Allergens and thunderstorm asthma

Alternaria Allergy and Immunotherapy

BACKGROUND

Allergen immunotherapy (AIT) is the only known causative treatment for Alternaria allergy, but the difficulty in standardizing Alternaria extracts hampers its effectiveness and safety.

SUMMARY

Alternaria, a potent airborne allergen, has a high sensitization rate and is known to trigger the onset and exacerbation of respiratory allergies, even inducing fungal food allergy syndrome in some cases. It can trigger a type 2 inflammatory response, leading to an increase in the secretion of type 2 inflammatory cytokines and eosinophils, which are the culprits behind allergic symptoms. Diagnosing Alternaria allergy is a multistep process, involving a careful examination of clinical symptoms, medical history, skin prick tests, serum-specific IgE detection, or provocation tests. Alt a1, the major component of Alternaria, is a vital player in diagnosing Alternaria allergy through component-resolved diagnosis. Interestingly, Alternaria can reduce the protein activity of other allergens like pollen and cat dander when mixed with them. In order to solve the problems of standardization, efficacy and safety of traditional Alternaria AIT, novel AIT methods targeting Alt a1 and innovative vaccines such as epitope, DNA, and mRNA vaccines seem promising in bypassing the standardization issue of Alternaria extracts. But these studies are in early stages, and most researches are still focused on animal models, calling for more evidence to validate their use in humans.

KEY MESSAGES

This review delves into the various aspects of Alternaria allergy, including characteristics, epidemiology, immune mechanisms, diagnosis, clinical manifestations, and the application and limitations of Alternaria AIT, aiming to provide a foundation for the management of patients with Alternaria allergy.

Special Issue "Molecular and Cellular Advances in Atopic Diseases"

Atopic diseases, which currently affect around one billion people worldwide, are experiencing a rising prevalence [...].

Role of mechanoregulation in mast cell-mediated immune inflammation of the smooth muscle in the pathophysiology of esophageal motility disorders

Major esophageal disorders involve obstructive transport of bolus to the stomach, causing symptoms of dysphagia and impaired clearing of the refluxed gastric contents. These may occur due to mechanical constriction of the esophageal lumen or loss of relaxation associated with deglutitive inhibition, as in achalasia-like disorders. Recently, immune inflammation has been identified as an important cause of esophageal strictures and the loss of inhibitory neurotransmission. These disorders are also associated with smooth muscle hypertrophy and hypercontractility, whose cause is unknown. This review investigated immune inflammation in the causation of smooth muscle changes in obstructive esophageal bolus transport. Findings suggest that smooth muscle hypertrophy occurs above the obstruction and is due to mechanical stress on the smooth muscles. The mechanostressed smooth muscles release cytokines and other molecules that may recruit and microlocalize mast cells to smooth muscle bundles, so that their products may have a close bidirectional effect on each other. Acting in a paracrine fashion, the inflammatory cytokines induce genetic and epigenetic changes in the smooth muscles, leading to smooth muscle hypercontractility, hypertrophy, and impaired relaxation. These changes may worsen difficulty in the esophageal transport. Immune processes differ in the first phase of obstructive bolus transport, and the second phase of muscle hypertrophy and hypercontractility. Moreover, changes in the type of mechanical stress may change immune response and effect on smooth muscles. Understanding immune signaling in causes of obstructive bolus transport, type of mechanical stress, and associated smooth muscle changes may help pathophysiology-based prevention and targeted treatment of esophageal motility disorders.NEW & NOTEWORTHY Esophageal disorders such as esophageal stricture or achalasia, and diffuse esophageal spasm are associated with smooth muscle hypertrophy and hypercontractility, above the obstruction, yet the cause of such changes is unknown. This review suggests that smooth muscle obstructive disorders may cause mechanical stress on smooth muscle, which then secretes chemicals that recruit, microlocalize, and activate mast cells to initiate immune inflammation, producing functional and structural changes in smooth muscles. Understanding the immune signaling in these changes may help pathophysiology-based prevention and targeted treatment of esophageal motility disorders.

Outdoor Alternaria and Cladosporium spores and acute asthma

BACKGROUND

Outdoor Alternaria and Cladosporium spores are ubiquitous. Few studies have assessed their impact on asthma hospitalizations providing conflicting results, mainly focused on vulnerable paediatric populations. We aimed to study the impact of outdoor Alternaria and Cladosporium concentrations on acute hospitalizations in the Capital Region of Denmark.

METHODS

This is a bi-directional case-crossover study with 26 years of national registry data at individual level on acute asthma hospitalizations and daily average data on Alternaria and Cladosporium, pollen (Artemisia, Poaceae), maximal temperature, and air pollution. Conditional logistic regression models were applied to assess the associations. Concentration quartiles at lag 0 were used for categorizing the exposure.

