Anti-immunoglobulin E in the treatment of refractory atopic dermatitis

Regulation of Trafficking and Signaling of the High Affinity IgE Receptor by FcεRIβ and the Potential Impact of FcεRIβ Splicing in Allergic Inflammation

Mast cells are tissue-resident immune cells that function in both innate and adaptive immunity through the release of both preformed granule-stored mediators, and newly generated proinflammatory mediators that contribute to the generation of both the early and late phases of the allergic inflammatory response. Although mast cells can be activated by a vast array of mediators to contribute to homeostasis and pathophysiology in diverse settings and contexts, in this review, we will focus on the canonical setting of IgE-mediated activation and allergic inflammation. IgE-dependent activation of mast cells occurs through the high affinity IgE receptor, FcεRI, which is a multimeric receptor complex that, once crosslinked by antigen, triggers a cascade of signaling to generate a robust response in mast cells. Here, we discuss FcεRI structure and function, and describe established and emerging roles of the β subunit of FcεRI (FcεRIβ) in regulating mast cell function and FcεRI trafficking and signaling. We discuss current approaches to target IgE and FcεRI signaling and emerging approaches that could target FcεRIβ specifically. We examine how alternative splicing of FcεRIβ alters protein function and how manipulation of splicing could be employed as a therapeutic approach. Targeting FcεRI directly and/or IgE binding to FcεRI are promising approaches to therapeutics for allergic inflammation. The characteristic role of FcεRIβ in both trafficking and signaling of the FcεRI receptor complex, the specificity to IgE-mediated activation pathways, and the preferential expression in mast cells and basophils, makes FcεRIβ an excellent, but challenging, candidate for therapeutic strategies in allergy and asthma, if targeting can be realized.

Novel Targeted Biological Agents for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a common inflammatory dermatologic disease clinically characterized by intense itch, recurrent eczematous lesions, and a chronic or relapsing disease course. Mild-to-moderate AD can be controlled by using moisturizers and topical immunomodulators such as topical corticosteroids and calcineurin inhibitors. If topical therapies fail, phototherapy and systemic immunosuppressant therapies, such as ciclosporin, methotrexate, and azathioprine, can be considered. However, relapse and side effects could still occur. The pathogenesis of AD involves epidermal barrier dysfunction, skin microbiome abnormalities, and cutaneous inflammation. Inflammatory mediators, such as interleukin (IL)-4, IL-13, IL-31, IL-33, IL-17, IL-23, and thymic stromal lymphopoietin, are involved in AD development. Therefore, a series of biological agents targeting these cytokines are promising approaches for treating AD. Dupilumab is the first biological agent approved for the treatment of AD in patients aged 6 years and older in the United States. Tralokinumab, lebrikizumab, and nemolizumab have also been confirmed to have significant efficacy against AD in phase III or IIb clinical trials. Also, fezakinumab was effective in severe AD patients in a phase IIa trial. However, phase II trials of ustekinumab, tezepelumab, etokimab, secukinumab, and omalizumab have failed to meet their primary endpoints. Phase II trials of GBR 830 and KHK 4083 are ongoing. In general, further studies are needed to explore new therapeutic targets and improve the efficacy of biological agents.

Targeting immunoglobulin E in atopic dermatitis: A review of the existing evidence

Immunoglobulin E (IgE) plays an essential role in many allergic diseases. This review highlights the role of IgE in atopic dermatitis (AD), a common, chronic, and complex skin inflammation, and the available therapeutic approaches that target IgE in AD. We examine the existing data showing the use of omalizumab, the only biologic anti-IgE therapy available in clinical use, plasma apheresis, and a combination of both therapeutic approaches for the treatment of AD. Existing data on the efficacy of omalizumab in AD are inconclusive. A limited number of randomised controlled studies, few uncontrolled prospective and retrospective reports, as well as multiple case series and case reports observed varying degrees of the efficacy of omalizumab in AD. Omalizumab displays a trend of higher efficacy in AD patients with low IgE levels compared with those with very high-to-extremely high serum IgE concentrations. Plasma apheresis and its combination with omalizumab show good efficacy, even in patients with unusually high serum IgE concentrations. Combining apheresis and anti-IgE treatment may serve as a comprehensive therapeutic approach for patients with elevated levels of IgE. Dedicated clinical studies with robust study designs are needed to establish the therapeutic efficacy of omalizumab in AD.

IgE-mediated regulation of IL-10 and type I IFN enhances rhinovirus-induced Th2 differentiation by primary human monocytes

Rhinovirus (RV) infections are linked to the development and exacerbation of allergic diseases including allergic asthma. IgE, another contributor to atopic disease pathogenesis, has been shown to regulate DC antiviral functions and influence T cell priming by monocytes. We previously demonstrated that IgE-mediated stimulation of monocytes alters multiple cellular functions including cytokine secretion, phagocytosis, and influenza-induced Th1 development. In this study, we investigate the effects of IgE-mediated stimulation on monocyte-driven, RV-induced T cell development utilizing primary human monocyte-T cell co-cultures. We demonstrate that IgE crosslinking of RV-exposed monocytes enhances monocyte-driven Th2 differentiation. This increase in RV-induced Th2 development was regulated by IgE-mediated inhibition of virus-induced type I IFN and induction of IL-10. These findings suggest an additional mechanism by which two clinically significant risk factors for allergic disease exacerbations-IgE-mediated stimulation and rhinovirus infection-may synergistically promote Th2 differentiation and allergic inflammation.

