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ispartof: CONTACT DERMATITIS vol:87 issue:5 pages:468-471 ispartof: location:England status: published

Epithelial ovarian cancer (EOC) is the fifth most common cause of cancer death among women. Despite its immunogenicity, effective antitumor responses are limited, due, in part, to the presence of forkhead box protein 3–positive (Foxp3+) T regulatory (Treg) cells in the tumor microenvironment. However, the mechanisms that regulate the accumulation and the suppressive function of these Foxp3+ Treg cells are poorly understood. Here, we found that the majority of Foxp3+ Treg cells accumulating in the tumor microenvironment of EOCs belong to the subset of Foxp3+ Treg cells expressing inducible costimulator (ICOS). The expansion and the suppressive function of these cells were strictly dependent on ICOS-L costimulation provided by tumor plasmacytoid dendritic cells (pDC). Accordingly, ICOS+ Foxp3+ Treg cells were found to localize in close vicinity of tumor pDCs, and their number directly correlated with the numbers of pDCs in the tumors. Furthermore, pDCs and ICOS+ Foxp3+ Treg cells were found to be strong predictors for disease progression in patients with ovarian cancer, with ICOS+ Treg cell subset being a stronger predictor than total Foxp3+ Treg cells. These findings suggest an essential role for pDCs and ICOS-L in immunosuppression mediated by ICOS+ Foxp3+ Treg cells, leading to tumor progression in ovarian cancer. Cancer Res; 72(20); 5240–9. ©2012 AACR.

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PDF file - 68K, Survival of ICOS+ but not ICOS- T regulatory cells are dependent on ICOS-L provided by plasmacytoid dendritic cells. ICOS+ and ICOS- T regulatory cells isolated from peripheral blood of healthy volunteers were co-cultured with or without autologous plasmacytoid dendritic cells in the presence or absence of neutralizing anti-ICOS-L antibodies as described. Data depicted represent numbers of viable cells after four days of culture. Representative experiment of at least three independent experiments is shown. pDC = plasmacytoid dendritic cells, Treg = T regulatory cells

PDF file - 54K, Plasmacytoid dendritic cells do not correlate with ICOS- Foxp3+ T regulatory cells in the tumor microenvironment. Percentages of plasmacytoid dendritic cells (pDC) and percentages of ICOS- Foxp3+ T regulatory cells as analyzed by FACS show no correlation within the tumor microenvironment of ovarian cancer

ispartof: CONTACT DERMATITIS vol:88 issue:1 pages:68-70 ispartof: location:England status: published

Rosacea is a common chronic inflammatory skin disease that is characterized by a fluctuating course of excessive inflammation and apparent neovascularization. Microbial dysbiosis with high density of B. oleronius and increased activity of the serine protease kallikrein 5, which cleaves cathelicidin antimicrobial peptide, have been recognized as key pathogenic triggers in rosacea. However, how these events are linked to the hallmarks of the disease remains unknown. Here, we show that type I interferons produced by plasmacytoid dendritic cells represent the pivotal link between dysbiosis, an aberrant immune response, and neovascularization in rosacea. In fact, compared to other commensal bacteria, B. oleronius is highly susceptible and preferentially killed by cathelicidin antimicrobial peptides leading to enhanced generation of complexes with DNA. DNA from skin-associated microbiota but not from host cells is required for cathelicidin-induced activation of plasmacytoid dendritic cells and type I-interferon production, which is further amplified by B. oleronius. Moreover, kallikrein 5 cleaves cathelicidin into peptides with heightened DNA binding and type I interferon-inducing capacities, further facilitating type I interferon production within the skin. In turn, type I interferons induce IL22 whilst simultaneously rendering endothelial cells responsive through upregulation of the IL22-receptor, and thereby driving drive neoangiogenesis. These findings unravel novel pathomechanisms, which directly link several hallmarks of rosacea to the killing of dysbiotic commensal bacteria and the induction of a pathogenic type-I interferon-TH17/22 pathway.

Human cells produce thousands of lipids that change during cell differentiation and can vary across individual cells of the same type. However, we are only starting to characterize the function of these cell-to-cell differences in lipid composition. Here, we measured the lipidomes and transcriptomes of individual human dermal fibroblasts by coupling high-resolution mass spectrometry imaging with single-cell transcriptomics. We found that the cell-to-cell variations of specific lipid metabolic pathways contribute to the establishment of cell states involved in the organization of skin architecture. Sphingolipid composition is shown to define fibroblast subpopulations, with sphingolipid metabolic rewiring driving cell-state transitions. Therefore, cell-to-cell lipid heterogeneity affects the determination of cell states, adding a new regulatory component to the self-organization of multicellular systems.

