Atopic dermatitis (AD) is a chronic inflammatory skin condition that affects diverse ethnic groups with varying prevalence. Despite a predominance of studies in individuals of European ancestry, AD ...has been found to occur more frequently in Asian and Black individuals than Whites. Therefore, an understanding of the unique clinical features of AD in diverse ethnic groups, as well as the differences in genetic polymorphisms that influence susceptibility to AD and response to current therapies, is paramount for management of an increasingly diverse patient population. In this article, we review key nuances in the epidemiology, pathophysiology, clinical presentation and treatment of AD in non‐White ethnic groups, which are largely underappreciated in the literature. We highlight the need for studies evaluating the tissue molecular and cellular phenotypes of AD in non‐White patients, as well as greater inclusion of minority groups in clinical trials, to develop targeted treatments for a multi‐ethnic population.
Type 2 immunity in the skin and lungs Akdis, Cezmi A.; Arkwright, Peter D.; Brüggen, Marie-Charlotte ...
Allergy (Copenhagen),
July 2020, Letnik:
75, Številka:
7
Journal Article
Recenzirano
Odprti dostop
There has been extensive progress in understanding the cellular and molecular mechanisms of inflammation and immune regulation in allergic diseases of the skin and lungs during the last few years. ...Asthma and atopic dermatitis (AD) are typical diseases of type 2 immune responses. interleukin (IL)‐25, IL‐33, and thymic stromal lymphopoietin are essential cytokines of epithelial cells that are activated by allergens, pollutants, viruses, bacteria, and toxins that derive type 2 responses. Th2 cells and innate lymphoid cells (ILC) produce and secrete type 2 cytokines such as IL‐4, IL‐5, IL‐9, and IL‐13. IL‐4 and IL‐13 activate B cells to class‐switch to IgE and also play a role in T‐cell and eosinophil migration to allergic inflammatory tissues. IL‐13 contributes to maturation, activation, nitric oxide production and differentiation of epithelia, production of mucus as well as smooth muscle contraction, and extracellular matrix generation. IL‐4 and IL‐13 open tight junction barrier and cause barrier leakiness in the skin and lungs. IL‐5 acts on activation, recruitment, and survival of eosinophils. IL‐9 contributes to general allergic phenotype by enhancing all of the aspects, such as IgE and eosinophilia. Type 2 ILC contribute to inflammation in AD and asthma by enhancing the activity of Th2 cells, eosinophils, and their cytokines. Currently, five biologics are licensed to suppress type 2 inflammation via IgE, IL‐5 and its receptor, and IL‐4 receptor alpha. Some patients with severe atopic disease have little evidence of type 2 hyperactivity and do not respond to biologics which target this pathway. Studies in responder and nonresponder patients demonstrate the complexity of these diseases. In addition, primary immune deficiency diseases related to T‐cell maturation, regulatory T‐cell development, and T‐cell signaling, such as Omenn syndrome, severe combined immune deficiencies, immunodysregulation, polyendocrinopathy, enteropathy, X‐linked syndrome, and DOCK8, STAT3, and CARD11 deficiencies, help in our understanding of the importance and redundancy of various type 2 immune components. The present review aims to highlight recent advances in type 2 immunity and discuss the cellular sources, targets, and roles of type 2 mechanisms in asthma and AD.
Atopic dermatitis (AD) and psoriasis are inflammatory skin diseases that negatively affect patients’ quality of life. Although distinctions exist between these diseases, both are characterized by ...erythematous, thickened epidermal lesions that vary in intensity and affected body surface area. Early models of aetiology attributed symptoms of both diseases to cutaneous inflammation at lesion sites, but recent studies have established that activated immune mediators in the circulation drive disease severity. Activation of T helper 2 (Th2) and Th22 cells in the circulation appears to be the principal initiator of acute AD pathology, with the emergence of Th1 and Th17/interleukin (IL)‐23 pathway activation marking the transition to a chronic state. The Th17/IL‐23 pathway also has an important role in psoriasis. The role of systemic inflammation in AD and psoriasis is supported by the occurrence of non‐cutaneous comorbidities that affect patients, most of which intensify morbidity and disability associated with lesional skin. Atopic dermatitis is associated with allergic disorders consisting of the “atopic march,” whereas psoriasis is frequently accompanied by psoriatic arthritis. Patients with both disorders are at significantly higher risk of obesity, metabolic disorders, and cardiovascular diseases, all of which feature inflammatory components in their pathology models. These insights have led to novel therapeutics aimed at addressing psoriasis by targeting tumor necrosis factor‐ and Th17‐related cytokine pathways. The success of these agents in psoriasis management is driving new therapeutic approaches for moderate‐to‐severe AD, including agents targeting the Th2 and Th17/Th22 cytokine pathways.
