Publications by authors named "Tilman Schneider-Hohendorf"

41 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

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

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

Plasma kallikrein modulates immune cell trafficking during neuroinflammation via PAR2 and bradykinin release.

Proc Natl Acad Sci U S A 2019 01 17;116(1):271-276. Epub 2018 Dec 17.

Clinic of Neurology, Institute of Translational Neurology, University of Münster, 48149 Münster, Germany.

Blood-brain barrier (BBB) disruption and transendothelial trafficking of immune cells into the central nervous system (CNS) are pathophysiological hallmarks of neuroinflammatory disorders like multiple sclerosis (MS). Recent evidence suggests that the kallikrein-kinin and coagulation system might participate in this process. Here, we identify plasma kallikrein (KK) as a specific direct modulator of BBB integrity. Levels of plasma prekallikrein (PK), the precursor of KK, were markedly enhanced in active CNS lesions of MS patients. Deficiency or pharmacologic blockade of PK renders mice less susceptible to experimental autoimmune encephalomyelitis (a model of MS) and is accompanied by a remarkable reduction of BBB disruption and CNS inflammation. In vitro analysis revealed that KK modulates endothelial cell function in a protease-activated receptor-2-dependent manner, leading to an up-regulation of the cellular adhesion molecules Intercellular Adhesion Molecule 1 and Vascular Cell Adhesion Molecule 1, thereby amplifying leukocyte trafficking. Our study demonstrates that PK is an important direct regulator of BBB integrity as a result of its protease function. Therefore, KK inhibition can decrease BBB damage and cell invasion during neuroinflammation and may offer a strategy for the treatment of MS.
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http://dx.doi.org/10.1073/pnas.1810020116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6320546PMC
January 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

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

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

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

Progressive multifocal leukoencephalopathy and black fungus in a patient with rheumatoid arthritis without severe lymphocytopenia.

JMM Case Rep 2016 Aug 30;3(4):e005053. Epub 2016 Aug 30.

Department of Internal Medicine and infectious Diseases, University Medical Centre Utrecht, the Netherlands.

Introduction: Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating brain infection caused by JC polyomavirus (JCV), primarily seen in patients with severely compromised cellular immunity. Clinical presentation varies depending on the affected white matter. PML prognosis is variable and effective treatments are lacking.

Case Presentation: A 75-year-old Chinese woman with type 2 diabetes mellitus, chronic kidney disease and rheumatoid arthritis, treated with low-dose methotrexate and prednisolone for 2.5 years, developed a infection of her left arm. After 6 months of treating this rare black fungus infection with voriconazole, surgery and immunosuppression discontinuation, she presented with progressive afebrile encephalopathy with right-sided hemiparesis. There were no signs of inflammation or metabolic abnormalities. Brain magnetic resonance imaging revealed diffuse frontal white matter lesions and a cerebrospinal fluid PCR confirmed PML due to JC virus. Severe lymphopenia was never present, and at PML diagnosis, CD4 and CD8 T-cell counts were 454 mm and 277 mm. CD8 T-cells were able to respond to JCV VP1 peptide stimulation with TNFα secretion. Peripheral B-cell count was only 8 mm. Mirtazapine and Maraviroc were started, but unfortunately, she rapidly deteriorated and died 5 weeks after PML diagnosis.

Conclusion: Although peripheral lymphocyte counts were never low and CD4 T-cell count was close to normal, the persistent black fungus infection was a hallmark of severely compromised cellular immunity. The unexpected extremely low absolute B-cell count might suggest a protective role for B-cells. The paradoxical, clinical PML onset months after immunosuppressive discontinuation suggests that it was only discovered in the context of an immune reconstitution inflammatory syndrome.
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http://dx.doi.org/10.1099/jmmcr.0.005053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5330243PMC
August 2016

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

Impaired NK-mediated regulation of T-cell activity in multiple sclerosis is reconstituted by IL-2 receptor modulation.

Proc Natl Acad Sci U S A 2016 May 9;113(21):E2973-82. Epub 2016 May 9.

Department of Neurology, University Hospital Münster, Muenster D-48149, Germany; Cluster of Excellence EXC 1003, Cells in Motion, Westfälische Wilhelms-University, 48149 Muenster, Germany

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS) resulting from a breakdown in peripheral immune tolerance. Although a beneficial role of natural killer (NK)-cell immune-regulatory function has been proposed, it still needs to be elucidated whether NK cells are functionally impaired as part of the disease. We observed NK cells in active MS lesions in close proximity to T cells. In accordance with a higher migratory capacity across the blood-brain barrier, CD56(bright) NK cells represent the major intrathecal NK-cell subset in both MS patients and healthy individuals. Investigating the peripheral blood and cerebrospinal fluid of MS patients treated with natalizumab revealed that transmigration of this subset depends on the α4β1 integrin very late antigen (VLA)-4. Although no MS-related changes in the migratory capacity of NK cells were observed, NK cells derived from patients with MS exhibit a reduced cytolytic activity in response to antigen-activated CD4(+) T cells. Defective NK-mediated immune regulation in MS is mainly attributable to a CD4(+) T-cell evasion caused by an impaired DNAX accessory molecule (DNAM)-1/CD155 interaction. Both the expression of the activating NK-cell receptor DNAM-1, a genetic alteration consistently found in MS-association studies, and up-regulation of the receptor's ligand CD155 on CD4(+) T cells are reduced in MS. Therapeutic immune modulation of IL-2 receptor restores impaired immune regulation in MS by increasing the proportion of CD155-expressing CD4(+) T cells and the cytolytic activity of NK cells.
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http://dx.doi.org/10.1073/pnas.1524924113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4889377PMC
May 2016

CD8(+) T-cell pathogenicity in Rasmussen encephalitis elucidated by large-scale T-cell receptor sequencing.

