the CP into the CNS was restricted, where laminin 411 (composed of α4, β1, γ1 chains), the proposed major ligand of MCAM, is detected in the endothelial basement membranes of murine CP tissue. This finding was translated to the human system; blockade of MCAM with a therapeutic antibody reduced in vitro transmigration of MCAM-expressing T cells across a human fibroblast-derived extracellular matrix layer and a brain-derived endothelial monolayer, both expressing laminin α4. Laminin α4 was further detected in situ in CP endothelial-basement membranes in MS patients' brain tissue.

Conclusions: Our findings suggest that MCAM-laminin 411 interactions facilitate trans-endothelial migration of MCAM-expressing T cells into the CNS, which seems to be highly relevant to migration via the CP and to potential future clinical applications in neuroinflammatory disorders.
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http://dx.doi.org/10.1186/s12974-018-1276-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6106934PMC
August 2018

Immune Cell Profiling During Switching from Natalizumab to Fingolimod Reveals Differential Effects on Systemic Immune-Regulatory Networks and on Trafficking of Non-T Cell Populations into the Cerebrospinal Fluid-Results from the ToFingo Successor Study.

Front Immunol 2018 9;9:1560. Epub 2018 Jul 9.

Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Muenster, Germany.

Leukocyte sequestration is an established therapeutic concept in multiple sclerosis (MS) as represented by the trafficking drugs natalizumab (NAT) and fingolimod (FTY). However, the precise consequences of targeting immune cell trafficking for immunoregulatory network functions are only incompletely understood. In the present study, we performed an in-depth longitudinal characterization of functional and phenotypic immune signatures in peripheral blood (PB) and cerebrospinal fluid (CSF) of 15 MS patients during switching from long-term NAT to FTY treatment after a defined 8-week washout period within a clinical trial (ToFingo successor study; ClinicalTrials.gov: NCT02325440). Unbiased visualization and analysis of high-dimensional single cell flow-cytometry data revealed that switching resulted in a profound alteration of more than 80% of investigated innate and adaptive immune cell subpopulations in the PB, revealing an unexpectedly broad effect of trafficking drugs on peripheral immune signatures. Longitudinal CSF analysis demonstrated that NAT and FTY both reduced T cell subset counts and proportions in the CSF of MS patients with equal potency; NAT however was superior with regard to sequestering non-T cell populations out of the CSF, including B cells, natural killer cells and inflammatory monocytes, suggesting that disease exacerbation in the context of switching might be driven by non-T cell populations. Finally, correlation of our immunological data with signs of disease exacerbation in this small cohort suggested that both (i) CD49d expression levels under NAT at the time of treatment cessation and (ii) swiftness of FTY-mediated effects on immune cell subsets in the PB together may predict stability during switching later on.
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http://dx.doi.org/10.3389/fimmu.2018.01560DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6052886PMC
July 2018

Does the environment influence multiple sclerosis pathogenesis via UVB light and/or induction of vitamin D?

J Neuroimmunol 2019 04 18;329:1-8. Epub 2018 May 18.

Department of Neurology, University of Münster, Münster, Germany. Electronic address:

Multiple sclerosis (MS) is a disease of presumed auto-immune origin. Long-standing observations such as the correlation between MS incidence and geographical latitude or the levels of Vitamin D (Vit D) in the serum have implicated the environmental factors UVB radiation and diet in the etiology of the disease. Clinical trials have been conducted and are currently underway to elucidate whether a Vit D enriched diet or treatment with UVB can influence MS incidence, -severity, and -progression, as well as the ideal time point for treatment. This review summarizes the current scientific knowledge to the environmental factors UVB-light and Vit D concerning the clinical aspects of MS in epidemiological studies and clinical trials.
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http://dx.doi.org/10.1016/j.jneuroim.2018.05.006DOI Listing
April 2019

Sex bias in MHC I-associated shaping of the adaptive immune system.

Proc Natl Acad Sci U S A 2018 02 12;115(9):2168-2173. Epub 2018 Feb 12.

