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European Baseline Series (EBS) of haptens (contact allergens) is used throughout Europe, containing patch tests essential for the diagnosis of contact allergy (Tables I and II) [1]. Exposure to environmental allergens is constantly evolving and the EBS must be adapted accordingly in order to guarantee its relevance of the molecules tested, in particular by the addition of emerging allergens [1].

Background Cancer patients are being exposed to antineoplastic drugs more frequently and for longer periods, resulting in a higher risk of hypersensitivity reactions. The aim of this study was to assess the pharmaceutical time and direct cost of drug allergy explorations following immediate hypersensitivity reactions to antineoplastic agents. Methods A micro-costing method was used to collect data on consumption of human and material resources for allergy exploration preparations. The monetisation was carried out on the basis of prices and hourly wage costs applied in 2018. The number and type of allergy explorations prepared by the pharmacy as well as nature of antineoplastic drugs tested, and the number of culprit drugs reintroductions were collected. Results Almost 1.5 h is required to realise allergy tests for one patient including pharmacist time for prescription analysis and pharmacy technician's time for tests preparation. The mean manufacturing cost of these tests is estimated at €62.87 (€57.82–65.49) per culprit drug for one patient. Programming patients according to culprit drugs tested allows rationalising healthcare provider time and increasing efficiency. From January 2010 to December 2018, 277 patients were tested and 490 allergy explorations were performed, corresponding to more than 5000 preparations. Mostly, the culprit drug could be reintroduced ( n = 383, 78.2%) allowing patients to receive the best possible treatment. Conclusion Management of hypersensitivity reactions is constantly progressing, as it contributes to improving patient care in oncology. This activity is time-consuming for the pharmacy team but allows patients with previous hypersensitivity reaction to continue effective treatment.

Background Chronic venous disease (CVD) is secondary to venous hypertension, leading to vascular inflammation and tissue changes. The impact of CVD on skin structure and barrier function is not well characterized. Objective We aimed to assess the characteristics of skin alterations in mild-to-moderate CVD by non-invasive techniques based on a prospective exploratory study. Material & methods Female subjects (30-75 years) with CVD (Stage C2 to C4, CEAP classification) were eligible. Stage C0-C1 CVD subjects were used as controls. Women with leg surgery or a medical history that could impact the results were excluded. The skin changes on lesional (LS) and non-lesional (NLS) areas were assessed by biometric analysis including skin echography, viscoelasticity evaluation, confocal microscopy and trans epidermal water loss (TEWL) measurements. Results Thirty-four subjects were enrolled. Based on computation of 26 biometric parameters using Principal Component Analysis, a significant difference between LS and NLS zones, regardless of the CEAP class, was evidenced. C2-C4 subjects presented with dermal thickening suggesting oedema associated with decreased cell density, while no difference in skin viscoelasticity was observed compared to the C0-C1 control group. Epidermal structural modifications were associated with increased TEWL correlating with CVD severity. Conclusion Skin alterations in CVD patients are detectable by non-invasive methods. These findings may help to better assess new therapeutic strategies.

Background The therapeutic options in atopic dermatitis rely on consensus-based guidelines, also established for psoriasis and chronic urticaria. However, the therapeutic approach in atopic dermatitis, especially in the moderate-to-severe forms of the disease, seems less aggressive than in psoriasis and in chronic urticaria with a less frequent use of systemic agents. Objectives To compare in real-life conditions the therapeutic management of adults with atopic dermatitis with those with psoriasis and chronic urticaria. Methods A transversal analysis was performed in May 2017, using retrospective data from a monocentric database. Data on epidemiology, severity, therapeutic educational intervention and systemic treatments were analysed from 401 patients with atopic dermatitis, compared with data from 230 patients with chronic urticaria and 535 patients with psoriasis. Results A high proportion (73%) of atopic dermatitis patients presented with a moderate-to-severe form of the disease compared to only 39% of chronic urticaria and 17% of psoriasis patients. Most of atopic dermatitis patients (78%) had completed a therapeutic educational programme, while the adherence was lower in chronic urticaria (35%) and in psoriasis (3%) patients. A systemic treatment, including biologicals, was recorded in 8% of atopic dermatitis patients, while it concerned 26% and 47% of chronic urticaria and psoriasis patients, respectively. Conclusions We confirmed that atopic dermatitis treatment mostly relies on topical treatments. Only a minority of moderate-to-severe atopic dermatitis patients who are eligible for a systemic treatment receive such therapy. This may suggest promoting a more frequent use of systemic agents in moderate-to-severe atopic dermatitis.