Immunotherapy and Oral Immunotherapy with Omalizumab for Food Allergies

Food allergy is potentially life-threatening and has a major impact on quality of life. Avoidance is currently the only approved therapy, and, although effective, avoidance diets can be difficult and may also put children at risk of nutritional deficiencies and impaired growth. At least 80% of milk and egg-allergic children are expected to achieve natural tolerance to these foods by adulthood, and 15–20% of peanut or tree nut-allergic individuals ‘outgrow’ their allergies. Effective therapies for food allergies are therefore highly desirable. There have been several immunotherapies for food allergy such as oral immunotherapy (OIT), sublingual immunotherapy (SLIT), epicutaneous immunotherapy (EPIT), and OIT combined with anti-IgE monoclonal antibodies (omalizumab [OMB]). However, efficacy and safety have only been demonstrated in one large Phase III trial for peanut allergies. Additionally, there have only been three randomised, controlled studies of OMB–OIT combination and these were low-powered, single-centre trials; therefore, evidence levels were low in these trials. Studies that included long-term follow-up observations and clinical tolerance are rare. Additionally, clinical tolerance is not well-defined and remains unknown. Therefore, several problems remain to be resolved, but hopefully OIT in combination with OMB will resolve these problems in the future. Although there are only three randomised, controlled trials of OMB–OIT, the combination therapy enabled high dose desensitisation for a short duration without any adverse events, resulting in the sustained unresponsiveness in IgE-related food allergy. It is speculated that this combination therapy will be the most effective immunotherapy in the future.

Current Strategies to Inhibit High Affinity FcεRI-Mediated Signaling for the Treatment of Allergic Disease

Allergies and asthma are a major cause of chronic disease whose prevalence has been on the rise. Allergic disease including seasonal rhinitis, atopic dermatitis, urticaria, anaphylaxis, and asthma, are associated with activation of tissue-resident mast cells and circulating basophils. Although these cells can be activated in different ways, allergic reactions are normally associated with the crosslinking of the high affinity Fc receptor for Immunoglobulin E, FcεRI, with multivalent antigen. Inflammatory mediators released from cytoplasmic granules, or biosynthesized de novo, following FcεRI crosslinking induce immediate hypersensitivity reactions, including life-threatening anaphylaxis, and contribute to prolonged inflammation leading to chronic diseases like asthma. Thus, inappropriate or unregulated activation of mast cells and basophils through antigenic crosslinking of FcεRI can have deleterious, sometimes deadly, consequences. Accordingly, FcεRI has emerged as a viable target for the development of biologics that act to inhibit or attenuate the activation of mast cells and basophils. At the forefront of these strategies are (1) Anti-IgE monoclonal antibody, namely omalizumab, which has the secondary effect of reducing FcεRI surface expression, (2) Designed Ankyrin Repeat Proteins (DARPins), which take advantage of the most common structural motifs in nature involved in protein-protein interactions, to inhibit FcεRI-IgE interactions, and (3) Fusion proteins to co-aggregate FcεRI with the inhibitory FcγRIIb. This review presents the published research studies that support omalizumab, DARPins, and fusion proteins as, arguably, the three most currently viable strategies for inhibiting the expression and activation of the high affinity FcεRI on mast cells and basophils.

Omalizumab for atopic dermatitis: evidence for and against its use

INTRODUCTION

Omalizumab, has been used for almost two decades, mainly in allergic asthma and chronic spontaneous urticaria for which it is highly beneficial. Smaller studies have evaluated the effects of omalizumab in atopic dermatitis (AD). Current treatments options, such as cyclosporine and azathioprine have limited effect on AD and numerous side effects. The recently introduced biologic dupilumab (anti-IL4) shows promising results, however with conjunctivitis as a prevalent side effect. We evaluate the current evidence for the use of omalizumab in AD.

EVIDENCE ACQUISITION

Systematic literature searches were performed in PubMed, Web of Science, Embase and Clinicaltrials.gov to identify any study (case reports, case series, and controlled trials) evaluating the effect of treatment with omalizumab in AD.

EVIDENCE SYNTHESIS

Thirty-four studies (12 single case studies, 15 case series, 5 prospective studies and 2 small pilot randomized placebo-controlled trials [RCTs]), including a total of 214 patients with median of 3, ranging from 1-35 patients were identified. A total of 169 patients (79.0%) experienced a beneficial effect from treatment, ranging from little to complete response, whereas 45 patients (21.0%) reported no or negative effect from omalizumab treatment.