Department of Neurology, University of Muenster, 48149 Muenster, Germany;

HLA associations, T cell receptor (TCR) repertoire bias, and sex bias have independently been shown for many diseases. While some immunological differences between the sexes have been described, they do not fully explain bias in men toward many infections/cancers, and toward women in autoimmunity. Next-generation TCR variable beta chain (TCRBV) immunosequencing of 824 individuals was evaluated in a multiparametric analysis including HLA-A -B/MHC class I background, TCRBV usage, sex, age, ethnicity, and TCRBV selection/expansion dynamics. We found that HLA-associated shaping of TCRBV usage differed between the sexes. Furthermore, certain TCRBVs were selected and expanded in unison. Correlations between these TCRBV relationships and biochemical similarities in HLA-binding positions were different in CD8 T cells of patients with autoimmune diseases (multiple sclerosis and rheumatoid arthritis) compared with healthy controls. Within patients, men showed higher TCRBV relationship Spearman's rhos in relation to HLA-binding position similarities compared with women. In line with this, CD8 T cells of men with autoimmune diseases also showed higher degrees of TCRBV perturbation compared with women. Concerted selection and expansion of CD8 T cells in patients with autoimmune diseases, but especially in men, appears to be less dependent on high HLA-binding similarity than in CD4 T cells. These findings are consistent with studies attributing autoimmunity to processes of epitope spreading and expansion of low-avidity T cell clones and may have further implications for the interpretation of pathogenic mechanisms of infectious and autoimmune diseases with known HLA associations. Reanalysis of some HLA association studies, separating the data by sex, could be informative.
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http://dx.doi.org/10.1073/pnas.1716146115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5834686PMC
February 2018

Nitazoxanide May Modify the Course of Progressive Multifocal Leukoencephalopathy.

J Clin Immunol 2018 01 20;38(1):4-6. Epub 2017 Nov 20.

Immunodeficiency Unit, Inflammation Center and Center for Rare Diseases, Children's Hospital, Helsinki University and Helsinki University Hospital, Helsinki, Finland.

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http://dx.doi.org/10.1007/s10875-017-0463-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086546PMC
January 2018

Dual action by fumaric acid esters synergistically reduces adhesion to human endothelium.

Mult Scler 2018 12 6;24(14):1871-1882. Epub 2017 Oct 6.

Department of Neurology, University of Münster, Münster, Germany.

Objective: Dimethyl fumarate (DMF) is prescribed against relapsing-remitting multiple sclerosis (MS). Here, we investigated the effects of DMF and monomethyl fumarate (MMF), its metabolite in vivo, at the (inflamed) blood-brain barrier (BBB).

Methods: Effects of fumaric acid esters were analyzed using primary human brain-derived microvascular endothelial cells (HBMECs) in combination with peripheral blood mononuclear cells (PBMCs) derived from DMF-treated MS patients.

Results: MMF-binding to brain endothelium cells leads to activation of nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2)-induced downregulation of vascular cell adhesion molecule 1 (VCAM-1). This might be mediated via the G-protein-coupled receptor (GPCR) hydroxycarboxylic acid receptor 2 (HCA), a known molecular target of MMF, as we could demonstrate its expression and regulation on HBMECs. DMF treatment in vivo led to a strongly reduced expression of VCAM-1's ligand very late antigen 4 (VLA-4) by selectively reducing integrin high-expressing memory T cells of MS patients, potentially due to inhibition of their maturation by reduced trans-localization of NFκB.

Conclusion: DMF-mediated VCAM-1 downregulation on the endothelial side and reduction in T cells with a migratory phenotype on the lymphocyte side result in a synergistic reduction in T-cell adhesion to activated endothelium and, therefore, to reduced BBB transmigration in the setting of MS.
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http://dx.doi.org/10.1177/1352458517735189DOI Listing
December 2018

Liver X receptor activation promotes differentiation of regulatory T cells.

PLoS One 2017 19;12(9):e0184985. Epub 2017 Sep 19.

Department of Neurology, University of Muenster, Albert-Schweitzer-Campus 1, Muenster, Germany.

The nuclear receptor Liver X Receptor (LXR) is a ligand-activated transcription factor that has been implicated in control of chronic inflammation by downregulating pro-inflammatory T cell responses. An impaired function of regulatory T cells, a subset of CD4+ T cells with a crucial role in maintaining lymphocytes homeostasis and immune regulation, is frequently observed in chronic inflammatory diseases. We observed that pharmacological activation of LXR in T cells not only resulted in a thorough suppression of Th1 and Th17 polarization in vitro, but also significantly induced regulatory T cells (Treg) cell differentiation in a receptor-specific fashion. In line with this, systemic LXR activation by oral treatment of mice with the LXR agonist GW3965 induced gut-associated regulatory T cells in vivo. Importantly, such LXR-activated Tregs had a higher suppressive capacity in functional in vitro coculture assays with effector T cells. Our data thus point towards a dual role of LXR-mediated control of inflammation by suppression of pro-inflammatory T cells and reciprocal induction of regulatory T cells.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0184985PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5604992PMC
October 2017

Anti-JCV serology during natalizumab treatment: Review and meta-analysis of 17 independent patient cohorts analyzing anti-John Cunningham polyoma virus sero-conversion rates under natalizumab treatment and differences between technical and biological sero-converters.

