Allergies to food and airborne allergens in children and adolescents: role of epigenetics in a changing environment

Asthma Inception: Epidemiologic Risk Factors and Natural History Across the Life Course

Asthma is a descriptive label for an obstructive inflammatory disease in the lower airways manifesting with symptoms including breathlessness, cough, difficulty in breathing, and wheezing. From a clinician's point of view, asthma symptoms can commence at any age, although most patients with asthma-regardless of their age of onset-seem to have had some form of airway problems during childhood. Asthma inception and related pathophysiologic processes are therefore very likely to occur early in life, further evidenced by recent lung physiologic and mechanistic research. Herein, we present state-of-the-art updates on the role of genetics and epigenetics, early viral and bacterial infections, immune response, and pathophysiology, as well as lifestyle and environmental exposures, in asthma across the life course. We conclude that early environmental insults in genetically vulnerable individuals inducing abnormal, pre-asthmatic airway responses are key events in asthma inception, and we highlight disease heterogeneity across ages and the potential shortsightedness of treating all patients with asthma using the same treatments. Although there are no interventions that, at present, can modify long-term outcomes, a precision-medicine approach should be implemented to optimize treatment and tailor follow-up for all patients with asthma.

The potential of orally exposed risk factors and constituents aggravating food allergy: Possible mechanism and target cells

Food allergy is a significant concern for the health of humans worldwide. In addition to dietary exposure of food allergens, genetic and environmental factors also play an important role in the development of food allergy. However, only the tip of the iceberg of risk factors in food allergy has been identified. The importance of food allergy caused by orally exposed risk factors and constituents, including veterinary drugs, pesticides, processed foods/derivatives, nanoparticles, microplastics, pathogens, toxins, food additives, dietary intake of salt/sugar/total fat, vitamin D, and therapeutic drugs, are highlighted and discussed in this review. Moreover, the epithelial barrier hypothesis, which is closely associated with the occurrence of food allergy, is also introduced. Additionally, several orally exposed risk factors and constituents that have been reported to disrupt the epithelial barrier are elucidated. Finally, the possible mechanisms and key immune cells of orally exposed risk factors and constituents in aggravating food allergy are overviewed. Further work should be conducted to define the specific mechanism by which these risk factors and constituents are driving food allergy, which will be of central importance to the targeted therapy of food allergy.

High Degree of Desensitization After 1 Year of Early-Life Peanut Oral Immunotherapy: Small Children Oral Immunotherapy (SmaChO) Randomized Controlled Trial

BACKGROUND

The prevalence of peanut allergy is about 2% and mostly lifelong. Studies of oral immunotherapy (OIT) with peanut (the daily oral intake of an initially low and then increasing dose of peanut) often show problematic side effects, but there are indications of better safety and effect in younger children compared with older children and adults.

OBJECTIVE

To determine the safety and effectiveness of peanut OIT with a slow up-dosing strategy and low maintenance dose in children aged 1 to 3 years who were allergic to peanut, through a 1-year interim analysis.

METHOD

In a randomized controlled trial (2:1 ratio), 75 children, median age 31 months (interquartile range [IQR], 23-40 months) were assigned to receive peanut OIT (n = 50) or peanut avoidance (n = 25).

RESULTS

In the OIT and avoidance groups, 43 of 50 and 20 of 25 children, respectively, performed the 1-year open oral peanut challenge. A cumulative dose of 750 mg peanut protein after 1 year was tolerated by 72% (36 of 50 children) in the OIT group compared with 4% (1 of 25) in the avoidance group (P < .001). Median tolerated cumulative dose was 2,750 mg (IQR, 275-5,000 mg) peanut protein in the OIT group compared with 2.8 mg (IQR, 0.3-27.8 mg) in the avoidance group (P < .001). Of the doses administered at home during the first year of OIT, 1.4% resulted in adverse events and 79% were mild, and three doses of epinephrine were given at home to two individuals.

CONCLUSION

In children aged 1 to 3 years, peanut OIT with the combination of slow up-dosing and low maintenance dose seems safe and effective after 1 year.

