Heimo Breiteneder

and 14 more

Modern healthcare requires a proactive and individualized response to diseases, combining precision diagnosis and personalized treatment. Accordingly, the approach to patients with allergic diseases encompasses novel developments in the area of personalized medicine, disease phenotyping and endotyping and the development and application of reliable biomarkers. A detailed clinical history and physical examination followed by the detection of IgE immunoreactivity against specific allergens still represents the state of the art. However, nowadays, further emphasis focuses on the optimization of diagnostic and therapeutic standards and a large number of studies have been investigating the biomarkers of allergic diseases, including asthma, atopic dermatitis, allergic rhinitis, food allergy, urticaria and anaphylaxis. Various biomarkers have been developed by omics technologies, some of which lead to a better classification of the distinct phenotypes or endotypes. The introduction of biologicals to clinical practice increases the need for biomarkers for patient selection, prediction of outcomes and monitoring, to allow for an adequate choice of the duration of these costly and long-lasting therapies. Escalating healthcare costs together with questions on the efficacy of the current management of allergic diseases requires further development of a biomarker-driven approach. Here, we review biomarkers in diagnosis and treatment of asthma, atopic dermatitis, allergic rhinitis, viral infections, chronic rhinosinusitis, food allergy, drug hypersensitivity and allergen-immunotherapy with a special emphasis on specific IgE, microbiome and epithelial barrier. In addition, EAACI guidelines on biologicals are discussed within the perspective of biomarkers.