CONCLUSIONS

Omalizumab is a safe and well-tolerated treatment with some clinical benefit in AD patients. However, the lack of larger RCTs and possible publication bias limit the recommendation of omalizumab for use in clinical practice for AD. Newer and more effective treatments exist and should be prioritized.

Biological therapies for atopic dermatitis: An update

Severe atopic dermatitis, which affects both adults and children, is a debilitating disorder with a significant decline of patients' quality of life. Although aetiopathogenic factors are currently a topic of study and interpretation, the main features of atopic eczema are skin barrier disturbance and immune dysregulation. Severe refractory disease that fails to improve with conventional therapy may benefit from biologic therapy. Progress in understanding immunopathology of atopic dermatitis have allowed identification of therapeutic molecular targets in the field of biological therapy. We reviewed the different biological treatments with a focus on novel targeted agents: Systemic immunotherapy (Omalizumab, Dupilumab, Lebrikizumab, Tralokinumab, Nemolizumab, Ustekinumab, Fezakinumab, Tezepelumab, Apremilast, allergen specific immunotherapy), and topical agents (Tofacitinib, Crisaborole).

Testing biologics and intracellular signaling inhibitors on pediatric atopic dermatitis: a stairway to modern therapeutic approaches

INTRODUCTION

Atopic dermatitis (AD) is the most common cutaneous inflammatory disease in adults and children. In the last few years, the pathogenesis of AD has been profoundly revised, and this has led to the identification of novel druggable targets and the development of new agents targeting specific molecular pathways. Despite the high prevalence of AD in the pediatric population, the clinical development of new treatments, either topical or systemic, has been focused on the adult population in recent years; only a limited number of these new agents have been tested in pediatric cohorts.

AREAS COVERED

In this review, we describe the pathogenic model of pediatric AD which shows similarities and substantial differences when compared to adult AD. The identification of therapeutic targets is highlighted, and novel targeted therapies, both topical and systemic, are discussed.

EXPERT OPINION

The current therapeutic armamentarium for pediatric AD is very limited, and this represents a critical unmet need. The enhancement of clinical research on pediatric patients is necessary to facilitate an increase in the number of new targeted therapeutic options being available on the market.

Systemic Treatment for Severe Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory, relapsing disease of the skin, characterized by intense pruritus, maculopapular or vesicular erythematous lesions and scaling, sometimes accompanied by oozing, crusts and/or lichenification that has a negative impact on patients' quality of life. Prevalence is higher in children, around 15%, and approximately 5% in adults. Before introducing systemic therapy, it is mandatory to review patients' adherence to the correct use of topical treatments (corticosteroids, calcineurin inhibitors or cresoborole) and/or phototherapy. Ensure that environmental measures are being taken care of, irritant or proven allergic substances are not in use and even if the diagnostic is correct. If all is being done and topical treatment with corticosteroid, emollients and phototherapy have not been sufficient to achieve a good control in AD of adults or children patients, it is time to consider systemic agents. Up to now, most of systemic treatments were based on immunosuppressive therapies, being cyclosporine A, the usually first choice for moderate-to-severe AD. Recently, biologic drugs have been developed and approved for AD, as dupilumab, and a whole new group of drugs is giving much hope for patients to have a better control of the disease with less side effects.

The effect of omalizumab treatment on severe allergic asthma and allergic comorbidities: real-life experience from the Czech Anti-IgE Registry

Introduction

Omalizumab is indicated for the treatment of severe allergic asthma (SAA) and chronic spontaneous urticaria, although a number of studies have confirmed the effectiveness of this therapy also for other IgE-mediated diseases.

Aim

To assess the impact of anti-IgE therapy on SAA and comorbid IgE-mediated allergic diseases in patients treated with omalizumab for SAA enrolled in the CAR (Czech Anti-IgE Registry).

Material and methods

Three hundred and ten patients with SAA treated with omalizumab were enrolled in the CAR. Two hundred and twenty-nine individuals were evaluated after 12 months of omalizumab treatment for asthma control test (ACT), examination of fractional exhaled nitric oxide (FENO), forced expiratory volume in 1 s (FEV₁), the use of systemic corticosteroids, side effects of treatment and clinical effect of omalizumab on allergic comorbidities (allergic rhinitis, chronic urticaria, atopic dermatitis and food allergy).

Results

After 12 months of treatment with omalizumab, patients experienced a significant improvement of ACT and FEV₁, reduction of FENO, use of systemic corticosteroids for asthma exacerbations and dose of maintenance oral corticosteroid therapy. The positive effect of treatment with omalizumab was observed in 82.2% of patients with allergic rhinitis, in 85.7% of patients with chronic urticaria, in 82.1% of patients with atopic dermatitis, and in 67.3% of patients with food allergy.

Conclusions

In the CAR registry, patients with SAA treated with omalizumab showed a significant positive effect of anti-IgE therapy not only on the asthma control, but also on allergic comorbidities.