Mult Scler 2018 04 29;24(5):563-573. Epub 2017 Aug 29.

Department of Neurology, University of Münster, Münster, Germany.

Background: Anti-John Cunningham virus (JCV) serology has been studied with varying results concerning longitudinal changes.

Objectives And Methods: Results from 17 published natalizumab-treated multiple sclerosis (MS) patient cohorts were analyzed with common parameters and subsequently verified in two large independent cohorts with 722 and 499 patients from Germany and the United States.

Results: Published studies and the verification showed (1) a mean of 10.80% sero-negative patients presented with sero-status change to positivity per year; (2) patients, who sero-convert to index values <0.9, convert from near the threshold and have a high probability of reverting with time; (3) patients, who convert to index values >0.9, start with low index values; (4) while JCV sero-positive patients with low index values sometimes revert to sero-negativity, patients with high index values almost never revert; and (5) the conversion rate of natalizumab-treated patients is three to four times higher than the biological conversion by age.

Conclusion: JCV sero-conversion was comparable using standardized parameters and indicates influence of natalizumab on JCV immune control. Converters to low index values are probably consistently infected with JCV with varying low levels of activity, in line with their low risk to develop progressive multifocal leukoencephalopathy (PML). Patients with high index values rarely revert back to sero-negativity.
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http://dx.doi.org/10.1177/1352458517728814DOI Listing
April 2018

Single-cell profiling reveals GPCR heterogeneity and functional patterning during neuroinflammation.

JCI Insight 2017 Aug 3;2(15). Epub 2017 Aug 3.

Department of Pharmacology.

GPCR expression was intensively studied in bulk cDNA of leukocyte populations, but limited data are available with respect to expression in individual cells. Here, we show a microfluidic-based single-cell GPCR expression analysis in primary T cells, myeloid cells, and endothelial cells under naive conditions and during experimental autoimmune encephalomyelitis, the mouse model of multiple sclerosis. We found that neuroinflammation induces characteristic changes in GPCR heterogeneity and patterning, and we identify various functionally relevant subgroups with specific GPCR profiles among spinal cord-infiltrating CD4 T cells, macrophages, microglia, or endothelial cells. Using GPCRs CXCR4, S1P1, and LPHN2 as examples, we show how this information can be used to develop new strategies for the functional modulation of Th17 cells and activated endothelial cells. Taken together, single-cell GPCR expression analysis identifies functionally relevant subpopulations with specific GPCR repertoires and provides a basis for the development of new therapeutic strategies in immune disorders.
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http://dx.doi.org/10.1172/jci.insight.95063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5543912PMC
August 2017

Chemokine CCL17 is expressed by dendritic cells in the CNS during experimental autoimmune encephalomyelitis and promotes pathogenesis of disease.

Brain Behav Immun 2017 Nov 19;66:382-393. Epub 2017 Jun 19.

Department of Psychiatry, University of Münster, 48149 Münster, Germany; Cells in Motion, Cluster of Excellence EXC 1003, University of Münster, 48149 Münster, Germany. Electronic address:

The CC chemokine ligand 17 (CCL17) and its cognate CC chemokine receptor 4 (CCR4) are known to control leukocyte migration, maintenance of T17 cells, and regulatory T cell (T) expansion in vivo. In this study we characterized the expression and functional role of CCL17 in the pathogenesis of experimental autoimmune encephalomyelitis (EAE). Using a CCL17/EGFP reporter mouse model, we could show that CCL17 expression in the CNS can be found in a subset of classical dendritic cells (DCs) that immigrate into the CNS during the effector phase of MOG-induced EAE. CCL17 deficient (CCL17) mice exhibited an ameliorated disease course upon MOG-immunization, associated with reduced immigration of IL-17 producing CD4 T cells and peripheral DCs into the CNS. CCL17 DCs further showed equivalent MHC class II and costimulatory molecule expression and an equivalent capacity to secrete IL-23 and induce myelin-reactive T17 cells when compared to wildtype DCs. In contrast, their transmigration in an in vitro model of the blood-brain barrier was markedly impaired. In addition, peripheral T cells were enhanced in CCL17 mice at peak of disease pointing towards an immunoregulatory function of CCL17 in EAE. Our study identifies CCL17 as a unique modulator of EAE pathogenesis regulating DC trafficking as well as peripheral T cell expansion in EAE. Thus, CCL17 operates at distinct levels and on different cell subsets during immune response in EAE, a property harboring therapeutic potential for the treatment of CNS autoimmunity.
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http://dx.doi.org/10.1016/j.bbi.2017.06.010DOI Listing
November 2017

