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ZusammenfassungIm Kindesalter ist die isolierte Gonarthritis sowohl bei infektiöser als auch bei nichtinfektiöser Ätiologie ein häufiger Manifestationsort. Nicht immer ist die klinische Präsentation klassisch, was zu Schwierigkeiten bei der unmittelbaren Differenzierung zwischen beiden Entitäten führen kann. Im vorliegenden Fall berichten wir von einem Patienten mit chronisch-rezidivierendem Verlauf einer Gonarthritis vor dem Hintergrund einer Autoimmunneutropenie. Bei initial milder Symptomatik und fehlendem Keimnachweis mittels Kultur und eubakterieller PCR konnte durch eine antientzündliche Behandlung mit nichtsteroidalen Antirheumatika (NSAR), Methotrexat und intraartikulären Kortison-Infiltrationen keine anhaltende Remission erzielt werden. Mit Stabilisierung der Neutrophilenzahlen zeigte sich eine (paradoxe) Aggravierung der Gonarthritis. Erst mit Erweiterung der mikrobiologischen Aufarbeitung der Punktate ließ sich schließlich Mycobacterium kansasii in der Synovialkultur anzüchten. Nach chirurgischer Spülung des Gelenks, Einleitung einer antimykobakteriellen Dreifachtherapie und Umstellung der NSAR-Therapie auf Indometacin kam es schließlich zu einem kontinuierlichen Rückgang der Arthritis.

BACKGROUND: Inborn errors of immunity (IEI) are rare diseases, which makes diagnosis a challenge. A better description of the initial presenting manifestations should improve awareness and avoid diagnostic delay. Although increased infection susceptibility is a well-known initial IEI manifestation, less is known about the frequency of other presenting manifestations.OBJECTIVE: We sought to analyze age-related initial presenting manifestations of IEI including different IEI disease cohorts.METHODS: We analyzed data on 16,486 patients of the European Society for Immunodeficiencies Registry. Patients with autoinflammatory diseases were excluded because of the limited number registered.RESULTS: Overall, 68% of patients initially presented with infections only, 9% with immune dysregulation only, and 9% with a combination of both. Syndromic features were the presenting feature in 12%, 4% had laboratory abnormalities only, 1.5% were diagnosed because of family history only, and 0.8% presented with malignancy. Two-third of patients with IEI presented before the age of 6 years, but a quarter of patients developed initial symptoms only as adults. Immune dysregulation was most frequently recognized as an initial IEI manifestation between age 6 and 25 years, with male predominance until age 10 years, shifting to female predominance after age 40 years. Infections were most prevalent as a first manifestation in patients presenting after age 30 years.CONCLUSIONS: An exclusive focus on infection-centered warning signs would have missed around 25% of patients with IEI who initially present with other manifestations.

Since 1997 an effective prevention and treatment of infections with human immunodeficiency virus (HIV) have been available in the form of antiretroviral combination therapy.What has been achieved during this time by transmission prophylaxis and treatment of HIV infections in children in Germany?Presentation of the development of transmission prophylaxis and the epidemiological surveys of the Robert Koch Institute, presentation of drug development and guidelines for antiretroviral therapy in children and adolescents and presentation of surveys of the German pediatric and adolescent HIV cohort (GEPIC).The introduction of HIV testing of pregnant women has made regular antiretroviral treatment of HIV positive pregnant women and the introduction of transmission-reducing measures possible. This has reduced the risk of vertical transmission from about 30% to 1%. Currently, it is being investigated whether children exposed to HIV can be breastfed without risk. Antiretroviral therapy in children has decisively improved the survival rates and the physical and cognitive development of HIV positive children. New active substances have a more favorable side effect profile. In Germany, the World Health Organization (WHO) target of achieving complete suppression of the viral load in 90% of the children has been achieved. A delayed diagnosis in children and adolescents is still associated with severe infections. An HIV infection remains a disease with a stigma and is therefore usually kept secret from the children and their environment.With the transmission prophylaxis and therapy that are now available, it is possible to prevent transmission to a large extent and with a timely diagnosis to enable HIV positive children to lead a largely healthy life. The goal of children being able to know and name their disease without fear has still not been achieved.