RESULTS

For lags 0-2, the odds of hospitalization were significantly higher for both Alternaria and Cladosporium at concentration quartile 2-4 compared with quartile 1. When stratified for age and sex, odds of hospitalization at Alternaria quartiles 2-4 were significantly higher in males below 40 years at lag 0-2, and at lag 0 in females (18-30 years), while quartiles 2-4 of Cladosporium concentrations were associated with significantly higher odds in boys (0-17 years) at lag 1-3, males (18-39 years) at lag 0-1, females (18-39 years) at lag 1-2, males (40-64 years) at lag 0-2, females (40-64 years) at lag 0 and 2, in seniors (65+ years) male at lag 1-2 and female at lag 0-1. The effect of Alternaria varied significantly depending on the level of Cladosporium (p < .0001).

CONCLUSION

Ambient Alternaria and Cladosporium spores can induce asthma hospitalizations. Males are more susceptible to both genera. Males and females under age 40 years are more susceptible to Alternaria.

Seasonal variation characteristics of inhalable bacteria in bioaerosols and antibiotic resistance genes in Harbin

Bioaerosols have received extensive attention due to their impact on climate, ecological environment, and human health. This study aimed to reveal the driving factors that structure bacterial community composition and the transmission route of antibiotic resistance genes (ARGs) in PM_2.5. The results showed that the bacterial concentration in spring (8.76 × 10⁵ copies/m³) was significantly higher than that in summer (1.03 × 10⁵ copies/m³) and winter (4.74 × 10⁴ copies/m³). Low temperatures and air pollution in winter negatively affected bacterial concentrations. Keystone taxa were identified by network analysis. Although about 50 % of the keystone taxa had low relative abundances, the strong impact of complex interactions between keystone taxa and other taxa on bacterial community structure deserved attention. The bacterial community assembly was dominated by stochastic processes (79.3 %). Interactions between bacteria and environmental filtering together affected bacterial community composition. Vertical gene transfer played an important role in the transmission of airborne ARGs. Given the potential integration and expression of ARGs in recipients, the human exposure risk due to high concentrations of ARGs and mobile genetic elements cannot be ignored. This study highlights human exposure to inhalable bacterial pathogens and ARGs in urban areas.

Gone with the Wind: Microbial Communities Associated with Dust from Emissive Farmlands

Dust is a major vehicle for the dispersal of microorganisms across the globe. While much attention has been focused on microbial dispersal in dust plumes from major natural dust sources, very little is known about the fractionation processes that select for the "dust microbiome." The recent identification of highly emissive, agricultural land dust sources in South Africa has provided the opportunity to study the displacement of microbial communities through dust generation and transport. In this study, we aimed to document the microbial communities that are carried in the dust from one of South Africa's most emissive locations, and to investigate the selective factors that control the partitioning of microbial communities from soil to dust. For this purpose, dust samples were generated at different emission sources using a Portable In-Situ Wind Erosion Lab (PI-SWERL), and the taxonomic composition of the resulting microbiomes was compared with the source soils. Dust emission processes resulted in the clear fractionation of the soil bacterial community, where dust samples were significantly enriched in spore-forming taxa. Conversely, little fractionation was observed in the soil fungal communities, such that the dust fungal fingerprint could be used to identify the source soil. Dust microbiomes were also found to vary according to the emission source, suggesting that land use significantly affected the structure and fractionation of microbial communities transported in dust plumes. In addition, several potential biological allergens of fungal origin were detected in the dust microbiomes, highlighting the potential detrimental effects of dust plumes emitted in South Africa. This study represents the first description of the fractionation of microbial taxa occurring at the source of dust plumes and provides a direct link between land use and its impact on the dust microbiome.

Alternaria as an Inducer of Allergic Sensitization

Alternaria alternata is a saprophytic mold whose spores are disseminated in warm dry air, the typical weather of the Mediterranean climate region (from 30° to 45°), with a peak during the late summer and early autumn. Alternaria spores are known to be biological contaminants and a potent source of aeroallergens. One consequence of human exposure to Alternaria is an increased risk of developing asthma, with Alt a 1 as its main elicitor and a marker of primary sensitization. Although the action mechanism needs further investigation, a key role of the epithelium in cytokine production, TLR-activated alveolar macrophages and innate lymphoid cells in the adaptive response was demonstrated. Furthermore, sensitization to A. alternata seems to be a trigger for the development of co-sensitization to other allergen sources and may act as an exacerbator of symptoms and an elicitor of food allergies. The prevalence of A. alternata allergy is increasing and has led to expanding research on the role of this fungal species in the induction of IgE-mediated respiratory diseases. Indeed, recent research has allowed new perspectives to be considered in the assessment of exposure and diagnosis of fungi-induced allergies, although more studies are needed for the standardization of immunotherapy formulations.