Analysis of Lymphocyte Extravasation Using an In Vitro Model of the Human Blood-brain Barrier.

J Vis Exp 2017 04 5(122). Epub 2017 Apr 5.

Department of Neurology with Institute of Translational Neurology, University Hospital Münster;

Lymphocyte extravasation into the central nervous system (CNS) is critical for immune surveillance. Disease-related alterations of lymphocyte extravasation might result in pathophysiological changes in the CNS. Thus, investigation of lymphocyte migration into the CNS is important to understand inflammatory CNS diseases and to develop new therapy approaches. Here we present an in vitro model of the human blood-brain barrier to study lymphocyte extravasation. Human brain microvascular endothelial cells (HBMEC) are confluently grown on a porous polyethylene terephthalate transwell insert to mimic the endothelium of the blood-brain barrier. Barrier function is validated by zonula occludens immunohistochemistry, transendothelial electrical resistance (TEER) measurements as well as analysis of evans blue permeation. This model allows investigation of the diapedesis of rare lymphocyte subsets such as CD56CD16 NK cells. Furthermore, the effects of other cells, cytokines and chemokines, disease-related alterations, and distinct treatment regimens on the migratory capacity of lymphocytes can be studied. Finally, the impact of inflammatory stimuli as well as different treatment regimens on the endothelial barrier can be analyzed.
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http://dx.doi.org/10.3791/55390DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5564469PMC
April 2017

Natalizumab-associated PML: Challenges with incidence, resulting risk, and risk stratification.

Neurology 2017 Mar 22;88(12):1197-1205. Epub 2017 Feb 22.

From the Department of Neurology (N.S., T.S.-H., N.M., H.W.), University of Münster, Germany; and University of Alabama School of Public Health (G.C.), Birmingham.

Progressive multifocal leukoencephalopathy (PML) associated with natalizumab treatment continues to be a severe problem of clinically successful therapy. This is an update of risk stratification developments and discusses the current approach to depict and calculate PML incidence and PML risk. (1) PML incidence and resulting risk used in today's clinical practice are potentially outdated and the risk for patients with prior immunosuppression might have been underestimated. (2) Risk stratification according to treatment duration epochs likely suggests lower risk due to patients stopping treatment within a given epoch. PML incidence within the complete treatment epoch is statistically lowered due to the fact that patients at the beginning of an epoch presumably have a lower PML risk than the patients at the end. Periodic risk is not accurate in assessing risk for long treatment durations. (3) The JC virus (JCV) serostatus risk factor has low specificity concerning PML prediction and anti-JCV seroconversion during treatment with natalizumab further lowers its specificity over time. Specificity of the risk factor treatment duration varies depending on the average treatment duration and the number of short-term patients. These short-term patients reduce overall average treatment duration and thus enhance the specificity of the risk factor and reduce overall PML incidence. It is also suggested that short-term natalizumab patients are exclusively non-PML, even though they might still develop PML. Clinicians have to consider the cumulative risk of patients to stratify efficiently.
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http://dx.doi.org/10.1212/WNL.0000000000003739DOI Listing
March 2017

CD62L test at 2 years of natalizumab predicts progressive multifocal leukoencephalopathy.

Neurology 2016 12 4;87(23):2491-2494. Epub 2016 Nov 4.

