Prospective study validating a multidimensional treatment decision score predicting the 24-month outcome in untreated patients with clinically isolated syndrome and early relapsing-remitting multiple sclerosis, the ProVal-MS study.

INTRODUCTION: In Multiple Sclerosis (MS), patients´ characteristics and (bio)markers that reliably predict the individual disease prognosis at disease onset are lacking. Cohort studies allow a close follow-up of MS histories and a thorough phenotyping of patients. Therefore, a multicenter cohort study was initiated to implement a wide spectrum of data and (bio)markers in newly diagnosed patients. METHODS: ProVal-MS (Prospective study to validate a multidimensional decision score that predicts treatment outcome at 24 months in untreated patients with clinically isolated syndrome or early Relapsing-Remitting-MS) is a prospective cohort study in patients with clinically isolated syndrome (CIS) or Relapsing-Remitting (RR)-MS (McDonald 2017 criteria), diagnosed within the last two years, conducted at five academic centers in Southern Germany. The collection of clinical, laboratory, imaging, and paraclinical data as well as biosamples is harmonized across centers. The primary goal is to validate (discrimination and calibration) the previously published DIFUTURE MS-Treatment Decision score (MS-TDS). The score supports clinical decision-making regarding the options of early (within 6 months after study baseline) platform medication (Interferon beta, glatiramer acetate, dimethyl/diroximel fumarate, teriflunomide), or no immediate treatment (> 6 months after baseline) of patients with early RR-MS and CIS by predicting the probability of new or enlarging lesions in cerebral magnetic resonance images (MRIs) between 6 and 24 months. Further objectives are refining the MS-TDS score and providing data to identify new markers reflecting disease course and severity. The project also provides a technical evaluation of the ProVal-MS cohort within the IT-infrastructure of the DIFUTURE consortium (Data Integration for Future Medicine) and assesses the efficacy of the data sharing techniques developed. PERSPECTIVE: Clinical cohorts provide the infrastructure to discover and to validate relevant disease-specific findings. A successful validation of the MS-TDS will add a new clinical decision tool to the armamentarium of practicing MS neurologists from which newly diagnosed MS patients may take advantage. Trial registration ProVal-MS has been registered in the German Clinical Trials Register, `Deutsches Register Klinischer Studien` (DRKS)-ID: DRKS00014034, date of registration: 21 December 2018; https://drks.de/search/en/trial/DRKS00014034.

Initial Quenching Efficiency Determines Light-Driven H2 Evolution of [Mo3 S13 ]2- in Lipid Bilayers.

Nature uses reactive components embedded in biological membranes to perform light-driven photosynthesis. Here, a model artificial photosynthetic system for light-driven hydrogen (H2 ) evolution is reported. The system is based on liposomes where amphiphilic ruthenium trisbipyridine based photosensitizer (RuC9 ) and the H2 evolution reaction (HER) catalyst [Mo3 S13 ]2- are embedded in biomimetic phospholipid membranes. When DMPC was used as the main lipid of these light-active liposomes, increased catalytic activity (TONCAT ~200) was observed compared to purely aqueous conditions. Although all tested lipid matrixes, including DMPC, DOPG, DPPC and DOPG liposomes provided similar liposomal structures according to TEM analysis, only DMPC yielded high H2 amounts. In situ scanning electrochemical microscopy (SECM) measurements using Pd microsensors revealed an induction period of around 26 minutes prior to H2 evolution, indicating an activation mechanism which might be induced by the fluid-gel phase transition of DMPC at room temperature. Stern-Volmer-type quenching studies revealed that electron transfer dynamics from the excited state photosensitizer are most efficient in the DMPC lipid environment giving insight for design of artificial photosynthetic systems using lipid bilayer membranes.

Humoral COVID-19 vaccine response in patients with NMOSD/MOGAD during anti-IL-6 receptor therapy compared to other immunotherapies.