Skin wounds heal by coordinated induction of inflammation and tissue repair, but the initiating events are poorly defined. Here we uncover a fundamental role of commensal skin microbiota in this process and show that it is mediated by the recruitment and the activation of type I interferon (IFN)-producing plasmacytoid DC (pDC). Commensal bacteria colonizing skin wounds trigger activation of neutrophils to express the chemokine CXCL10, which recruits pDC and acts as an antimicrobial protein to kill exposed microbiota, leading to the formation of CXCL10–bacterial DNA complexes. These complexes and not complexes with host-derived DNA activate pDC to produce type I IFNs, which accelerate wound closure by triggering skin inflammation and early T cell–independent wound repair responses, mediated by macrophages and fibroblasts that produce major growth factors required for healing. These findings identify a key function of commensal microbiota in driving a central innate wound healing response of the skin. Gilliet and colleagues demonstrate that skin wound healing occurs through the coordinated action of plasmacytoid dendritic cells, chemokines and skin microbiota.

LL37 exerts a dual pathogenic role in psoriasis. Bound to self-DNA/RNA, LL37 licenses autoreactivity by stimulating plasmacytoid dendritic cells-(pDCs)-Type I interferon (IFN-I) and acts as autoantigen for pathogenic Th17-cells. In systemic lupus erythematosus (SLE), LL37 also triggers IFN-I in pDCs and is target of pathogenic autoantibodies. However, whether LL37 activates T-cells in SLE and how the latter differ from psoriasis LL37-specific T-cells is unknown. Here we found that 45% SLE patients had circulating T-cells strongly responding to LL37, which correlate with anti-LL37 antibodies/disease activity. In contrast to psoriatic Th17-cells, these LL37-specific SLE T-cells displayed a T-follicular helper-(TFH)-like phenotype, with CXCR5/Bcl-6 and IL-21 expression, implicating a role in stimulation of pathogenic autoantibodies. Accordingly, SLE LL37-specific T-cells promoted B-cell secretion of pathogenic anti-LL37 antibodies in vitro. Importantly, we identified abundant citrullinated LL37 (cit-LL37) in SLE tissues (skin and kidney) and observed very pronounced reactivity of LL37-specific SLE T-cells to cit-LL37, compared to native-LL37, which was much more occasional in psoriasis. Thus, in SLE, we identified LL37-specific T-cells with a distinct functional specialization and antigenic specificity. This suggests that autoantigenic specificity is independent from the nature of the autoantigen, but rather relies on the disease-specific milieu driving T-cell subset polarization and autoantigen modifications.

DUSP22 gene rearrangements are recurrent in systemic and cutaneous ALK-negative anaplastic large cell lymphomas, rarely encountered in other cutaneous CD30+ lymphoproliferations, and typically absent in other peripheral T-cell lymphomas. We report the case of a 51-year-old woman, with longstanding celiac disease and a rapidly enlarging leg ulcer, due to a DUSP22-rearranged CD30+ T-cell lymphoproliferation. Subsequent history revealed an intestinal enteropathy-associated T-cell lymphoma (EATL). Identical monoclonal TR gene rearrangements and mutations in STAT3 and JAK1 typical of EATL were present in the cutaneous and intestinal lesions. No DUSP22 rearrangement was detected in the patient's intestinal tumour, nor in 15 additional EATLs tested. These findings indicate that DUSP22 rearrangements are not entirely specific of ALCLs, may rarely occur as a secondary aberration in EATL, and expand the differential diagnosis of DUSP22-rearranged cutaneous CD30+ lymphoproliferative disorders.

Papillon-Lefevre Syndrome (PLS) is (OMIM 245'000) a rare genodermatosis, transmitted in an autosomal recessive mode. The disease results from mutations in the CTSC gene (11q14.2) encoding cathepsin C or dipeptidyl peptidase1 . The clinic is marked by recurrent gingivitis, tooth loss and palmoplantar hyperkeratosis. We report the case of a 19-year-old patient who presented with palmoplantar hyperkeratosis and erythemato-squamous plaques (figure 1), with involvement of knees and elbows. The patient had recurrent abscesses mainly on inguinal and axillary areas.