Changing perspectives in atopic dermatitis

Atopic dermatitis (AD) is a multifaceted disease that involves a complex interplay between the skin and the immune system. The course of the disease depends strongly on the genetic background of the patient and on yet poorly-defined environmental factors. Changes in lifestyle could be behind the dramatic rise in the prevalence of AD across continents; including hygienic conditions, food, social habits, skin microbiome or exposure to a number of allergens. Although AD typically develops in childhood and disappears after a few years, in a relatively large number of patients it continues into adulthood. Adult AD can also appear de novo but it is often underdiagnosed and its treatment can be challenging. New, highly effective drugs are being developed to manage moderate and severe forms of the disease in adults. In this review, we highlight the most recent developments in diagnostic tools, current insights into the mechanistic basis of this disease, and therapeutic innovations.

Are Biologics Efficacious in Atopic Dermatitis? A Systematic Review and Meta-Analysis

BACKGROUND

Current systemic treatments for atopic dermatitis (AD) offer limited efficacy and are often restricted by safety concerns. Biologics may address the unmet need for improved AD therapeutics.

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of biologic agents in AD.

METHODS

A systematic review and meta-analysis of studies evaluating AD patients treated with biologics was performed. The primary outcome was the Eczema Area and Severity Index (EASI)-75 response, while secondary outcomes were SCOring Atopic Dermatitis (SCORAD)-75, EASI-50, SCORAD-50, Investigator Global Assessment 0/1 responses, change in responses from baseline, and adverse events.

RESULTS

We included 13 randomized controlled trials (RCTs) and 10 observational studies evaluating nine biologics. High-quality evidence was available for dupilumab, nemolizumab and ustekinumab. Pooling five studies, at weeks 12-16 dupilumab 300 mg every week to every 2 weeks achieved EASI-75 responses of 55%, superior to placebo [relative risk (RR) 3.3, 95% confidence interval (CI) 2.9-3.6]. Nemolizumab had similar EASI-75 responses as placebo, but significantly improved pruritus. In online reports, lebrikizumab demonstrated superior EASI-50 responses versus placebo (RR 1.3, 95% CI 1.04-1.7), while tralokinumab had superior SCORAD-50 responses versus placebo, with borderline significance (RR 1.7, 95% CI 0.97-3.1). In two RCTs each, omalizumab and ustekinumab were comparable with placebo, while antithymic stromal lymphopoietin receptor, infliximab, and rituximab lacked adequate evidence of efficacy. All medications had a comparable safety profile to placebo.

LIMITATIONS

Lack of RCTs and the use of variable outcome measures limited conclusions.

CONCLUSION

Dupilumab is currently the only biologic with robust evidence of efficacy in AD. Nemolizumab, lebrikizumab, and tralokinumab show promise but further data are needed. Longer follow-up and larger studies will establish their safety profile.

New and emerging targeted systemic therapies: a new era for atopic dermatitis

PURPOSE

This is a review of emerging targeted, systemic therapies for atopic dermatitis (AD). The information presented aims to provide dermatologists with updated therapeutic options, stimulate academic interest, and spark future research.

MATERIAL AND METHODS

Extensive search of ClinicalTrials.gov, the National Eczema Association, and PubMed was performed for clinical trials examining the effect of emerging targeted, systemic therapies in patients with AD. Results were included if they demonstrated efficacy in reversing AD symptoms. Studies that did not demonstrate clinical benefit were excluded.

RESULTS

A number of emerging systemic agents targeting specific mediators involved in the pathogenesis of AD were found. These targets include IL-4, IL-13, IgE, B-cells, IL-5, IL-31, JAK-STAT, SYK, IL-6, PDE-4, IL-12, IL-17, IL-23, IL-22, H4R, NKR1, κOR, TSLP, PPAR-γ, and DGLA. Treatment of AD patients with these therapies has, in many cases, led to statistically significant improvements in clinical severity scores and patient-reported outcomes.

CONCLUSIONS

While multiple agents have demonstrated efficacy, only dupilumab is currently approved for adults with AD. Large-scale, randomized, placebo-controlled, double-blind trials, especially in children, are needed. As we enter the dawn of targeted therapy for AD, a comprehensive clinical trial registry is needed to facilitate data pooling and comparison among international registries.

Novel Therapeutic Approaches to Atopic Dermatitis

Atopic dermatitis (AD) is one of the most common inflammatory skin diseases. The number of people affected by AD is relatively high and seems to be rising. Although mild and moderate forms of the disease can be well controlled by the use of emollients, topical corticosteroids, and topical calcineurin inhibitors, treatment of severe is still a huge challenge. The new hope is biologic drugs, magic bullets in allergy, targeted at different points of the complex pathomechanism of inflammation in AD. In this review, novel biologic therapies are discussed, including recombinant monoclonal antibodies directed against various interleukin pathways (such as IL-4, IL-13, TSLP, IL-31, and IL-12/23), on immunoglobulin E, molecules acting as T cells, B cells, etc. Of biological drugs, the most promising seems to be anti-IL-4/IL-13 therapy (dupilumab-the biological agent) and phosphodiesterase-4 inhibitor (crisaborole-a small molecule). A deep understanding of the AD pathomechanism provides a new perspective for tailor-made treatment of severe atopic dermatitis.

