Exploring recent advances in drugs severe cutaneous adverse reactions immunopathology.

Severe cutaneous adverse reactions to drugs (SCARs) are rare but life-threatening delayed allergies. While they primarily affect the skin, they can also affect internal organs. Accordingly, they present with diverse clinical symptoms that vary not only between SCARs subtypes but also among patients.

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 to the exacerbation of atopic dermatitis (AD) is widely documented, but its role as a primary trigger of AD skin symptoms remains poorly explored.

Objectives: This study sought to reappraise the main bacterial factors and underlying immune mechanisms by which S aureus triggers AD-like inflammation.

Methods: This study capitalized on a preclinical model, in which different clinical isolates were applied in the absence of any prior experimental skin injury.

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 (T ) 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 T cells in a preclinical model of ACD to 2,4-dinitrofluorobenzene. TA 0.

Hyperactivation of the JAK2/STAT5 Signaling Pathway and Evaluation of Baricitinib Treatment Among Patients With Eosinophilic Cellulitis.

Importance: The pathogenesis of eosinophilic cellulitis (EC) is poorly understood, limiting available treatment options. The current treatment paradigm focuses on delayed type 2 hypersensitivity reaction to various triggers.

Objective: To gain further insight into the nature of EC inflammation and into the cellular signal transduction pathways that are activated in the context of EC.

Role of miR-24-3p and miR-146a-5p in dendritic cells' maturation process induced by contact sensitizers.

MiRNAs are non-coding RNA molecules that regulate gene expression at the post-transcriptional level. Although allergic contact dermatitis has been studied extensively, few studies addressed miRNA expression and their role in dendritic cell activation. The main aim of this work was to investigate the role of miRNAs in the underlying mechanism of dendritic cell maturation induced by contact sensitizers of different potency.

Ultraviolet exposure regulates skin metabolome based on the microbiome.

Skin metabolites (< 1500 Da) play a critical role in barrier function, hydration, immune response, microbial invasion, and allergen penetration. We aimed to understand the global metabolic profile changes of the skin in relation to the microbiome and UV exposure and exposed germ-free (devoid of microbiome), disinfected mice (partially devoid of skin microbiome) and control mice with intact microbiome to immunosuppressive doses of UVB radiation. Targeted and untargeted lipidome and metabolome profiling was performed with skin tissue by high-resolution mass spectrometry.

Deciphering Differential Behavior of Immune Responses as the Foundation for Precision Dosing in Allergen Immunotherapy.

Like in many fields of medicine, the concept of precision dosing has re-emerged in routine practice in allergology. Only one retrospective study on French physicians' practice has addressed this topic so far and generated preliminary data supporting dose adaptation, mainly based on experience, patient profile understanding and response to treatment. Both intrinsic and extrinsic factors shape the individual immune system response to allergen immunotherapy (AIT).

Microbial derived antimicrobial peptides as potential therapeutics in atopic dermatitis.

Atopic dermatitis (AD) is a common chronic inflammatory skin disease that significantly affects the patient's quality of life. A disrupted skin barrier, type 2 cytokine-dominated inflammation, and microbial dysbiosis with increased colonization are critical components of AD pathogenesis. Patients with AD exhibit decreased expression of antimicrobial peptides (AMPs) which is linked to increased colonization by .

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.

Epicutaneous allergen immunotherapy induces a profound and selective modulation in skin dendritic-cell subsets.

Background: Epicutaneous immunotherapy (EPIT) protocols have recently been developed to restore tolerance in patients with food allergy. The mechanisms by which EPIT protocols promote desensitization rely on a profound immune deviation of pathogenic T- and B-cell responses.

Objective: To date, little is known about the contribution of skin dendritic cells (skDCs) to T-cell remodeling and EPIT efficacy.

Accumulation of Cytotoxic Skin Resident Memory T Cells and Increased Expression of IL-15 in Lesional Skin of Polymorphic Light Eruption.

Patients with polymorphic light eruption (PLE) develop lesions upon the first exposure to sun in spring/summer, but lesions usually subside during season due to the natural (or medical) photohardening. However, these lesions tend to reappear the following year and continue to do so in most patients, suggesting the presence of a disease memory. To study the potential role of skin resident memory T cells (Trm), we investigated the functional phenotype of Trm and the expression of IL-15 in PLE.

In-Depth Immunophenotyping With Mass Cytometry During TB Treatment Reveals New T-Cell Subsets Associated With Culture Conversion.

Tuberculosis (TB) is a difficult-to-treat infection because of multidrug regimen requirements based on drug susceptibility profiles and treatment observance issues. TB cure is defined by mycobacterial sterilization, technically complex to systematically assess. We hypothesized that microbiological outcome was associated with stage-specific immune changes in peripheral whole blood during TB treatment.

Priming With Red Blood Cells Allows Red Blood Cell Exchange for Sickle Cell Disease in Low-Weight Children.

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.

A T cell-intrinsic function for NF-κB RelB in experimental autoimmune encephalomyelitis.

NF-kappaB (NF-κB) is a family of transcription factors with pleiotropic functions in immune responses. The alternative NF-κB pathway that leads to the activation of RelB and NF-κB2, was previously associated with the activation and function of T cells, though the exact contribution of these NF-κB subunits remains unclear. Here, using mice carrying conditional ablation of RelB in T cells, we evaluated its role in the development of conventional CD4 T (Tconv) cells and their function in autoimmune diseases.

Unique molecular signatures typify skin inflammation induced by chemical allergens and irritants.

Background: Skin exposure to chemicals may induce an inflammatory disease known as contact dermatitis (CD). Distinguishing the allergic and irritant forms of CD often proves challenging in the clinic.

Methods: To characterize the molecular signatures of chemical-induced skin inflammation, we conducted a comprehensive transcriptomic analysis on the skin lesions of 47 patients with positive patch tests to reference contact allergens and nonallergenic irritants.

Role of tissue-resident memory T cells in the pathophysiology of allergic contact dermatitis.

Purpose Of Review: We bring updated knowledge on tissue-resident memory T cells (TRM), underlining their major role in the recurrence and the severity of allergic contact dermatitis (ACD).

Recent Findings: ACD is a frequently encountered skin disease. It is defined as a delayed-type hypersensitivity reaction initiated by the recruitment of antigen-specific T cells into the skin of sensitized patients.