Natural course of pollen-induced allergic rhinitis from childhood to adulthood: A 20-year follow up

BACKGROUND

Allergic rhinitis (AR) is one of the most common chronic diseases worldwide. There are limited prospective long-term data regarding persistency and remission of AR. The objective of this study was to investigate the natural course of pollen-induced AR (pollen-AR) over 20 years, from childhood into early adulthood.

METHODS

Data from 1137 subjects in the Barn/Children Allergi/Allergy Milieu Stockholm Epidemiologic birth cohort (BAMSE) with a completed questionnaire regarding symptoms, asthma, treatment with allergen immunotherapy (AIT) and results of allergen-specific IgE for inhalant allergens at 4, 8, 16 and 24 years were analyzed. Pollen-AR was defined as sneezing, runny, itchy or blocked nose; and itchy or watery eyes when exposed to birch and/or grass pollen in combination with allergen-specific IgE ≥0.35kUA/L to birch and/or grass.

RESULTS

Approximately 75% of children with pollen-AR at 4 or 8 years had persistent disease up to 24 years, and 30% developed asthma. The probability of persistency was high already at low levels of pollen-specific IgE. The highest rate of remission from pollen-AR was seen between 16 and 24 years (21.5%); however, the majority remained sensitized. This period was also when pollen-specific IgE-levels stopped increasing and the average estimated annual incidence of pollen-AR decreased from 1.5% to 0.8% per year.

CONCLUSION

Children with pollen-AR are at high risk of persistent disease for at least 20 years. Childhood up to adolescence seems to be the most dynamic period of AR progression. Our findings underline the close cross-sectional and longitudinal relationship between sensitization, AR and asthma.

Systemic allergic contact dermatitis to palladium, platinum, and titanium: mechanisms, clinical manifestations, prevalence, and therapeutic approaches

Contact dermatitis (CD) is an inflammatory skin disease of eczema that is elicited by chemicals or metal ions that have toxic effects without eliciting a T-cell response (contact elicitation) or by small reactive chemicals that modify proteins and induce innate and adaptive immune responses (contact allergens). The clinical condition is characterized by localized skin rash, pruritus, redness, swelling, and lesions, which are mainly detected by patch tests and lymphocyte stimulation. Heavy metals such as palladium (Pd), platinum (Pt), and titanium (Ti) are ubiquitous in our environment. These heavy metals have shown CD effects as allergic agents. Immunological responses result from the interaction of cytokines and T cells. Occupational metal CD accounts for most cases of work-related cutaneous disorders. In this systematic review, the allergic effects of heavy metals, including Pd, Pt, and Ti, and the mechanisms, clinical manifestations, prevalence, and therapeutic approaches are discussed in detail. Furthermore, the therapeutic approaches introduced to treat CD, including corticosteroids, topical calcineurin inhibitors, systemic immunosuppressive agents, phototherapy, and antihistamines, can be effective in the treatment of these diseases in the future. Ultimately, the insights identified could lead to improved therapeutic and diagnostic pathways.

Climate change and epigenetic biomarkers in allergic and airway diseases

Human epigenetic variation is associated with both environmental exposures and allergic diseases and can potentially serve as a biomarker connecting climate change with allergy and airway diseases. In this narrative review, we summarize recent human epigenetic studies examining exposure to temperature, precipitation, extreme weather events, and malnutrition to discuss findings as they relate to allergic and airway diseases. Temperature has been the most widely studied exposure, with the studies implicating both short-term and long-term exposures with epigenetic alterations and epigenetic aging. Few studies have examined natural disasters or extreme weather events. The studies available have reported differential DNA methylation of multiple genes and pathways, some of which were previously associated with asthma or allergy. Few studies have integrated climate-related events, epigenetic biomarkers, and allergic disease together. Prospective longitudinal studies are needed along with the collection of target tissues beyond blood samples, such as nasal and skin cells. Finally, global collaboration to increase diverse representation of study participants, particularly those most affected by climate injustice, as well as strengthen replication, validation, and harmonization of measurements will be needed to elucidate the impacts of climate change on the human epigenome.