Contains fulltext : 283099.pdf (Publisher’s version ) (Open Access) BACKGROUND: Young children living with HIV have few treatment options. We aimed to assess the efficacy and safety of dolutegravir-based antiretroviral therapy (ART) in children weighing between 3 kg and less than 14 kg. METHODS: ODYSSEY is an open-label, randomised, non-inferiority trial (10% margin) comparing dolutegravir-based ART with standard of care and comprises two cohorts (children weighing ≥14 kg and

Contains fulltext : 282959.pdf (Publisher’s version ) (Open Access) BACKGROUND: Children with HIV-associated tuberculosis (TB) have few antiretroviral therapy (ART) options. We aimed to evaluate the safety and pharmacokinetics of dolutegravir twice-daily dosing in children receiving rifampicin for HIV-associated TB. METHODS: We nested a two-period, fixed-order pharmacokinetic substudy within the open-label, multicentre, randomised, controlled, non-inferiority ODYSSEY trial at research centres in South Africa, Uganda, and Zimbabwe. Children (aged 4 weeks to

To evaluate the 5-year real-world benefit-risk profile of fingolimod in patients with relapsing-remitting MS (RRMS) in Germany.Post-Authorization Non-interventional German sAfety study of GilEnyA (PANGAEA) is a non-interventional real-world study to prospectively assess the effectiveness and safety of fingolimod in routine clinical practice in Germany. The follow-up period comprised 5 years. Patients were included if they had been diagnosed with RRMS and had been prescribed fingolimod as part of clinical routine. There were no exclusion criteria except the contraindications for fingolimod as defined in the European label. The effectiveness and safety analysis set comprised 4032 and 4067 RRMS patients, respectively.At the time of the 5-year follow-up of PANGAEA, 66.57% of patients still continued fingolimod therapy. Annualized relapse rates decreased from baseline 1.5 ± 1.15 to 0.42 ± 0.734 at year 1 and 0.21 ± 0.483 at year 5, and the disability status remained stable, as demonstrated by the Expanded Disability Status Scale mean change from baseline (0.1 ± 2.51), the decrease of the Multiple Sclerosis Severity Score from 5.1 ± 2.59 at baseline to 3.9 ± 2.31 at the 60-months follow-up, and the percentage of patients with 'no change' in the Clinical Global Impression scale at the 60-months follow-up (78.11%). Adverse events (AE) occurring in 75.04% of patients were in line with the known safety profile of fingolimod and were mostly non-serious AE (33.62%) and non-serious adverse drug reactions (50.59%; serious AE 4.98%; serious ADR 10.82%).PANGAEA demonstrated the sustained beneficial effectiveness and safety of fingolimod in the long-term real-world treatment of patients with RRMS.

Background Intravenous artesunate (ivA) is the standard treatment for severe malaria. Data systematically evaluating the use of ivA in pediatric patients outside malaria-endemic regions are limited. The aim of this case series was to summarize efficacy and safety of ivA for imported severe malaria in children in Germany. Methods Our retrospective case series included pediatric patients with imported severe malaria treated with at least 1 dose of ivA (Artesun, Guilin Pharmaceutical; Shanghai, China) at 4 German tertiary care centers. Severe malaria was defined according to World Health Organization criteria. Results Between 2010 and 2018, 14 children with a median [interquartile range (IQR)] age of 6 (1;9.5) years were included. All children were of African descent. All but 2 patients had Plasmodium falciparum malaria; 1 child had P. vivax malaria and 1 child had P. falciparum and P. vivax co-infection. Median (IQR) parasitemia at admission in patients with P. falciparum was 9.5% (3;16.5). Patients were treated with 1-10 [median (IQR) 3 (3;4)] doses ivA. All but one patient received a full course of oral antimalarial treatment. Parasite clearance was achieved within 2-4 days, with the exception of 1 patient with prolonged clearance of peripheral parasitemia. Three patients experienced posttreatment hemolysis but none needed blood transfusion. Otherwise ivA was safe and well tolerated. Conclusions ivA was highly efficacious in this pediatric cohort. We observed episodes of mild to moderate posttreatment hemolysis in approximately one-third of patients. The legal status and usage of potentially lifesaving ivA should be evaluated in Europe.

(1) Background: Fingolimod (Gilenya®) was the first oral treatment for patients with relapsing-remitting multiple sclerosis (RRMS). Since its approval, the treatment landscape has changed enormously. (2) Methods: Data of PANGAEA and PANGAEA 2.0, two German real-world studies, were descriptively analysed for possible evolution of patient profiles and treatment behavior. Both are prospective, multi-center, non-interventional, long-term studies on fingolimod use in RRMS in real life. Data of 4229 PANGAEA patients (recruited 2011–2013) and 2441 PANGAEA 2.0 patients (recruited 2015–2018) were available. Baseline data included demographics, RRMS characteristics and disease severity. (3) Results: The mean age of PANGAEA and PANGAEA 2.0 patients was similar (38.8 vs. 39.2 years). Patients in PANGAEA 2.0 had shorter disease duration (7.1 vs. 8.2 years) and fewer relapses in the year before baseline (1.2 vs. 1.6). Disease severity at baseline estimated by EDSS and SDMT was lower in PANGAEA 2.0 patients compared to PANGAEA (EDSS difference 1.0 points, SDMT difference 3.3 points). (4) Conclusions: The results hint at an influence of changes in the treatment guidelines and the label on fingolimod patients profiles over time. Patients tended to have lower disease activity at fingolimod initiation, suggesting an earlier intervention. This indicates increased experience in using fingolimod for sub-optimally treated RRMS patients and a change in mindset towards an early treatment optimization.