Lacin Cevhertas

and 21 more

Paulina Wawrzyniak

and 12 more

To the Editor: Asthma is a complex and heterogeneous chronic airway inflammatory disease with the involvement of environmental factors through epigenetic mechanisms.1 Accordingly, repeated injury, repair and regeneration of the airway epithelium following exposure to environmental factors and inflammation results in histological changes and functional abnormalities in the airway mucosal epithelium, which are associated with the pathophysiology of asthma.2Epigenetics is defined by heritable changes in gene expression without changes in the DNA sequence.3 Regulation of gene expression is mediated by different mechanisms such as DNA methylation, histone modifications and RNA-associated silencing by small non-coding RNAs. CpG sites are dinucleotides consisting of guanine and cytosine concentrated in clusters referred to CpG islands found at important regulatory sites, such as promoter and enhancer regions.4 Their de novo methylation occurs in response to various cellular stressors and signals by DNA methyltransferases (DNMT3a and 3b), which add a methyl group to position 5 of cytosine residues at the CpG site. During DNA replication both of the separated strands of DNA carry one methylated cytosine to be used as a template for duplication. Daughter DNA duplex strands will thus be hemi-methylated, which is recognized by a different DNA methyltransferase isoform (DNMT1).5 Because DNA methylation is a reversible process, the DNMTs are considered as a therapeutic target. Several DNMT inhibitors have been identified recently, among the non-nucleoside inhibitors, 4-aminoquoline-based inhibitors, such as SGI-1027 showed potent inhibitory activity. SGI-1027 occupies the binding site of DNMTs resulting in the prevention of access of target DNA to the substrate binding pocket.6We have demonstrated in previous studies from our laboratory that human primary bronchial epithelial cells (HBEC) isolated from patients with asthma showed lower barrier integrity compared to controls.7 To investigate the level of global methylation in HBEC, we investigated control and asthma samples for the long interspersed nuclear element-1 (LINE-1) methylation levels (Figure 1A). HBEC from asthma patients showed a tendency for higher global methylation levels, together with higher expression of 5-methylcytosine (5-mc) in immunofluorescence staining (Figure 1B). Next, we performed methylation profiling (Illumina Infinium EPIC array) to investigate genes methylated in ALI cultures of HBEC. Interestingly, in a highly methylated group of top 100 genes, we found many genes associated with cell growth, ion transport, and cytoskeletal remodeling (Figure S1). We kept our attention on the methylated epigenetic and tight junction (TJ) genes and further focused on TJs, especially zonula occludens and claudins which showed higher methylation in contrast to occludin, which was not methylated (Figure S2). As higher methylation levels were observed in HBEC of asthmatic origin, we inhibited the DNA methyltransferase enzyme with a specific inhibitor, SGI-1027, to demonstrate the role of CpG methylation on epithelial barrier integrity. ALI cultures were treated with the DNA methyltransferase inhibitor for 72 hours. Significantly decreased expression of 5-mc was observed after 48 hours of DNA-methyltransferase inhibition, demonstrating that the methylation of 5-methylcytosine (5-mc) in bronchial epithelium was reversed (Figure 2A). This prompted us to investigate the changes triggered by the inhibitor in epithelial cells. Further experiments showed increased transepithelial electric resistance (TER) in bronchial epithelial cells, in ALI from asthmatic donors after 48 hours of DNMT inhibition (Figure 2B). The link between barrier integrity and TER results were confirmed by the significantly decreased paracellular passage of FITC-labelled 4kD dextran after inhibition of DNMTs (Figure 2C). The reconstitution of TER in asthmatic ALI was associated with decreased protein DNMT1 expression and increased ZO-1 and claudin-18 proteins (Figure 2D). We also observed increased claudin-4, but not occludin expression upon DNMT inhibition (Figure S3). Increased expression of ZO-1 with an intact and honeycomb-like structure in the immunofluorescence staining of bronchial epithelial cells confirmed the effect on protein expression of bronchial epithelial barrier in asthma donors (Figure S4).Defective epithelial barrier has been established in asthma in addition to several chronic inflammatory diseases.8 Direct targeting of the epithelial barrier leakiness for the treatments represents an important target, however so far there is no treatment possibility targeting epigenetic mechanisms. The present study demonstrates an increased global methylation level in HBEC from asthmatic individuals. CpG methylation of specific genes is essential for the defect of epithelial barrier integrity, which is reversed upon DNMT inhibition. The inversion of CpG methylation, restores leakiness in the epithelium in asthma by increasing TER, decreasing paracellular flux and improves the structure of bronchial epithelial cells by increasing the expression of TJ proteins. The better understanding of the importance of epigenetic memory in chronic tissue inflammatory diseases together with the availability of treatment modalities targeting epigenetic mechanisms and transition of these molecules into the clinical studies may lead to curative treatment of allergic and autoimmune inflammatory diseases.9Paulina Wawrzyniak1, PhD,Krzysztof Krawczyk1,3, MSc,Swati Acharya5, PhD,Ge Tan1,7, PhD,Marcin Wawrzyniak1, PhD,Emmanuel Karouzakis4, PhD,Anita Dreher, Sci. Tech.,Bogdan Jakiela2, MD, PhD,Can Altunbulakli1, PhD,Marek Sanak2, MD, PhD,Liam O‘Mahony1,6, PD, PhD,Kari Nadeau5, MD, PhD,Cezmi A. Akdis1, MD1Swiss Institute of Allergy and Asthma Research (SIAF), University of Zürich, Davos, Switzerland, Christine Kühne-Center for Allergy Research and Education (CK-CARE)2Department of Medicine, Jagiellonian University Medical College, Krakow, Poland3Faculty of Biology and Environmental Protection, Department of Cellular Immunology, Lodz, Poland4Department of Rheumatology, University Hospital of Zurich5Departament of Medicine, Stanford University, United States6 Department of Medicine and School of Microbiology, APC Microbiome Ireland, University College Cork, Cork, Ireland.7 Functional Genomics Center Zurich, ETH Zurich/University of ZurichCorresponding author:Paulina WawrzyniakSwiss Institute of Allergy and Asthma Research (SIAF), University of Zürich, Davos, SwitzerlandObere Strasse 22,7270 Davos, SwitzerlandTel: +41 81 410 08 48Fax: +41 81 410 08 40paulina.wawrzyniak@uzh.chConflict of interest:The authors declare that they have no conflicts of interest.Founding sources:Supported by Swiss National Science Foundation grants 310030_156823, and 320030_176190.Word count: 765Keywords: asthma, tight junction, CpG methylation, DNA methyltransferases,

