Das ZNS als B-Zell-permissives Milieu bei der Multiplen Sklerose

Bei der MS ist das ZNS nicht nur passives Zielorgan des überaktiven Immunsystems, sondern hirneigene Zellen, wie z.B. Astrozyten, greifen auch selber aktiv in den Erkrankungsprozess ein, z.B. durch die Produktion von Zytokinen. Bzgl. der Frage „Wie entsteht im ZNS ein B-Zell-permissives Milieu?“ konnten wir zeigen, dass Astrozyten bereits im gesunden Gehirn BAFF produzieren. Unter entzündlichen Bedingungen steigerte sich die BAFF-Expression erheblich und erreichte in situ das Niveau sekundärer lymphatischer Organe, und überstieg in vitro sogar deutlich das Niveau optimal aktivierter Makrophagen. Daher ist anzunehmen, dass das von Astrozyten produzierte BAFF bei Patienten mit MS dazu beiträgt, dass B-Zellen eine Überlebensnische im ZNS finden. Die Migration von B-Zellen in das ZNS wird u.a. von Chemokinen kontrolliert. B-Zellen tragen Chemokinrezeptoren insb. für CCL19 und CCL21, CXCL12 und CXCL13. Wir haben eine differentielle Expression dieser Chemokine bzgl. der Aktivität der Läsionen und der produzierenden Zellen gefunden. CCL19 und CXCL12 wurden bereits im gesunden Gehirn und verstärkt in MS-Läsionen exprimiert. Im Gegensatz zu CCL19 fanden wir CCL21, das an den gleichen Rezeptor wie CCL19, CCR7, bindet, weder in gesundem Gehirn noch in MS-Läsionen. CXCL13 fand sich ausschließlich in aktiven MS-Läsionen. Der Gehalt von sowohl CCL19 als auch CXCL13 korrelierte mit dem IgG-Quotienten, derjenige von CXCL13 zusätzlich mit der Zahl der B- und Plasmazellen im Liquor. Neben den molekularen Faktoren, die ein B-Zell-permissives Milieu im ZNS schaffen, haben wir untersucht, welche Auswirkung Medikamenten zur Therapie der MS speziell auf CD20-positive Zellen und das BAFF-/B-Zell-System haben, insb. da dies oft nicht der initial intendierte Wirkmechanismus war. Hierbei zeigte sich, dass Interferon- und Fingolimod die BAFF-Expression in Astrozyten beeinflussen. Rituximab führt – a.e. durch den Depletions-bedingt verminderten Verbrauch – zu einer Erhöhung der verfügbaren BAFF-Spiegels im Blut. Somit wird BAFF durch mehr Medikamente reguliert, als ursprünglich angenommen. Für welche Patientengruppe dieser Aspekt am relevantesten ist, wird sich in weiteren Arbeiten zeigen. Natalizumab hatte unter den verschiedenen Lymphozytensubpopulationen im Blut den größten Effekt auf B-Zellen. Andersherum konnten wir zeigen, dass eine hochselektive Anti-CD20-Therapie nicht nur B-Zellen, sondern auch eine ungewöhnliche Subpopulation CD3+CD20+ T-Zellen depletiert, jedoch nicht so lange anhaltend wir B-Zellen. Diese CD3+CD20+ T-Zellen wiesen bevorzugt, aber nicht ausschließlich, den Phänotyp von CD8+ Effektor-Memory-Zellen auf. Bzgl. der Frage „Lässt sich an intrathekal produziertem IgG ein inflammatorisches Glykosylierungsmuster feststellen?“ konnten wir zeigen, dass das Glykosylierungsmuster von IgG im Liquor, aber nicht im Blut, bei Patienten mit MS in Richtung eines pro-inflammatorischen Musters verschoben ist. Ursächlich ist vermutlich ein Einfluss des entzündlichen Milieus, in dem die Antikörper-produzierenden Zellen sich befinden, wobei die molekularen Regulationsmechanismen noch Gegenstand weiterer Forschung sind. Da ein solches IgG-Glykosylierungsmuster die IgG-Effektormechanismen wie CDC und ADCC moduliert, erscheint ein positiver Rückkopplungskreis plausibel. Die Kenntnis der molekularen Mechanismen, die ein B-Zell-permissives Milieu im ZNS schaffen, und wie dies bereits jetzt durch Medikamente beeinflusst wird, kann ebenso wie Details zur Pathophysiologie der B-Zell-Antwort im ZNS, z.B. der IgG-Glykosylierung, dazu beitragen, die Erkrankung MS genauer zu verstehen und in Zukunft besser behandeln zu können

Cytokine and immune cell profiling in the cerebrospinal fluid of patients with neuro-inflammatory diseases

