Staphylococcus aureus-specific skin resident memory T cells protect against bacteria colonization but exacerbate atopic dermatitis-like flares in mice.

BACKGROUND: The contribution of Staphylococcus aureus (S. aureus) to the exacerbation of atopic dermatitis (AD) is widely documented, but its role as a primary trigger of AD skin symptoms remains poorly explored. OBJECTIVE: To reappraise the main bacterial factors and underlying immune mechanisms by which S. aureus triggers AD-like inflammation. METHODS: We capitalized on a pre-clinical model, in which different clinical isolates were applied in the absence of any prior experimental skin injury. RESULTS: We report that the development of S. aureus-induced dermatitis depended on the nature of the S. aureus strain, its viability, the concentration of the applied bacterial suspension, the production of secreted and non-secreted factors, as well as the activation of accessory gene regulatory quorum sensing system. In addition, the rising dermatitis, which exhibited the well-documented AD cytokine signature, was significantly inhibited in inflammasome adaptor protein ASC- and monocyte/macrophage-deficient animals, but not in T- and B-cell-deficient mice, suggesting a major role for the innate response in the induction of skin inflammation. However, bacterial exposure generated a robust adaptive immune response against S. aureus, and an accumulation of S. aureus-specific γδ and CD4+ tissue resident memory T (Trm) cells at the site of previous dermatitis. The latter both contributed to worsen the flares of AD-like dermatitis upon new bacteria exposures, but also, protected the mice from persistent bacterial colonization. CONCLUSION: These data highlight the induction of unique AD-like inflammation, with the generation of pro-inflammatory but protective Trm cells in a context of natural exposure to pathogenic S. aureus strains.

Skin-centered strategies in food allergy prevention.

While the early introduction of food allergens in the infant diet has been shown to be effective at preventing the development of food allergy (FA), its implementation in real life has been associated with various challenges. Interventions aimed at correcting skin barrier dysfunction have been explored in recent decades as a distinct or complementary mean to prevent allergic sensitization through the skin and subsequent development of FA. Studies assessing the application of emollient from birth have yielded conflicting results, and meta-analyses have demonstrated either no effect or only a slight positive effect on FA prevention. However, a careful review of the clinical trials reveals that different emollients were used, which may have explained some of the discrepancies between study results. Emollient application protocols also varied widely between studies. While firm conclusions cannot be drawn with regard to their overall efficacy at preventing FA, the available data provide valuable insight into the characteristics that could be associated with a more effective intervention. Namely, successful trials tended to use emollients with an acidic pH of 5.5, applied over the entire body, and combined with topical corticosteroids in affected areas. Consensus on the optimal strategy to restore skin barrier function could help improve the homogeneity and clinical relevance of future trials on this topic. In the meantime, clinicians should avoid products associated with worse outcomes.

Case Report: Mast cell anergy: absence of symptoms after accidental re-exposure to amoxicillin/clavulanic acid 3 days after anaphylaxis.

Empty mast cell syndrome, also named post anaphylaxis mast cell anergy (PAMA), is a temporary state of loss of mast cell responsiveness after a severe immediate hypersensitivity reaction. In this study, we describe a case of PAMA after accidental re-exposure to amoxicillin in a patient who developed severe anaphylaxis to this drug three days earlier in the operating room. To our knowledge, this report is the second to document this phenomenon.

Comprehensive ophthalmological evaluation in atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD), a chronic Type 2 inflammatory skin disease, is frequently associated with ocular surface diseases (OSD) which may appear or worsen under anti-Type 2-targeted treatments. However, the exact prevalence of OSD and the ophthalmology referral criteria remain ill-defined in AD patients before initiating such biotherapies. OBJECTIVE: We aimed to characterize the prevalence, the nature and the factors related to OSD development in AD that may justify an ophthalmological management. METHODS: A total of 98 consecutive AD inpatients without biological treatment were retrospectively included. These were systematically evaluated by an ophthalmologist during their dermatological care. Clinical and laboratory data were analyzed to characterize OSD and their risk factors. RESULTS: OSD were found in 83/98 AD patients (85%); mainly dry eye syndrome (64%, 63/98), allergic conjunctivitis (42%, 41/98), posterior (33%, 32/98), and anterior blepharitis (27%, 26/98). In AD patients without ocular symptoms, OSD were also frequently found (63%, 12/19) and were mostly mild. Risk factors for OSD were history of allergic rhinitis, allergic sensitization, head and neck AD, ocular symptoms (foreign body sensation in the eye, burning, itching, photophobia), and total IgE level >3000kU/L. CONCLUSION: The prevalence of OSD was high, even in asymptomatic patients. The risk factors identified may indicate the need for ophthalmological examination for therapeutic management, especially when biological agents targeting Type 2 inflammation are considered.