Red blood cell exchanges are frequently used to treat and prevent cerebrovascular complications in patients with sickle cell anemia (SCA). However, the low weight of young children represents serious concerns for this procedure. The Spectra Optia device can perform automatic priming using red blood cells (RBCs) (RCE/RBC-primed) which could allow RBC exchanges (RCE) to be performed in young children without hypovolemic complications, but this method requires evaluation. We prospectively analyzed the clinical safety of the RCE/RBC-primed procedure in 12 SCA low-weight children under either a chronic RCE program or emergency treatment over 65 sessions. We monitored grade 2 adverse events (AEs) such as a decrease in blood pressure, increase in heart rate, fainting sensation, or transfusion reactions and identified the critical times during the sessions in which AEs could occur. Post-apheresis hematocrit (Hct) and a fraction of cell remaining (FCR) values were compared to the expected values. We also compared the impact of automatic RCE (n = 7) vs. RCE/RBC-primed (n = 8) on blood viscosity and RBC rheology. A low incidence of complications was observed in the 65 RCE sessions with only seven episodes of transient grade 2 AEs. Post-apheresis Hct and FCR reached expected values with the RCE/RBC-primed method. Both the automatic and priming procedures improved RBC deformability and decreased the sickling tendency during deoxygenation. Blood rheological features improved in both RCE/RBC-primed and automatic RCE without priming conditions. The RCE/RBC-primed procedure provides blood rheological benefits, and is safe and efficient to treat, notably in young children with SCA in prophylactic programs or curatively when a SCA complication occurs.

Psoriasis is a multifactorial skin pathology resulting from genetic susceptibility and environmental triggers that lead to epidermal and immune dysfunction. There is now strong evidence that non-lesional (NL) psoriatic skin, despite its normal appearance, represents an intermediate state between healthy and lesional skin. Changes observed in NL skin mainly affect the skin barrier, keratinocytes, innate and adaptive immune responses, the microbiota and neurogenic tissue innervation. Several epidermal barrier defects are commonly observed in NL skin compared to healthy skin, including an elevated pH, delayed barrier function repair after injury and lower expression of epidermal differentiation complex proteins. NL keratinocytes also show a predisposition for activation and proliferation, and an increased sensitivity to cytokine or microbial triggers, probably linked to their unique transcriptome and proteome, associated with their intermediate state between healthy and lesional cells. In addition, the accumulation of pathogenic IL-17-producing resident memory T cells, which can (re)instigate the formation of new lesions, characterises both the NL and never-lesional skin of patients with psoriasis. Although the contribution of NL skin dysbiosis to psoriasis pathophysiology remains to be clarified, the expression of numerous pruritogenic mediators appears to be involved in disease progression due to an iterative itch-scratch cycle. In summary, the NL skin of patients with psoriasis exhibits numerous hallmarks of dormant psoriasis. The fact that these alterations are mostly located in the epidermis suggests that they are readily accessible to topical treatments, which could prevent the recurrence/spread of this chronic disease.