Background: Fingolimod (Gilenya®) is approved for adult and pediatric patients with highly active relapsing–remitting multiple sclerosis (RRMS).Objectives: The objective was to describe the effectiveness of fingolimod in young adults compared to older patients in clinical practice.Methods: PANGAEA is the largest prospective, multi-center, non-interventional, long-term study evaluating fingolimod in RRMS. We descriptively analyzed demographics, MS characteristics, and severity in two subgroups of young adults (≤20 and >20 to ≤30 years) and older patients (>30 years).Results: Young adults had lower Expanded Disability Status Scale (EDSS) scores compared to older patients (1.8 and 2.3 vs. 3.2) at baseline. The mean EDSS scores remained stable over 5 years in all subgroups. Young adults had higher annual relapse rates (2.0 and 1.7 vs. 1.4) at study entry, which were reduced by approximately 80% in all subgroups over 5 years. The proportion of patients with no clinical disease activity in year 4 was 52.6 and 73.4 vs. 66.9% in patients ≤20, >20 to ≤30 years and >30 years, respectively. The symbol digit modalities test score increased by 15.25 ± 8.3 and 8.3 ± 11.3 (mean ± SD) from baseline in patients >20 to ≤30 and >30 years.Conclusions: Real-world evidence suggests a long-term treatment benefit of fingolimod in young RRMS patients.

Background: Investigating the role of children in the COVID-19 pandemic is pivotal to prevent the virus spreading. In most cases, children infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) develop non-specific symptoms or are asymptomatic. Therefore, the infection rate among this age group remains unclear. Seroprevalence studies, including clinical questionnaires, may contribute to our understanding of the time course and clinical manifestations of SARS-CoV-2 infections. Methods: SARS-CoV-2-KIDS is a longitudinal, hospital-based, multicentre study in Germany on the seroprevalence of anti-SARS-CoV-2 immunoglobulin G, as determined by an Enzyme-Linked Immunosorbent Assay in children (aged ≤17 years). A study-specific questionnaire provided additional information on clinical aspects. Findings: This analysis included 10,358 participants recruited from June 2020 to May 2021. The estimated anti-SARS-CoV-2 seroprevalence increased from 2·0% (95% confidence interval (95% CI) 1·6, 2·5) to 10·8% (95% CI 8·7, 12·9) in March 2021, without major change afterwards and was higher in children with migrant background (on average 6·6% vs. 2·8%). In the pandemic early stages, children under three years were 3·5 (95% CI 2·2, 5·6) times more likely to be seropositive than older children, with the levels equalising in later observations. History of self-reported respiratory tract infections or pneumonia was associated with seropositivity (OR 1·8 (95% CI 1·4, 2·3);2·7 (95% CI 1·7, 4·1)). Interpretation: The majority of children in Germany do not have detectable SARS-CoV-2 IgG. To some extent, this may reflect the effect of differing containment measures implemented in the federal states. Detection levels might have been greater in certain age groups or migrant background. Lifting containment measurements is likely to cause a general increase in respiratory tract infections, which already pose a challenge to paediatric medical care during regular winter seasons. This challenge might become critical with additional infections caused by SARS-CoV-2.

An amendment to this paper has been published and can be accessed via the original article.

Mammalian podocytes, the key determinants of the kidney's filtration barrier, differentiate from columnar epithelial cells and several key determinants of apical-basal polarity in the conventional epithelia have been shown to regulate podocyte morphogenesis and function. However, little is known about the role of Crumbs, a conserved polarity regulator in many epithelia, for slit-diaphragm formation and podocyte function. In this study, we used Drosophila nephrocytes as model system for mammalian podocytes and identified a conserved function of Crumbs proteins for cellular morphogenesis, nephrocyte diaphragm assembly/maintenance, and endocytosis. Nephrocyte-specific knock-down of Crumbs results in disturbed nephrocyte diaphragm assembly/maintenance and decreased endocytosis, which can be rescued by Drosophila Crumbs as well as human Crumbs2 and Crumbs3, which were both expressed in human podocytes. In contrast to the extracellular domain, which facilitates nephrocyte diaphragm assembly/maintenance, the intracellular FERM-interaction motif of Crumbs is essential for regulating endocytosis. Moreover, Moesin, which binds to the FERM-binding domain of Crumbs, is essential for efficient endocytosis. Thus, we describe here a new mechanism of nephrocyte development and function, which is likely to be conserved in mammalian podocytes.