Thunderstorm asthma: an overview of mechanisms and management strategies

INTRODUCTION

Epidemic thunderstorm asthma (ETSA) is due to a complex interaction of environmental and individual susceptibility factors, with outbreaks reported globally over the last four decades. Australia has been particularly susceptible with nearly half of episodes reported internationally, culminating in the catastrophic Melbourne 2016 event.

AREAS COVERED

Reported ETSA episodes are reviewed for common environmental and meteorological risk factors. Allergen aerobiology interaction with thunderstorm activity and rapid weather condition changes is examined. Assessment of the clinical and immunological data highlights risk factors for ETSA presentation, hospital admission, and intensive care admission. Risk factors associated with ETSA deaths are evaluated. Public health strategies, as well as pharmacological and immunological management approaches to reduce individual susceptibility and prevent ETSA are discussed.

EXPERT OPINION

Improved understanding of the specific meteorological factors predisposing to the greatest risk of ETSA to improve forecasting is required. Better monitoring of aeroallergen levels in areas of greatest geographic risk, with further research into allergen aerobiology underpinning mechanisms of allergen exposure is needed. The role of climate change in increasing the risk of ETSA outbreaks requires further research. Public awareness and education are required to reduce exposure, and to improve uptake of pharmacological and immunological risk reduction and preventive strategies.

Investigating the culturable atmospheric fungal and bacterial microbiome in West Texas: implication of dust storms and origins of the air parcels

Individuals often experience ailments such as allergies, asthma and respiratory tract infections throughout the year. Weather reports often include estimations of common allergens that can affect these individuals. To describe the local 'atmospheric microbiome' in Lubbock, Texas, USA, we examined the culturable fungal and bacterial microbiome present in the air on calm and dust storm days using internal transcribed spacer (ITS)-1 and 16S rRNA amplicon sequencing, respectively. While some types of airborne fungi were frequently present throughout the year, distinct differences were also observed between calm and dust storm days. We also observed the influence of the origin of air parcels and wind elevation of the air trajectory. The most abundant genera of fungi identified during the study period were Cryptococcus, Aureobasidium, Alternaria, Cladosporium and Filobasidium. This observation was not surprising considering the agricultural intensive environment of West Texas. Interestingly, Cladosporium, a common allergenic mold, was increased during days with dust storm events. The predominant bacterial genera observed were Bacillus, Pseudomonas, Psychrobacter, Massilia and Exiguobacterium. The relative abundance of the psychrophiles, Psychrobacter and Exiguobacterium, was surprising, given the semi-aridity of West Texas. Coupling our observations with back trajectories of the wind (Hybrid Single-Particle Lagrangian Integrated Trajectory models) demonstrated that dust storms, regional anthropogenic activity and origin of air parcels are important influences on the diversity and temporal presence of the atmospheric microbiome.

Alternaria alternata Accelerates Loss of Alveolar Macrophages and Promotes Lethal Influenza A Infection

Chronic inhalation of fungi and fungal components has been linked to the development of respiratory disorders, although their role with respect to the pathogenesis of acute respiratory virus infection remains unclear. Here, we evaluate inflammatory pathology induced by repetitive administration of a filtrate of the ubiquitous fungus, Alternaria alternata, and its impact on susceptibility to infection with influenza A. We showed previously that A. alternata at the nasal mucosae resulted in increased susceptibility to an otherwise sublethal inoculum of influenza A in wild-type mice. Here we demonstrate that A. alternata-induced potentiation of influenza A infection was not dependent on fungal serine protease or ribonuclease activity. Repetitive challenge with A. alternata prior to virus infection resulted proinflammatory cytokines, neutrophil recruitment, and loss of alveolar macrophages to a degree that substantially exceeded that observed in response to influenza A infection alone. Concomitant administration of immunomodulatory Lactobacillus plantarum, a strategy shown previously to limit virus-induced inflammation in the airways, blocked the exaggerated lethal response. These observations promote an improved understanding of severe influenza infection with potential clinical relevance for individuals subjected to continuous exposure to molds and fungi.

