β-1,3-glucanase rOle e 9 and MnSOD rAsp f 6 IgE reactivity are the signature of atopic dermatitis in the Mediterranean area

A systematic review of allergen cross-reactivity: Translating basic concepts into clinical relevance

Access to the molecular culprits of allergic reactions allows for the leveraging of molecular allergology as a new precision medicine approach-one built on interdisciplinary, basic, and clinical knowledge. Molecular allergology relies on the use of allergen molecules as in vitro tools for the diagnosis and management of allergic patients. It complements the conventional approach based on skin and in vitro allergen extract testing. Major applications of molecular allergology comprise accurate identification of the offending allergen thanks to discrimination between genuine sensitization and allergen cross-reactivity, evaluation of potential severity, patient-tailored choice of the adequate allergen immunotherapy, and prediction of its expected efficacy and safety. Allergen cross-reactivity, defined as the recognition of 2 or more allergen molecules by antibodies or T cells of the same specificity, frequently interferes with allergen extract testing. At the mechanistic level, allergen cross-reactivity depends on the allergen, the host's immune response, and the context of their interaction. The multiplicity of allergen molecules and families adds further difficulty. Understanding allergen cross-reactivity at the immunologic level and translating it into a daily tool for the management of allergic patients is further complicated by the ever-increasing number of characterized allergenic molecules, the lack of dedicated resources, and the need for a personalized, patient-centered approach. Conversely, knowledge sharing paves the way for improved clinical use, innovative diagnostic tools, and further interdisciplinary research. Here, we aimed to provide a comprehensive and unbiased state-of-the art systematic review on allergen cross-reactivity. To optimize learning, we enhanced the review with basic, translational, and clinical definitions, clinical vignettes, and an overview of online allergen databases.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Multiplex Proteomic Evaluation in Inborn Errors with Deregulated IgE Response

(1) Background: Atopic dermatitis constitutes one of the most common inflammatory skin manifestations of the pediatric population. The onset of many inborn errors occurs early in life with an AD-like picture associated with a deregulated IgE response. The availability of proteomic tests for the simultaneous evaluation of hundreds of molecules allows for more precise diagnosis in these cases. (2) Methods: Comparative genomic hybridization microarray (Array-CGH) analysis and specific IgE evaluation by using allergenic microarray (ISAC) and microarray (ALEX2) systems were performed. (3) Results: Proteomic investigations that use multiplex methods have proven to be extremely useful to diagnose the sensitization profile in inborn errors with deregulated IgE synthesis. Four patients with rare diseases, such as recessive X-linked ichthyosis (RXLI, OMIM 308100), Comel-Netherton syndrome (NS, OMIM256500), monosomy 1p36 syndrome (OMIM: 607872), and a microduplication of Xp11.4 associated with extremely high levels of IgE: 7.710 kU/L, 5.300 kU/L, 1.826 kU/L, and 10.430 kU/L, respectively, were evaluated by micro- and macroarray multiplex methods. Polyreactivity to both environmental and food allergens was observed in all cases, including the first described case of association of X-chromosome microduplication and HIE. (4) Conclusions: Extensive use of proteomic diagnostics should be included among the procedures to be implemented in inborn errors with hyper-IgE.

Molecular diagnosis contribution for personalized medicine

PURPOSE OF REVIEW

The purpose of the current review is to highlight the most recent findings in molecular allergy and its applicability in precision medicine for allergic patients.

RECENT FINDINGS

Molecular allergy provides useful information in areas of respiratory allergy (house dust mites, pet dander and pollen allergy), food allergy (tree nuts, peanuts, fruits and vegetables), hymenoptera venom allergy and others, in order to improve management of patients. Regional differences in sensitization profiles, assay characteristics and interpretation of molecular sensitization in relation to whole extracts and total immunoglobulin E need to be taken into account. Studies of the impact of such strategies are needed.

SUMMARY

Molecular allergy diagnosis represents a major contribution for personalized medicine. It aids in the assesment of risk prediction, disease severity, genuine/cross-reactive sensitization, and finally to apply precise management strategies.

A comprehensive comparison between ISAC and ALEX2 multiplex test systems

OBJECTIVES

Diagnosis of type I hypersensitivity is based on anamnesis, provocation as well as blood- and skin testing. Multiplex specific IgE (sIgE) testing enables determination of sIgE antibodies against multiple recombinant or purified natural allergen components. The aim of this study was to evaluate the performance of the novel ALEX^2® (Allergy Explorer, ALEX² test introduced on the market November 2019) multiplex platform and to compare it with the ImmunoCAP ISAC^® test system.

METHODS

Serum samples of 49 patients, routinely determined with ISAC, were selected based on positive results covering in total most of the 112 ISAC components. Cohen's kappa, negative percent agreement (NPA), and positive percent agreement (PPA) of ALEX² data compared to ISAC data (as a non-reference standard) were computed for those allergen components present on both platforms (n=103). Furthermore, in some samples sIgE results against allergen extracts and/or -components tested with either ImmunoCAP^® (ThermoFisher) or IMMULITE^® (Siemens) were available and compared to ALEX² results.

RESULTS

The overall agreement between ISAC and ALEX² common allergen components was 94%. NPA and PPA were respectively 95 and 90%. Kappa values differed for specific allergen groups and varied between 0.60 and 0.92 showing moderate to almost perfect agreement. Of the qualitative discrepancies between ALEX² and ISAC, 59% were related to weak positive results i.e. results under 1 kUA/L or 1 ISU, respectively.

CONCLUSIONS

The method comparison between ISAC and ALEX² multiplex tests showed a high concordance for those allergen components present on both platforms.