More than 1 million joint replacement surgeries are performed each year in the United States, and failure occurs in 10% of them, raising major health and economic burdens. The reasons for failure are multiple and include malposition, infection, and hypersensitivity (HS)/allergy to implant components. The term "hypersensitivity", defining an inflammatory reaction to the implant components, is more appropriate than the term "allergy," because the implant-induced inflammation can be mediated by innate or adaptive immunity. Implant HS, also sometimes called "adverse reaction to metal debris" or "pseudotumor- like periprosthetic tissue reactions" in the specific condition or metal-on-metal hip replacement, undoubtedly exists, but it cannot be stated to always be an allergic reaction. Innate HS, also referred to as nonallergic HS, may develop in response to the generation of metal/polymer wear debris, which causes local inflammation due to activation of macrophages, thus leading to osteoclast triggering, bone resorption, and implant loosening. There is no diagnostic test for nonallergic HS. Conversely, adaptive HS, that is, allergy to prosthesis, also called type IV HS, is mediated by specific T cells that infiltrate the periimplant tissue where they are activated by antigen-presenting cells. The main allergens are metals (nickel, chromium, cobalt) and bone cement compounds. T-cell activation leads to the recruitment of leucocytes, which will cause joint inflammation, pain, and loosening.

Summary Background To address the unmet medical need for an effective prophylactic vaccine against Ebola virus we assessed the safety and immunogenicity of three different two-dose heterologous vaccination regimens with a replication-deficient adenovirus type 26 vector-based vaccine (Ad26.ZEBOV), expressing Zaire Ebola virus glycoprotein, and a non-replicating, recombinant, modified vaccinia Ankara (MVA) vector-based vaccine, encoding glycoproteins from Zaire Ebola virus, Sudan virus, and Marburg virus, and nucleoprotein from the Tai Forest virus. Methods This randomised, observer-blind, placebo-controlled, phase 2 trial was done at seven hospitals in France and two research centres in the UK. Healthy adults (aged 18–65 years) with no history of Ebola vaccination were enrolled into four cohorts. Participants in cohorts I–III were randomly assigned (1:1:1) using computer-generated randomisation codes into three parallel groups (randomisation for cohorts II and III was stratified by country and age), in which participants were to receive an intramuscular injection of Ad26.ZEBOV on day 1, followed by intramuscular injection of MVA-BN-Filo at either 28 days (28-day interval group), 56 days (56-day interval group), or 84 days (84-day interval group) after the first vaccine. Within these three groups, participants in cohort II (14:1) and cohort III (10:3) were further randomly assigned to receive either Ad26.ZEBOV or placebo on day 1, followed by either MVA-BN-Filo or placebo on days 28, 56, or 84. Participants in cohort IV were randomly assigned (5:1) to receive one dose of either Ad26.ZEBOV or placebo on day 1 for vector shedding assessments. For cohorts II and III, study site personnel, sponsor personnel, and participants were masked to vaccine allocation until all participants in these cohorts had completed the post-MVA-BN-Filo vaccination visit at 6 months or had discontinued the trial, whereas cohort I was open-label. For cohort IV, study site personnel and participants were masked to vaccine allocation until all participants in this cohort had completed the post-vaccination visit at 28 days or had discontinued the trial. The primary outcome, analysed in all participants who had received at least one dose of vaccine or placebo (full analysis set), was the safety and tolerability of the three vaccination regimens, as assessed by participant-reported solicited local and systemic adverse events within 7 days of receiving both vaccines, unsolicited adverse events within 42 days of receiving the MVA-BN-Filo vaccine, and serious adverse events over 365 days of follow-up. The secondary outcome was humoral immunogenicity, as measured by the concentration of Ebola virus glycoprotein-binding antibodies at 21 days after receiving the MVA-BN-Filo vaccine. The secondary outcome was assessed in the per-protocol analysis set. This study is registered at ClinicalTrials.gov , NCT02416453 , and EudraCT, 2015-000596-27. Findings Between June 23, 2015, and April 27, 2016, 423 participants were enrolled: 408 in cohorts I–III were randomly assigned to the 28-day interval group (123 to receive Ad26.ZEBOV and MVA-BN-Filo, and 13 to receive placebo), the 56-day interval group (124 to receive Ad26.ZEBOV and MVA-BN-Filo, and 13 to receive placebo), and the 84-day interval group (117 to receive Ad26.ZEBOV and MVA-BN-Filo, and 18 to receive placebo), and 15 participants in cohort IV were assigned to receive Ad26.ZEBOV and MVA-BN-Filo (n=13) or to receive placebo (n=2). 421 (99·5%) participants received at least one dose of vaccine or placebo. The trial was temporarily suspended after two serious neurological adverse events were reported, one of which was considered as possibly related to vaccination, and per-protocol vaccination was disrupted for some participants. Vaccinations were generally well tolerated. Mild or moderate local adverse events (mostly pain) were reported after 206 (62%) of 332 Ad26.ZEBOV vaccinations, 136 (58%) of 236 MVA-BN-Filo vaccinations, and 11 (15%) of 72 placebo injections. Systemic adverse events were reported after 255 (77%) Ad26.ZEBOV vaccinations, 116 (49%) MVA-BN-Filo vaccinations, and 33 (46%) placebo injections, and included mostly mild or moderate fatigue, headache, or myalgia. Unsolicited adverse events occurred after 115 (35%) of 332 Ad26.ZEBOV vaccinations, 81 (34%) of 236 MVA-BN-Filo vaccinations, and 24 (33%) of 72 placebo injections. At 21 days after receiving the MVA-BN-Filo vaccine, geometric mean concentrations of Ebola virus glycoprotein-binding antibodies were 4627 ELISA units (EU)/mL (95% CI 3649–5867) in the 28-day interval group, 10 131 EU/mL (8554–11 999) in the 56-day interval group, and 11 312 mL (9072–14106) in the 84-day interval group, with antibody concentrations persisting at 1149–1205 EU/mL up to day 365. Interpretation The two-dose heterologous regimen with Ad26.ZEBOV and MVA-BN-Filo was safe, well tolerated, and immunogenic, with humoral and cellular immune responses persisting for 1 year after vaccination. Taken together, these data support the intended prophylactic indication for the vaccine regimen. Funding Innovative Medicines Initiative and Janssen Vaccines & Prevention BV. Translation For the French translation of the abstract see Supplementary Materials section.

