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.

This systematic review evaluates the efficacy, safety and economic impact of dupilumabcompared to standard of care for uncontrolled moderate-to-severe atopic dermatitis (AD). Pubmed, EMBASE and Cochrane Library were searched for RCTs and health economic evaluations. Critical and important AD-related outcomes were considered. The risk of bias and the certainty of the evidence were assessed using GRADE. Seven RCTs including 1845 subjects > 12 years treated with dupilumab16 to 52 weeks were evaluated. For adultsthere is high certainty that dupilumabdecreasesSCORAD (MD -30,72; 95%CI -34,65% to -26,79%) and EASI-75 (RR 3.09; 95%CI 2.45 to 3.89), pruritus (RR 2.96; 95%CI 2.37 to 3.70), rescue medication (RR 3.46; 95%CI 2.79 to 4.30), sleep disturbance (MD -7.29; 95%CI -8.23 to -6.35), anxiety/depression (MD -3.08; 95% CI -4.41 to -1.75) and improves quality of life (MD -4.80; 95% CI -5.55 to -4.06). The efficacy for adolescents is similar. Dupilumab-related adverse events (AEs) slightly increase (low certainty). The evidence for dupilumab-related serious AE is uncertain. The incremental cost-effectiveness ratio ranged from 28,500 £ (low certainty) to 124,541 US$ (moderate certainty).More data on long term safety are needed both for children and adults, together with more efficacy data in the paediatric population.

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage were associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin converting enzyme 2 (ACE2). As a result of SARS-Cov-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT1R) axis associated with oxidative stress. This leads to insulin resistance, lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block the AT1R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects helpful in mitigating COVID-19 severity.

This systematic review evaluates the efficacyand safety of omalizumab for chronic spontaneous urticaria (CSU). Pubmed, EMBASE and Cochrane Library were searched for RCTs. Critical and important CSU-related outcomes were considered. The risk of bias and the certainty of the evidence were assessed using GRADE. Ten RCTs including 1620 subjects aged 12 to 75 years old treated with omalizumab for 16 to 40 weeks were evaluated. Omalizumab 150 mg: does not result in clinically meaningful improvement(high certainty) of the urticaria activity score (UAS)7 (mean difference (MD) -5; 95%CI -7.75 to -2.25) and the itch severity score(ISS)7 (MD -2.15; 95% CI -3.2 to -1.1); does not increase (moderate certainty) quality of life (QoL) (Dermatology Life Quality Index (DLQI); MD -2.01; 95%CI -3.22 to -0.81); decreases (moderate certainty) rescue medication use (MD -1.68; 95%CI -2.95 to -0.4). Omalizumab 300 mg:results in clinically meaningful improvements(moderate certainty)of the UAS7 (MD -11.05; 95%CI -12.87 to -9.24), theISS7 (MD -4.45; 95%CI -5.39 to -3.51), and QoL (high certainty)(DLQI; MD -4.03; 95% CI -5.56 to -2.5); decreases (moderate certainty) rescue medication use (MD -2.04; 95%CI -3.19 to -0.88) and drug-related serious AEs (RR 0.77; 95%CI 0.20 to 2.91).

To the Editor, The fermentation process, born as a preservation method in the Neolithic age, enabled humans to eat not-so-fresh food and to survive.1 Fermented foods are “foods or beverages made via controlled microbial growth (including lactic acid bacteria (LAB)) and enzymatic conversions of food components.” 2 Not all fermented foods contain live cultures, as some undergo further processing after fermentation: pasteurization, smoking, baking, or filtration. These processes kill or remove the live microorganisms in foods such as soy sauces, bread, most beers and wines as well as chocolate. Live cultures can be found in fermented vegetables and fermented milk (fermented sour milk, yoghurt, probiotics, …). The westernized diet is lacking many traditional fermented foods.3The gut microbiota has an inter-individual variability due to genetic predisposition and diet 3. Some foods like cabbage can be fermented by the gut microbiota. 4 The westernized diet has been associated with changes in the gut microbiome.5In this Rostrum, we consider loss of food fermentation either as a reduction of fermented food consumption in the diet or as a change in the microbiome leading to a reduction of fermentation of foods in the gut. This paper is based on the hypothesis that diet may partly explain differences in COVID-19 death rates within and between countries.6