Effects of Allergic Sensitization on Antiviral Immunity: Allergen, Virus, and Host Cell Mechanisms

PURPOSE OF REVIEW

Multiple clinical and epidemiological studies demonstrate links between allergic sensitization and virus-induced atopic disease exacerbations. This review summarizes the recent findings regarding allergen, viral, and host cellular mechanisms relevant to these observations.

RECENT FINDINGS

Recent studies have focused on the molecular pathways and genetic influences involved in allergen-mediated inhibition of innate antiviral immune responses. Multiple tissue and cell types from atopic individuals across the atopy spectrum exhibit deficient interferon responses to a variety of virus infections. Impairment in barrier function, viral RNA and DNA recognition by intracellular sensing molecules, and dysregulation of signaling components are broadly affected by allergic sensitization. Finally, genetic predisposition by numerous nucleotide polymorphisms also impacts immune pathways and potentially contributes to virus-associated atopic disease pathogenesis. Allergen-virus interactions in the setting of atopy involve complex tissue and cellular mechanisms. Future studies defining the pathways underlying these interactions could uncover potential therapeutic targets. Available data suggest that therapies tailored to restore specific components of antiviral responses will likely lead to improved clinical outcomes in allergic disease.

Systemic Treatment of Adult Atopic Dermatitis: A Review

Atopic dermatitis (AD) is a common chronic inflammatory skin disease that predominantly affects children. However, it can persist in adulthood and/or start at older ages. Due to its chronic nature and frequently occurring relapses, AD has a substantial effect on patients' quality of life, often requiring long-term systemic treatment, especially in adult patients, who are more frequently refractory to adequate topical treatment with mid- to high-potent corticosteroids and/or calcineurin inhibitors. Therefore, treatment with systemic therapies is often needed to take control of the disease, prevent exacerbations and improve quality of life. However, data regarding systemic treatment effectiveness and long-term safety in adult patients with AD are insufficient. Indeed, standardized international guidelines are lacking, and the treatment approach widely differs among diverse countries. This review focuses on the use of systemic treatments in adult AD patients analyzing published literature.

Treatment of Eczema: Corticosteroids and Beyond

Atopic dermatitis (AD) is a chronic inflammatory skin condition that requires a manifold approach to therapy. The goal of therapy is to restore the function of the epidermal barrier and to reduce skin inflammation. This can be achieved with skin moisturization and topical anti-inflammatory agents, such as topical corticosteroids and calcineurin inhibitors. Furthermore, proactive therapy with twice weekly use of both topical corticosteroids and calcineurin inhibitors in previously affected areas has been found to reduce the time to the next eczematous flare. Adjunctive treatment options include wet wrap therapy, anti-histamines, and vitamin D supplementation. Bacterial colonization, in particular Staphylococcus aureus, can contribute to eczematous flares and overt infection. Use of systemic antibiotics in infected lesions is warranted; however, empiric antibiotics use in uninfected lesions is controversial. Local antiseptic measures (i.e., bleach baths) and topical antimicrobial therapies can be considered in patients with high bacterial colonization. Difficult-to-treat AD is a complex clinical problem that may require re-evaluation of the initial diagnosis of AD, especially if the onset of disease occurs in adulthood. It may also necessitate evaluation for contact, food, and inhaled allergens that may exacerbate the underlying AD. There are a host of systemic therapies that have been successful in patients with difficult-to-treat AD, however, these agents are limited by their side effect profiles. Lastly, with further insight into the pathophysiology of AD, new biological agents have been investigated with promising results.

Off-Label Uses of Omalizumab

The off-label use of medicines is a common and extensive clinical practice. Omalizumab has been licensed for use in severe allergic asthma and chronic urticaria. Omalizumab dosing was based on body weight and baseline serum IgE concentration. All patients are required to have a baseline IgE between 30 and 700 IU/ml and body weight not more than 150 kg. The use of off-label drugs may lead to several problems including adverse effects and an increased risk/benefit balance. In this article, there are summarized off-label uses of omalizumab in the last recent years in diseases in which IgE maybe or certainly has a corner role such as allergic rhinitis, allergic bronchopulmonary aspergillosis, anaphylaxis, keratoconjunctivitis, food allergy, drug allergy, urticaria, angioedema, non-atopic asthma, atopic dermatitis, nasal polyps, Churg-Strauss syndrome, eosinophilic otitis media, chronic rhinosinusitis, bullous pemphigoid, contact dermatitis, and others. Use in pregnancy asthmatic women and pre-co-administration with specific immunotherapy will also be revised.