Gene profiling in active dermatitis lesions strengthens the diagnosis of allergic contact dermatitis.

BACKGROUND: Distinguishing between allergic and nonallergic forms of Contact Dermatitis (CD) is challenging and requires investigations based on patch-testing. Early detection of allergy biomarkers in active CD lesions could refine and simplify the management of CD patients. OBJECTIVE: To characterize the molecular signatures of active CD lesions. METHODS: We studied the expression of 12 allergy biomarkers by qRT-PCR in active lesions of 38 CD patients. Allergic CD (ACD) was diagnosed based on patch test (PT) results and exposure assessment. Molecular signatures of active lesions, as well as positive PT reactions, were compared with those of reference chemical allergens and irritants. RESULTS: Nineteen of the 38 CD patients reacted positively upon patch-testing and exposure assessment confirmed ACD diagnosis for 17 of them. Gene profiling of active CD lesions revealed 2 distinct molecular patterns: patients harboring signatures similar to reference allergens (n = 23) or irritants (n = 15). Among the 23 patients with an "allergy signature," we found the 17 patients with confirmed ACD, while no culprit allergen was identified for the 6 other patients. Interestingly, the 15 patients without biomarker induction had negative PT, suggesting that they developed nonallergic CD reactions. CONCLUSION: Molecular signatures from active skin lesions may help to stratify CD patients and predict those suffering from ACD.

Atopic Dermatitis and Self-Image Design: A Real-Life Study in Children Using Drawings.

Background: Atopic dermatitis (AD) induces alterations of external appearance and self-esteem, with impact on the personal development of the children. However, tools for estimating such suffering are lacking. We aimed to assess how children with AD represent themselves through their drawings. Methods: In this retrospective study, we included children (<18 years) suffering from AD who followed the instruction "draw yourself with and without eczema" at the end of a routine follow-up consultation. Drawings were interpreted with the child and then classified in different analysis groups by 5 independent evaluators. Results: A total of 64 children (41 [64.1%] girls and 23 [35.9%] boys, median [range] age 8 [3-7] years) made 64 drawings. Five groups of drawing were identified: "amputee" (n = 8, 12.5%), "identical" (n = 18, 28.1%), "sad" (n = 19, 29.7%), "complex" (n = 11, 17.2%), and "other" (n = 8, 12.5%). Univariate analysis found that age was differently distributed among the different drawing groups (P = 0.0047), as was the predominance of light colors (P = 0.038). The distribution of the other variables (gender, investigator global assessment score, active AD, and duration of activity) was not different among drawing groups. Conclusions: The drawing allows a majority of the AD children to express their self-image with and without eczema, as well as their feelings and their interactions with the environment and with their entourage. The visual tool proposed herein could be used during consultations, to (a) become aware of the need to treat AD, (b) better evaluate the impact of AD burden in childhood, and (c) adjust appropriately AD treatment.

Topical corticosteroids inhibit allergic skin inflammation but are ineffective in impeding the formation and expansion of resident memory T cells.