BACKGROUND: Data on the humoral vaccine response in patients on anti-interleukin-6 (IL-6) receptor therapy remain scarce. OBJECTIVE: The main objective of our study was to investigate the humoral response after vaccination against SARS-CoV-2 in neuromyelitis optica spectrum disorder (NMOSD)/myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) patients treated with anti-IL-6 receptor therapy. Secondarily, we analyzed relapse activity timely associated with vaccination. METHODS: In this retrospective cross-sectional multicenter study, we included 15 healthy controls and 48 adult NMOSD/MOGAD patients without previous COVID-19 infection. SARS-CoV-2 spike protein antibody titers during anti-IL-6 receptor therapy were compared to anti-CD20 antibody therapy, oral immunosuppressants, and to nonimmunosuppressed individuals. RESULTS: We observed 100% seroconversion in the anti-IL-6 receptor treatment group. Titers of SARS-CoV-2 spike protein antibodies were lower compared to healthy controls (720 vs 2500 binding antibody units (BAU)/mL, p = 0.004), but higher than in the anti-CD20 (720 vs 0.4 BAU/mL, p < 0.001) and comparable to the oral immunosuppressant group (720 vs 795 BAU/mL, p = 1.0). We found no association between mRNA-based vaccines and relapse activity in patients with or without immunotherapy. CONCLUSIONS: Despite being lower than in healthy controls, the humoral vaccine response during anti-IL-6 receptor therapy was evident in all patients and substantially stronger compared to anti-CD20 treatment. No relevant disease activity occurred after mRNA vaccination against SARS-CoV-2.

Ocrelizumab Treatment Modulates B-Cell Regulating Factors in Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: Antibodies to CD20 efficiently reduce new relapses in multiple sclerosis (MS), and ocrelizumab has been shown to be effective also in primary progressive MS. Although anti-CD20 treatments efficiently deplete B cells in blood, some B cells and CD20- plasma cells persist in lymphatic organs and the inflamed CNS; their survival is regulated by the B cell-activating factor (BAFF)/A proliferation-inducing ligand (APRIL) system. The administration of a soluble receptor for BAFF and APRIL, atacicept, unexpectedly worsened MS. Here, we explored the long-term effects of ocrelizumab on immune cell subsets as well as on cytokines and endogenous soluble receptors comprising the BAFF-APRIL system. METHODS: We analyzed immune cell subsets and B cell-regulating factors longitudinally for up to 2.5 years in patients with MS treated with ocrelizumab. In a second cohort, we determined B-cell regulatory factors in the CSF before and after ocrelizumab. We quantified the cytokines BAFF and APRIL along with their endogenous soluble receptors soluble B-cell maturation antigen (sBCMA) and soluble transmembrane activator and calcium-modulator and cyclophilin ligand (CAML) interactor (sTACI) using enzyme-linked immunosorbent assays (ELISAs). In addition, we established an in-house ELISA to measure sTACI-BAFF complexes. RESULTS: Ocrelizumab treatment of people with MS persistently depleted B cells and CD20+ T cells. This treatment enhanced BAFF and reduced the free endogenous soluble receptor and decoy sTACI in both serum and CSF. Levels of sTACI negatively correlated with BAFF levels. Reduction of sTACI was associated with formation of sTACI-BAFF complexes. DISCUSSION: We describe a novel effect of anti-CD20 therapy on the BAFF-APRIL system, namely reduction of sTACI. Because sTACI is a decoy for APRIL, its reduction may enhance local APRIL activity, thereby promoting regulatory IgA+ plasma cells and astrocytic interleukin (IL)-10 production. Thus, reducing sTACI might contribute to the beneficial effect of anti-CD20 as exogenous sTACI (atacicept) worsened MS. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that endogenous sTACI in blood and CSF is decreased after ocrelizumab treatment.

Immune cell infiltration pattern in non-small cell lung cancer PDX models is a model immanent feature and correlates with a distinct molecular and phenotypic make-up.