Atopic dermatitis (AD) is a chronic, systemic, inflammatory disease that affects the skin and is characterized by persistent itch and marked redness. AD is associated with an increased risk of skin ...infections and a reduced quality of life. Most AD treatment options to date were not designed to selectively target disease‐causing pathways that have been established for this indication. Topical therapies have limited efficacy in moderate‐to‐severe disease, and systemic agents such as corticosteroids and immunosuppressants present with tolerability issues. Advances in the understanding of AD pathobiology have made possible a new generation of more disease‐specific AD therapies. AD is characterized by the inappropriate activation of type 2 T helper (Th2) cells and type 2 innate lymphoid (ILC2) cells, with a predominant increase in type 2 cytokines in the skin, including interleukin (IL)‐13 and IL‐4. Both cytokines are implicated in tissue inflammation and epidermal barrier dysfunction, and monoclonal antibodies targeting each of these interleukins or their receptors are in clinical development in AD. In March 2017, dupilumab, a human anti–IL‐4Rα antibody, became the first biologic to receive approval in the United States for the treatment of moderate‐to‐severe AD. The anti–IL‐13 monoclonal antibodies lebrikizumab and tralokinumab, which bind different IL‐13 epitopes with potentially different effects, are currently in advanced‐stage trials. Here, we briefly review the underlying pathobiology of AD, the scientific basis for current AD targets, and summarize current clinical studies of these agents, including new research to develop both predictive and response biomarkers to further advance AD therapy in the era of precision medicine.
Atopic dermatitis (AD) is the most common chronic inflammatory skin disease. It often precedes the development of food allergy and asthma. Recent insights into AD reveal abnormalities in terminal ...differentiation of the epidermal epithelium leading to a defective stratum corneum, which allows enhanced allergen penetration and systemic IgE sensitization. Atopic skin is also predisposed to colonization or infection by pathogenic microbes, most notably Staphylococcus aureus and herpes simplex virus. Causes of this abnormal skin barrier are complex and driven by a combination of genetic, environmental, and immunologic factors. These factors likely account for the heterogeneity of AD onset and the severity and natural history of this skin disease. Recent studies suggest prevention of AD can be achieved through early interventions to protect the skin barrier. Onset of lesional AD requires effective control of local and systemic immune activation for optimal management. Early intervention might improve long-term outcomes for AD and reduce the systemic allergen sensitization that leads to associated allergic diseases in the gastrointestinal and respiratory tract.
The underlying mechanism of seborrheic dermatitis (SD) is poorly understood but major scientific progress has been made in recent years related to microbiology, immunology and genetics. In light of ...this, the major goal of this article was to summarize the most recent articles on SD, specifically related to underlying pathophysiology. SD results from Malassezia hydrolysation of free fatty acids with activation of the immune system by the way of pattern recognition receptors, inflammasome, IL‐1β and NF‐kB. M. restricta and M. globosa are likely the most virulent subspecies, producing large quantities of irritating oleic acids, leading to IL‐8 and IL‐17 activation. IL‐17 and IL‐4 might play a big role in pathogenesis, but this needs to be further studied using novel biologics. No clear genetic predisposition has been established; however, recent studies implicated certain increased‐risk human leucocyte antigen (HLA) alleles, such as A*32, DQB1*05 and DRB1*01 as well as possible associations with psoriasis and atopic dermatitis (AD) through the LCE3 gene cluster while SD, and SD‐like syndromes, shares genetic mutations that appear to impair the ability of the immune system to restrict Malassezia growth, partially due to complement system dysfunction. A paucity of studies exists looking at the relationship between SD and systemic disease. In HIV, SD is thought to be secondary to a combination of immune dysregulation and disruption in skin microbiota with unhindered Malassezia proliferation. In Parkinson's disease, SD is most likely secondary to parasympathetic hyperactivity with increased sebum production as well as facial immobility which leads to sebum accumulation.