BACKGROUND: Tissue-resident memory T (TRM ) cells are detrimental in allergic contact dermatitis (ACD), in which they contribute to the chronicity and severity of the disease. METHODS: We assessed the impact of a standard topical corticosteroid (TCS) treatment, triamcinolone acetonide (TA), on the formation, maintenance and reactivation of epidermal TRM cells in a preclinical model of ACD to 2,4-dinitrofluorobenzene. TA 0.01% was applied at different time points of ACD response and we monitored skin inflammation and tracked CD8+ CD69+ CD103+ TRM by flow cytometry and RNA sequencing. RESULTS: The impact of TA on TRM formation depended on treatment regimen: (i) in a preventive mode, that is, in sensitized mice before challenge, TA transiently inhibited the infiltration of effector T cells and the accumulation of TRM upon hapten challenge. In contrast, (ii) in a curative mode, that is, at the peak of the ACD response, TA blocked skin inflammation but failed to prevent the formation of TRM . Finally, (iii) in a proactive mode, that is, on previous eczema lesions, TA had no effect on the survival of skin TRM , but transiently inhibited their reactivation program upon allergen reexposure. Indeed, specific TRM progressively regained proliferative functions upon TA discontinuation and expanded in the tissue, leading to exaggerated iterative responses. Interestingly, TRM re-expansion correlated with the decreased clearance of hapten moieties from the skin induced by repeated TA applications. CONCLUSIONS: Our results demonstrate that TCS successfully treat ACD inflammation, but are mostly ineffective in impeding the formation and expansion of allergen-specific TRM , which certainly restricts the induction of lasting tolerance in patients with chronic dermatitis.

Treatment satisfaction of adult patients with moderate-to-severe atopic dermatitis treated with baricitinib in France, Germany, and the United Kingdom: results from a cross-sectional international patient survey.

INTRODUCTION: We explored patient satisfaction with baricitinib, an oral Janus kinase inhibitor, in patients with atopic dermatitis (AD) treated in routine clinical practice. METHODS: Adults with moderate-to-severe AD treated with baricitinib in clinical practice for ≥4 weeks in France, Germany, and the UK completed a one-time online survey under market research methodologies. Treatment satisfaction was assessed using a Likert scale and abbreviated Treatment Satisfaction Questionnaire for Medication (TSQM-9). Patients reported demographic, disease, and treatment information. Data were analyzed descriptively. RESULTS: The survey was completed by 170 patients with a mean age of 39.3 years (SD = 13.5), 59% (n = 101) were female. At baricitinib initiation, 79% rated their AD as "Severe", yet 28% reported body surface area (BSA) involvement ≥10%. Most were "Satisfied" or "Very satisfied" (76%/18%) with baricitinib, with high rates reported for controlling itch (36%/56%). Itch improvements were noted by 97% of patients. Some tapered/stopped (50%/32%) topical corticosteroid use, aligned with reported improvements on the patient global assessment and BSA. Mean TSQM-9 convenience score was 78.0 (SD = 14.0). CONCLUSIONS: Satisfaction with itch control was particularly high, reflected in rates of improvement in itch since starting baricitinib. On the TSQM-9, the convenience score was the highest. Many patients tapered/stopped concomitant topicals, indicating baricitinib's effect in controlling AD symptoms.

Hand eczema in glove-wearing patients.

BACKGROUND: Allergic contact dermatitis to gloves is mostly induced by rubber accelerators. The European baseline series (EBS) appears insufficient to detect glove allergy. Since 2017, it is recommended to use the European rubber series (ERS) and to test the patients' own gloves. OBJECTIVES: To investigate the clinical profile of glove-wearing patients with hand eczema (HE) and to evaluate their sensitisation profile to glove allergens and the value of testing the patients' own gloves. METHODS: We conducted a French multicentre study of patients evaluated for HE between 2018 and 2020 and tested with the EBS, the ERS and their own gloves in patch tests and semi-open (SO) tests. RESULTS: A total of 279 patients were included; 32.6% of patients had positive tests to their own gloves or to glove allergens. Almost 45% of the sensitisations to glove allergens were detected only by the ERS. Among the patients tested both in patch tests and SO tests with their own gloves with positive results, 28% had positive SO tests only. Polyvinylchloride (PVC) gloves were positive in four patients. CONCLUSION: Our series confirms the need to test the ERS. All the patients' gloves must also be tested including PVC gloves. SO tests with gloves are useful as a complement to patch tests.

Baricitinib provides rapid and sustained improvements in absolute EASI and SCORAD outcomes in adults with moderate-to-severe atopic dermatitis.