BACKGROUND: The field of cancer immunology is rapidly moving towards innovative therapeutic strategies, resulting in the need for robust and predictive preclinical platforms reflecting the immunological response to cancer. Well characterized preclinical models are essential for the development of predictive biomarkers in the oncology as well as the immune-oncology space. In the current study, gold standard preclinical models are being refined and combined with novel image analysis tools to meet those requirements. METHODS: A panel of 14 non-small cell lung cancer patient-derived xenograft models (NSCLC PDX) was propagated in humanized NOD/Shi-scid/IL-2Rnull mice. The models were comprehensively characterized for relevant phenotypic and molecular features, including flow cytometry, immunohistochemistry, histology, whole exome sequencing and cytokine secretion. RESULTS: Models reflecting hot (>5% tumor-infiltrating lymphocytes/TILs) as opposed to cold tumors (<5% TILs) significantly differed regarding their cytokine profiles, molecular genetic aberrations, stroma content, and programmed cell death ligand-1 status. Treatment experiments including anti cytotoxic T-lymphocyte-associated protein 4, anti-programmed cell death 1 or the combination thereof across all 14 models in the single mouse trial format showed distinctive tumor growth response and spatial immune cell patterns as monitored by computerized analysis of digitized whole-slide images. Image analysis provided for the first time qualitative evaluation of the extent to which PDX models retain the histological features from their original human donors. CONCLUSIONS: Deep phenotyping of PDX models in a humanized setting by combinations of computational pathology, immunohistochemistry, flow cytometry and proteomics enables the exhaustive analysis of innovative preclinical models and paves the way towards the development of translational biomarkers for immuno-oncology drugs.

Cobaloxime Complex Salts: Synthesis, Patterning on Carbon Nanomembranes and Heterogeneous Hydrogen Evolution Studies.

Cobaloximes are promising, earth-abundant catalysts for the light-driven hydrogen evolution reaction (HER). Typically, these cobalt(III) complexes are prepared in situ or employed in their neutral form, for example, [Co(dmgH)2 (py)Cl], even though related complex salts have been reported previously and could, in principle, offer improved catalytic activity as well as more efficient immobilization on solid support. Herein, we report an interdisciplinary investigation into complex salts [Co(dmgH)2 (py)2 ]+ [Co(dmgBPh2 )2 Cl2 ]- , TBA + [ Co ( dmgBPh 2 ) 2 Cl 2 ] - and [Co(dmgH)2 (py)2 ]+ BArF- . We describe their strategic syntheses from the commercially available complex [Co(dmgH)2 (py)Cl] and demonstrate that these double and single complex salts are potent catalysts for the light-driven HER. We also show that scanning electrochemical cell microscopy can be used to deposit arrays of catalysts [Co(dmgH)2 (py)2 ]+ [Co(dmgBPh2 )2 Cl2 ]- , TBA + [ Co ( dmgBPh 2 ) 2 Cl 2 ] - and [Co(dmgH)2 (py)Cl] on supported and free-standing amino-terminated ∼1-nm-thick carbon nanomembranes (CNMs). Photocatalytic H2 evolution at such arrays was quantified with Pd microsensors by scanning electrochemical microscopy, thus providing a new approach for catalytic evaluation and opening up novel routes for the creation and analysis of "designer catalyst arrays", nanoprinted in a desired pattern on a solid support.

Effects of Natalizumab Therapy on Intrathecal Immunoglobulin G Production Indicate Targeting of Plasmablasts.