Gennaro D'Amato

and 1 more

EDITORIAL The average global temperatures on our planet are increasing due to rising anthropogenic greenhouse gases in the atmosphere, in particular carbon dioxide (CO2).1,2 There is an urgent need to call for action on global warming, which is resulting in extreme weather and related catastrophes.1 ,2 The Earth’s rising temperature is evidenced by warming of the oceans, melting glaciers, rising sea levels, and the diminished snow cover in the Northern Hemisphere. Climate-related factors can affect interactive atmospheric components (chemical and biological) and their interrelationship with human health.Climate change, a physics and meteorological event that affects health in the whole biosphere started to receive attention around the mid-twentieth century. Air pollution is the driving force of the Earth’s warming powered by the greenhouse effect (Figure 1). Environmental changes are occurring in frequency, intensity, type of precipitation, and extreme weather events, such as heatwaves, droughts, floods, blizzards, thunderstorms, sandstorms, and hurricanes. These are real and daunting challenges for the human and biosphere health, impacting the food and water supplies.1 ,2 Urbanization, with its high level of vehicle emissions and westernized lifestyle, is linked to the rising levels of particulate matter in the air, food supplies, soil, freshwater, and oceans. These environmental changes are correlated with the increased frequency of respiratory allergic diseases and bronchial asthma observed over recent decades in most industrialized countries and is continuously rising in developing countries.1-5This issue of Allergy focuses on the interrelationship between climate change, air pollution and human health.3-7Climate change is an important medical aspect in allergology as we are observing an increasing incidence of allergic diseases indirectly related to rising temperatures and are becoming a high socio-economic burden.1-3,8 Allergies and asthma appear to be at the front line of the sequelae of climate change along with infectious and cardiovascular diseases.1,5Cecchi et al. focus on the development and exacerbation of allergic diseases can be explained in terms of the exposome, a concept that includes all the environmental exposures from conception onwards. Multiple factors can trigger a pollen-induced respiratory allergy, such as airborne endotoxin levels and microbial composition of pollen, and these comprise a “pollen exposome”.4,9Susan Prescott has written an editorial in this issue bringing the attention to climate change and bidiversity aspects. At the time of Neil Armstrong’s lunar landing 50 years ago, Prof. Rene Dubos, a renowned microbiologist, delivered the seminal lecture “The Spaceship Earth”. He was ahead of his time and warned of an “altered immunity” driven by environmental problems and loss of biodiversity. Most of his predictions proved correct and we are now understanding at a molecular level the pathophysiological mechanisms involved in allergic diseases.8Climate change indirectly affects allergies by altering the pollen concentrations, allergenic potential, composition, migration of species and growth of new ones. Air pollution and climate change have resulted in the faster growth of allergenic plants, increasing the aeroallergen load for patients with inhalant allergy. Phenological studies indicate longer pollen seasons and emerge earlier in the year.1,4,5,8 Pollen and mold allergies are generally used to evaluate the interrelationship between air pollution and allergic respiratory diseases, such as rhinitis and asthma. Studies show that plants exhibit enhanced photosynthesis and reproductive effects and produce more pollen as a response to high atmospheric levels of CO2. 1,4,8 Pollen allergens have been demonstrated to trigger the release of pro-inflammatory and immunomodulatory mediators that accelerate the onset of allergy and the IgE-mediated sensitization. Lightning storms or wet conditions rupture the pollen grains releasing the allergenic proteins that cause asthma exacerbations in patients with pollinosis (thunderstorm-asthma).1,3,4,7,10 As a result of climate change, patients with seasonal allergic rhinoconjunctivitis and asthma have more intense symptoms and need stronger medication.1,4,8 In addition to respiratory illnesses, Fairweather et al. demonstrate the effect of environmental changes on cardiovascular, brain and mind, gastrointestinal, skin, immunologic and metabolic effects.1,3,4,7 The migration of stinging and biting insects to cooler climates has caused an increase in insect allergies in those areas.Prunicki et al. focus on the contribution of wildfires and deforestation and their contribution to global warming and immunological effects. It should be noted that in the last fifty years, half of the pluvial forests on Earth have been lost. Deforestation and forestation degradation is estimated to occur at a rate of 13 million hectares per year, mostly for agricultural purposes. Wildfires are becoming increasingly frequent, posing a serious risk to human health. The fine particulate matter (PM2.5) in wildfire smoke exacerbates asthma attacks, among other health problems. A study of 67 subjects demonstrated that those exposed to wildfire smoke had significantly higher levels of C-reactive protein and IL-1β compared with controls.6 The elevated levels of these two biomarkers are indicative of airway inflammation.Global warming and climate change need actions throughout the whole world with joined forces of all capabilities. These efforts are sometimes hampered by the unresponsiveness of governmental institutions and the general population, the lack of infrastructure and poverty. An action plan is needed to disseminate information on health-related problems associated with climate change. Patients with pollen allergies or asthma should be educated on the higher health risk during a thunderstorm or pollen season and the need for appropriate medication if staying outdoors. In collaboration with environmental organizations, physicians should take the lead to promote actions to mitigate air pollution and advocate the need to reduce global warming to protect our health.