A conversation on allergy: recognizing the past and looking to the future

Allergy is an ever-evolving group of disorders, which includes asthma, atopic dermatitis, rhinitis and food allergies and that currently affects over 1 billion people worldwide. This group of disorders has exploded in incidence since around the start of the 20th century, implying that genetics is not solely responsible for its development but that environmental factors have an important role. Here, Fabio Luciani and Jonathan Coquet, in their role as editors at Immunology & Cell Biology, asked nine prominent researchers in the field of allergy to define the term 'allergy', discuss the role of genetics and the environment, nominate the most important discoveries of the past decade and describe the best strategies to combat allergy at the population level going forward.

Precision medicine in complex diseases-Molecular subgrouping for improved prediction and treatment stratification

Complex diseases are caused by a combination of genetic, lifestyle, and environmental factors and comprise common noncommunicable diseases, including allergies, cardiovascular disease, and psychiatric and metabolic disorders. More than 25% of Europeans suffer from a complex disease, and together these diseases account for 70% of all deaths. The use of genomic, molecular, or imaging data to develop accurate diagnostic tools for treatment recommendations and preventive strategies, and for disease prognosis and prediction, is an important step toward precision medicine. However, for complex diseases, precision medicine is associated with several challenges. There is a significant heterogeneity between patients of a specific disease-both with regards to symptoms and underlying causal mechanisms-and the number of underlying genetic and nongenetic risk factors is often high. Here, we summarize precision medicine approaches for complex diseases and highlight the current breakthroughs as well as the challenges. We conclude that genomic-based precision medicine has been used mainly for patients with highly penetrant monogenic disease forms, such as cardiomyopathies. However, for most complex diseases-including psychiatric disorders and allergies-available polygenic risk scores are more probabilistic than deterministic and have not yet been validated for clinical utility. However, subclassifying patients of a specific disease into discrete homogenous subtypes based on molecular or phenotypic data is a promising strategy for improving diagnosis, prediction, treatment, prevention, and prognosis. The availability of high-throughput molecular technologies, together with large collections of health data and novel data-driven approaches, offers promise toward improved individual health through precision medicine.

Clean air in Europe for all! Taking stock of the proposed revision to the ambient air quality directives: a joint ERS, HEI and ISEE workshop report

Ambient air pollution is a major public health concern and comprehensive new legislation is currently being considered to improve air quality in Europe. The European Respiratory Society (ERS), Health Effects Institute (HEI), and International Society for Environmental Epidemiology (ISEE) organised a joint meeting on May 24, 2023 in Brussels, Belgium, to review and critically evaluate the latest evidence on the health effects of air pollution and discuss ongoing revisions of the European Ambient Air Quality Directives (AAQDs). A multi-disciplinary expert group of air pollution and health researchers, patient and medical societies, and policy representatives participated. This report summarises key discussions at the meeting.

The Effects of a Healthy Diet on Asthma and Wheezing in Children and Adolescents: A Systematic Review and Meta-Analysis

Background

Asthma is a public health problem requiring focused attention. This study aimed to systematically evaluate the association between dietary structure and asthma or wheezing in children.

Methods

The study protocol of this meta-analysis has been registered in the International Prospective Register of Systematic Reviews (PROSPERO) with the registration code CRD42023390191. A total of 8397 articles were retrieved, searching PubMed, Medline, Embase, Web of Science, and Scopus databases as of November 21, 2022. Two independent authors were responsible for independently conducting the literature screening process. Effect-size estimates were expressed as odds ratio (OR) in cross-sectional studies and risk ratio (RR) in cohort studies with a 95% confidence interval (CI). Summary effect estimates were evaluated with random-effect models. Meanwhile, subgroup and sensitivity analyses were performed to assess the potential sources of heterogeneity and the robustness of the pooled estimation.