Nat Commun 2016 Apr 4;7:11153. Epub 2016 Apr 4.

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

Rasmussen encephalitis (RE) is a rare paediatric epilepsy with uni-hemispheric inflammation and progressive neurological deficits. To elucidate RE immunopathology, we applied T-cell receptor (TCR) sequencing to blood (n=23), cerebrospinal fluid (n=2) and brain biopsies (n=5) of RE patients, and paediatric controls. RE patients present with peripheral CD8(+) T-cell expansion and its strength correlates with disease severity. In addition, RE is the only paediatric epilepsy with prominent T-cell expansions in the CNS. Consistently, common clones are shared between RE patients, who also share MHC-I alleles. Public RE clones share Vβ genes and length of the CDR3. Rituximab/natalizumab/basiliximab treatment does not change TCR diversity, stem cell transplantation replaces the TCR repertoire with minimal overlap between donor and recipient, as observed in individual cases. Our study supports the hypothesis of an antigen-specific attack of peripherally expanded CD8(+) lymphocytes against CNS structures in RE, which might be ameliorated by restricting access to the CNS.
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http://dx.doi.org/10.1038/ncomms11153DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4822013PMC
April 2016

Therapy with natalizumab is associated with high JCV seroconversion and rising JCV index values.

Neurol Neuroimmunol Neuroinflamm 2016 Feb 27;3(1):e195. Epub 2016 Jan 27.

Department of Neurology (N.S., T.S.-H., J.B., C.C.G., K.G., H.W.), University of Münster, Germany; and Pole des Neurosciences Centre Hospitalier Universitaire Toulouse (B.P., D.B.), CPTP INSERM UMR 1043 et Université de Toulouse, UPS, Toulouse, France. D.B. also represents the BioNAT Study Group.

Objective: The aim of the study was to analyze John Cunningham virus (JCV) serology in natalizumab-treated patients over time and assess whether they are influenced by natalizumab treatment.

Methods: German (n = 1,921; 525 longitudinally) and French (n = 1,259; 711 longitudinally) patients were assessed for JCV serology alongside their therapy with natalizumab.

Results: JCV serostatus changed in 69 of 525 longitudinally followed German patients (13.1%) over 14.8 months. Seroconversion according to serostatus was seen in 43 of 339 initially JCV- German patients (12.7% in 14.8 months; 10.3% per year) and 41 of 243 initially JCV- French patients (16.9% in 24 months; 8.5% per year). JCV index values could be reproduced (R (2) = 0.89) with the caveat of 8 of 50 samples (16%) being set into different risk categories between 2 assessments. Index values of JCV+ patients rose over time (p = 0.009) but not because of aging. Treatment with natalizumab was associated with a 15.9% increase of value in JCV+ patients in 14.8 months (12.9% per year).

Conclusions: JCV seroconversion and index values may be influenced by treatment with natalizumab. It is therefore important to monitor patients' JCV serology but also to incorporate additional risk factors into the progressive multifocal leukoencephalopathy risk stratification.
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http://dx.doi.org/10.1212/NXI.0000000000000195DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4733149PMC
February 2016

CD4+ T effector memory cell dysfunction is associated with the accumulation of granulocytic myeloid-derived suppressor cells in glioblastoma patients.

Neuro Oncol 2016 06 17;18(6):807-18. Epub 2015 Nov 17.

Department of Neurology, University Hospital of Regensburg, Regensburg, Germany (D.D., U.B.); Department of Neurosurgery, University Hospital of Muenster, Muenster, Germany (J.W., W.S.); Institute of Neuropathology, University Hospital of Muenster, Muenster, Germany (M.H.); Department of Neurology, University Hospital of Muenster, Muenster, Germany (T.S.-H., H.W., O.M.G.).

Background: Myeloid-derived suppressor cells (MDSCs) comprise a heterogeneous population of myeloid cells that are significantly expanded in cancer patients and are associated with tumor progression.

Methods: Multicolor flow cytometry was used to study the frequency, phenotype, and function of MDSCs in peripheral blood and freshly resected tumors of 52 participants with primary glioblastoma (GBM).

