T Cells Induce Prolonged Downregulation of Barrier Molecules in a Mouse Model of Allergic Contact Dermatitis.

Background: Dysfunction of the skin barrier is regarded as a key event in the initiation and progression of inflammatory skin diseases. In many cases of allergic contact dermatitis (ACD), epidermal-resident memory CD8 T (T) cells play a central role in the immune response to contact allergens. However, if and how allergen-specific CD8 T cells affect the expression of skin barrier molecules is not known.

Keratinocytes Present Staphylococcus aureus Enterotoxins and Promote Malignant and Nonmalignant T Cell Proliferation in Cutaneous T-Cell Lymphoma.

Cutaneous T-cell lymphoma is characterized by malignant T cells proliferating in a unique tumor microenvironment dominated by keratinocytes (KCs). Skin colonization and infection by Staphylococcus aureus are a common cause of morbidity and are suspected of fueling disease activity. In this study, we show that expression of HLA-DRs, high-affinity receptors for staphylococcal enterotoxins (SEs), by KCs correlates with IFN-γ expression in the tumor microenvironment.

Subclinical immune responses to nickel in sensitized individuals-a dose-response study.

Background: Nickel is the leading cause of contact allergy in Europe, with 14.5% of the adult population being sensitized. Despite regulations limiting nickel release from consumer items, the incidence and prevalence of nickel allergy remain high.

Regulation of immune response genes in the skin of allergic and clinically tolerant individuals exposed to p-phenylenediamine.

Background: p-Phenylenediamine (PPD) is a potent contact allergen found in many hair colour products. However, not all individuals develop allergic contact dermatitis (ACD) although they are regularly exposed to PPD. It is unclear whether these asymptomatic individuals are true non-responders to PPD or whether they mount a response to PPD without showing any symptoms.

Contact allergens in African countries: A review of published patch test studies.

Only few studies on contact allergy in African countries have been published. The aim of the present study was to provide an overview of the most common contact allergens identified by the use of patch tests in African countries based on a review of the existing literature. A total of twenty-four publications from eight African countries were initially identified by search in PubMed.

CD100 boosts the inflammatory response in the challenge phase of allergic contact dermatitis in mice.

Background: Allergic contact dermatitis (ACD) is an inflammatory disease with a complex pathophysiology in which epidermal-resident memory CD8 T (T ) cells play a key role. The mechanisms involved in the activation of CD8 T cells during allergic flare-up responses are not understood.

Methods: The expression of CD100 and its ligand Plexin B2 on CD8 T cells and keratinocytes before and after allergen exposure was determined by flow cytometry and RT-qPCR.

The junctional adhesion molecule-like protein (JAML) is important for the inflammatory response during contact hypersensitivity.

Background: The junctional adhesion molecule-like protein (JAML) plays important roles in wound healing and activation of epidermal γδ T cells in mice. Whether JAML plays a role in contact hypersensitivity (CHS), the animal model of allergic contact dermatitis (ACD), is not known.

Methods: To examine the role of JAML in CHS, we used various mouse models of CHS in JAML knockout (KO) and wild-type (WT) mice.

In-Depth Proteomic Map of Innate Lymphoid Cells from Healthy Human Skin and Blood.

Innate lymphoid cells (ILCs) are essential players in the skin-associated immune system, nevertheless little is known about their proteomes and proteomic diversity. In this study, we describe about 6,600 proteins constitutively expressed by ILC2s and ILC3s from healthy human skin and blood using state-of-the-art proteomics. Although the vast majority of proteins was expressed by both ILC subsets and in both compartments, the skin ILC2s and ILC3s were more distinct than their counterparts in blood.

differentiated human CD4 T cells produce hepatocyte growth factor.

Differentiation of naive CD4 T cells into effector T cells is a dynamic process in which the cells are polarized into T helper (Th) subsets. The subsets largely consist of four fundamental categories: Th1, Th2, Th17, and regulatory T cells. We show that human memory CD4 T cells can produce hepatocyte growth factor (HGF), a pleiotropic cytokine which can affect several tissue types through signaling by its receptor, c-Met.

Endolysin Inhibits Skin Colonization by Patient-Derived Staphylococcus Aureus and Malignant T-Cell Activation in Cutaneous T-Cell Lymphoma.

Staphylococcus aureus is suspected to fuel disease activity in cutaneous T-cell lymphomas. In this study, we investigate the effect of a recombinant, antibacterial protein, endolysin (XZ.700), on S.

Reduced vitamin D-induced cathelicidin production and killing of in macrophages from a patient with a non-functional vitamin D receptor: A case report.