Results

A total of 65 studies, including 567,426 subjects had been analyzed. Overall analyses of cross-sectional studies revealed that a healthy diet was protective against asthma (adjusted OR=0.85, 95% CI: 0.80-0.89, P <0.001, I2=69.8%, Tau2=0.026) and wheezing (adjusted OR=0.85, 95% CI: 0.81-0.89, P <0.001, I2=66.8%, Tau2=0.015) in children and adolescents. Conversely, unhealthy diets can exacerbate asthma (adjusted OR=1.28, 95% CI: 1.20-1.36, P <0.001, I2=64.9%, Tau2=0.019) and wheeze (adjusted OR=1.09, 95% CI: 1.02-1.16, P =0.006, I2=75.2%, Tau2=0.023) in children and adolescents. The same trend was found in cohort studies (adjusted RR=0.72, 95% CI: 0.58-0.90, P =0.003, I2=83.5%, Tau2=0.105). A clear trend was observed between high-frequency healthy diets (OR=0.80; 95% CI: 0.71-0.89; P <0.001) is more protective against asthma than low-frequency healthy diets (OR=0.81; 95% CI: 0.70-0.94; P =0.007).

Conclusion

Our findings highlight the protective effects of a healthy diet on asthma and wheezing in children, including fruit, seafood, cereals, and the Mediterranean diet.

Epigenome-wide association studies of allergic disease and the environment

The epigenome is at the intersection of the environment, genotype, and cellular response. DNA methylation of cytosine nucleotides, the most studied epigenetic modification, has been systematically evaluated in human studies by using untargeted epigenome-wide association studies (EWASs) and shown to be both sensitive to environmental exposures and associated with allergic diseases. In this narrative review, we summarize findings from key EWASs previously conducted on this topic; interpret results from recent studies; and discuss the strengths, challenges, and opportunities regarding epigenetics research on the environment-allergy relationship. The majority of these EWASs have systematically investigated select environmental exposures during the prenatal and early childhood periods and allergy-associated epigenetic changes in leukocyte-isolated DNA and more recently in nasal cells. Overall, many studies have found consistent DNA methylation associations across cohorts for certain exposures, such as smoking (eg, aryl hydrocarbon receptor repressor gene [AHRR] gene), and allergic diseases (eg, EPX gene). We recommend the integration of both environmental exposures and allergy or asthma within long-term prospective designs to strengthen causality as well as biomarker development. Future studies should collect paired target tissues to examine compartment-specific epigenetic responses, incorporate genetic influences in DNA methylation (methylation quantitative trait locus), replicate findings across diverse populations, and carefully interpret epigenetic signatures from bulk, target tissue or isolated cells.

EUFOREA summit in Brussels 2023: inspiring the future of allergy & respiratory care

In March 2023, the European Forum for Research and Education in Allergy and Airways diseases (EUFOREA) organized its bi-annual Summit in Brussels with expert panel members of EUFOREA, representatives of the EUFOREA patient advisory board, and the EUFOREA board and management teams. Its aim was to define the research, educational and advocacy initiatives to be developed by EUFOREA over the next 2 years until the 10th anniversary in 2025. EUFOREA is an international non-for-profit organization forming an alliance of all stakeholders dedicated to reducing the prevalence and burden of chronic allergic and respiratory diseases via research, education, and advocacy. Based on its medical scientific core competency, EUFOREA offers an evidence-supported platform to introduce innovation and education in healthcare leading to optimal patient care, bridging the gap between latest scientific evidence and daily practice. Aligned with the mission of improving health care, the expert panels of asthma, allergic rhinitis (AR), chronic rhinosinusitis (CRS) & European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS), allergen immunotherapy (AIT) and paediatrics have proposed and elaborated a variety of activities that correspond to major unmet needs in the allergy and respiratory field. The current report provides a concise overview of the achievements, ambitions, and action plan of EUFOREA for the future, allowing all stakeholders in the allergy and respiratory field to be up-dated and inspired to join forces in Europe and beyond.