BACKGROUND: Baricitinib is an oral selective Janus kinase 1/2 inhibitor approved for moderate-to-severe atopic dermatitis (AD) in adults. OBJECTIVES: To evaluate absolute Eczema Area and Severity Index (EASI) and SCORing of Atopic Dermatitis (SCORAD) outcomes over 16 weeks and to link disease severity categories to quality of life (QoL) improvements. METHODS: This post-hoc analysis included patients enrolled in Phase3 monotherapy (BREEZE-AD1/AD2) and topical corticosteroid (TCS) combination therapy (BREEZE-AD7) trials and analyzed baricitinib 2 and 4 mg vs. placebo. Categorical outcomes were analyzed using Fisher's exact test. RESULTS: Significantly more baricitinib-treated patients reached EASI ≤ 7 and SCORAD < 25 as early as week 1 in monotherapy and week 2 in TCS combination therapy, compared to placebo. Significant response vs. placebo was sustained until week 16 for EASI ≤ 7 (AD1/2 [p-value vs. placebo]: 2 mg = 19.9%, 4 mg = 25.4% [p = 0.001] and AD7: 2 mg = 40.4% [p = 0.087], 4 mg = 48.6% [p = 0.003]) and SCORAD < 25 (AD1/2: 2 mg = 12.2%, 4 mg = 19.4% [p = 0.001] and AD7: 2 mg = 30.3% [p = 0.025], 4 mg = 34.2% [p = 0.004]) severity categories. These effects were accompanied by rapid improvements in QoL. CONCLUSION: Baricitinib-treated patients rapidly achieved recommended absolute EASI and SCORAD treatment outcomes which were sustained until week 16. Improvements in QoL were greater than EASI severity categories reflected, indicating that physician-assessed scores do not necessarily correlate with patients' impression of AD severity.

Multicenter prospective observational study of dupilumab-induced ocular events in atopic dermatitis patients.

BACKGROUND: Although ocular adverse events are frequent in AD patients treated with dupilumab, their characterization remains limited due to a lack of prospective studies with a systematic ophthalmological examination. OBJECTIVE: To examine the incidence, characteristics and risk factors of dupilumab-induced ocular adverse events. METHODS: A prospective, multicenter, and real-life study in adult AD patients treated with dupilumab. RESULTS: At baseline, 27 out of 181 patients (14.9%) had conjunctivitis. At week 16 (W16), 25 out of 27 had improved their conjunctivitis and 2 remained stable and 34 out of 181 patients (18.7%) had dupilumab-induced blepharoconjunctivitis: either de novo (n = 32) or worsening of underlying blepharoconjunctivitis (n = 2). Most events (27/34; 79.4%) were moderate. A multivariate analysis showed that head and neck AD (OR = 7.254; 95%CI [1.938-30.07]; p = 0.004), erythroderma (OR = 5.635; 95%CI [1.635-21.50]; p = 0.007) and the presence of dry eye syndrome at baseline (OR = 3.51; 95%CI [3.158-13.90]; p = 0.031) were independent factors associated with dupilumab-induced blepharoconjunctivitis. LIMITATIONS: Our follow-up period was 16 weeks and some late-onset time effects may still occur. CONCLUSION: This study showed that most dupilumab-induced blepharoconjunctivitis cases are de novo. AD severity and conjunctivitis at baseline were not found to be associated risk factors in this study.

IL-4/IL-13 Inhibitors for Atopic Dermatitis Induce Psoriatic Rash Transcriptionally Close to Pustular Psoriasis.

Dupilumab is a therapeutic antibody targeting IL-4 and IL-13 receptor subunit alpha used for the treatment of patients with atopic dermatitis (AD). Cases of psoriasis-like reactions induced under dupilumab treatment (dupilumab-induced psoriatic eruption [DI-Pso]) for AD were recently reported. To understand the pathogenesis of DI-Pso, we performed gene expression profiling studies on skin biopsies of DI-Pso (n = 7) compared with those of plaque psoriasis, AD, and healthy controls (n = 4 each). Differential gene expression was performed using enrichment and Gene Ontology analysis. Gene expression was validated by qPCR, and protein levels were assessed by immunohistochemistry. Transcriptomic and protein analysis of DI-Pso compared with that of healthy controls, plaque psoriasis, and AD skins revealed activation of T helper 17/IL-23 pathways associated with a significant expression of IL-36, surrogate marker of pustular psoriasis. By contrast, T helper 2 representative genes' expression was strongly decreased in DI-Pso across comparison. Matching analysis with public data of pustular psoriasis skin corroborated that DI-Pso and pustular psoriasis upstream regulators overlap, greater than the overlap with plaque psoriasis. Furthermore, DI-Pso showed strongly decreased expression of many barrier skin genes compared with healthy controls, plaque psoriasis, and AD. Our data indicate that the pathogenesis of DI-Pso relied on a shift of skin immune responses from a T helper 2 to an IL-36 and T helper 17 polarization and on intensified skin barrier alterations.