A report in the June 2019 issue of the Journal of Investigative Dermatology reveals a role of neutrophil extracellular traps (NETs) in the induction of T helper type 17 cell responses and shows the relevance of this pathway in patients with psoriasis carrying a common risk variant in the TRAF3IP2 gene (Lambert et al., 2019). This work provides a new piece to the puzzle that links neutrophils to the T helper type 17–mediated pathogenesis of psoriasis.

COVID-19, which is caused by infection with SARS-CoV-2, is characterized by lung pathology and extrapulmonary complications

Since the beginning of the COVID-19 pandemic, dermatologists around the world have reported patients with chilblain-like skin lesions on their toes, called COVID-toes. Surprisingly, the majority of these patients do not develop COVID-19 symptoms, and their nasal swabs and serological tests are unable to confirm SARS-CoV-2 infection, despite a clear exposure to the virus. Recent evidence suggests that these patients mount a robust type I interferon response to SARS-CoV-2, making them resistant to the infection. Because chilblains are hallmarks of excessive type I interferons, COVID-toes may represent the skin expression of interferon-mediated resistance to SARS-CoV-2. Uncovering the molecular patho-mechanisms of COVID-toes may provide new avenues to promote SARS-CoV-2 resistance and control the COVID-19 pandemic.Depuis le début de la pandémie de Covid-19, les dermatologues du monde entier ont signalé des cas inexpliqués de pseudo-engelures, surnommées « orteils Covid » (COVID-toes). Cette recrudescence inhabituelle de pseudo-engelures est d’autant plus intrigante que la majorité des cas ne présentent pas de symptômes de Covid-19 ni de PCR ou de sérologie positive, malgré une exposition probable au SARS-CoV-2. Les données actuelles suggèrent que ces personnes sont prédisposées à induire une immunité innée robuste contre le SARS-CoV-2, ce qui les rend résistantes à l’infection. Une forte réponse interféron de type I, dont les pseudo-engelures sont l’expression clinique, pourrait favoriser une clairance rapide du virus, évitant à la fois la maladie et la séroconversion. Les mécanismes génétiques et moléculaires qui sous-tendent cette résistance naturelle au SARS-CoV-2 restent cependant à élucider.

Basal cell carcinoma (BCC) is the most frequent human cancer and is becoming an important health problem in an aging population. Based on their clinical and histological characteristics, thick BCC are typically divided into low-risk nodular and high-risk infiltrative subtypes, although the underlying mechanisms are poorly understood. We have identified molecular mechanisms that explain the aggressiveness of high-risk infiltrative BCC, with a potential direct clinical impact. In this study, we first show that fibroblasts, transforming growth factor-β, and fibronectin are found preferentially in infiltrative human BCC. This allowed us to develop in vivo models for the study of infiltrative BCC, which in turn let us confirm the role of transforming growth factor-β in inducing peritumoral fibronectin deposition and tumor infiltration. We then show that fibronectin promotes adhesion and migration of BCC cell lines through integrin α5β1-mediated phosphorylation of focal adhesion kinase. Fittingly, both inhibition of integrin α5β1 and phospho-focal adhesion kinase prevent fibronectin-induced migration of BCC cells in vitro as well as BCC infiltration in vivo. Altogether, our results open important insights into the pathogenesis of aggressive infiltrative BCC and identify integrin α5β1 or focal adhesion kinase inhibition as promising strategies for the treatment of advanced BCC.

Lupus erythematosus (LE) patients develop autoantibodies that form circulating immune complexes (ICs) with extracellular self-nucleic acids. These ICs are deposited into peripheral tissues, where they trigger detrimental organ inflammation. Recent evidence suggests that ICs contain LL37–DNA complexes derived from neutrophil extracellular traps (NETs) and that LE patients develop pathogenic autoantibodies against these structures, including Abs to LL37. However, the mechanism that leads to the generation of these Abs is unknown. In this study, we show that NETs directly trigger Ab production by human memory B cells. This occurs via LL37–DNA complexes present in NETs, which have the unique ability to gain access to endosomal compartments of B cells and to trigger TLR9 activation. In LE patients, NET-derived LL37–DNA complexes trigger polyclonal B cell activation via TLR9, but also specifically expand self-reactive memory B cells producing anti-LL37 Abs in an Ag-dependent manner. These findings suggest a unique link between neutrophils and B cells in which NETs trigger a concerted activation of TLR9 and BCR leading to anti-NET autoantibody production in lupus.