Contact dermatitis comprises two main groups: irritant (ICD) and allergic (ACD) contact dermatitis. It presents as acute, subacute, or chronic eczema. Although it is possible to differentiate ICD from ACD on clinical ground, both diseases can have very similar clinical, histological, and molecular presentations.

Immune-mediated skin diseases induced by chemicals and drugs are mainly T-cell mediated reactions, i.e. type IV hypersensitivity of the Gell & Coombs classification. Clinical expressions depend on the exposition route of the chemical with allergic contact dermatitis in case of skin exposure and delayed drug allergy in case of oral or parenteral intake. Allergic contact dermatitis and delayed drug allergy share common pathophysiologic pathways with chemical-specific T cells recruitment to the skin to eliminate chemical-expressing keratinocytes. In this review, we discuss the pathophysiology of allergic contact dermatitis and delayed drug allergy with focus on their common pathways.

Resume La necrolyse epidermique toxique est une reaction cutanee medicamenteuse rare et severe qui se caracterise par une necrose brutale de l’epiderme, entrainant un decollement cutane plus ou moins etendu. Il s’agit d’une urgence vitale avec jusqu’a 30 % de deces a la phase aigue. L’importance de la surface decollee definit deux entites cliniques : le syndrome de Stevens-Johnson quand le decollement est inferieur a 10 % et le syndrome de Lyell quand il est superieur a 30 %. A distance, le risque de complications, notamment sous forme de synechies des muqueuses, est particulierement eleve et doit etre prevenu systematiquement. Le mecanisme physiopathologique repose essentiellement sur une reaction d’hypersensibilite medicamenteuse retardee dans laquelle les lymphocytes cytotoxiques jouent un role majeur. Le terrain genetique intervient egalement avec des associations HLA-medicament maintenant bien decrites, notamment dans les populations asiatiques. La question du traitement reste encore tres debattue : il repose essentiellement sur la corticotherapie systemique, la ciclosporine ou encore les immunoglobulines IV. Quelques etudes suggerent egalement un interet des anti-TNF-alpha.