Immunologic Targets in Atopic Dermatitis and Emerging Therapies: An Update

Atopic dermatitis is one of the most common chronic inflammatory skin diseases. It usually begins in childhood, has a considerable impact on patients' quality of life, and incurs substantial healthcare costs. The standard-of-care treatments for patients with moderate to severe disease are very limited and have variable and typically insufficient efficacy and many side effects, some of which are quite serious. However, over the last decade, considerable advances in our understanding of the pathogenesis of atopic dermatitis have paved the way for a number of new treatments. Most notable are the drugs that target the Th2-polarized immune system, which is thought to play a key role in many of the signs and symptoms characteristic of this disease. In this article, we briefly review the pathophysiology of atopic dermatitis, while noting that each patient's disease phenotype is likely due to a unique interplay of several disease-specific dysregulated pathways. Lastly, we cover emerging therapies for atopic dermatitis, focusing on those that target specific components of the immune system, which are altered in atopic dermatitis. The hope is that these new biologics or small-molecule antagonists, which have high specificity for their target molecules, will decrease the undesirable side effects caused by off-target effects commonly observed with current immunosuppressive agents that are characterized by broad biological actions.

Systemic Agents for Severe Atopic Dermatitis in Children

Atopic dermatitis (AD), or eczema, is a chronic inflammatory skin condition characterized by relapsing pruritic, scaly, erythematous papules and plaques frequently associated with superinfection. The lifelong prevalence of AD is over 20 % in affluent countries. When a child with severe AD is not responding to optimized topical therapy including phototherapy, and relevant triggers cannot be identified or avoided, systemic therapy should be considered. If studies show early aggressive intervention can prevent one from advancing along the atopic march, and relevant triggers such as food allergies cannot be either identified or avoided, systemic therapy may also play a prophylactic role. Though the majority of evidence exists in adult populations, four systemic non-specific immunosuppressive or immunomodulatory drugs have demonstrated efficacy in AD and are used in most patients requiring this level of intervention regardless of age: cyclosporine, mycophenolate mofetil, methotrexate, and azathioprine. This article reviews the use of these medications as well as several promising targeted therapies currently in development including dupilumab and apremilast. We briefly cover several other systemic interventions that have been studied in children with atopic dermatitis.

Advances in understanding and managing atopic dermatitis

Atopic dermatitis is a chronic, pruritic skin disease characterized by an improperly functioning skin barrier and immune dysregulation. We review proposed atopic dermatitis pathomechanisms, emphasizing how these impact current perspectives on natural history, role of allergic sensitization, and future therapeutic targets.

Consensus Guidelines for the Treatment of Atopic Dermatitis in Korea (Part II): Systemic Treatment

BACKGROUND

Since the treatment guidelines for atopic dermatitis (AD) were issued by the Korean Atopic Dermatitis Association (KADA) work group in 2006, there have been further advances in the systemic treatment of AD.

OBJECTIVE

We aimed to establish updated evidence- and experience-based systemic treatment guidelines for Korean AD.

METHODS

We compiled a database of references from relevant systematic reviews and guidelines regarding the systemic management of AD, including antihistamines, antimicrobials, systemic immunomodulators, allergen-specific immunotherapy, phototherapy, adjunctive treatment, and complementary and alternative medicines. Evidence for each statement was graded and classified based on the strength of the recommendation. Thirty-nine council members of KADA participated in the three rounds of votes and expert consensus recommendations were established.

RESULTS

The use of antihistamines is recommended to relieve pruritus and to prevent exacerbation due to scratching in AD patients. Infection should be controlled as needed and long-term medication should be avoided. For moderate to severe AD patients, concomitant active treatments with systemic immunomodulators are indicated. Cyclosporine is the first choice among systemic immunomodulators and others should be considered as second-line alternatives. Allergen-specific immunotherapy could be effective in AD patients with aeroallergen hypersensitivity. Phototherapy can be useful for moderate to severe AD patients and narrow-band ultraviolet B is the most effective option. Complementary and alternative medicines cannot be recommended for treating AD.

CONCLUSION

We expect these recommendations to be a reference guide for physicians and AD patients in choosing the appropriate treatment to improve quality of life and decrease unnecessary social medical costs.

The use of biologicals in cutaneous allergies - present and future

PURPOSE OF REVIEW

Up-to-date biologicals in cutaneous allergies play - unfortunately - only a minor role. However, this situation might change. Recently, omalizumab was licensed for chronic urticaria; this article reviews recent advances in the use of biologicals in cutaneous allergies.

RECENT FINDINGS

Interestingly, the mechanism of omalizumab appears to be different in urticaria and allergic asthma for which the drug has been licensed previously. In urticaria dosage is not dependent on serum IgE-levels and response is seen very often after only 12 h. Other indications in cutaneous allergy in which biologicals have been investigated, at least in case reports or small studies, are TNF-α-antagonists and rituximab in chronic urticaria, omalizumab, rituximab and TNF-α-antagonists in atopic dermatitis as well as mepolizumab in this disease. However, all these studies appear to show a benefit for individual patients but not a clear breakthrough for the whole group of patients involved. This, however, might also be one of the future approaches that sub-groups of patients who have different responses to biologicals may be identified, as apparently different cytokine patterns are predominantly involved in the individual patient.