Climate change and respiratory disease: clinical guidance for healthcare professionals

Climate change is one of the major public health emergencies with already unprecedented impacts on our planet, environment and health. Climate change has already resulted in substantial increases in temperatures globally and more frequent and extreme weather in terms of heatwaves, droughts, dust storms, wildfires, rainstorms and flooding, with prolonged and altered allergen and microbial exposure as well as the introduction of new allergens to certain areas. All these exposures may have a major burden on patients with respiratory conditions, which will pose increasing challenges for respiratory clinicians and other healthcare providers. In addition, complex interactions between these different factors, along with other major environmental risk factors (e.g. air pollution), will exacerbate adverse health effects on the lung. For example, an increase in heat and sunlight in urban areas will lead to increases in ozone exposure among urban populations; effects of very high exposure to smoke and pollution from wildfires will be exacerbated by the accompanying heat and drought; and extreme precipitation events and flooding will increase exposure to humidity and mould indoors. This review aims to bring respiratory healthcare providers up to date with the newest research on the impacts of climate change on respiratory health. Respiratory clinicians and other healthcare providers need to be continually educated about the challenges of this emerging and growing public health problem and be equipped to be the key players in solutions to mitigate the impacts of climate change on patients with respiratory conditions.

Educational aims

To define climate change and describe major related environmental factors that pose a threat to patients with respiratory conditions.To provide an overview of the epidemiological evidence on climate change and respiratory diseases.To explain how climate change interacts with air pollution and other related environmental hazards to pose additional challenges for patients.To outline recommendations to protect the health of patients with respiratory conditions from climate-related environmental hazards in clinical practice.To outline recommendations to clinicians and patients with respiratory conditions on how to contribute to mitigating climate change.

Asthma

Asthma is one of the most common chronic non-communicable diseases worldwide and is characterised by variable airflow obstruction, causing dyspnoea and wheezing. Highly effective therapies are available; asthma morbidity and mortality have vastly improved in the past 15 years, and most patients can attain good asthma control. However, undertreatment is still common, and improving patient and health-care provider understanding of when and how to adjust treatment is crucial. Asthma management consists of a cycle of assessment of asthma control and risk factors and adjustment of medications accordingly. With the introduction of biological therapies, management of severe asthma has entered the precision medicine era-a shift that is driving clinical ambitions towards disease remission. Patients with severe asthma often have co-existing conditions contributing to their symptoms, mandating a multidimensional management approach. In this Seminar, we provide a clinically focused overview of asthma; epidemiology, pathophysiology, diagnosis, and management in children and adults.

Climate change, airborne allergens, and three translational mitigation approaches

One of the important adverse impacts of climate change on human health is increases in allergic respiratory diseases such as allergic rhinitis and asthma. This impact is via the effects of increases in atmospheric carbon dioxide concentration and air temperature on sources of airborne allergens such as pollen and fungal spores. This review describes these effects and then explores three translational mitigation approaches that may lead to improved health outcomes, with recent examples and developments highlighted. Impacts have already been observed on the seasonality, production and atmospheric concentration, allergenicity, and geographic distribution of airborne allergens, and these are projected to continue into the future. A technological revolution is underway that has the potential to advance patient management by better avoiding associated increased exposures, including automated real-time airborne allergen monitoring, airborne allergen forecasting and modelling, and smartphone apps for mitigating the health impacts of airborne allergens.

Dietary Emulsifiers Exacerbate Food Allergy and Colonic Type 2 Immune Response through Microbiota Modulation

The significant increase in food allergy incidence is correlated with dietary changes in modernized countries. Here, we investigated the impact of dietary emulsifiers on food allergy by employing an experimental murine model. Mice were exposed to drinking water containing 1.0% carboxymethylcellulose (CMC) or Polysorbate-80 (P80) for 12 weeks, a treatment that was previously demonstrated to induce significant alterations in microbiota composition and function leading to chronic intestinal inflammation and metabolic abnormalities. Subsequently, the ovalbumin food allergy model was applied and characterized. As a result, we observed that dietary emulsifiers, especially P80, significantly exacerbated food allergy symptoms, with increased OVA-specific IgE induction and accelerated type 2 cytokine expressions, such as IL-4, IL-5, and IL-13, in the colon. Administration of an antibiotic regimen completely reversed the emulsifier-induced exacerbated susceptibility to food allergy, suggesting a critical role played by the intestinal microbiota in food allergy and type 2 immune responses.