To develop an in vitro assay that recapitulates the key event of Allergic Contact Dermatitis (ACD), that is the priming of human effector T cells by hapten-presenting dendritic cells (DCs), and then allows for the sensitive detection of chemical allergens, represents a highly desirable goal but also a major challenge. Substantial progress has been made in recent years in the development of T cell-based assays, also referred to as human T Cell Priming Assays (hTCPA). hTCPA classically consists of an autologous mixed DC-lymphocyte reaction (MDLR) using test chemical-loaded DCs, as stimulatory cells, and normal human naive lymphocytes, as responding cells. Combining diverse strategies which (i) boosted the stimulatory capacities of DCs, (ii) bypassed the cellular or molecular brakes that mitigate T cell activation, or (iii) improved the solubilisation of test chemicals in culture media, the most newly-refined hTCPA protocols showed good results to predict the allergenic potential of chemicals. Although current protocols still require further investment to improve usability and to demonstrate their capacity to establish the sensitizing potency of chemicals, there is no doubt that the hTCPA will be of great help in the forthcoming years to support the immunotoxicologic assessment of new or challenging chemicals.

Atopic dermatitis (AD) is a common skin inflammatory disease characterized by the production of thymic stromal lymphopoietin (TSLP) and marked TH 2 polarization. Recent studies suggest that IL-1β contributes to the development of AD skin inflammation. Here, we have investigated the impact of IL-1β signalling on the epidermal homeostasis of both healthy subjects and AD patients [with functional filaggrin (FLG) alleles], with particular attention to TSLP production and keratinocyte differentiation. In healthy reconstructed human epidermis (RHE), IL-1β promoted (i) robust secretion of TSLP in an NF-κB-dependent manner and (ii) a significant decrease in the expression of filaggrin and other proteins of the epidermal differentiation complex. These effects were prevented by treatment of RHE with the anti-IL-1β mAb canakinumab and by the IL-1 receptor antagonist anakinra. Interestingly, RHE generated from AD donors behaved like that of healthy individuals and showed comparable responses to IL-1β signals. Collectively, our results suggest that IL-1β may be an early key mediator for the acquisition of an AD phenotype through induction of TSLP and alteration of the epidermal homeostasis. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

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Background Tissue-resident memory T (Trm) cells are detrimental in patients with numerous chronic inflammatory diseases, including allergic contact dermatitis (ACD). Objectives We sought to analyze the contribution of Trm cells to the chronicity and severity of ACD and to define the local parameters regulating their development and functions. Methods We used an experimental model of ACD (ie, contact hypersensitivity to 2,4-dinitrofluorobenzene) that is mediated by CD8+ T cells. Results Our data show that early effector T cells accumulated in the skin during the acute contact hypersensitivity reaction and gave rise to epidermal CD8+ Trm cells expressing a specific set of inhibitory checkpoint receptors (ICRs), such as programmed cell death protein 1 (PD-1) and T cell immunoglobulin and mucin domain 3 (TIM-3). Those Trm cells remained in the epidermis for several weeks and mediated the eczema exacerbations, which developed on allergen re-exposure without the contribution of circulating specific T cells. Furthermore, allergen-induced Trm cell reactivation was constrained because treatment with ICR antagonists dramatically enhanced the magnitude and severity of eczema exacerbations. Finally, we show that the persistence of the allergen in the epidermis for long periods of time was responsible for both the development and maintenance of epidermal Trm cells, as well as the sustained expression of ICRs. Conclusion Although CD8+ Trm cells are key for the pathophysiology of ACD, intrinsic mechanisms control their reactivation to prevent damaging immunopathology. Developing strategies targeting the reactivation of skin Trm cells in situ through their ICRs should open new perspectives for the treatment of ACD.