SUMMARY

In conclusion, although currently only one biological is approved in chronic urticaria, there is hope that a rapid better understanding of individual disease factors will support the development of other novel drugs in this field.

Asthma phenotypes and the use of biologic medications in asthma and allergic disease: the next steps toward personalized care

Traditionally, asthma and allergic diseases have been defined by broad definitions and treated with nonspecific medications, including corticosteroids and bronchodilators. There is an increasing appreciation of heterogeneity within asthma and allergic diseases based primarily on recent cluster analyses, molecular phenotyping, biomarkers, and differential responses to targeted and nontargeted therapies. These pioneering studies have led to successful therapeutic trials of molecularly targeted therapies in defined phenotypes. This review analyzed randomized double-blind, placebo-controlled trials of molecularly targeted therapies in defined allergic disease and asthma phenotypes. IgE was the first successful biological target used in patients with allergic disease and asthma. This review shows that therapies targeting the canonical type 2 cytokines IL-4, IL-5, and IL-13 have shown consistent efficacy, especially in asthmatic patients with evidence of TH2/type 2 inflammation ("type 2 high"). As of yet, there are no successful trials of targeted therapies in asthmatic patients without evidence for type 2 inflammation. We conclude that further refinement of type 2 therapies to specific type 2 phenotypes and novel approaches for patients without type 2 inflammation are needed for asthma and allergic disease treatment.

Biological Treatments in Atopic Dermatitis

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases that affect both children and adults with a prevalence of 30% and 10%, respectively. Even though most of patients respond satisfactory to topical anti-inflammatory drugs, about 10% require one or more systemic treatments to achieve good control of their illness. The progressive and increasingly detailed knowledge in the immunopathogenesis of AD has allowed research on new therapeutic targets with very promising results in the field of biological therapy. In this article, we will review the different biological treatments with a focus on novel drugs. Their mechanism of action, current status and results from clinical trials and observational studies will be specified.

The translational revolution and use of biologics in patients with inflammatory skin diseases

Psoriasis and atopic dermatitis (AD) are common inflammatory skin diseases characterized by immune-mediated inflammation and abnormal keratinocyte differentiation. Although T-cell infiltration characterizes both diseases, T-cell polarization differs. Psoriasis is currently the best model for translational medicine because many targeted therapeutics have been developed and testing of targeted therapeutics has cemented psoriasis as IL-23/TH17 polarized. In patients with AD, although therapeutic development is approximately a decade behind that in patients with psoriasis, there is now active development and testing of targeted therapeutics against various immune axes (TH2, TH22, and IL-23/TH17). These clinical trials and subsequent molecular analyses using human samples will be able to clarify the relative roles of polar cytokines in patients with AD.

Systemic therapy of childhood atopic dermatitis

Atopic dermatitis (AD) is a common childhood inflammatory disease that, in a small percentage of cases, can become severe enough to require potent systemic treatment. Many trials have been conducted with systemic agents for the treatment of severe pediatric AD; we review the evidence here. Although corticosteroids are widely used in practice, they are not generally recommended as a systemic treatment option for AD in children. Most patients experience a relatively rapid and robust response to cyclosporine. Treating children with cyclosporine long term is troubling; however, azathioprine, mycophenolate mofetil, and methotrexate are all reasonable alternatives for maintenance therapy in recalcitrant cases. Several additional options are available for the most refractory cases, including interferon-γ, intravenous immunoglobulin, and various biologics. Phototherapy is another modality that can be effective in treating severe AD. Ultimately the choice of agent is individualized. Systemic therapy options are associated with potentially severe adverse effects and require careful monitoring. Nonsystemic approaches toward prevention of flares and long-term control of atopic dermatitis in pediatric patients should be continued in conjunction with systemic therapy. In the future, more targeted systemic treatments hold the potential for effective control of disease with fewer side effects than broadly immunosuppressive agents.

Novel investigational therapies for atopic dermatitis

Introduction: Atopic dermatitis (AD) is a common skin disease. Although most patients are well served by existing therapies, a subset of patients with severe AD are still not adequately treated. An improved understanding of the pathogenic mechanisms behind the disease has led to the development of a range of potential new drugs for this indication. Areas covered: The authors provide a narrative review of the drugs in Phase II trials listed on Clinicaltrials.gov. The authors supplement this information with recently published literature located through PubMed. The main target of new treatments appears to be the inflammation process, whereas drugs aimed at reducing itching or increasing the barrier function are fewer to nonexistent. A wide range of drugs, including small molecules and antibodies, are being tested. Expert opinion: The focus on inflammation is not only driven by the limitations posed by our current understanding of biology, but also by the broader scope of these drugs, which may be used in other diseases. In alignment with the recent drug development of other dermatological diseases, antibodies directed at key molecules in the pathogenesis of AD appear to be the most promising.