From the CHU Toulouse Purpan (B.P., F.B., D.B., D.A.-P., D.B.), Pôle Neurosciences; INSERM U1043-CNRS UMR 5282 (B.P., F.B., D.B.), Université Toulouse III, Centre de Physiopathologie Toulouse Purpan, France; University of Münster (N.S., T.S.-H., H.W.), Germany; University of Lille (O.O., H.Z., P.V.); Hôpital Civil (J.-C. Ongagna, J.d.S.), Strasbourg; CHU Pellegrin (B.B., J.-C. Ouallet), Bordeaux; CHU Nancy (M.D., S.P.); CHU Caen (G.D., N.D.); CH St Vincent (P.H.), GHICL, Lille; CHU Reims (A.T.); CHU Montpellier (P.L.); CHU Nîmes (G.C., W.C., O.C.); CHRU Clermont Ferrand (P.C.); CHU Besançon (E.B.); Aix Marseille University (J.P., A.R.), APHM, CHU Timone, Marseille; CHU Nantes (D.L., S.W.); CHU Grenoble (E.T.); CHU Dijon (T.M., A.F.); CHU Lyon (S.V.), Bron; Hôpital de la Salpêtrière (C.P.), Paris, France; Centre d'Esclerosi Múltiple de Catalunya (CEMCAT) (M.C.), Institut de Recerca Vall d'Hebron (VHIR), Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Spain; and CHU Nice (C.L.-F.), France.

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http://dx.doi.org/10.1212/WNL.0000000000003401DOI Listing
December 2016

Melanocortin-1 receptor activation is neuroprotective in mouse models of neuroinflammatory disease.

Sci Transl Med 2016 10;8(362):362ra146

Department of Dermatology, University of Münster, 48149 Münster, Germany.

In inflammation-associated progressive neuroinflammatory disorders, such as multiple sclerosis (MS), inflammatory infiltrates containing T helper 1 (T1) and T17 cells cause demyelination and neuronal degeneration. Regulatory T cells (T) control the activation and infiltration of autoreactive T cells into the central nervous system (CNS). In MS and experimental autoimmune encephalomyelitis (EAE) in mice, T function is impaired. We show that a recently approved drug, Nle-d-Phe-α-melanocyte-stimulating hormone (NDP-MSH), induced functional T, resulting in amelioration of EAE progression in mice. NDP-MSH also prevented immune cell infiltration into the CNS by restoring the integrity of the blood-brain barrier. NDP-MSH exerted long-lasting neuroprotective effects in mice with EAE and prevented excitotoxic death and reestablished action potential firing in mouse and human neurons in vitro. Neuroprotection by NDP-MSH was mediated via signaling through the melanocortin-1 and orphan nuclear 4 receptors in mouse and human neurons. NDP-MSH may be of benefit in treating neuroinflammatory diseases such as relapsing-remitting MS and related disorders.
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http://dx.doi.org/10.1126/scitranslmed.aaf8732DOI Listing
October 2016

B7-H1 shapes T-cell-mediated brain endothelial cell dysfunction and regional encephalitogenicity in spontaneous CNS autoimmunity.

Proc Natl Acad Sci U S A 2016 10 26;113(41):E6182-E6191. Epub 2016 Sep 26.

Department of Neurology, University Hospital Münster, 48149 Muenster, Germany;

Molecular mechanisms that determine lesion localization or phenotype variation in multiple sclerosis are mostly unidentified. Although transmigration of activated encephalitogenic T cells across the blood-brain barrier (BBB) is a crucial step in the disease pathogenesis of CNS autoimmunity, the consequences on brain endothelial barrier integrity upon interaction with such T cells and subsequent lesion formation and distribution are largely unknown. We made use of a transgenic spontaneous mouse model of CNS autoimmunity characterized by inflammatory demyelinating lesions confined to optic nerves and spinal cord (OSE mice). Genetic ablation of a single immune-regulatory molecule in this model [i.e., B7-homolog 1 (B7-H1, PD-L1)] not only significantly increased incidence of spontaneous CNS autoimmunity and aggravated disease course, especially in the later stages of disease, but also importantly resulted in encephalitogenic T-cell infiltration and lesion formation in normally unaffected brain regions, such as the cerebrum and cerebellum. Interestingly, B7-H1 ablation on myelin oligodendrocyte glycoprotein-specific CD4 T cells, but not on antigen-presenting cells, amplified T-cell effector functions, such as IFN-γ and granzyme B production. Therefore, these T cells were rendered more capable of eliciting cell contact-dependent brain endothelial cell dysfunction and increased barrier permeability in an in vitro model of the BBB. Our findings suggest that a single immune-regulatory molecule on T cells can be ultimately responsible for localized BBB breakdown, and thus substantial changes in lesion topography in the context of CNS autoimmunity.
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http://dx.doi.org/10.1073/pnas.1601350113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5068266PMC
October 2016