Summer storms and their effects on the spectrum and quantity of airborne bioparticles in Bratislava, Central Europe

A thunderstorm is a risk factor for severe respiratory allergy or asthma attacks in patients suffering from pollen/spore allergy. This study aimed to investigate the changes in the spectrum and quantity of pollen and fungal spores in the air of Bratislava during summer storms as well as the impact of selected environmental parameters on these changes. Pollen/spore samples were collected using a Burkard volumetric aerospore trap during summer 2016. To identify those types of pollen/spores that may harm human health during the storm episodes, we analysed how the concentration of individual bioparticles in the air changed during pre-storm/storm/post-storm periods. The effect of environmental variables on the concentration of selected pollen/spore types was evaluated through Spearman's correlation analysis. The results of our study suggest that thunderstorm-related respiratory allergy symptoms in the study area may be caused by (1) spores of Myxomycetes, the airborne concentration of which increases due to an increase in wind speed during the pre-storm period; (2) ruptured pollen and Diatripaceae spores, the concentration of which increases due to increase in precipitation and relative air humidity, respectively, during the storm period; and (3) spores of Fusarium and Leptosphaeria, the concentration of which increases due to increase in precipitation and air temperature, respectively, during the post-storm period.

Thunderstorm asthma outbreak, a rare phenomenon in southwest Iran: patients' perspectives

Previous studies that described thunderstorm asthma, which is a rare event, are not being well explained. This study was conducted, to describe the patient perspective on their asthma attack experience during Ahvaz post-rain phenomenon. We have interviewed patients present in the Naft clinic of Ahvaz, during 28th October and the first week of November 2015. Recruitment was continued as saturation ensued by 33 participants. An inductive content analysis was used to evaluate the interviews. The key finding indicated a climatic condition, direct or indirect contact with rain, history of allergy, and physical conditions are the main categories. The patient emphasized the importance of dust, humidity, first autumn rainfall, and environmental air pollution in occurrences of the event. When exposed to further rains (third rainfall onward), they were less likely to experience dyspnea or shortness of breath. However, being indoor or out at the time of rainfall reported not to be related to the onset of asthma exacerbation. This study yielded that patients' asthma outbreak is a climate-related health impact and many individual factors triggering this issue. Patients concerns need future investigation and public health emergency planning and response arrangements.

Seasonal asthma in Melbourne, Australia, and some observations on the occurrence of thunderstorm asthma and its predictability

We examine the seasonality of asthma-related hospital admissions in Melbourne, Australia, in particular the contribution and predictability of episodic thunderstorm asthma. Using a time-series ecological approach based on asthma admissions to Melbourne metropolitan hospitals, we identified seasonal peaks in asthma admissions that were centred in late February, June and mid-November. These peaks were most likely due to the return to school, winter viral infections and seasonal allergies, respectively. We performed non-linear statistical regression to predict daily admission rates as functions of the seasonal cycle, weather conditions, reported thunderstorms, pollen counts and air quality. Important predictor variables were the seasonal cycle and mean relative humidity in the preceding two weeks, with higher humidity associated with higher asthma admissions. Although various attempts were made to model asthma admissions, none of the models explained substantially more variation above that associated with the annual cycle. We also identified a list of high asthma admissions days (HAADs). Most HAADs fell in the late-February return-to-school peak and the November allergy peak, with the latter containing the greatest number of daily admissions. Many HAADs in the spring allergy peak may represent episodes of thunderstorm asthma, as they were associated with rainfall, thunderstorms, high ambient grass pollen levels and high humidity, a finding that suggests thunderstorm asthma is a recurrent phenomenon in Melbourne that occurs roughly once per five years. The rarity of thunderstorm asthma events makes prediction challenging, underscoring the importance of maintaining high standards of asthma management, both for patients and health professionals, especially during late spring and early summer.

An epidemic of thunderstorm asthma in Melbourne 2016: asthma, rhinitis, and other previous allergies

Background

On 21st November 2016, Melbourne experienced an epidemic of ‘thunderstorm asthma.’ Although previously described in the literature, risk factors and natural history remain incompletely understood.

Objective

Our aim was to follow up those presenting to the 3 Emergency Departments (EDs) in our health service during the epidemic, and assess their history for previous asthma, rhinitis, and allergies.

Methods

ED notes of all respiratory presentations within 48 hours of the thunderstorm event were reviewed and patients with acute asthma included. A standardised questionnaire was devised encompassing asthma diagnosis, undiagnosed asthma symptoms and rhinitis severity. Patients were contacted by phone within 30 days of the event.

Results

Three hundred forty-four patients were identified overall; 263 patients were contactable and completed a phone or mail questionnaire. The mean age was 32.7 ± 19.2 years (range, 6 months–87 years; 25% < 18 years) with 58% male sex. A previous diagnosis of asthma was present in 42% (n = 111), and there was no previous asthma diagnosis in 58% (n = 152). Of those who had no asthma diagnosis 53% had probable undiagnosed asthma. Overall, rhinitis prevalence was 88%, of which 72% were moderate or severe (Allergic Rhinitis and its Impact on Asthma guidelines) and 51% (n = 133) reported a history of grass pollen allergy.