Intravenous and subcutaneous immunoglobulins-associated eczematous reactions occur with a broad range of immunoglobulin types: A French national multicenter study.

BACKGROUND: Human immunoglobulins are used for treating diverse inflammatory and autoimmune disorders. Eczema is an adverse event reported but poorly described. OBJECTIVES: To describe the clinical presentation, severity, outcome, and therapeutic management of immunoglobulin-associated eczema. METHODS: This retrospective and descriptive study included a query of the French national pharmacovigilance database, together with a national call for cases among dermatologists. RESULTS: We included 322 patients. Eczema occurred preferentially in men (78.9%) and in patients treated for neurological pathologies (76%). The clinical presentation consisted mainly of dyshidrosis (32.7%) and dry palmoplantar eczema (32.6%); 5% of cases exhibited erythroderma. Sixty-two percent of the eczema flares occurred after the first immunoglobulin course. Eczema was observed with 13 intravenous or subcutaneous immunoglobulin types and recurred in 84% of patients who maintained the same treatment and in 68% who switched the immunoglobulin type. After immunoglobulin discontinuation, 30% of patients still had persistent eczema. LIMITATIONS: Retrospective study, with possible missing data or memory bias. CONCLUSION: Immunoglobulin-associated eczema occurred with all immunoglobulin types, preferentially in patients with neurologic diseases who required prolonged immunoglobulin treatment. Recurrence was frequent, even after switching the immunoglobulin type, which can lead to a challenging therapeutic situation when immunoglobulin maintenance is required.

The role of skin dysbiosis in atopic dermatitis

The cutaneous microbiota contributes to skin barrier function, ensuring effective protection against pathogens and contributing to the maintenance of epidermal integrity. Dysbiosis is frequently present in atopic dermatitis (AD), a chronic inflammatory disease associated with skin barrier defects. Dysbiosis is associated with reduced bacterial diversity and marked Staphylococcus aureus colonization, which is favoured in the case of certain local AD-specific properties such as reduced skin acidity, eased bacterial adhesion and decreased antimicrobial peptide production. Furthermore, S. aureus-associated skin dysbiosis, via the production of staphylococcal virulence factors, may also participate in the immunopathology of AD by altering the epidermal barrier and inducing an inflammatory response. However, there are currently no arguments for recommending screening for, and treatment of S. aureus-associated dysbiosis outside the setting of cutaneous superinfection. Nonetheless, modulation of the skin microbiota may hold promise for AD management. Here, we describe the relationships that exist between the skin microbiota and AD.

The aryl hydrocarbon receptor pathway plays a central role in the cutaneous response to pollutants

Short- and long-term exposure to atmospheric pollution has significant health effects. The skin is the organ directly in contact with pollutants and is responsible for protection of the organism. Particulate matter (PM) such as polycyclic aromatic hydrocarbons (PAHs) are the basis of certain pulmonary as well as dermatological complications. Pollution exacerbates certain illnesses such as atopic dermatitis and cancer, and it may also participate in delaying wound healing and in the occurrence of chronic ailments such as diabetes. The aryl hydrocarbon receptor (AhR) transcription factor, at the core of these responses to pollutants, is expressed by all cells of the skin. The AhR is subject to tight regulation that depends on its ligand. Pollutants act in a deleterious manner via the AhR, influencing the behaviour of keratinocytes as well as fibroblasts. Natural ligands, on the other hand, allow the noxious effects of pollution to be countered. This non-systematic review of the literature shows that modulation of AhR appears to be an excellent therapeutic approach to improve or stop the cutaneous problems linked to pollution.