Kutane Dendritische Zell-Subpopulationen in Pathogenese und Therapie dermatologischer Erkrankungen

Dendritische Zellen (DCs) sind die wichtigsten antigen-präsentierenden Zellen des Immunsystems. Sie stellen die Verbindung zwischen angeborenem und erworbenem Immunsystem dar und entscheiden über die Art der Immunantwort, über Toleranz oder Immunität. Inzwischen ist bekannt, dass es zahlreiche unterschiedliche DC Subtypen gibt. Bis vor kurzem war eine eindeutige Differenzierung von Makrophagen, cDCs und moDCs in der Haut unmöglich. Somit blieb der Beitrag der einzelnen myeloiden Subpopulationen in der Hautintegrität und Hautimmunität ungeklärt. Mit unseren hier beschriebenen Arbeiten konnten wir dazu beitragen, die verschiedenen myeloiden Zellsubpopulationen der Haut zu identifizieren und zu differenzieren. Durch eine Kombination verschiedener Oberflächenmarker in der Durchflußzytometrie ist es uns nun gelungen, bislang unbekannte Funktionen der verschiedenen myeloiden Subpopulationen in der Maushaut zu charakterisieren. Im Kontaktekzemmodell infiltrieren eine große Anzahl von Ly-6C+-Monozyten aus dem Blut in die entzündete Dermis und generieren moDCs. Während der frühen Phase eines Psoriasismodells infiltrierten Neutrophile die Epidermis, Monozyten und moDCs waren in der Dermis vorherrschend. Während der späten Phase dominierten lokal proliferierende Langerhans Zellen in der Epidermis und Makrophagen in der Dermis. Weiterhin untersuchten wir die Rolle der einzelnen DC-Subpopulationen im therapeutischen Kontext im Mausmodell. In der Allergen-spezifischen Immuntherapie (ASIT) haben Mikropartikel-Adjuvanzien, nämlich Strontium-doped hydroxyapatite porous spheres (SHAS), nicht nur Adjuvanseigenschaften, sondern sie sind auch vielversprechende Vakzinierungsträger infolge ihrer einmaligen Proteinbindungseigenschaften. Im Mausmodell konnten wir weiterhin zeigen, dass das direkte Targeting von Impfstoff-Molekülen auf kreuzpräsentierende DCs mittels XCR1 eine neuartige und vielversprechende Methode zur Induktion von protektiven CD8+ T-Zell-Antworten darstellt. Mittels Laser-generierten Mikroporen konnten wir die XCR1+ DCs in der oberen Dermis direkt erreichen und so ohne den Zusatz von exogenen Adjuvanzien ein starke protektive Immunantwort im Tumormodell hervorrufen. Die Existenz funktionell äquivalenter XCR1+ dermaler DCs beim Menschen sollte die Translation der laser-assistierten intradermalen Applikation von Tumor-spezifischen Vakzinen ermöglichen. In den nächsten Jahren werden sicherlich zahlreiche weitere neue Erkenntnisse über diese faszinierenden Zellen erforscht werden. Dies wird hoffentlich auch zu innovativen und effektiven Therapien verschiedener Erkrankungen führen.Dendritic cells (DCs) are the most important antigen-presenting cells of the immune system. They represent the connection between the innate and acquired immune system and decide on the type of immune response, on tolerance or immunity. Until recently, a clear differentiation of macrophages and the different DC subpopulations, conventional DCs and monocyte-derived DCs (moDCs) in the skin was impossible. Thus, the role of the individual myeloid subpopulations remained unresolved in skin integrity and skin immunity. With our work described here, we have been able to help identify and differentiate the various myeloid cell subpopulations of the skin. Through a combination of different surface markers in flow cytometry, we have now succeeded in characterizing hitherto unknown functions of the various myeloid subpopulations in the murine skin. In a model of contact allergy, a large number of LY-6C+-monocytes from the blood infiltrates the inflamed dermis and generates moDCs. During the early phase of a model mimicking psoriatic inflammation neutrophils infiltrate the epidermis, whereas monocytes and moDCs were prevalent in the dermis. During the late phase, local proliferating Langerhans cells dominated the epidermis and macrophages the dermis. We also investigated the role of the different DC subpopulations in therapies in the mouse model. In allergen-specific immunotherapy (ASIT), a microparticle adjuvant, namely strontium-doped hydroxyapatite porous Spheres (SHAS), has not only adjuvant properties on DCs, but was also a promising vaccine carrier due to its unique Protein binding properties. We furthermore showed that direct targeting of vaccine molecules on cross-presenting DCs by means of XCR1 is a novel and promising method for induction of protective CD8+ T-cell responses. Using laser-generated micropores, we were able to reach the XCR1+ DCS directly in the upper dermis and thus produce a strong protective immune response in the tumor model without the addition of exogenous adjuvant. The existence of functionally equivalent XCR1+ dermal DCs in humans should enable the translation of the laser-assisted intradermal application of tumor-specific vaccines. In the next few years, more insights will be explored about these fascinating cells. This will hopefully also lead to innovative and effective therapies of various diseases