Conclusion

Our data highlights the importance of atopy and rhinitis as risk factors for epidemic thunderstorm asthma. Better identification of undiagnosed asthma, and implementing treatment of asthma and rhinitis may be important.

Outdoor Environment and Pediatric Asthma: An Update on the Evidence from North America

Introduction. The evidence about the association between asthma and outdoor environmental factors has been inadequate for certain allergens. Even less is known about how these associations vary across seasons and climate regions. We reviewed recent literature from North America for research related to outdoor environmental factors and pediatric asthma, with attention to spatial-temporal variations of these associations. Method. We included indexed literature between years 2010 and 2015 on outdoor environmental factors and pediatric asthma, by searching PubMed. Results. Our search resulted in 33 manuscripts. Studies about the link between pediatric asthma and traffic-related air pollutants (TRAP) consistently confirmed the correlation between TRAP and asthma. For general air pollution, the roles of PM_2.5 and CO were consistent across studies. The link between asthma and O₃ varied across seasons. Regional variation exists in the role of SO₂. The impact of pollen was consistent across seasons, whereas the role of polycyclic aromatic hydrocarbon was less consistent. Discussion. Recent studies strengthened the evidence about the roles of PM_2.5, TRAP, CO, and pollen in asthma, while the evidence for roles of PM_10-2.5, PM₁₀, O₃, NO₂, SO₂, and polycyclic aromatic hydrocarbon in asthma was less consistent. Spatial-temporal details of the environment are needed in future studies of asthma and environment.

Is allergic sensitization relevant in severe asthma? Which allergens may be culprit?

Severe asthma is a major health concern. The allergic (IgE-mediated) form of asthma is well known from a pathogenic viewpoint. We searched the available literature to identify which allergens are most frequently associated with severe, refractory or life threatening asthma. According to the results, molds, pet dander, cockroach and ragweed were more frequently responsible for severe asthma. Thunderstorm asthma, in addition, represents a special association between allergic sensitization and an external climatic factor. A detailed knowledge of the most harmful allergens is mandatory for an appropriate diagnostic and preventive approach.

Thunderstorm-related asthma: what happens and why

The fifth report issued by the Intergovernmental Panel on Climate Change forecasts that greenhouse gases will increase the global temperature as well as the frequency of extreme weather phenomena. An increasing body of evidence shows the occurrence of severe asthma epidemics during thunderstorms in the pollen season, in various geographical zones. The main hypotheses explaining association between thunderstorms and asthma claim that thunderstorms can concentrate pollen grains at ground level which may then release allergenic particles of respirable size in the atmosphere after their rupture by osmotic shock. During the first 20-30 min of a thunderstorm, patients suffering from pollen allergies may inhale a high concentration of the allergenic material that is dispersed into the atmosphere, which in turn can induce asthmatic reactions, often severe. Subjects without asthma symptoms, but affected by seasonal rhinitis can also experience an asthma attack. All subjects affected by pollen allergy should be alerted to the danger of being outdoors during a thunderstorm in the pollen season, as such events may be an important cause of severe exacerbations. In light of these observations, it is useful to predict thunderstorms and thus minimize thunderstorm-related events.

Mast cells in asthma--state of the art

Mast cells (MCs) play a central role in tissue homoeostasis, sensing the local environment through numerous innate cell surface receptors. This enables them to respond rapidly to perceived tissue insults with a view to initiating a co-ordinated programme of inflammation and repair. However, when the tissue insult is chronic, the ongoing release of multiple pro-inflammatory mediators, proteases, cytokines and chemokines leads to tissue damage and remodelling. In asthma, there is strong evidence of ongoing MC activation, and their mediators and cell-cell signals are capable of regulating many facets of asthma pathophysiology. This article reviews the evidence behind this.

The spectrum of allergic fungal diseases of the upper and lower airways

Fungi cause a wide spectrum of fungal diseases of the upper and lower airways. There are three main phyla involved in allergic fungal disease: (1) Ascomycota (2) Basidiomycota (3) Zygomycota. Allergic fungal rhinosinusitis (AFRS) causes chronic rhinosinusitis symptoms and is caused predominantly by Aspergillus fumigatus in India and Bipolaris in the United States. The recommended treatment approach for AFRS is surgical intervention and systemic steroids. Allergic bronchopulmonary aspergillosis (APBA) is most commonly diagnosed in patients with asthma or cystic fibrosis. Long term systemic steroids are the mainstay treatment option for ABPA with the addition of an antifungal medication. Fungal sensitization or exposure increases a patient's risk of developing severe asthma and has been termed severe asthma associated with fungal sensitivity (SAFS). Investigating for triggers and causes of a patient's asthma should be sought to decrease worsening progression of the disease.