To the Editor, A COVID-19 epidemic started in China and then disseminated to other Asian countries before becoming a pandemic. It appears that the pandemic has so far resulted in proportionately fewer deaths in China and most Eastern Asian countries. Many reasons can explain this picture.1 One of them is the type of diet in the low mortality countries. 2This paper is the sixth of a series attempting to understand the role of diet in the differences of COVID-19 death rates between and within countries with the aim to identify potential preventive measures against COVID-19. The concept paper 2 was followed by two ecological studies comparing death rates in European countries and the consumption of vegetables or fermented foods. 3,4 We then proposed that sulforaphane from cruciferous vegetables1 and lactobacilli from fermented foods (submitted) were possibly involved in the reduction of insulin resistance in COVID-19.It is noteworthy that fermented foods are largely used in Asia.5,6 It is therefore important to check whether some commonly eaten fermented foods in these countries may explain geographic differences in COVID-19. Kimchi will be used as a model of fermented cabbage.

To the Editor, Sulforaphane [1-isothiocyanato-4-(methylsulfinyl)butane] is a clinically relevant nutraceutical compound present in cruciferous vegetables (Brassicaceae). It is used for the prevention and treatment of chronic diseases and may be involved in ageing.1Along with other natural nutrients, sulforaphane has been suggested to have a therapeutic value for the treatment of the coronavirus disease 2019 (COVID-19).2 Sulforaphane is an isothiocyanate stored in its inactive form glucoraphanin.3 The enzyme myrosinase, found in plant tissue and in the gut microbiome, is involved in the conversion of glucoraphanin to its active form sulforaphane.4

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.

Background Currently, the coronavirus disease 2019 (COVID-19) has become pandemic globally. 10-20% of the cases are severe and more than 397,000 deaths have occurred. The risk factors for the mortality of critically ill COVID-19 patients remain to be elucidated. Conclusions Survived severe and non-survived COVID-19 patients had distinct clinical and laboratory characteristics, which were separated by principle component analysis. Logistic regression revealed several risk factors such as elder age, greater affected lobe numbers and higher level of serum CRP for the mortality of severe COVID-19 patients. Longitudinal changes of laboratory findings indicate the advancement of the disease and may be helpful in predicting the progression of severe patients.

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

In December 2019, China reported the first cases of the coronavirus disease 2019 (COVID-19). This disease, caused by the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2), has developed into a pandemic. To date it has resulted in ~5.6 million confirmed cases and caused 353,334 related deaths worldwide. Unequivocally, the COVID-19 pandemic is the gravest health and socio-economic crisis of our time. In this context, numerous questions have emerged in demand of basic scientific information and evidence-based medical advice on SARS-CoV-2 and COVID-19. Although the majority of the patients show a very mild, self-limiting viral respiratory disease, many clinical manifestations in severe patients are unique to COVID-19, such as severe lymphopenia and eosinopenia, extensive pneumonia, a “cytokine storm” leading to acute respiratory distress syndrome, endothelitis, thrombo-embolic complications and multiorgan failure. The epidemiologic features of COVID-19 are distinctive and have changed throughout the pandemic. Vaccine and drug development studies and clinical trials are rapidly growing at an unprecedented speed. However, basic and clinical research on COVID-19-related topics should be based on more coordinated high-quality studies. This paper answers pressing questions, formulated by young clinicians and scientists, on SARS-CoV-2, COVID-19 and allergy, focusing on the following topics: virology, immunology, diagnosis, management of patients with allergic disease and asthma, treatment, clinical trials, drug discovery, vaccine development and epidemiology. Over 140 questions were answered by experts in the field providing a comprehensive and practical overview of COVID-19 and allergic disease.

The pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has made widespread impact recently. We aim to investigate the clinical characteristics of COVID-19 children with different severities and allergic status. Pediatric COVID-19 patients tended to have a mild clinical course. Patients with pneumonia had higher proportion of fever and cough and increased inflammatory biomarkers than those without pneumonia. There was no difference between allergic and non-allergic COVID-19 children in aspects of incidence, clinical features, laboratory and immunological findings. Allergy was not a risk factor for developing and severity of SARS-CoV-2 infection and hardly influenced the disease course of COVID-19 in children.