The nephron is the basic physiologic subunit of the mammalian kidney and is made up of several apicobasally polarized epithelial cell types. The process of apicobasal polarization in animal cells is controlled by the evolutionarily conserved Crumbs (CRB), Partitioning-defective, and Scribble protein complexes. Here, we investigated the role of protein associated with LIN-7 1 (Pals1, also known as Mpp5), a core component of the apical membrane–determining CRB complex in the nephron. Pals1 interacting proteins, including Crb3 and Wwtr1/Taz, have been linked to renal cyst formation in mice before. Immunohistologic analysis revealed Pals1 expression in renal tubular cells and podocytes of human kidneys. Mice lacking one Pals1 allele (functionally haploid for Pals1) in nephrons developed a fully penetrant phenotype, characterized by cyst formation and severe defects in renal barrier function, which led to death within 6–8 weeks. In Drosophila nephrocytes, deficiency of the Pals1 ortholog caused alterations in slit-diaphragm–like structures. Additional studies in epithelial cell culture models revealed that Pals1 functions as a dose-dependent upstream regulator of the crosstalk between Hippo- and TGF-β–mediated signaling. Furthermore, Pals1 haploinsufficiency in mouse kidneys associated with the upregulation of Hippo pathway target genes and marker genes of TGF-β signaling, including biomarkers of renal diseases. These findings support a link between apical polarity proteins and renal diseases, especially renal cyst diseases. Further investigation of the Pals1-linked networks is required to decipher the mechanisms underlying the pathogenesis of these diseases.

Using retrospectively collected data from 383 infants born to HIV-1-infected mothers receiving antiretroviral therapy, we compared transmission rates and hematologic toxicity between infants receiving 2-week (short course) versus longer duration zidovudine postexposure prophylaxis. Short course resulted in lower hematologic toxicity without evidence of increased vertical transmission risk.

Due to early antenatal screening and treatment, HIV mother-to-child transmission (MTCT) rarely occurs in Germany. The study aimed to investigate the impact on prevalence of HIV infection in the antenatal population and the incidence of late-presenting HIV-infected mothers attributable to increased numbers of refugees. Retrospective analysis and comparison were performed for all deliveries in HIV-infected pregnant women presenting to medical care in Munich (southern Germany) and Hamburg (northern Germany) covering two time periods, A (2010–2012) and B (2013–2015). In Munich, deliveries in HIV-infected pregnant women increased 1.6-fold from period A (n = 50) to B (n = 79) with late-presenting cases rising significantly from 2% (1/50) in period A to 13% (10/79) in B. In contrast, late-presenting cases in Hamburg decreased from 14% (14/100) in period A to 7% (7/107) in B, while the total number of HIV-infected women giving birth remained stable. From 2010 to 2015, one late-presenting pregnant woman transmitted HIV in Munich by presumed in utero mode of infection (case reviewed here), while no MTCT occurred in Hamburg. HIV infections diagnosed late in pregnancy and leading to delayed ART initiation are rising in Munich compared to Hamburg. Antenatal care of HIV-infected pregnant women in Munich appears to have been more affected by the recent refugee influx than Hamburg. Our study highlights the importance of screening all pregnant women for HIV early in pregnancy and providing timely health care access for pregnant refugees and asylum seekers to effectively prevent MTCT in Germany.

Recently, gain-of-function (GOF) mutations in the gene encoding signal transducer and activator of transcription 1 (STAT1) have been associated with chronic mucocutaneous candidiasis (CMC). This case report describes a 10-year-old boy presenting with signs of common variable immunodeficiency (CVID), failure to thrive, impaired neurological development, and a history of recurrent mucocutaneous Candida infections. Sequencing of the STAT1 gene identified a heterozygous missense mutation in exon 7 encoding the STAT1 coiled-coil domain (c.514T>C, p.Phe172Leu). In addition to hypogammaglobulinemia with B-cell deficiency, and a low percentage of Th17 cells, immunological analysis of the patient revealed a marked depletion of forkhead-box P3(+)-expressing regulatory T cells (Tregs). In vitro stimulation of T cells from the patient with interferon-α (IFNα) and/or IFNɣ resulted in a significantly increased expression of STAT1-regulated target genes such as MIG1, IRF1, MX1, MCP1/CCL2, IFI-56K, and CXCL10 as compared to IFN-treated cells from a healthy control, while no IFNα/ɣ-mediated up-regulation of the FOXP3 gene was found. These data demonstrate that the STAT1 GOF mutation F172L, which results in impaired stability of the antiparallel STAT1 dimer conformation, is associated with inhibited Treg cell development and neurological symptoms.

Using a combined approach of pulse chase labeling and single-particle tracking of Crb3A or 3B loaded vesicles we collected trajectories of different vesicle population in living podocyte cells and evaluated statistically their different mobility patterns. Differences in their intracellular mobility and in their directed transport correspond well to the role of Crb3A and 3B in renal plasma membrane sorting (Djuric et al., 2016) [1].