Sensitization to fungal allergens: Resolved and unresolved issues

Exposure and sensitization to fungal allergens can promote the development and worsening of allergic diseases. Although numerous species of fungi have been associated with allergic diseases in the literature, the significance of fungi from the genera Alternaria, Cladosporium, Penicillium, Aspergillus, and Malassezia has been well documented. However, it should be emphasized that the contribution of different fungal allergens to allergic diseases is not identical, but species-specific. Alternaria and Cladosporium species are considered to be important outdoor allergens, and sensitization and exposure to species of these genera is related to the development of asthma and rhinitis, as well as epidemics of asthma exacerbation, including life-threatening asthma exacerbation. In contrast, xerophilic species of Penicillium and Aspergillus, excluding Aspergillus fumigatus, are implicated in allergic diseases as indoor allergens. A. fumigatus has a high capacity to colonize the bronchial tract of asthmatic patients, causing severe persistent asthma and low lung function, and sometimes leading to allergic bronchopulmonary aspergillosis. Malassezia are common commensals of healthy skin, although they are also associated with atopic dermatitis, especially on the head and neck, but not with respiratory allergies. Despite its importance in the management of allergic diseases, precise recognition of species-specific IgE sensitization to fungal allergens is often challenging because the majority of fungal extracts exhibit broad cross-reactivity with taxonomically unrelated fungi. Recent progress in gene technology has contributed to the identification of specific and cross-reactive allergen components from different fungal sources. However, data demonstrating the clinical relevance of IgE reactivity to these allergen components are still insufficient.

Targeting allergenic fungi in agricultural environments aids the identification of major sources and potential risks for human health

Fungi are, after pollen, the second most important producers of outdoor airborne allergens. To identify sources of airborne fungal allergens, a workflow for qPCR quantification from environmental samples was developed, thoroughly tested, and finally applied. We concentrated on determining the levels of allergenic fungi belonging to Alternaria, Cladosporium, Fusarium, and Trichoderma in plant and soil samples from agricultural fields in which cereals were grown. Our aims were to identify the major sources of allergenic fungi and factors potentially influencing their occurrence. Plant materials were the main source of the tested fungi at and after harvest. Amounts of A. alternata and C. cladosporioides varied significantly in fields under different management conditions, but absolute levels were very high in all cases. This finding suggests that high numbers of allergenic fungi may be an inevitable side effect of farming in several crops. Applied in large-scale studies, the concept described here may help to explain the high number of sensitization to airborne fungal allergens.

Anti-inflammatory actions of Chemoattractant Receptor-homologous molecule expressed on Th2 by the antagonist MK-7246 in a novel rat model of Alternaria alternata elicited pulmonary inflammation

Alternaria alternata is a fungal allergen linked to the development of severe asthma in humans. In view of the clinical relationship between A. alternata and asthma, we sought to investigate the allergic activity of this antigen after direct application to the lungs of Brown Norway rats. Here we demonstrate that a single intratracheal instillation of A. alternata induces dose and time dependent eosinophil influx, edema and Type 2 helper cell cytokine production in the lungs of BN rats. We established the temporal profile of eosinophilic infiltration and cytokine production, such as Interleukin-5 and Interleukin-13, following A. alternata challenge. These responses were comparable to Ovalbumin induced models of asthma and resulted in peak inflammatory responses 48h following a single challenge, eliminating the need for multiple sensitizations and challenges. The initial perivascular and peribronchiolar inflammation preceded alveolar inflammation, progressing to a more sub-acute inflammatory response with notable epithelial cell hypertrophy. To limit the effects of an A. alternata inflammatory response, MK-7246 was utilized as it is an antagonist for Chemoattractant Receptor-homologous molecule expressed in Th2 cells. In a dose-dependent manner, MK-7246 decreased eosinophil influx and Th2 cytokine production following the A. alternata challenge. Furthermore, therapeutic administration of corticosteroids resulted in a dose-dependent decrease in eosinophil influx and Th2 cytokine production. Reproducible asthma-related outcomes and amenability to pharmacological intervention by mechanisms relevant to asthma demonstrate that an A. alternata induced pulmonary inflammation in BN rats is a valuable preclinical pharmacodynamic in vivo model for evaluating the pharmacological inhibitors of allergic pulmonary inflammation.