Results: The frequency of CD14(high)CD15(pos) monocytic and CD14(low)CD15(pos) granulocytic MDSCs was significantly higher in peripheral blood of GBM participants compared with healthy donors. The majority of granulocytic MDSCs consisted of CD14(low)CD15(high) neutrophilic MDSCs with high T-cell suppressive capacities. At the tumor side, we found an increase in CD14(high)CD15(pos) monocytic MDSCs and high frequencies of CD14(low)CD15(pos) granulocytic MDSCs that displayed an activated phenotype with downregulation of CD16 and upregulation of HLA-DR molecules, which did not inhibit T-cell proliferative responses in vitro. However, a strong association between granulocytic MDSCs and CD4(+) effector memory T-cells (TEM) within the tumors was detected. Tumor-derived CD4(+) TEM expressed high levels of PD-1 when compared with their blood-derived counterparts and were functionally exhausted. The respective ligand, PD-L1, was significantly upregulated on tumor-derived MDSCs, and T-cell co-culture experiments confirmed that glioma-infiltrating MDSCs can induce PD-1 expression on CD4(+) TEM.

Conclusions: Our findings provide a detailed characterization of different MDSC subsets in GBM patients and indicate that both granulocytic MDSCs in peripheral blood and at the tumor site play a major role in GBM-induced T-cell suppression.
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http://dx.doi.org/10.1093/neuonc/nov280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4864257PMC
June 2016

PML risk stratification using anti-JCV antibody index and L-selectin.

Mult Scler 2016 07 2;22(8):1048-60. Epub 2015 Oct 2.

Department of Neurology, University of Münster, Germany.

Background: Natalizumab treatment is associated with progressive multifocal leukoencephalopathy (PML) development. Treatment duration, prior immunosuppressant use, and JCV serostatus are currently used for risk stratification, but PML incidence stays high. Anti-JCV antibody index and L-selectin (CD62L) have been proposed as additional risk stratification parameters.

Objective: This study aimed at verifying and integrating both parameters into one algorithm for risk stratification.

Methods: Multicentric, international cohorts of natalizumab-treated MS patients were assessed for JCV index (1921 control patients and nine pre-PML patients) and CD62L (1410 control patients and 17 pre-PML patients).

Results: CD62L values correlate with JCV serostatus, as well as JCV index values. Low CD62L in natalizumab-treated patients was confirmed and validated as a biomarker for PML risk with the risk factor "CD62L low" increasing a patient's relative risk 55-fold (p < 0.0001). Validation efforts established 86% sensitivity/91% specificity for CD62L and 100% sensitivity/59% specificity for JCV index as predictors of PML. Using both parameters identified 1.9% of natalizumab-treated patients in the reference center as the risk group.

Conclusions: Both JCV index and CD62L have merit for risk stratification and share a potential biological relationship with implications for general PML etiology. A risk algorithm incorporating both biomarkers could strongly reduce PML incidence.
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http://dx.doi.org/10.1177/1352458515607651DOI Listing
July 2016

Neurocognitive decline in HIV patients is associated with ongoing T-cell activation in the cerebrospinal fluid.

Ann Clin Transl Neurol 2015 Sep 18;2(9):906-19. Epub 2015 Aug 18.

Department of Neurology, University Hospital of Muenster Albert-Schweitzer-Campus 1, D-48149, Muenster, Germany.

Objective: HIV-associated neurocognitive disorders (HAND) remain a challenge despite combination antiretroviral therapy (cART). Immune cell activation has been implicated to play a major role in the development of HAND.

Methods: In this study, we used multicolor flow cytometry on peripheral blood (PB) and cerebrospinal fluid (CSF) samples to determine the expression of HLA-DR and programmed death-1 (PD-1) on CD4+ and CD8+ T cells in patients with chronic HIV infection. Expression levels were correlated with HI virus load in PB and CSF, classification of HAND and severity of magnetic resonance imaging (MRI) signal abnormalities.

Results: In a cohort of 86 HIV patients we found that the grade of neurocognitive impairment and the severity of MRI signal abnormalities correlated with decreasing CD4/CD8-ratios and increased frequencies of HLA-DR expressing CD4+ and CD8+ T cells reaching the highest values in the CSF samples. Importantly, HLA-DR upregulation was still detectable in virologically suppressed HIV patients. Further, T-cell subpopulation analysis of 40 HIV patients showed a significant shift from naïve to effector memory (EM) T cells that was negatively correlated with the grade of neurocognitive impairment in the PB samples. Moreover, PD-1 was significantly increased on CD4+ memory T cells with highest levels on EM T cells in HIV patients with mild or severe neurocognitive alterations.

Interpretation: The CD4/CD8 ratio, the proportion of EM to naïve T cells and the immune activation profile of CD4+ and CD8+ T cells in PB and CSF might be useful parameters to monitor the efficacy of cART and to identify HIV patients at risk of further neurocognitive deterioration.
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http://dx.doi.org/10.1002/acn3.227DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4574808PMC
September 2015

Trafficking of lymphocytes into the CNS.

Oncotarget 2015 Jul;6(20):17863-4

Department of Neurology, University of Muenster, Muenster, Germany.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4627217PMC
http://dx.doi.org/10.18632/oncotarget.5014DOI Listing
July 2015