Background In Germany, the incidence of tuberculosis (TB) in children has been on the rise since 2009. High numbers of foreign-born asylum seekers have contributed considerably to the disease burden. Therefore, effective screening strategies for latent TB infection (LTBI) and active TB in asylum seeking children are needed. Aim: Our aim was to investigate the prevalence of LTBI and active TB in asylum seeking children up to 15 years of age in two geographic regions in Germany. Methods: Screening for TB was performed in children in asylum seeker reception centres by tuberculin skin test (TST) or interferon gamma release assay (IGRA). Children with positive results were evaluated for active TB. Additionally, country of origin, sex, travel time, TB symptoms, TB contact and Bacille Calmette-Guérin (BCG) vaccination status were registered. Results: Of 968 screened children 66 (6.8%) had TB infection (58 LTBI, 8 active TB). LTBI prevalence was similar in children from high (Afghanistan) and low (Syria) incidence countries (8.7% vs 6.4%). There were no differences regarding sex, age or travel time between infected and non-infected children. Children under the age of 6 years were at higher risk of progression to active TB (19% vs 2% respectively, p=0,07). Most children (7/8) with active TB were asymptomatic at the time of diagnosis. None of the children had been knowingly exposed to TB. Conclusions: Asylum seeking children from high and low incidence countries are both at risk of developing LTBI or active TB. Universal TB screening for all asylum seeking children should be considered.

Contains fulltext : 172345.pdf (Publisher’s version ) (Closed access)

The epithelial cells of the choroid plexus separate the central nervous system from the blood forming the blood-cerebrospinal fluid (CSF) barrier. The choroid plexus is the main source of CSF, whose composition is markedly changed during pathological disorders, for example regarding matrix metalloproteases (MMPs) and tissue inhibitors of matrix metalloproteases (TIMPs). In the present study, we analyzed the impact of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) on the blood-CSF barrier using an in vitro model based on porcine choroid plexus epithelial cells (PCPEC). TNF-alpha evoked distinct inflammatory processes as shown by mRNA upregulation of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. The cytokine caused a drastic decrease in transepithelial electrical resistance within several hours representing an enhanced permeability of PCPEC monolayers. In addition, the distribution of tight junction proteins was altered. Moreover, MMP activity in PCPEC supernatants was significantly increased by TNF-alpha, presumably due to a diminished expression of TIMP-3 that was similarly observed. MMP-2, -3, and -9 as well as TIMP-1 and -2 were also analyzed and found to be differentially regulated by the cytokine. The TNF-alpha-induced breakdown of the blood-CSF barrier could partially be blocked by the MMP inhibitor GM-6001. Our results show a contribution of MMPs to the inflammatory breakdown of the blood-CSF barrier in vitro. Thus TNF-alpha may mediate the binding of leukocytes to cellular adhesion molecules and the transmigration across the blood-CSF barrier.

CD63 is a ubiquitously expressed member of the tetraspanin superfamily. Using a mating-based split-ubiquitin-yeast 2-hybrid system, pull-down experiments, total internal reflection fluorescence microscopy, Forster resonance energy transfer, and biotinylation assays, we found that CD63 interacts with human organic cation transporter 2 (hOCT2), which transports endogenous and exogenous substrates, such as neurotransmitters and drugs in several epithelial cells. CD63 overexpression affects cellular localization of hOCT2 expressed in human embryonic kidney (HEK)293 cells. Studies with CD63-knockout mice indicate that in renal proximal tubules, CD63 determines the insertion of the mouse ortholog of the transporter into the proper membrane domain and mediates transporter regulation by trafficking processes. In polarized Madin-Darby kidney canine kidney (MDCK) epithelial cells, CD63 and hOCT2 colocalize with the small GTPase Rab4, which controls the rapid recycling from sorting endosomes back to the cell surface. Suitable negative and positive control experiments were performed for each experimental approach. Empty vector transfected cells and wild-type mice were used as control. CD63 seems to play a role in the recycling of hOCT2 from endosomes to the basolateral membrane in polarized epithelia. These data indicate that CD63 has a previously uncharacterized function in regulating trafficking of specific membrane proteins in polarized cells.-Schulze, U., Brast, S., Grabner, A., Albiker, C., Snieder, B., Holle, S., Schlatter, E., Schroter, R., Pavenstadt, H., Herrmann, E., Lambert, C., Spoden, G. A., Florin, L., Saftig, P., Ciarimboli, G. Tetraspanin CD63 controls basolateral sorting of organic cation transporter 2 in renal proximal tubules.