Background Chronic red blood cell exchanges (RBCXs) are frequently used to prevent complications in patients with sickle cell anemia, but the scarcity of matched red blood cell packs (RBCPs) is a serious concern. The main goal of this study was to compare the number of RBCPs used during RBCXs between the Spectra Optia (SO) device (with the automatic depletion step) and the former Cobe Spectra (CSP) device. Study design and methods The performances and safety of 300 SO sessions using the automatic depletion step (SO/DE) in 50 patients with sickle cell anemia under a chronic transfusion program over a 1-year period were prospectively analyzed. The numbers of RBCPs saved using this protocol compared to the SO device without depletion and to the CSP device were determined. Results The SO/DE protocol appeared to be safe, as only 5% and 17% of the sessions were characterized by a significant decrease in blood pressure and increase in heart rate (grade 2 adverse events), respectively. Postapheresis hematocrit and fraction of cells remaining reached expected values. The SO/DE protocol required 16% fewer RBCPs compared to SO without depletion, allowing a mean saving of 12 RBCPs per patient and per year and 13% fewer compared to CSP device. Interestingly, the saving was more important for patients with high total blood volume and/or high preapheresis hematocrit. Conclusion The SO/DE protocol is an efficient, safe and cost-effective procedure for patients with sickle cell anemia under a chronic transfusion program.

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International audience; BACKGROUND: Epidermolysis bullosa simplex generalized severe is a genetic disorder caused by mutation in KRT5 or KRT14 genes. Usually considered as a mechanical disease, recent data argue for additional inflammatory mechanisms. OBJECTIVES: The aim of this study was to assess the inflammation in the skin of patients with EBS. METHODS: A first immunohistochemical retrospective study was performed on frozen skin samples from 17 EBS-gen sev patients. A second multicenter prospective study was conducted on 10 patients with severe EBS-gen sev. Blister fluid and epidermis were processed for immunochemistry analysis and quantitative real time PCR. Cytokine expression was analyzed in blister fluid and compared with controls. RESULTS: Histological analysis showed a constant dermal perivascular CD4+ lymphocytes infiltrate in skin biopsies of blister (n=17) as well as in rubbed skin (n=5), an epidermal infiltration of neutrophils and eosinophils in 70% of cases and an increased immunostaining for CXCL9 and CXCL10 in blistering skin. High levels of Th17 cytokines were detected in lesional skin. Three adult patients with EBS-gen sev were treated with apremilast with a dramatic improvement of skin blistering and good tolerance. CONCLUSION: Our study demonstrates the importance of inflammation in EBS-gen sev patients and underlines the key role for Th17 cells in its pathogenesis. In addition, this study provides promising new therapeutic approaches for this disabling disorder. This article is protected by copyright. All rights reserved.

International audience; BACKGROUND: Methotrexate is currently used to treat atopic dermatitis but has never been assessed versus cyclosporine in adults. OBJECTIVE: This study evaluated the efficacy and safety of methotrexate versus cyclosporine in patients with moderate-to-severe atopic dermatitis. METHODS: Patients were randomized to receive either oral methotrexate (15 mg/wk) or cyclosporine (2.5 mg/kg/d) for 8~weeks. The primary end point was a patient achieving 50% improvement in the SCORing Atopic Dermatitis index (SCORAD 50) at week 8. When the primary end point was not achieved, methotrexate was increased to 25 mg and cyclosporine to 5 mg during the next 16 weeks. The secondary end points were a patient achieving a 50% reduction in the Eczema Area Severity Intensity index (EASI 50) and SCORAD 50 at each visit (ClinicalTrials.gov no. NCT00809172). RESULTS: A total of 97 patients received methotrexate 15 mg (n~= 50) or cyclosporine 2.5 mg (n~= 47). Regarding the primary end point at week 8, methotrexate was inferior to cyclosporine because the proportion of patients with SCORAD 50 was 8% (4 of 50) in the methotrexate arm versus 42% (18 of 43) in the cyclosporine arm. The difference in percentages for the 2 treatment groups (2-sided 90% CI) was~-34% (-48% to~-20%). At week 8, methotrexate and cyclosporine dosages were increased in 56% and 49% of the patients, respectively. Regarding EASI 50, the noninferiority end point was reached at week 20 in 92% (22 of 24) of patients in the methotrexate arm and 87% (26 of 30) of patients in the cyclosporine arm. The treatment-related adverse events were more frequent with cyclosporine (P \textless .0001). CONCLUSIONS: Methotrexate 15 mg/wk was inferior to cyclosporine 2.5 mg/kg/d at week 8. Increasing the doses of methotrexate to 25 mg/wk induced a significant improvement versus cyclosporine at week~20.