Seroprevalence and epidemiological correlates of Toxoplasma gondii infections among patients referred for hospital-based serological testing in Doha, Qatar

Background. The city of Doha in Qatar has a high density of feral cats and there is a high risk of toxoplasmosis for the resident human population. No data currently exist for the prevalence of infection with Toxoplasma gondii in the city. Methods. We analysed the serological response to Toxoplasma gondii of 1625 subjects referred for routine hospital based serological tests in Doha, Qatar. Prevalence of current/recent infection was assessed through an enzyme-linked immunosorbent assay (ELISA) for the presence of specific anti-T. gondii IgM antibodies, and previous history of infection through IgG. Results. Overall prevalence of IgG responses was 29.8% and this did not differ between the sexes nor between the three years of the study although there was a marked age effect. Among children less than 1 year old prevalence was 22.9%, but then dropped to 45 years). The prevalence of IgG antibody also varied significantly with region of origin, with higher rates for subjects from Africa, followed by those from the Eastern Mediterranean or Asia and lowest rates for subjects from the Arabian Peninsula. No IgM antibodies were detected in any subjects younger than 19 years, but prevalence increased to plateau at 7 - 9% in subjects aged over 20 years, and also varied with region of origin. In this case prevalence was highest among subjects from the Arabian Peninsula and least among those from Asia. Prevalence of IgM was higher among male subjects but did not vary between the three years of the study. Conclusion. Although these data are based on a selected subset of the population, they nevertheless provide the first evidence that toxoplasmosis is endemic in Qatar in the human population, and that both age and region of origin play a role in the epidemiology of the infection. Concerns relating to the role of high density of feral cats in sustaining the infection were highlighted

Clonal expansion of CD4+CD8+ T cells in an adult patient with Mycoplasma pneumoniae-associated Erythema multiforme majus

Background: Erythema multiforme (EM) is an acute, immune-mediated mucocutaneous disease, most often preceded by herpes simplex virus (HSV) infection or reactivation. Mycoplasma pneumoniae (Mp) is considered the second major trigger of EM and is often associated with an atypical and more severe presentation of disease, characterized by prominent mucosal involvement. However, contrary to HSV-associated Erythema multiforme (HAEM), immunological mechanisms of Mp-associated EM remain unclear. Case presentation: We present the case of a 50-year-old male patient presenting with community-acquired pneumonia (CAP) and erythema multiforme majus (EMM). Acute Mp infection was diagnosed by seroconversion, with no evidence of HSV infection as a cause of EMM. We performed immune phenotyping of blister fluid (BF) and peripheral blood (PB) T cells and detected a clonally expanded TCRV beta 2(+) T cell population that was double positive for CD4 and CD8, and expressed the cytotoxic markers granulysin and perforin. This CD4(+)CD8(+) population comprised up to 50.7% of BF T cells and 24.9% of PB T cells. Two years prior to the onset of disease, the frequency of PB CD4(+)CD8(+)T cells had been within normal range and it gradually returned to baseline levels with the resolution of symptoms, suggesting an involvement of this population in EMM disease pathophysiology. Conclusions: This report is the first to provide a phenotypic description of lesional T cells in Mp-associated EMM. Characterizing the local immune response might help to address pathophysiological questions and warrants further systematic research

Impaired sweating in patients with cholinergic urticaria is linked to low expression of acetylcholine receptor CHRM3 and acetylcholine esterase in sweat glands