Although anti-tumor necrosis factor (TNF) agents are highly effective in the treatment of psoriasis, 2–5% of treated patients develop psoriasis-like skin lesions called paradoxical psoriasis. The pathogenesis of this side effect and its distinction from classical psoriasis remain unknown. Here we show that skin lesions from patients with paradoxical psoriasis are characterized by a selective overexpression of type I interferons, dermal accumulation of plasmacytoid dendritic cells (pDC), and reduced T-cell numbers, when compared to classical psoriasis. Anti-TNF treatment prolongs type I interferon production by pDCs through inhibition of their maturation. The resulting type I interferon overexpression is responsible for the skin phenotype of paradoxical psoriasis, which, unlike classical psoriasis, is independent of T cells. These findings indicate that paradoxical psoriasis represents an ongoing overactive innate inflammatory process, driven by pDC-derived type I interferon that does not lead to T-cell autoimmunity., The pathogenesis of paradoxical psoriasis in patients receiving anti-TNF treatments for classical psoriasis is unclear. Here, the authors show that anti-TNF drugs enhance the production of type I interferon by plasmacytoid dendritic cells, causing skin lesions that, unlike classical psoriasis, lack T- cell autoimmunity.

Background: Squamous cell carcinomas and basal cell carcinomas are both induced by chronic UV exposure. However, their predilection for specific areas of the face remains unexplained. Regional factors such as arterial blood flow may explain specific tumor localization. Objective: To determine whether in the fronto-temporal area of the face there is a preferential localization of non-melanoma skin cancer (NMSC) at sites of arterial blood vessels. Methods: Twenty-two patients with NMSC of the fronto-temporal area were selected for this study. The clinical tumor margins were demarked based on clinical examination. Arterial colocalization was determined using both sonography and histological analysis. Results: Echo-Doppler analysis revealed the colocalization of NMSC with an arterial branch in 59% of the patients. Histologically, colocalization between NMSC and artery was found in 68% of the patients. When combining echo-Doppler and histological results, colocalization of NMSC and arteries were found in 82% of the patients. Conclusion: In this study, we found an unexpectedly high colocalization of NMSC with arterial branches in the fronto-temporal area of the face. These results suggest that in addition to UV exposure, pulsatile arterial blood flow may represent an additional factor determining the precise facial localization of NMSC.

BACKGROUND Several treatment options are currently available for the treatment of psoriasis. OBJECTIVE To explore the main associations between patients' characteristics and systemic treatments prescribed for psoriasis in a large group of patients observed in real-life clinical practice. METHODS This was a retrospective analysis of baseline data collected within the Swiss Dermatology Network for Targeted Therapies registry in Switzerland between March 2011 and December 2017. Semantic map analysis was used in order to capture the best associations between variables taking into account other covariates in the system. RESULTS A total of 549 patients (mean age 46.7 ± 14.7 years) were included in the analysis. Conventional therapies such as retinoids and methotrexate were associated with no previous systemic therapies for psoriasis, a moderate quality of life (QoL) at therapy onset and older age (≥60 years). Fumaric acid derivatives were associated with mild psoriasis (psoriasis area severity index

Endosomal and cytosolic nucleic acid receptors are important immune sensors required for the detection of infecting or replicating viruses. The intracellular location of these receptors allows viral recognition and, at the same time, avoids unnecessary immune activation to self-nucleic acids that are continuously released by dying host cells. Recent evidence, however, indicates that endogenous factors such as anti-microbial peptides have the ability to break this protective mechanism. Here, we discuss these factors and illustrate how they drive inflammatory responses by promoting immune recognition of self-nucleic acids in skin wounds and inflammatory skin diseases such as psoriasis and lupus.

Over the last years, several immune pathways in the skin have been identified. These discoveries have been translated into targeted therapies for inflammatory skin diseases, which have revolutionized our clinical practice. The perturbed molecular network in the skin may serve as a biomarker for disease prediction and as a source of targets for early therapeutic intervention or prevention. With rising costs, this disease-focused healthcare model will become unsustainable, therefore next-generation healthcare must not focus solely on treatment personalisation (the right treatment for the right patient), but also needs to shift its focus towards disease prevention and early therapeutic intervention prior to disease manifestation.