OBJECTIVES: To evaluate the long-term effects of natalizumab (NTZ) on different features of intrathecal immunoglobulin (Ig) synthesis in patients with multiple sclerosis (MS) and to quantify the expression of α4-integrin in stages of B-cell maturation. METHODS: We combined a cross-sectional (49 NTZ-treated MS patients, mean treatment duration 5.1 years, and 47 untreated MS patients) and a longitudinal study (33 patients with MS before and during NTZ, mean treatment duration: 4.8 years), analyzing paired serum and CSF samples for IgG, IgA, and IgM levels, reactivity against selected viruses (measles virus, rubella virus, and varicella zoster virus [MRZ] reaction), and oligoclonal bands (OCBs). Banding patterns before and after therapy were directly compared by isoelectric focusing in 1 patient. In addition, we determined the expression of α4-integrin by FACS analysis on blood-derived B-cell subsets (plasmablasts, memory B cells, and naive B cells) of healthy controls. RESULTS: In serum, NTZ decreased IgM and IgG, but not IgA, levels. IgM hypogammaglobulinemia occurred in 28% of NTZ-treated patients. In CSF, NTZ treatment resulted in a strong reduction of intrathecally produced IgG and, to a lesser extent, IgA, whereas IgM indices [(Ig CSF/Serum)/(Albumin CSF/Serum)] remained largely unchanged. Reduction of the IgG index correlated with NTZ treatment duration, as did serum IgM and IgA levels. MRZ reaction was unchanged and OCB persisted. Direct comparison of OCB pattern before and after NTZ revealed the persistence of individual bands. α4-Integrin expression was highest on plasmablasts (CD19+CD38+CD27+). CONCLUSION: Our data indicate that NTZ reduces short-lived plasmablasts in the CNS compartment but has little effect on locally persisting long-lived plasma cells.

Evidence-Based Examination Techniques for the Shoulder Joint. / Evidenzbasiertes Lehrvideo für Untersuchungstechniken am Schultergelenk.

OBJECTIVE: Digitalisation now almost covers all areas of medical student teaching. Teaching videos are a good way to help students learn practical skills. The existing evidence is a recognised aid for the classification of the respective technology. METHOD: This video presents the usual examination techniques of the shoulder joint on a patient with an unstable shoulder. The respective techniques, if available, were backed up with appropriate evidence. CONCLUSION: The examination techniques presented allow students to view them in a standardized manner on a patient. The evidence for the examination techniques can help with the classification of the respective technique.

Evidence-Based Examination Techniques for the Knee. / Evidenzbasiertes Lehrvideo für Untersuchungstechniken am Kniegelenk.

OBJECTIVE: Digitalisation now almost covers all areas of medical student teaching. Teaching videos are a good way to help students learn practical skills. The existing evidence is a recognised aid for the classification of the respective technology. METHOD: This video presents the usual examination techniques of the knee joint on a patient with an unstable knee. The respective techniques, if available, were backed up with the appropriate evidence. CONCLUSION: The examination techniques presented allow students to view the examination techniques in a standardised manner on a patient. The evidence for the examination techniques can help with the classification of the respective technique. ZIELSETZUNG: Die Digitalisierung erfasst inzwischen alle Bereiche der studentischen Lehre. Um die Studierenden im Erlernen praktischer Fertigkeiten zu unterstützen, sind Lehrvideos eine gute Methode. Für die Einordnung der jeweiligen Technik ist die vorhandene Evidenz eine anerkannte Hilfestellung. METHODE: Das hier vorliegende Video stellt die üblichen Untersuchungstechniken des Kniegelenkes an einer Patientin mit einem instabilen Knie dar. Die jeweiligen Techniken wurden, wenn vorhanden, mit der jeweiligen Evidenz unterlegt. SCHLUSSFOLGERUNG: Die dargestellten Untersuchungstechniken ermöglichen es Studierenden, sich die Untersuchungstechniken standardisiert an einem Patienten anzuschauen. Die eingeblendete Evidenz für die Untersuchungstechniken kann hierbei eine Hilfestellung bei der Einordnung der jeweiligen Technik leisten.

Impact of the Injection Site on Growth Characteristics, Phenotype and Sensitivity towards Cytarabine of Twenty Acute Leukaemia Patient-Derived Xenograft Models.