Tuberculosis (TB) presents a serious health problem with approximately a quarter of the world's population infected with () in an asymptomatic latent state of which 5-10% develops active TB at some point in their lives. The antimicrobial protein cathelicidin has broad antimicrobial activity towards viruses and bacteria including . Vitamin D increases the expression of cathelicidin in many cell types including macrophages, and it has been suggested that the vitamin D-mediated antimicrobial activity against is dependent on the induction of cathelicidin.

Concomitant Inhibition of FASN and SREBP Provides a Promising Therapy for CTCL.

Cutaneous T cell lymphoma (CTCL) is a group of non-Hodgkin's primary cutaneous T cell lymphomas, with Mycosis Fungoides and Sézary syndrome (SS) being the two most common subtypes. Fatty acid synthase (FASN) is a crucial enzyme that catalyses the biosynthesis of fatty acids, which has been reported to play an oncogenic role in various malignancies but not in CTCL so far. Herein, we show that FASN is highly expressed in CTCL cell lines and in peripheral blood mononuclear cells (PBMCs) from CTCL patients, while it is not in PBMCs from healthy individuals.

Malignant T cells induce skin barrier defects through cytokine-mediated JAK/STAT signaling in cutaneous T-cell lymphoma.

Cutaneous T-cell lymphoma (CTCL) is a devastating lymphoid malignancy characterized by the accumulation of malignant T cells in the dermis and epidermis. Skin lesions cause serious symptoms that hamper quality of life and are entry sites for bacterial infection, a major cause of morbidity and mortality in advanced diseases. The mechanism driving the pathological processes that compromise the skin barrier remains unknown.

Induced Human Regulatory T Cells Express the Glucagon-like Peptide-1 Receptor.

The glucagon-like peptide-1 receptor (GLP-1R) plays a key role in metabolism and is an important therapeutic target in diabetes and obesity. Recent studies in experimental animals have shown that certain subsets of T cells express functional GLP-1R, indicating an immune regulatory role of GLP-1. In contrast, less is known about the expression and function of the GLP-1R in human T cells.

Preclinical Efficacy of a Capsid Virus-like Particle-Based Vaccine Targeting IL-1β for Treatment of Allergic Contact Dermatitis.

Hypersensitivity to a contact allergen is one of the most abundant forms of inflammatory skin disease. Today, more than 20% of the general population are sensitized to one or more contact allergens, making this disease an important healthcare issue, as re-exposure to the allergen can initiate the clinical disease termed allergic contact dermatitis (ACD). The current standard treatment using corticosteroids is effective, but it has side effects when used for longer periods.

Novel insights into contact dermatitis.

Contact dermatitis is a common disease that is caused by repeated skin contact with contact allergens or irritants, resulting in allergic contact dermatitis (ACD) and/or irritant contact dermatitis. Attempts have been made to identify biomarkers to distinguish irritant and allergic patch test reactions, which could aid diagnosis. Some promising candidates have recently been identified, but verification and validation in clinical cases still need to be done.

Normal T and B Cell Responses Against SARS-CoV-2 in a Family With a Non-Functional Vitamin D Receptor: A Case Report.

The coronavirus disease 2019 (COVID-19) pandemic has severely impacted daily life all over the world. Any measures to slow down the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to decrease disease severity are highly requested. Recent studies have reported inverse correlations between plasma levels of vitamin D and susceptibility to SARS-CoV-2 infection and COVID-19 severity.

Macrophages Control the Bioavailability of Vitamin D and Vitamin D-Regulated T Cell Responses.

The active form of vitamin D (1,25(OH)D) has a great impact on T cell effector function. Thus, 1,25(OH)D promotes T helper 2 (Th2) and regulatory T (Treg) cell function and concomitantly inhibits Th1 and Th17 cell function. Thus, it is believed that vitamin D exerts anti-inflammatory effects.

Vitamin D Inhibits IL-22 Production Through a Repressive Vitamin D Response Element in the Promoter.

Th22 cells constitute a recently described CD4 T cell subset defined by its production of interleukin (IL)-22. The action of IL-22 is mainly restricted to epithelial cells. IL-22 enhances keratinocyte proliferation but inhibits their differentiation and maturation.

The role of interleukin-1β in the immune response to contact allergens.

Interleukin-1β (IL-1β) is an important pro-inflammatory cytokine that has an effect on almost every cell lineage in the body. By blocking IL-1β and investigating the IL-1β signaling pathway, several studies have demonstrated a central role of IL-1β in the response to contact allergens. This review summarizes the current literature regarding the basic immunological mechanisms mediated by IL-1β in the different phases of allergic contact dermatitis (ACD) and highlights potential IL-1β-targeted treatment options, which in the future may be relevant in the treatment of patients with ACD.