Phosphoinositides (PI) and converting enzymes are crucial determinants of organelle identity and morphology. One important endolysosomal specific PI is PI(3,5)P

Background / Aims: TMEM16F is a transmembrane protein from a conserved family of Ca2+-activated proteins, which is highly expressed in several tissues. TMEM16F confers phospholipid scramblase activity and Ca2+-activated electrolyte channel activity. Potentially thereby, TMEM16F is involved in cell cycle control and apoptotic signaling. The present study evaluated the role of TMEM16F on cell proliferation and viability in Human Embryonic Kidney cells. Methods: An inducible knockdown of TMEM16F was generated and markers of apoptosis and proliferation were assessed via flow cytometry, western blotting and MTT uptake assay under different conditions. Results: TMEM16F knockdown resulted in attenuated growth of HEK293 cells. This observation correlated with an increased phosphatidylserine exposure and a decreased fraction of viable cells. Interestingly, the cells were not sensitized to Staurosporine- induced cell death. Western blot analyses displayed a parallel activation of pro- and antiapoptotic signaling pathways: Caspase 3 cleavage and Cyclin D1 abundance were simultaneously increased. Furthermore, knockdown of TMEM16F led to activation of AKT signaling. Conclusion: TMEM16F modifies viability of Human Embryonic Kidney cells via its function as a phospholipid scramblase and activation of AKT signaling pathways.

Dimethyl fumarate (DMF) (BG-12, Tecfidera) is a fumaric acid ester (FAE) that was advanced as a multiple sclerosis (MS) therapy largely for potential neuroprotection as it was recognized that FAEs are capable of activating the antioxidative transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. However, DMF treatment in randomized controlled MS trials was associated with marked reductions in relapse rate and development of active brain MRI lesions, measures considered to reflect CNS inflammation. Here, we investigated the antiinflammatory contribution of Nrf2 in DMF treatment of the MS model, experimental autoimmune encephalomyelitis (EAE). C57BL/6 wild-type (WT) and Nrf2-deficient (Nrf2(-/-)) mice were immunized with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 (p35-55) for EAE induction and treated with oral DMF or vehicle daily. DMF protected WT and Nrf2(-/-) mice equally well from development of clinical and histologic EAE. The beneficial effect of DMF treatment in Nrf2(-/-) and WT mice was accompanied by reduced frequencies of IFN-γ and IL-17-producing CD4(+) cells and induction of antiinflammatory M2 (type II) monocytes. DMF also modulated B-cell MHC II expression and reduced the incidence of clinical disease in a B-cell-dependent model of spontaneous CNS autoimmunity. Our observations that oral DMF treatment promoted immune modulation and provided equal clinical benefit in acute EAE in Nrf2(-/-) and WT mice, suggest that the antiinflammatory activity of DMF in treatment of MS patients may occur through alternative pathways, independent of Nrf2.

Neuromyelitis optica (NMO) is a rare, disabling, sometimes fatal, central nervous system (CNS) demyelinating disease characterized by severe attacks of optic neuritis and transverse myelitis.1 NMO is considered to be primarily a humoral autoimmune disease, as a majority of NMO patients develop autoantibodies (NMO immunoglobulin [Ig]G) against aquaporin 4 (AQP4),2 the predominant CNS water channel, which is abundantly expressed on astrocytes. AQP4-specific antibodies in NMO serum are IgG1, a subclass of mature IgG that requires help from T cells,3 indicating that AQP4-specific CD4+ T cells participate in the genesis of this adaptive humoral response. Passive transfer of AQP4-specific antibodies alone did not produce CNS pathology, but did promote development of NMO-like lesions in recipient animals when CNS inflammation was induced by myelin-specific T cells.4, 5 T cells are detected within active NMO lesions.6 Further, NMO lesions are characterized by an abundance of eosinophils and neutrophils, and elevated levels of IL-17 have been associated with NMO,7 suggesting involvement of Th17 cells. However, as no previous studies have identified or characterized proliferative AQP4-specific T cells in NMO patients, their potential role in NMO pathogenesis is largely unknown. In this report, we first identified peripheral blood T cells from NMO patients and healthy controls (HC) that proliferated in response to discrete AQP4 peptides or intact AQP4. T cells from NMO patients demonstrated greater proliferation to this autoantigen than those from HC, and responded most frequently to p61–80. After defining the p61–80 core T-cell determinant, residues 63–76, we conducted a homology search with known microbes. We discovered that AQP4 p63–76 contains strong homology to aa 204–217 of an adenosine triphosphate-binding cassette (ABC) transporter permease of Clostridium perfringens, a bacterial species that contains both commensal and pathogenic strains for humans. T cells from NMO patients responded to the homologous ABC transporter peptide and exhibited cross-reactivity between this foreign antigen and AQP4 p63–76, findings that support molecular mimicry. When compared to HC, AQP4 p61–80-specific T cells from NMO patients exhibited Th17 polarization. Monocytes from NMO patients produced significantly higher levels of the Th17-polarizing cytokine interleukin (IL)-6, suggesting that immunologic dysfunction in NMO may also include the innate immune compartment. Collectively, our findings establish that AQP4-specific proliferative T cells exist, and support a Th17 bias in the adaptive immune response in NMO. Our demonstration of T-cell molecular mimicry may stimulate further evaluation of the potential role of the Clostridium species in NMO pathogenesis.