Background Cytokines play multiple roles during neuro-inflammatory processes and several cytokines have been studied in the context of specific diseases. This study provides a comprehensive picture of cerebrospinal fluid (CSF) changes during neuro-inflammation by analyzing multiple cytokines in combination with immune cell subsets and standard CSF parameters. Methods Using multiplex assays, we simultaneously measured 36 cytokines (CCL1-3, CCL7, CCL8, CCL11, CCL13, CCL19, CCL20, CCL22-27, CXCL1, CXCL2, CXCL5, CXCL6, CXCL8, CXCL9, CXCL11-13, CXCL16, CX3CL1, IL2, IL4, IL6, IL10, IL16, GM-CSF, IFN gamma, MIF, TNF alpha, and MIB1 beta) in the CSF and serum of 75 subjects. Diagnoses included clinically isolated syndrome and relapsing-remitting multiple sclerosis (MS, n = 18), secondary progressive MS (n = 8), neuro-syphilis (n = 6), Lyme neuro-borreliosis (n = 13), bacterial and viral meningitis (n = 20), and patients with non-inflammatory neurological diseases (NIND, n = 10). Cytokine concentrations were correlated with CSF standard parameters and CSF immune cell subsets (CD4 and CD8 T cells, B cells, plasmablasts, monocytes, and NK cells) quantified by flow cytometry. Results We observed increased levels of multiple cytokines (26/36) in patients with neuro-inflammatory diseases when compared to NIND that consistently correlated with CSF cell count and Q(Albumin). Most CSF cytokine concentrations correlated with each other, but correlations between CSF and serum values were scarce (3/36). Within the CSF compartment, CXCL13 showed a strong association with B cells when analyzing all patients, as well as patients with an intact blood-brain barrier (BBB). NK cells positively correlated with CSF concentrations of multiple cytokines (22/36) when analyzing all patients. These correlations were maintained when looking at patients with a disrupted BBB but not detectable in patients with an intact BBB. Conclusions Under conditions of neuro-inflammation, multiple CSF cytokines are regulated in parallel and most likely produced locally. A combined increase of CSF CXCL13 levels and B cells occurs under conditions of an intact BBB. Under conditions of a disrupted BBB, CSF NK cells show significantly increased values and seem to have a major contribution to overall inflammatory processes, reflected by a strong correlation with multiple cytokines. Future studies are necessary to address the exact kinetics of these cytokines during neuro-inflammation and their relation to specific diseases phenotypes

Differences and Similarities across Four Countries

Cyberbullying is a ubiquitous topic when considering young people and internet and communication technologies (ICTs). For interventional purposes, it is essential to take into account the perspective of adolescents. This is the reason why our main focus is (1) investigating the role of different criteria in the perceived severity of cyberbullying incidents, and (2) examining the differences between countries in the perceived severity of cyberbullying. The sample consisted of 1,964 adolescents (48.2% girls) from middle and high schools of four different countries, i.e., Estonia, Italy, Germany, and Turkey. The participants' age ranged from 12 to 20 years old with a mean age of 14.49 (SD = 1.66) years. To assess perceived severity, participants rated a set of 128 scenarios, which systematically included one or more of five criteria (intentionality, repetition, imbalance of power, public vs. private, and anonymity) and represented four types of cyberbullying behaviors (Written—Verbal, Visual, Exclusion, Impersonation). The role of different criteria was analyzed using the Exploratory Structural Equation Modeling (ESEM). Results showed a similar structure across the four countries (invariant except for the latent factors' means). Further, criteria of imbalance of power and, to a lesser extent, intentionality, anonymity, and repetition always in combination, were found to be the most important criteria to define the severity of cyberbullying. Differences between countries highlighted specific features of Turkish students, who perceived all scenarios as more severe than adolescents from other countries and were more sensitive to imbalance of power. German and Italian students showed an opposite perception of anonymity combined with intentionality. For Italian participants, an anonymous attack was less threatening than for participants of other countries, whereas for German students anonymity caused more insecurity and fear. In addition, Italian adolescents were more perceptive of the criterion of intentionality. Finally, Estonian adolescents did not show strong differences in their factor scores compared to adolescents from the other countries

Pro-inflammatory pattern of IgG1 Fc glycosylation in multiple sclerosis cerebrospinal fluid.

Background Immunoglobulin G (IgG) effector functions are regulated by the composition of glycans attached to a conserved N-glycosylation site in the Fc part. Intrathecal production of IgG, especially IgG1, is a hallmark of multiple sclerosis (MS), but nothing is known about IgG Fc glycosylation in MS and in cerebrospinal fluid (CSF) in general. Methods We applied mass spectrometry of tryptic Fc glycopeptides to analyze IgG Fc glycosylation (sialylation, galactosylation, fucosylation, and bisecting N-acetylglucosamine (GlcNAc)) in 48 paired CSF and serum samples from adult patients with MS or a first demyelinating event highly suggestive of MS (designated as MS cases), and from healthy volunteers and patients with other non-inflammatory diseases (control group). p values were adjusted for multiple testing. Results Our experiments revealed four main results. First, IgG1 glycosylation patterns were different in CSF vs. serum, in the MS group and even in control donors without intrathecal IgG synthesis. Second, in MS patients vs. controls, IgG1 glycosylation patterns were altered in CSF, but not in serum. Specifically, in CSF from the MS group, bisecting GlcNAc were elevated, and afucosylation and galactosylation were reduced. Elevated bisecting GlcNAc and reduced galactosylation are known to enhance IgG effector functions. Third, hypothesis-free regression analysis revealed that alterations of afucosylation and bisecting GlcNAc in CSF from MS cases peaked 2–3 months after the last relapse. Fourth, CSF IgG1 glycosylation correlated with the degree of intrathecal IgG synthesis and CSF cell count. Conclusions The CNS compartment as well as the inflammatory milieu in MS affect IgG1 Fc glycosylation. In MS, the CSF IgG1 glycosylation has features that enhance Fc effector functions