Rodent models have contributed significantly to the understanding of haematological malignancies. One important model system in this context are patient-derived xenografts (PDX). In the current study, we examined 20 acute leukaemia PDX models for growth behaviour, infiltration in haemopoietic organs and sensitivity towards cytarabine. PDX were injected intratibially (i.t.), intrasplenicaly (i.s.) or subcutaneously (s.c.) into immune compromised mice. For 18/20 models the engraftment capacity was independent of the implantation site. Two models could exclusively be propagated in one or two specific settings. The implantation site did influence tumour growth kinetics as median overall survival differed within one model depending on the injection route. The infiltration pattern was similar in i.t. and i.s. models. In contrast to the s.c. implantation, only one model displayed circulating leukaemic cells outside of the locally growing tumour mass. Cytarabine was active in all four tested models. Nevertheless, the degree of sensitivity was specific for an individual model and implantation site. In summary, all three application routes turned out to be feasible for the propagation of PDX. Nevertheless, the distinct differences between the settings highlight the need for well characterized platforms to ensure the meaningful interpretation of data generated using those powerful tools.

Induction of Acquired Resistance towards EGFR Inhibitor Gefitinib in a Patient-Derived Xenograft Model of Non-Small Cell Lung Cancer and Subsequent Molecular Characterization.

In up to 30% of non-small cell lung cancer (NSCLC) patients, the oncogenic driver of tumor growth is a constitutively activated epidermal growth factor receptor (EGFR). Although these patients gain great benefit from treatment with EGFR tyrosine kinase inhibitors, the development of resistance is inevitable. To model the emergence of drug resistance, an EGFR-driven, patient-derived xenograft (PDX) NSCLC model was treated continuously with Gefitinib in vivo. Over a period of more than three months, three separate clones developed and were subsequently analyzed: Whole exome sequencing and reverse phase protein arrays (RPPAs) were performed to identify the mechanism of resistance. In total, 13 genes were identified, which were mutated in all three resistant lines. Amongst them the mutations in NOMO2, ARHGEF5 and SMTNL2 were predicted as deleterious. The 53 mutated genes specific for at least two of the resistant lines were mainly involved in cell cycle activities or the Fanconi anemia pathway. On a protein level, total EGFR, total Axl, phospho-NFκB, and phospho-Stat1 were upregulated. Stat1, Stat3, MEK1/2, and NFκB displayed enhanced activation in the resistant clones determined by the phosphorylated vs. total protein ratio. In summary, we developed an NSCLC PDX line modelling possible escape mechanism under EGFR treatment. We identified three genes that have not been described before to be involved in an acquired EGFR resistance. Further functional studies are needed to decipher the underlying pathway regulation.

Semi-automated analysis of digital whole slides from humanized lung-cancer xenograft models for checkpoint inhibitor response prediction.

We propose a deep learning workflow for the classification of hematoxylin and eosin stained histological whole-slide images of non-small-cell lung cancer. The workflow includes automatic extraction of meta-features for the characterization of the tumor. We show that the tissue-classification produces state-of-the-art results with an average F1-score of 83%. Manual supervision indicates that experts, in practice, accept a far higher percentage of predictions. Furthermore, the extracted meta-features are validated via visualization revealing relevant biomedical relations between the different tissue classes. In a hypothetical decision-support scenario, these meta-features can be used to discriminate the tumor response with regard to available treatment options with an estimated accuracy of 84%. This workflow supports large-scale analysis of tissue obtained in preclinical animal experiments, enables reproducible quantification of tissue classes and immune system markers, and paves the way towards discovery of novel features predicting response in translational immune-oncology research.

A high-content image analysis approach for quantitative measurements of chemosensitivity in patient-derived tumor microtissues.

Organotypic, three-dimensional (3D) cancer models have enabled investigations of complex microtissues in increasingly realistic conditions. However, a drawback of these advanced models remains the poor biological relevance of cancer cell lines, while higher clinical significance would be obtainable with patient-derived cell cultures. Here, we describe the generation and data analysis of 3D microtissue models from patient-derived xenografts (PDX) of non-small cell lung carcinoma (NSCLC). Standard of care anti-cancer drugs were applied and the altered multicellular morphologies were captured by confocal microscopy, followed by automated image analyses to quantitatively measure phenotypic features for high-content chemosensitivity tests. The obtained image data were thresholded using a local entropy filter after which the image foreground was split into local regions, for a supervised classification into tumor or fibroblast cell types. Robust statistical methods were applied to evaluate treatment effects on growth and morphology. Both novel and existing computational approaches were compared at each step, while prioritizing high experimental throughput. Docetaxel was found to be the most effective drug that blocked both tumor growth and invasion. These effects were also validated in PDX tumors in vivo. Our research opens new avenues for high-content drug screening based on patient-derived cell cultures, and for personalized chemosensitivity testing.