Elevated serum IgE against MGL_1304 in patients with atopic dermatitis and cholinergic urticaria

BACKGROUND

MGL_1304 secreted by Malassezia globosa is contained in human sweat and induces histamine release from basophils in patients with atopic dermatitis (AD) at a high positive rate. The aims of this study were to establish the enzyme-linked immunosorbent assay (ELISA) measuring specific immunoglobulins against MGL_1304 and to investigate the levels of these immunoglobulins in sera of patients with various allergic diseases.

METHODS

Purified MGL_1304 from human sweat (QRX) and recombinant MGL_1304 (rMGL_1304) were prepared for ELISA. To quantify the amount of MGL_1304-specific immunoglobulins, the standard serum was created by pooling sera of 20 patients with AD whose basophils released histamine in response to QRX. A monoclonal antibody which exhibited the highest neutralizing ability against QRX was established as Smith-2, and used as a capture antibody for the assay of QRX-specific IgE. A total of 156 subjects [normal controls (n = 23), AD (n = 63), cholinergic urticaria (CU) (n = 24), bronchial asthma (n = 32), and allergic rhinitis (n = 14)] were enrolled in this study.

RESULTS

ELISA methods to quantify the specific IgE, IgG and IgG4 against MGL_1304 in sera were successfully established. Levels of QRX-specific IgE in sera of patients with AD and CU were significantly higher than those of normal controls. Moreover, the levels of QRX-specific IgE and rMGL_1304-specific IgE in patients with AD were significantly correlated with their disease severities.

CONCLUSIONS

These ELISA methods to quantify the specific immunoglobulins against MGL_1304 are easy and useful means to assess allergy to MGL_1304. MGL_1304 contained in sweat is an important antigen for patients with AD and CU.

Retrospective analysis of the efficacy of omalizumab in chronic refractory urticaria

Omalizumab has been shown to be effective in chronic urticaria (CU) patients in numerous reports. However, it remains unknown whether there are specific phenotypes of CU that are more responsive to omalizumab therapy. We sought to identify CU phenotypes responsive to treatment with omalizumab by characterizing patients and their response patterns. A retrospective chart review analysis of refractory CU patients unresponsive to high-dose H1-blockers and immunomodulators and subsequently treated with omalizumab at the University of Wisconsin Allergy Clinic was performed with particular focus on their autoimmune characteristics, response to therapy, and dosing parameters. We analyzed 19 refractory CU patients (16 patients failed or had toxic side effects to immunomodulators) treated with omalizumab with an overall response rate of 89% (17/19). Of these 19 patients, 9 patients (47%) had a complete response, 8 patients (42%) had a partial response, and 2 patients (11%) had no response. In comparing the response patterns to omalizumab, we found no statistically significant differences among "autoimmune positive" versus "autoimmune negative" patients. No statistically significant differences in responses were observed when comparing demographic parameters including age, gender, IgE levels, or dosing regimen. Our study shows that omalizumab has robust efficacy in refractory CU patients regardless of their autoimmune status, age, gender, IgE levels, or dosing protocol.

Intrinsic atopic dermatitis shows similar TH2 and higher TH17 immune activation compared with extrinsic atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is classified as extrinsic and intrinsic, representing approximately 80% and 20% of patients with the disease, respectively. Although sharing a similar clinical phenotype, only extrinsic AD is characterized by high serum IgE levels. Because most patients with AD exhibit high IgE levels, an "allergic"/IgE-mediated disease pathogenesis was hypothesized. However, current models associate AD with T-cell activation, particularly TH2/TH22 polarization, and epidermal barrier defects.

OBJECTIVE

We sought to define whether both variants share a common pathogenesis.

METHODS

We stratified 51 patients with severe AD into extrinsic AD (n = 42) and intrinsic AD (n = 9) groups (with similar mean disease activity/SCORAD scores) and analyzed the molecular and cellular skin pathology of lesional and nonlesional intrinsic AD and extrinsic AD by using gene expression (real-time PCR) and immunohistochemistry.

RESULTS

A significant correlation between IgE levels and SCORAD scores (r = 0.76, P < 10(-5)) was found only in patients with extrinsic AD. Marked infiltrates of T cells and dendritic cells and corresponding epidermal alterations (keratin 16, Mki67, and S100A7/A8/A9) defined lesional skin of patients with both variants. However, higher activation of all inflammatory axes (including TH2) was detected in patients with intrinsic AD, particularly TH17 and TH22 cytokines. Positive correlations between TH17-related molecules and SCORAD scores were only found in patients with intrinsic AD, whereas only patients with extrinsic AD showed positive correlations between SCORAD scores and TH2 cytokine (IL-4 and IL-5) levels and negative correlations with differentiation products (loricrin and periplakin).

CONCLUSIONS

Although differences in TH17 and TH22 activation exist between patients with intrinsic AD and those with extrinsic AD, we identified common disease-defining features of T-cell activation, production of polarized cytokines, and keratinocyte responses to immune products. Our data indicate that a TH2 bias is not the sole cause of high IgE levels in patients with extrinsic AD, with important implications for similar therapeutic interventions.