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent monogenic cause of kidney failure, characterized by the development of renal cysts. ADPKD is caused by mutations of the polycystin-1 (PC1) or polycystin-2 (PC2) genes. PC2 encodes a Ca(2+)-permeable cation channel, and its dysfunction has been implicated in cyst development. The transcriptional coactivator with PDZ binding motif (TAZ) is required for the integrity of renal cilia. Its absence results in the development of renal cysts in a knock-out mouse model. TAZ directly interacts with PC2, and it has been suggested that another yet unidentified PDZ domain protein may be involved in the TAZ/PC2 interaction. Here we describe a novel interaction of TAZ with the multi-PDZ-containing PALS1-associated tight junction protein (PATJ). TAZ interacts with both the N-terminal PDZ domains 1-3 and the C-terminal PDZ domains 8-10 of PATJ, suggesting two distinct TAZ binding domains. We also show that the C terminus of PC2 strongly interacts with PDZ domains 8-10 and to a weaker extent with PDZ domains 1-3 of PATJ. Finally, we demonstrate that both TAZ and PATJ impair PC2 channel activity when co-expressed with PC2 in oocytes of Xenopus laevis. These results implicate TAZ and PATJ as novel regulatory elements of the PC2 channel and might thus be involved in ADPKD pathology.

In the course of autoimmune CNS inflammation, inflammatory infiltrates form characteristic perivascular lymphocyte cuffs by mechanisms that are not yet well understood. Here, intravital two-photon imaging of the brain in anesthetized mice, with experimental autoimmune encephalomyelitis, revealed the highly dynamic nature of perivascular immune cells, refuting suggestions that vessel cuffs are the result of limited lymphocyte motility in the CNS. On the contrary, vessel-associated lymphocyte motility is an actively promoted mechanism which can be blocked by CXCR4 antagonism. In vivo interference with CXCR4 in experimental autoimmune encephalomyelitis disrupted dynamic vessel cuffs and resulted in tissue-invasive migration. CXCR4-mediated perivascular lymphocyte movement along CNS vessels was a key feature of CD4(+) T cell subsets in contrast to random motility of CD8(+) T cells, indicating a dominant role of the perivascular area primarily for CD4(+) T cells. Our results visualize dynamic T cell motility in the CNS and demonstrate differential CXCR4-mediated compartmentalization of CD4(+) T-cell motility within the healthy and diseased CNS.

The basic helix-loop-helix transcriptional repressor twist1, as an antagonist of nuclear factor kappaB (NF-kappaB)-dependent cytokine expression, is involved in the regulation of inflammation-induced immunopathology. We show that twist1 is expressed by activated T helper (Th) 1 effector memory (EM) cells. Induction of twist1 in Th cells depended on NF-kappaB, nuclear factor of activated T cells (NFAT), and interleukin (IL)-12 signaling via signal transducer and activator of transcription (STAT) 4. Expression of twist1 was transient after T cell receptor engagement, and increased upon repeated stimulation of Th1 cells. Imprinting for enhanced twist1 expression was characteristic of repeatedly restimulated EM Th cells, and thus of the pathogenic memory Th cells characteristic of chronic inflammation. Th lymphocytes from the inflamed joint or gut tissue of patients with rheumatic diseases, Crohn's disease or ulcerative colitis expressed high levels of twist1. Expression of twist1 in Th1 lymphocytes limited the expression of the cytokines interferon-gamma, IL-2, and tumor necrosis factor-alpha, and ameliorated Th1-mediated immunopathology in delayed-type hypersensitivity and antigen-induced arthritis.

The physiological function of epithelia depends on an asymmetric distribution of their membrane domains. Polarity proteins play a crucial role for distribution processes, however, little is known about their mobility in epithelial cells. In this study, we analyzed the intracellular and plasma-membrane-associated mobility of fluorescence-labeled Crb3A and Crb3B. Both variants belong to the Crumbs protein family, which control size and identity of apical membranes in epithelial cells. Fluorescence recovery after photo-bleaching measurements revealed different mobilities for the two Crb3 variants. They also differentially affected mobility and localization of the Pals1/Mpp5 protein, which binds to Crb3A but not to Crb3B. In addition, tracking of intracellular vesicles indicated that Crb3A containing vesicles are slightly more immobile than Crb3B ones. Taken together, our data revealed different intracellular mobility patterns for Crb3A and Crb3B.