Indoor fungal diversity and asthma: a meta-analysis and systematic review of risk factors

BACKGROUND

Indoor dampness increases the risk of indoor fungal growth. A complex interaction between occupant behaviors and the built environment are thought to affect indoor fungal concentrations and species diversity, which are believed to increase the risk of having asthma, exacerbation of asthma symptoms, or both. To date, no systematic review has investigated this relationship.

OBJECTIVE

This review aims to assess the relationship between exposure to indoor fungi identified to the genera or species level on asthma outcomes in children and adults.

METHODS

Ten databases were systematically searched on April 18, 2013, and limited to articles published since 1990. Reference lists were independently screened by 2 reviewers, and authors were contacted to identify relevant articles. Data were extracted from included studies meeting our eligibility criteria by 2 reviewers and quality assessed by using the Newcastle-Ottawa scale designed for assessment of case-control and cohort studies.

RESULTS

Cladosporium, Alternaria, Aspergillus, and Penicillium species were found to be present in higher concentrations in homes of asthmatic participants. Exposure to Penicillium, Aspergillus, and Cladosporium species were found to be associated with increased risk of reporting asthma symptoms by a limited number of studies. The presence of Cladosporium, Alternaria, Aspergillus, and Penicillium species increased the exacerbation of current asthma symptoms by 36% to 48% compared with those exposed to lower concentrations of these fungi, as shown by using random-effect estimates. Studies were of medium quality and showed medium-high heterogeneity, but evidence concerning the specific role of fungal species was limited.

CONCLUSION

Longitudinal studies assessing increased exposure to indoor fungi before the development of asthma symptoms suggests that Penicillium, Aspergillus, and Cladosporium species pose a respiratory health risk in susceptible populations. Increased exacerbation of current asthma symptoms in children and adults were associated with increased levels of Penicillium, Aspergillus, Cladosporium, and Alternaria species, although further work should consider the role of fungal diversity and increased exposure to other fungal species.

Climate change and air pollution: Effects on pollen allergy and other allergic respiratory diseases

The observational evidence indicates that recent regional changes in climate, particularly temperature increases, have already affected a diverse set of physical and biological systems in many parts of the world. Allergens patterns are also changing in response to climate change and air pollution can modify the allergenic potential of pollen grains especially in the presence of specific weather conditions.

Although genetic factors are important in the development of asthma and allergic diseases, their rising trend can be explained only by changes occurring in the environment and urban air pollution by motor vehicles has been indicated as one of the major risk factors responsible for this increase.

Despite some differences in the air pollution profile and decreasing trends of some key air pollutants, air quality is an important concern for public health in the cities throughout the world.

Due to climate change, air pollution patterns are changing in several urbanized areas of the world with a significant effect on respiratory health. The underlying mechanisms of all these interactions are not well known yet. The consequences on health vary from decreases in lung function to allergic diseases, new onset of diseases, and exacerbation of chronic respiratory diseases. In addition, it is important to recall that an individual’s response to pollution exposure depends on the source and components of air pollution, as well as meteorological conditions. Indeed, some air pollution-related incidents with asthma aggravation do not depend only on the increased production of air pollution, but rather on atmospheric factors that favor the accumulation of air pollutants at ground level.

Associations between thunderstorms and asthma morbidity of pollinosis-affected people have also been identified in multiple locations around the world (Fig.1).

Cite this as D’Amato G, Bergmann KC, Cecchi L, Annesi-Maesano I, Sanduzzi A, Liccardi G, Vitale C, Stanziola A, D’Amato M. Climate change and air pollution — Effects on pollen allergy and other allergic respiratory diseases. Allergo J Int 2014; 23: 17–23 DOI 10.1007/s40629-014-0003-7

A factor clouding the problem is that laboratory evaluations do not reflect what happens during natural exposition.

Considering these aspects, governments worldwide, international organizations, and cooperations such as the World Health Organization (WHO) and the European Health Policy of the European Union (EU) are facing a growing problem of the respiratory effects induced by gaseous and particulate pollutants arising from motor vehicle emissions.

Thunderstorm asthma: an overview of the evidence base and implications for public health advice

Thunderstorm asthma is a term used to describe an observed increase in acute bronchospasm cases following the occurrence of thunderstorms in the local vicinity. The roles of accompanying meteorological features and aeroallergens, such as pollen grains and fungal spores, have been studied in an effort to explain why thunderstorm asthma does not accompany all thunderstorms. Despite published evidence being limited and highly variable in quality due to thunderstorm asthma being a rare event, this article reviews this evidence in relation to the role of aeroallergens, meteorological features and the impact of thunderstorm asthma on health services. This review has found that several thunderstorm asthma events have had significant impacts on individuals' health and health services with a range of different aeroallergens identified. This review also makes recommendations for future public health advice relating to thunderstorm asthma on the basis of this identified evidence.