BackgroundCholinergic urticaria (CholU), a frequent form of chronic inducible urticaria, is characterized by itchy wheals and angioedema in response to sweating. As of now, the rate and pathophysiological relevance of impaired sweating in patients with CholU are ill-defined.AimTo assess in CholU patients the rate and extent of impaired sweating and its links to clinical and pathophysiological features of CholU.Patients and methodsWe assessed sweating in patients with CholU (n = 13) subjected to pulse-controlled ergometry (PCE) provocation testing. Pre- and post-PCE biopsies of lesional (L) and non-lesional (NL) skin were analyzed for the expression of acetylcholine receptor M3 (CHRM3) and acetylcholine esterase (ACh-E) by quantitative histomorphometry and compared to those of healthy control subjects (HCs). CholU patients were assessed for disease duration and severity as well as other clinical features.ResultsOf the 13 patients with CholU, 10 showed reduced sweating in response to PCE provocation, and 3 had severely reduced sweating. Reduced sweating was linked to long disease duration and high disease severity. CholU patients with impaired sweating responses showed reduced sweat gland epithelial expression of CHRM3 and ACh-E.ConclusionReduced sweating is common in CholU patients, especially in those with long-standing and severe disease, and it can be severe. Reduced expression of CHRM3 and ACh-E may be the cause or consequence of CholU in patients with impaired sweating, and this should be explored by further studies

Cold urticaria – What we know and what we do not know

Cold urticaria (ColdU) is a common form of chronic inducible urticaria characterized by the development of wheals, angioedema or both in response to cold exposure. Recent research and guideline updates have advanced our understanding and management of ColdU. Today, its pathophysiology is thought to involve the cold-induced formation of autoallergens and IgE to these autoallergens, which provoke a release of proinflammatory mediators from skin mast cells. The classification of ColdU includes typical and atypical subtypes. We know that cold-induced wheals usually develop on rewarming and resolve within an hour and that anaphylaxis can occur. The diagnosis relies on the patient's history and cold stimulation testing. Additional diagnostic work-up, including a search for underlying infections, should only be done if indicated by the patient's history. The management of ColdU includes cold avoidance, the regular use of nonsedating antihistamines and the off-label use of omalizumab. However, many questions regarding ColdU remain unanswered. Here, we review what is known about ColdU, and we present important unanswered questions on the epidemiology, underlying pathomechanisms, clinical heterogeneity and treatment outcomes. Our aim is to guide future efforts that will close these knowledge gaps and advance the management of ColdU

A hitchhiker's guide to myeloid cell subsets: practical implementation of a novel mononuclear phagocyte classification system

The classification of mononuclear phagocytes as either dendritic cells or macrophages has been mainly based on morphology, the expression of surface markers, and assumed functional specialization. We have recently proposed a novel classification system of mononuclear phagocytes based on their ontogeny. Here, we discuss the practical application of such a classification system through a number of prototypical examples we have encountered while hitchhiking from one subset to another, across species and between steady-state and inflammatory settings. Finally, we discuss the advantages and drawbacks of such a classification system and propose a number of improvements to move from theoretical concepts to concrete guidelines

Concise, enantioselective, and versatile synthesis of (−)-Englerin A Based on a platinum-catalyzed [4C+3C] cycloaddition of allenedienes

NOTICE: This is the peer reviewed version of the following article: Ronald Nelson, Moisés Gulías, José L. Mascareñas*, Fernando López* (2016), A Concise, Enantioselective and Versatile Synthesis of (-)-Englerin A based on a Pt-catalyzed [4C+3C] Cycloaddition of Allenedienes, Angew. Chem. Int. Ed., 55, 1-6 [doi:10.1002/anie.201607348]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archivingA practical synthesis of (−)-englerin A was accomplished in 17 steps and 11 % global yield from commercially available achiral precursors. The key step consists of a platinum-catalyzed [4C+3C] allenediene cycloaddition that directly delivers the trans-fused guaiane skeleton with complete diastereoselectivity. The high enantioselectivity (99 % ee) stems from an asymmetric ruthenium-catalyzed transfer hydrogenation of a readily assembled diene–ynone. The synthesis also features a highly stereoselective oxygenation, and a late-stage cuprate alkylation that enables the preparation of previously inaccessible structural analoguesSupport by the Spanish MINECO (SAF2013-41943-R), ERDF, ERC (Adv. Grant 340055), Xunta de Galicia (GRC2013-041 and 2015-CP082), Orfeo-cinqa CTQ2014-51912-REDC, and CONICYT-Becas Chile (grant to R.N.) is gratefully acknowledged. Dr. Isaac Alonso is acknowledged for preliminary contributionsS