International audience; This paper summarizes and reviews the mechanisms of action and data concerning efficacy of recommended treatments as well as other treatments that have been tested, independently of the outcomes, in the management of chronic spontaneous urticaria. Due to the central role of mast cells, basophils and histamine in the pathophysiology of this disease, H1-antihistamines remain the first-line treatment. However, current knowledge about this complex disease, also recognizes an important role for T lymphocytes, B lymphocytes, and autoantibodies. Implications of these others mediators thus provide further targets for treatment. Indeed, agents previously used to treat other autoimmune and inflammatory diseases, have demonstrated efficacy in chronic spontaneous urticaria and are therefore potential therapeutic alternatives for antihistamine unresponsive patients.

International audience; The human skin is known to be inhabited by diverse microbes, including bacteria, fungi, viruses, archaea, and mites. This microbiome exerts a protective role against infections by promoting immune development and inhibiting pathogenic microbes to colonize skin. One of the factors having an intense effect on the skin and its resident microbes is ultraviolet-radiation (UV-R). UV-R can promote or inhibit the growth of microbes on the skin and modulate the immune system which can be either favorable or harmful. Among potential UV-R targets, skin resident memory T cells (TRM) stand as well positioned immune cells at the forefront within the skin. Both CD4+ or CD8+ αβ TRM cells residing permanently in peripheral tissues have been shown to play prominent roles in providing accelerated and long-lived specific immunity, tissue homeostasis, wound repair. Nevertheless, their response upon UV-R exposure or signals from microbiome are poorly understood compared to resident TCRγδ cells. Skin TRM survive for long periods of time and are exposed to innumerable antigens during lifetime. The interplay of TRM with skin residing microbes may be crucial in pathophysiology of various diseases including psoriasis, atopic dermatitis and polymorphic light eruption. In this article, we share our perspective about how UV-R may directly shape the persistence, phenotype, specificity, and function of skin TRM; and moreover, whether UV-R alters barrier function, leading to microbial-specific skin TRM, disrupting the healthy balance between skin microbiome and skin immune cells, and resulting in chronic inflammation and diseased skin.

Most angioedemas are histaminergic and correspond to deep urticarial swelling. Recurrent histaminergic angioedema led to the diagnosis of chronic urticaria, even when there are no superficial associated hives. Chronic urticaria is a benign disease, and autoimmune in 40 % of cases. The occurrence of angioedema in chronic urticaria is not a sign of severity. The occurrence of angioedema in chronic urticaria is associated with a longer duration of urticarial disease. NSAIDs and/or systemic corticotherapy are classic triggers of angioedema in chronic urticaria. In the absence of clinical endpoints, there is no need to make further assessment in chronic urticaria good responders to antihistamines.

Human microbiota includes all microorganisms, saprophytes and pathogens that colonize our bodies. Recent advances in metagenomic analysis techniques have expanded our knowledge of the microbiota and fundamentally changed our view of its relationships with the immune system. The commensal flora appears to be essential to the development of the immune system, and the diversity of the microbiota is correlated with good health status of individuals. These findings open up new conceptual and therapeutic approaches in chronic inflammatory diseases.

International audience; There are currently no animal models of drug-induced liver injury (DILI) where the adaptive immune system has been shown to damage the liver. Thus, it is difficult to explore the mechanistic basis of the tissue injury. The aim of this study was to use C57BL/6 CD4+-deficient mice with a mutation in the αβ gene encoding for Major histocompatibilty complex (MHC) class II molecules to (1) develop a mouse model of flucloxacillin sensitization, (2) explore whether drug-specific CD8+ kill primary hepatocytes, and (3) analyze perturbations in liver integrity following oral exposure to flucloxacillin. CD8+ T-cells from lymph nodes of flucloxacillin-sensitized mice were stimulated to proliferate, secrete interferon (IFN-γ) and granzyme B, and induce hepatocyte apoptosis in a concentration-dependent manner following ex vivo stimulation. The T-cell response was antigen-specific; T-cells were not activated with other β-lactam antibiotics. Furthermore, T-cell responses only occurred in the presence of flucloxacillin-pulsed antigen presenting cells. In separate experiments, flucloxacillin-specific T-cells were induced to migrate to the mesenteric lymph nodes using retinoic acid, prior to administration of oral flucloxacillin, and analysis of plasma biomarkers of liver injury. Oral exposure to flucloxacillin resulted in mild elevations in alanine aminotransferase, liver, and gall bladder leukocyte infiltration and a marked swelling of the gall bladder. Thus, CD4+-deficient mice represent a promising model to study the role of the adaptive immune system in DILI.