Capturing complex tumour biology in vitro: histological and molecular characterisation of precision cut slices.

Precision-cut slices of in vivo tumours permit interrogation in vitro of heterogeneous cells from solid tumours together with their native microenvironment. They offer a low throughput but high content in vitro experimental platform. Using mouse models as surrogates for three common human solid tumours, we describe a standardised workflow for systematic comparison of tumour slice cultivation methods and a tissue microarray-based method to archive them. Cultivated slices were compared to their in vivo source tissue using immunohistochemical and transcriptional biomarkers, particularly of cellular stress. Mechanical slicing induced minimal stress. Cultivation of tumour slices required organotypic support materials and atmospheric oxygen for maintenance of integrity and was associated with significant temporal and loco-regional changes in protein expression, for example HIF-1α. We recommend adherence to the robust workflow described, with recognition of temporal-spatial changes in protein expression before interrogation of tumour slices by pharmacological or other means.

Neutrophils are required for both the sensitization and elicitation phase of contact hypersensitivity.

Allergic contact dermatitis and its animal model, contact hypersensitivity (CHS), are T cell-mediated inflammatory skin diseases induced by contact allergens. Though numerous cellular and molecular players are known, the mechanism of chemical-induced sensitization remains poorly understood. Here, we identify neutrophils as crucial players in the sensitization phase of CHS. Genetic deficiency of neutrophils caused by myeloid-specific deletion of Mcl-1 or antibody-mediated depletion of neutrophils before sensitization abrogated the CHS response. Neutrophil deficiency reduced contact allergen-induced cytokine production, gelatinase release, and reactive oxygen species production in naive mice. Mast cell deficiency inhibited neutrophil accumulation at the site of sensitization. In turn, neutrophils were required for contact allergen-induced release of further neutrophil-attracting chemokines, migration of DCs to the draining lymph nodes, and priming of allergen-specific T cells. Lymph node cells from mice sensitized in the absence of neutrophils failed to transfer sensitization to naive recipients. Furthermore, no CHS response could be induced when neutrophils were depleted before elicitation or when normally sensitized lymph node cells were transferred to neutrophil-deficient recipients, indicating an additional role for neutrophils in the elicitation phase. Collectively, our data identify neutrophils to be critically involved in both the sensitization and elicitation phase of CHS.

Why human pemphigoid autoantibodies do not trigger disease by the passive transfer into mice?

The recapitulation of disease features in animals by the transfer of patient autoantibodies has been used to demonstrate the autoimmune nature of several diseases. Failure of disease induction by the passive transfer of autoantibodies has been assigned to a limited cross-reactivity of the autoantibodies with the murine tissue. However, the possibility that the passively transferred "inflammatory" patient autoantibodies may not be able to unfold their pathogenic potential due to restricted Fc-dependent effector functions has not yet been systematically explored. In this study we analyze the interaction of patients' autoantibodies with murine complement and granulocytes. Bullous pemphigoid is a blistering disease associated with autoantibodies, which are thought to induce subepidermal blistering by activating complement and granulocytes. The passive transfer of patients autoantibodies failed to induce skin blistering in wild type mice. The cross-reactivity of pemphigoid autoantibodies with murine antigens was analyzed in silico, ex vivo and by the passive transfer of IgG in vivo. Complement-fixing ability of patients' autoantibodies was evaluated by complement-binding test. Granulocyte activation was assessed by reactive oxygen species production assay and the cryosection model. We have found that although pemphigoid autoantibodies bound to murine skin in vitro and in vivo, they showed a lower capacity to fix murine complement and a reduced ability to activate murine granulocytes when compared with human complement and cells, respectively. These results indicate that for disease models using the passive transfer of patient autoantibodies, their interaction with the innate factors of the host should be optimized to match the human situation.