Multiple Roles for Cytokines in Atopic Dermatitis: From Pathogenic Mediators to Endotype-Specific Biomarkers to Therapeutic Targets

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases, which generally presents with intense itching and recurrent eczematous lesions. AD affects up to 20% of children and 10% of adults in high-income countries. The prevalence and incidence of AD have increased in recent years. The onset of AD mostly occurs in childhood, although in some cases AD may persist in adult life or even manifest in middle age (adult-onset AD). AD pathophysiology is made of a complex net, in which genetic background, skin barrier dysfunction, innate and adaptive immune responses, as well as itch contribute to disease development, progression, and chronicization. One of the most important features of AD is skin dehydration, which is mainly caused by filaggrin mutations that determine trans-epidermal water loss, pH alterations, and antigen penetration. In accordance with the “outside-inside” theory of AD pathogenesis, in a context of an altered epidermal barrier, antigens encounter epidermal antigen presentation cells (APCs), such as epidermal Langerhans cells and inflammatory epidermal dendritic cells, leading to their maturation and Th-2 cell-mediated inflammation. APCs also bear trimeric high-affinity receptors for immunoglobulin E (IgE), which induce IgE-mediated sensitizations as part of pathogenic mechanisms leading to AD. In this review, we discuss the role of cytokines in the pathogenesis of AD, considering patients with various clinical AD phenotypes. Moreover, we describe the cytokine patterns in patients with AD at different phases of the disease evolution, as well as in relation to different phenotypes/endotypes, including age, race, and intrinsic/extrinsic subtypes. We also discuss the outcomes of current biologics for AD, which corroborate the presence of multiple cytokine axes involved in the background of AD. A deep insight into the correlation between cytokine patterns and the related clinical forms of AD is a crucial step towards increasingly personalized, and therefore more efficient therapy.

Precision medicine in the allergy clinic: the application of component resolved diagnosis

INTRODUCTION

A precise diagnosis is key for the optimal management of allergic diseases and asthma. In vivo or in vitro diagnostic methods that use allergen extracts often fail to identify the molecules eliciting the allergic reactions.

AREAS COVERED

Component-resolved diagnosis (CRD) has solved most of the limitations of extract-based diagnostic procedures and is currently valuable tool for the precision diagnosis in the allergy clinic, for venom and food allergy, asthma, allergic rhinitis, and atopic dermatitis. Its implementation in daily practice facilitates: a) the distinction between genuine multiple sensitizations and cross-reactive sensitization in polysensitized patients; b) the prediction of a severe, systemic reaction in food or insect venom allergy; c) the optimal selection of allergen immunotherapy based on the patient sensitization profile. This paper describes its main advantages and disadvantages, cost-effectiveness and future perspectives.

EXPERT OPINION

The diagnostic strategy based on CRD is part of the new concept of precision immunology, which aims to improve the management of allergic diseases.

Developments in the field of allergy in 2020 through the eyes of Clinical and Experimental Allergy

While 2020 will be remembered for the global coronavirus pandemic, there were also important advances in the field of allergy. In this review article, we summarize key findings reported in Clinical and Experimental Allergy during 2020. We hope this provides readers with an accessible snapshot of the work published in our journal during this time.

Importance of food in the control of inflammation in atopic dermatitis

Patients that suffer from inflammatory diseases need to pay special attention to nutrition. For this reason, it is very important to change the approach of both health professionals and food industry specialists. There must be a close collaboration, starting from research, the development phase of foods for special nutrition states. Our primary objective was to identify foods or potential dietary ingredients, which efficacy in the treatment of atopic dermatitis had been scientifically demonstrated in vitro, in vivo and clinically. Furthemore, our perspective is presented regarding the research and development of foods for special nutritional states in atopic dermatitis. The PubMed database was analyzed for the period 2018-2020, as well as the European Legislation regarding the appropriate requirements for the composition and knowledge applicable to foods destined for use in special medical purposes. The search criteria were 'chronic dermatitis', 'atopic dermatitis', 'psoriasis', 'alternative treatments', 'natural treatments', 'complementary treatments', 'treatments for chronic dermatitis'. We also looked for undesirable effects or side effects of the foods included in the research in order to treat atopic dermatitis. The results showed that prebiotics, probiotics and certain plant extracts had a high efficacy in controlling inflammation in atopic dermatitis. The food development research for special nutrition states (atopic dermatitis) involves a multidisciplinary team. We started with the establishment of the general objective and continued with the consultation of the PubMed, EMBASE and other databases, and with the in vitro, preclinical and/or clinical determination of the efficacy of new developed foods, that must be protected with patents. The development of foods for special nutrition states represents a solution for improving the quality of life of atopic dermatitis patients.

The clinical impact of cross-reactions between allergens on allergic skin diseases

PURPOSE OF REVIEW

The route of allergen sensing via the skin appears to influence the immune system towards mounting a type 2 response, especially in genetically predisposed individuals. Allergens recognized this way may derive from microbial, animal, food, or other plant sources and trigger atopic dermatitis. Allergens can be grouped into families depending on their structure and function, harboring significant structural and sequence similarities. Cross-reactivity between allergens is believed to arise as a consequence, and to underlie the development of further atopic diseases.

RECENT FINDINGS

Especially for the plant allergens of the families of PR10-related proteins and profilins, immune cross-reactions have been described. Actual studies support that food and pollen allergens can aggravate skin lesions in patients suffering from atopic dermatitis. Further on, allergens derived from air-borne or skin-borne fungi belong to common allergen families and bear cross-reactivity potential. Cross-reactivity to human homologous proteins, so-called autoallergens, is discussed to contribute to the chronification of atopic dermatitis.

SUMMARY

Due to high evolutionary conservation, allergic reactions can be triggered by highly homologous members of allergen families on the humoral as well as on the cellular level.