International audience; BACKGROUND: Ivermectin (IVM) is widely used in both human and veterinary medicine to treat parasitic infections. Recent reports have suggested that IVM could also have anti-inflammatory properties. METHODS: Here, we investigated the activity of IVM in a murine model of atopic dermatitis (AD) induced by repeated exposure to the allergen Dermatophagoides farinae, and in standard cellular immunological assays. RESULTS: Our results show that topical IVM improved allergic skin inflammation by reducing the priming and activation of allergen-specific T cells, as well as the production of inflammatory cytokines. While IVM had no major impact on the functions of dendritic cells in vivo and in vitro, IVM impaired T-cell activation, proliferation, and cytokine production following polyclonal and antigen-specific stimulation. CONCLUSION: Altogether, our results show that IVM is endowed with topical anti-inflammatory properties that could have important applications for the treatment of T-cell-mediated skin inflammatory diseases.

International audience

International audience

Resume Les reactions allergiques systemiques aux prick-tests sont exceptionnelles. Ce risque est proportionnel a la quantite d’allergene administree et est correle a la severite de l’accident initial. Nous decrivons un cas de reaction systemique au prick-test a l’amoxicilline a type d’urticaire generalisee, chez qui une batterie de prick-tests a 17 betalactamines a pu etre realisee avec une excellente tolerance grâce a la mise au point d’un protocole de dilution des solutions prick.

Allergic contact dermatitis is a disease that to a great extent can be limited or even avoided. Limitation of allergic contact dermatitis can be realized by the predictive identification of sensitizing chemicals (hazard identification), measurement of their relative sensitizing potency (hazard characterization) and subsequent use of proper risk assessment/management strategies in relation to the anticipated skin exposure. Several in vivo methods exist that are known to be reliable predictors of chemicals that can behave as skin sensitizers. One particular method, the local lymph node assay, also produces vital information on the relative potency of identified sensitizers. This potency information can be applied to quantitative risk assessment for skin sensitization, although the completion of quantitative risk assessment is dependent also on access to information on human skin exposure. However, the challenge in 2013 is how to obtain the same type of information on the potency of skin sensitising chemical...

Invariant natural killer T (iNKT) cells expressing a CD1d-restricted invariant αβTCR have key regulatory roles in autoimmunity, pathogen immunity, and tumor surveillance, but their function in the control of allergic skin diseases remains poorly documented. Using a model of contact hypersensitivity (CHS) to the hapten DNFB, we show here that iNKT cell deficiency results in enhanced skin inflammation due to augmented hapten-specific IFN-γ-producing CD8(+) effectors in skin draining lymph nodes (dLNs) and their massive recruitment into the allergen-exposed skin. Adoptive transfer and antibody depletion experiments as well as in vitro studies revealed that iNKT cells (1) reduce the severity of CHS, even in presensitized mice, (2) require hapten presentation by CD1d(+) dendritic cells (DCs) to dampen skin inflammation, and (3) produce IL-4 and IL-13 after CD1d-dependent in vitro stimulation by hapten-loaded DCs only in the presence of IFN-γ released from activated CD8(+) effector T cells. In corollary, mice double deficient in IL-4 and IL-13 exhibit an exacerbated CHS. Finally, iNKT-suppressive function is independent of Foxp3(+) regulatory T cells (Tregs). These data highlight that, besides Foxp3(+) Tregs, iNKT cells are potent downregulators of CD8(+) T cell-mediated CHS, and underscore that both cell types are important for the regulation of allergic skin inflammation.