Co-occurrence of two cases of progressive multifocal leukoencephalopathy in a natalizumab ``infusion group''

We observed two cases of progressive multifocal leukoencephalopathy (PML) that occurred in the same infusion group. The group consisted of four patients with relapsing-remitting multiple sclerosis (RRMS) who had been treated with natalizumab (NAT) in the same medical practice for more than four years at the same times and in the same room, raising concerns about viral transmission between members of the infusion group. DNA amplification and sequence comparison of the non-coding control region (NCCR) of JC virus (JCV) present in cerebrospinal fluid (CSF) samples from PML patients #1 and #2 revealed that the amplified JCV sequences differed from the JCV archetype. The NCRR of the viral DNA was unique to each patient, arguing against the possibility of viral transmission between patients. Statistical considerations predict that similar co-occurrences of PML are likely to happen in the future

Co-occurrence of two cases of progressive multifocal leukoencephalopathy in a natalizumab ``infusion group''

We observed two cases of progressive multifocal leukoencephalopathy (PML) that occurred in the same infusion group. The group consisted of four patients with relapsing-remitting multiple sclerosis (RRMS) who had been treated with natalizumab (NAT) in the same medical practice for more than four years at the same times and in the same room, raising concerns about viral transmission between members of the infusion group. DNA amplification and sequence comparison of the non-coding control region (NCCR) of JC virus (JCV) present in cerebrospinal fluid (CSF) samples from PML patients #1 and #2 revealed that the amplified JCV sequences differed from the JCV archetype. The NCRR of the viral DNA was unique to each patient, arguing against the possibility of viral transmission between patients. Statistical considerations predict that similar co-occurrences of PML are likely to happen in the future

BAFF is produced by astrocytes and up-regulated in multiple sclerosis lesions and primary central nervous system lymphoma

We report that B cell–activating factor of the tumor necrosis factor (TNF) family (BAFF) is expressed in the normal human brain at ∼10% of that in lymphatic tissues (tonsils and adenoids) and is produced by astrocytes. BAFF was regularly detected by enzyme-linked immunosorbent assay in brain tissue lysates and in normal spinal fluid, and in astrocytes by double fluorescence microscopy. Cultured human astrocytes secreted functionally active BAFF after stimulation with interferon-γ and TNF-α via a furin-like protease-dependent pathway. BAFF secretion per cell was manifold higher in activated astrocytes than in monocytes and macrophages. We studied brain lesions with B cell components, and found that in multiple sclerosis plaques, BAFF expression was strongly up-regulated to levels observed in lymphatic tissues. BAFF was localized in astrocytes close to BAFF-R–expressing immune cells. BAFF receptors were strongly expressed in situ in primary central nervous system (CNS) lymphomas. This paper identifies astrocytes as a nonimmune source of BAFF. CNS-produced BAFF may support B cell survival in inflammatory diseases and primary B cell lymphoma

Age-dependent favorable visual recovery despite significant retinal atrophy in pediatric MOGAD: how much retina do you really need to see well?

BACKGROUND To investigate age-related severity, patterns of retinal structural damage, and functional visual recovery in pediatric and adult cohorts of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) optic neuritis (ON). METHODS All MOGAD patients from the 5 participating centers were included. Patients with initial manifestation 0.5) visual impairment. Independent of retinal atrophy, age at ON onset significantly correlated with visual outcome. CONCLUSION Pediatric MOGAD ON showed better visual recovery than adult MOGAD ON despite profound and almost identical neuroaxonal retinal atrophy. Age-related cortical neuroplasticity may account for the substantial discrepancy between structural changes and functional outcomes

Cerebrospinal Fluid B Cells Correlate with Early Brain Inflammation in Multiple Sclerosis

Background: There is accumulating evidence from immunological, pathological and therapeutic studies that B cells are key components in the pathophysiology of multiple sclerosis (MS). Methodology/Principal Findings: In this prospective study we have for the first time investigated the differences in the inflammatory response between relapsing and progressive MS by comparing cerebrospinal fluid (CSF) cell profiles from patients at the onset of the disease (clinically isolated syndrome, CIS), relapsing-remitting (RR) and chronic progressive (CP) MS by flow cytometry. As controls we have used patients with other neurological diseases. We have found a statistically significant accumulation of CSF mature B cells (CD19+CD1382) and plasma blasts (CD19+CD138+) in CIS and RRMS. Both B cell populations were, however, not significantly increased in CPMS. Further, this accumulation of B cells correlated with acute brain inflammation measured by magnetic resonance imaging and with inflammatory CSF parameters such as the number of CSF leukocytes, intrathecal immunoglobulin M and G synthesis and intrathecal production of matri