Acute liver failure (ALF) is a life threatening disease for which only few treatment options exist. The molecular pathways of disease progression are not well defined, but the death receptor Fas (CD95/Apo-1) appears to play a pivotal role in hepatocyte cell death and the development of ALF. Here, we explored posttranscriptional gene silencing of Fas by RNAi to inhibit pathophysiological gene expression. For targeting Fas expression in mice, Fas siRNA was formulated with the liver-specific siRNA delivery system DBTC. Treatment of mice with DBTC/siRNA(Fas) reduced Fas expression in the liver, but not in the spleen, lung, kidney or heart. Furthermore, silencing of Fas receptor was effective in blocking or reducing several aspects of ALF when it was tested in mice exposed to galactosamine/lipopolysaccharide (G/L), a well-known model of ALF. The application of DBTC/siRNA(Fas) 48 h prior G/L exposure resulted in amelioration of hepatic perfusion, reduction of hepatocellular death and increase of survival rate. The administration of DBTC/siRNA(Fas) formulation further diminished the inflammatory response upon G/L challenge, as indicated by a marked decrease of TNFα mRNA expression. However, IL-6 plasma concentration remained unaffectedly by DBTC/siRNA(Fas) formulation. Since the specific silencing of hepatic Fas expression only partially protected from inflammation, but completely attenuated apoptotic and necrotic cell death as well as microcirculatory dysfunction, the development of therapeutic strategies with DBTC lipoplex formulations to treat ALF should be combined with anti-inflammatory strategies to reach maximal therapeutic efficacy.

OBJECTIVE: Glatiramer acetate (GA; Copaxone), a disease-modifying therapy for multiple sclerosis (MS), promotes development of anti-inflammatory (M2, type II) monocytes that can direct differentiation of regulatory T cells. We investigated the innate immune signaling pathways that participate in GA-mediated M2 monocyte polarization. METHODS: Monocytes were isolated from myeloid differentiation primary response gene 88 (MyD88)-deficient, Toll-IL-1 receptor domain-containing adaptor inducing interferon (IFN)-β (TRIF)-deficient, IFN-α/β receptor subunit 1 (IFNAR1)-deficient, and wild-type (WT) mice and human peripheral blood. GA-treated monocytes were stimulated with Toll-like receptor ligands, then evaluated for activation of kinases and transcription factors involved in innate immunity, and secretion of proinflammatory cytokines. GA-treated mice were evaluated for cytokine secretion and susceptibility to experimental autoimmune encephalomyelitis. RESULTS: GA-mediated inhibition of proinflammatory cytokine production by monocytes occurred independently of MyD88 and nuclear factor-κB, but was blocked by TRIF deficiency. Furthermore, GA did not provide clinical benefit in TRIF-deficient mice. GA inhibited activation of p38 mitogen-activated protein kinase, an upstream regulator of activating transcription factor (ATF)-2, and c-Jun N-terminal kinase 1, which regulates IFN regulatory factor 3 (IRF3). Consequently, nuclear translocation of ATF-2 and IRF3, components of the IFN-β enhanceosome, was impaired. Consistent with these observations, GA inhibited production of IFN-β in vivo in WT mice, but did not modulate proinflammatory cytokine production by monocytes from IFNAR1-deficient mice. CONCLUSION: Our results demonstrate that GA inhibits the type I IFN pathway in M2 polarization of monocytes independently of MyD88, providing an important mechanism connecting innate and adaptive immune modulation in GA therapy and valuable insight regarding its potential use with other MS treatments. peerReviewed

Laquinimod is a novel oral drug that is currently being evaluated for the treatment of relapsing–remitting multiple sclerosis (RRMS). Although the mode of action of laquinimod remains to be fully elucidated, current knowledge indicates that laquinimod exerts beneficial activities both on the peripheral immune system and within the central nervous system (CNS). The immunomodulatory properties have been deciphered primarily from studies of laquinimod in the animal model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). Data indicate that laquinimod has a primary effect on innate immunity. Laquinimod modulates the function of various myeloid antigen presenting cell populations, which then downregulate proinflammatory T cell responses. Further, data also indicate that laquinimod acts directly on resident cells within the CNS to reduce demyelination and axonal damage. Results from clinical trials that tested laquinimod in RRMS demonstrated that it reduced relapse rate and the mean cumulative number of active lesions, and had a more marked reduction in disability progression than relapse rate. Laquinimod treatment was associated with an excellent safety and tolerability profile. These data indicate that laquinimod will offer a valuable new treatment option for RRMS patients.

SummaryHere, we provide evidence for a detrimental role of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in neural death in T cell-induced experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Clinical severity and neuronal apoptosis in brainstem motor areas were substantially reduced upon brain-specific blockade of TRAIL after induction of EAE through adoptive transfer of encephalitogenic T cells. Furthermore, TRAIL-deficient myelin-specific lymphocytes showed reduced encephalitogenicity when transferred to wild-type mice. Conversely, intracerebral delivery of TRAIL to animals with EAE increased clinical deficits, while naive mice were not susceptible to TRAIL. Using organotypic slice cultures as a model for living brain tissue, we found that neurons were susceptible to TRAIL-mediated injury induced by encephalitogenic T cells. Thus, in addition to its known immunoregulatory effects, the death ligand TRAIL contributes to neural damage in the inflamed brain.