Oliver Pfaar

and 2 more

The “coronavirus disease 2019 (COVID-19)” outbreak was first reported in December 2019 (China). Since then, this disease has rapidly spread across the globe and in March 2020 the World Health Organization (WHO) declared the COVID-19 pandemic.1 Since the outbreak was first announced, our journal has extensively focused on the clinical features, outcomes, diagnosis, immunology, and pathogenesis of COVID-19 and its infectious agent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We published our first COVID-19 article on 19 February, focusing for the first time on the clinical characteristics of 140 cases of human-to-human coronavirus transmission without any links to the Huanan Wet Market.2 Hypertension and diabetes were mentioned as risk factors and there was no increased prevalence in allergic patients. This early study reported that the main symptoms at hospital admission were fever (91.7%), cough (75.0%), fatigue (75.0%), gastrointestinal symptoms (39.6%), and dyspnea (36.7%). Lymphopenia and eosinopenia were also reported as important signs and biomarkers for monitoring and severity of the patients.2 The prevalent eosinopenia in COVID-19 patients and the possible anti-viral role of eosinophils were further discussed in several following publications inAllergy .3,4 Our second COVID-19 paper brought attention to the wide range of clinical manifestations of this disease, from asymptomatic cases to patients with mild and severe symptoms, with or without pneumonia as well as with only diarrhea.5Patients with common allergic diseases did not develop distinct symptoms and severe courses. Cases with pre-existing chronic obstructive pulmonary disease or complicated with a secondary bacterial pneumonia were severe. Another article, timely appearing in our journal, alerted the scientific community that even in experienced hands there was a 14.1% false negative polymerase chain reaction (PCR) diagnosis in COVID-19 cases and were later diagnosed positive after repeated tests.6 A pediatric article was also published extensively analyzing 182 cases and it was reported that children with COVID-19 showed a mild clinical course.7 Patients with pneumonia had a higher proportion of fever and cough and increased inflammatory biomarkers compared to those without pneumonia. There were 43 allergic patients in this series and there was no significant difference between allergic and non-allergic COVID-19 children in disease incidence, clinical features, laboratory, and immunological findings. Allergy was not a risk factor for disease and severity of SARS-CoV-2 infection and did not significantly influence the disease course of COVID-19 in children.7The immunology of COVID-19 was extensively reviewed in two articles from leading experts with a comprehensive discussion of the tip of the iceberg in COVID-19 epidemiology, anti-viral response, antibody response to SARS-CoV-2, acute phase reactants, cytokine storm, and pathogenesis of tissue injury and severity. 8,9Two studies timely reported the role of possible trained immunity in countries with a Bacillus Calmette-Guérin (BCG) vaccination programme and a relatively low COVID-19 prevalence and mortality rate.10,11 In an extensive RNA sequencing analyses of SARS-CoV-2 receptor and their molecular partners revealed that ACE2 and TMPRSS2 were coexpressed at the epithelial sites of the lung and skin, whereas CD147 (BSG), cyclophilins (PPIA and PPIB), CD26 (DPP4) and related molecules were expressed in both, epithelium and in immune cells.12Allergists, respiratory physicians, pediatricians, and other health care providers treating patients with allergic diseases are frequently in contact with patients potentially infected with SARS-CoV-2. Practical considerations and recommendations given by experts in the field of allergic diseases can provide useful recommendations for clinical daily work. Since the beginning of this current pandemic, our journal has disseminated clinical reports, 2,3,5,6,13 statements on the urgent need for accuracy in designing and reporting clinical trials in COVID-19,14 preventive measures,10,11,15 and Position Statements elaborated by experts in the field in close collaboration with the European Academy of Allergy and Clinical Immunology (EAACI) and its task force “Allergy and Its Impact on Asthma (ARIA) ”.16-28 (keynote information in table 1). A compendium answering 150 frequently encountered questions regarding COVID-19 and allergic diseases has been recently published by experts in their respective area.29 In addition, readers can put further questions regarding this “living ” compendium electronically to the authors and their answers will be available through a new category in the journal’s webpage.30Besides, EAACI in collaboration with ARIA, has provided recommendations on operational plans and practical procedures for ensuring optimal standards in the daily clinical care of patients with allergic diseases, whilst ensuring the safety of patients and healthcare workers.23Table 1: Examples of recently published recommendations, statements and Position Papers of the EAACI