•Psoriasis and AD are diseases of distinct T-cell ‘polar’ subsets.•Targeting Th17/IL-17 is an extremely effective treatment for psoriasis.•Targeting Th2/IL-4 & IL-13 is a highly effective treatment ...for atopic dermatitis.•However, specific sub-types of atopic dermatitis blend Th17 and Th2 cytokine axes.•Optimal treatment of AD across subtypes might require targeting multiple cytokines.
Psoriasis and atopic dermatitis (AD) are common T-cell mediated inflammatory diseases of the skin that can be treated by specific cytokine antagonists or more broad immunosuppressive drugs. The diseases are similar in that epidermal keratinocytes respond to T-cell derived cytokines by altering growth and differentiation responses, accounting for major parts of the overall disease phenotype. When studied across European-American populations, psoriasis and AD display differing T-cell polarity and different arrays of cytokines. Psoriasis is a disease largely driven by Th17 T-cells and associated IL-17 activation, while AD has a strong Th2 component associated with IL-4 and IL-13 over-production, and both diseases have activation of Th22 T-cells and Th1 pathways with increased IL-22 and IFNγ production, respectively. AD is a disease frequently associated with increased IgE production and overt allergies or asthma, most likely due to increased Th2 activation, which is largely lacking in psoriasis. Hence, psoriasis and AD can be viewed as distinct diseases with differing clinical, tissue, and molecular disease phenotypes, but this view does not account for specific subtypes of AD, including Asian-origin, intrinsic, and pediatric AD, that have a prominent IL-17 component and also tissue patterning that overlaps with distinctive psoriasis histopathology. Hence, when considering the range of AD phenotypes, a case can be made that psoriasis and AD exist across a spectrum where polar T-cell axes can be variably present and create some overlapping disease characteristics. Today, ∼90% of psoriasis patients have extremely controlled disease by targeting the IL-23/Th17 T-cell axis with IL-23 or IL-17-targeting antibodies. An outstanding question is whether targeting a single cytokine axis in AD, for example, Th2 axis, will lead to disease suppression in the majority of patients and across all subtypes, including those with higher IL-17 expression, or whether it is necessary to personalize therapies and target multiple T-cell axes to attain similar disease improvement to psoriasis.
Dupilumab, a human monoclonal antibody against interleukin-4 receptor alpha, inhibits signaling of interleukin-4 and interleukin-13, type 2 cytokines that may be important drivers of atopic or ...allergic diseases such as atopic dermatitis.
In two randomized, placebo-controlled, phase 3 trials of identical design (SOLO 1 and SOLO 2), we enrolled adults with moderate-to-severe atopic dermatitis whose disease was inadequately controlled by topical treatment. Patients were randomly assigned in a 1:1:1 ratio to receive, for 16 weeks, subcutaneous dupilumab (300 mg) or placebo weekly or the same dose of dupilumab every other week alternating with placebo. The primary outcome was the proportion of patients who had both a score of 0 or 1 (clear or almost clear) on the Investigator's Global Assessment and a reduction of 2 points or more in that score from baseline at week 16.
We enrolled 671 patients in SOLO 1 and 708 in SOLO 2. In SOLO 1, the primary outcome occurred in 85 patients (38%) who received dupilumab every other week and in 83 (37%) who received dupilumab weekly, as compared with 23 (10%) who received placebo (P<0.001 for both comparisons with placebo). The results were similar in SOLO 2, with the primary outcome occurring in 84 patients (36%) who received dupilumab every other week and in 87 (36%) who received dupilumab weekly, as compared with 20 (8%) who received placebo (P<0.001 for both comparisons). In addition, in the two trials, an improvement from baseline to week 16 of at least 75% on the Eczema Area and Severity Index was reported in significantly more patients who received each regimen of dupilumab than in patients who received placebo (P<0.001 for all comparisons). Dupilumab was also associated with improvement in other clinical end points, including reduction in pruritus and symptoms of anxiety or depression and improvement in quality of life. Injection-site reactions and conjunctivitis were more frequent in the dupilumab groups than in the placebo groups.
In two phase 3 trials of identical design involving patients with atopic dermatitis, dupilumab improved the signs and symptoms of atopic dermatitis, including pruritus, symptoms of anxiety and depression, and quality of life, as compared with placebo. Trials of longer duration are needed to assess the long-term effectiveness and safety of dupilumab. (Funded by Sanofi and Regeneron Pharmaceuticals; SOLO 1 ClinicalTrials.gov number, NCT02277743 ; SOLO 2 ClinicalTrials.gov number, NCT02277769 .).
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