The flavonoid luteolin inhibits Fcγ-dependent respiratory burst in granulocytes, but not skin blistering in a new model of pemphigoid in adult mice.

Bullous pemphigoid is an autoimmune blistering skin disease associated with autoantibodies against the dermal-epidermal junction. Passive transfer of antibodies against BP180/collagen (C) XVII, a major hemidesmosomal pemphigoid antigen, into neonatal mice results in dermal-epidermal separation upon applying gentle pressure to their skin, but not in spontaneous skin blistering. In addition, this neonatal mouse model precludes treatment and observation of diseased animals beyond 2-3 days. Therefore, in the present study we have developed a new disease model in mice reproducing the spontaneous blistering and the chronic course characteristic of the human condition. Adult mice were pre-immunized with rabbit IgG followed by injection of BP180/CXVII rabbit IgG. Mice pre-immunized against rabbit IgG and injected 6 times every second day with the BP180/CXVII-specific antibodies (n = 35) developed spontaneous sustained blistering of the skin, while mice pre-immunized and then treated with normal rabbit IgG (n = 5) did not. Blistering was associated with IgG and complement C3 deposits at the epidermal basement membrane and recruitment of inflammatory cells, and was partly dependent on Ly-6G-positive cells. We further used this new experimental model to investigate the therapeutic potential of luteolin, a plant flavonoid with potent anti-inflammatory and anti-oxidative properties and good safety profile, in experimental BP. Luteolin inhibited the Fcγ-dependent respiratory burst in immune complex-stimulated granulocytes and the autoantibody-induced dermal-epidermal separation in skin cryosections, but was not effective in suppressing the skin blistering in vivo. These studies establish a robust animal model that will be a useful tool for dissecting the mechanisms of blister formation and will facilitate the development of more effective therapeutic strategies for managing pemphigoid diseases.

Cross-reactivity of autoantibodies from patients with epidermolysis bullosa acquisita with murine collagen VII.

The pathomechanism of antibody-mediated tissue damage in autoimmune diseases can be best studied in experimental models by passively transferring specific autoantibodies into animals. The reproduction of the disease in animals depends on several factors, including the cross-reactivity of patient autoantibodies with the animal tissue. Here, we show that autoantibodies from patients with epidermolysis bullosa acquisita (EBA), a subepidermal autoimmune blistering disease, recognize multiple epitopes on murine collagen VII. Indirect immunofluorescence microscopy revealed that EBA patients' IgG cross-reacts with mouse skin. Overlapping, recombinant fragments of murine collagen VII were used to characterize the reactivity of EBA sera and to map the epitopes on the murine antigen by ELISA and immunoblotting. The patients' autoantibody binding to murine collagen VII triggered pathogenic events as demonstrated by a complement fixing and an ex vivo granulocyte-dependent dermal-epidermal separation assay. These findings should greatly facilitate the development of improved disease models and novel therapeutic strategies.

Reduced numbers of circulating gammadelta T cells in patients with bullous pemphigoid.

Bullous pemphigoid (BP) is an autoimmune blistering skin disease characterized by autoantibodies to hemidesmosomal proteins. The initiation and regulation of the autoimmune response are poorly understood. We analysed cell subsets with immunoregulatory functions in untreated BP patients. While the numbers of circulating NKT and NK cells were normal, gammadelta T cells were reduced in BP patients. gammadelta T cells were rarely detected in lesional skin, arguing against their sequestration in the skin. In most patients, clinical remission and reduction of autoantibody titres after immunosuppressive therapy was not accompanied by an increase of circulating gammadelta T cells. V gammadelta gene usage was not altered in BP patients and the gammadelta T cells of BP patients were functional as they proliferated in response to isopentenyl pyrophosphate. Our data provide a basis for further investigations on the role of gammadelta T cells in the immunopathogenesis of BP.