Climate change, air pollution and extreme events leading to increasing prevalence of allergic respiratory diseases

The prevalence of asthma and allergic diseases has increased dramatically during the past few decades not only in industrialized countries. Urban air pollution from motor vehicles has been indicated as one of the major risk factors responsible for this increase.Although genetic factors are important in the development of asthma and allergic diseases, the rising trend can be explained only in changes occurred in the environment. Despite some differences in the air pollution profile and decreasing trends of some key air pollutants, air quality is an important concern for public health in the cities throughout the world.Due to climate change, air pollution patterns are changing in several urbanized areas of the world, with a significant effect on respiratory health.The observational evidence indicates that recent regional changes in climate, particularly temperature increases, have already affected a diverse set of physical and biological systems in many parts of the world. Associations between thunderstorms and asthma morbidity in pollinosis subjects have been also identified in multiple locations around the world.Allergens patterns are also changing in response to climate change and air pollution can modify the allergenic potential of pollens especially in presence of specific weather conditions.The underlying mechanisms of all these interactions are not well known yet. The consequences on health vary from decreases in lung function to allergic diseases, new onset of diseases, and exacerbation of chronic respiratory diseases.Factor clouding the issue is that laboratory evaluations do not reflect what happens during natural exposition, when atmospheric pollution mixtures in polluted cities are inhaled. In addition, it is important to recall that an individual's response to pollution exposure depends on the source and components of air pollution, as well as meteorological conditions. Indeed, some air pollution-related incidents with asthma aggravation do not depend only on the increased production of air pollution, but rather on atmospheric factors that favour the accumulation of air pollutants at ground level.Considering these aspects governments worldwide and international organizations such as the World Health Organization and the European Union are facing a growing problem of the respiratory effects induced by gaseous and particulate pollutants arising from motor vehicle emissions.

Risk factors for childhood asthma deaths from the UK Eastern Region Confidential Enquiry 2001-2006

BACKGROUND

Confidential enquiries into asthma deaths can identify inadequacies in medical management and factors which contribute to patients' death.

AIMS

To identify risk factors for paediatric asthma deaths over a 6-year period.

METHODS

Observational case-series study of paediatric asthma deaths between 2001-2006 in the UK Eastern Region. Hospital, primary care and post-mortem data were obtained for every child (≤17 yrs) with asthma recorded on the death certificate, and a detailed questionnaire was completed. Information was obtained on asthma severity, medications, hospital admissions, GP and hospital follow-up, adherence, psychosocial / behavioural factors, allergies, details of the terminal attack and precipitating factors.

RESULTS

20 children (10 male; 8-17 yrs; median: 11.5 yrs) died of asthma between 2001-2006. 9/20 had mild to moderate asthma (BTS/ SIGN criteria), 10/20 had severe asthma and 1 child was not known to have asthma. 13/20 were clinically atopic. Only 3 had undergone allergy assessment. 10/20 died between June and August. 12/20 children had adverse psychosocial and behavioural factors. 7/20 children were on non-combination long-acting β2-agonist (LABA) treatment without inhaled corticosteroids (ICS).

CONCLUSIONS

Almost half the deaths occurred in children with mild/moderate asthma. We recommend that allergic factors and seasonal allergy should be identified early, non-combination LABAs avoided, and speculate that overuse of short-acting β2-agonists (SABAs) may indicate non-adherence with ICS. Asthma deaths in children can be avoided if risk factors are identified early.

[Respiratory allergens and asthma exacerbation]

INTRODUCTION

Asthma exacerbations are characterized by a progressive aggravation of respiratory symptoms such as dyspnea, cough, wheezing or chest tightness.

BACKGROUND

The relationship between allergy and asthma exacerbations has been evaluated by epidemiological studies based on various criteria such as oral corticosteroid requirement, emergency room visits and hospital admission for asthma. Many studies have observed that deteriorating asthma can be related to increased exposure to allergens, particularly allergens from house dust mite, cockroach, cat, rodent, mold or pollen. Several studies have demonstrated that sensitization to respiratory allergens and allergen exposure increases the risk of exacerbation of asthma. When asthma exacerbations are work-related, occupational allergens may be implicated.

CONCLUSIONS AND PERSPECTIVES

Most studies provide evidence that allergen exposure contributes to the risk of asthma exacerbations, but other precipitating factors, such as viruses, can interact and increase the risk.

Increased presentations to emergency departments for asthma associated with rye grass pollen season in inland NSW

AIM

This study measured the frequency and geographical extent of peaks in asthma presentations to emergency departments in inland NSW; it assessed the characteristics of patients who presented at peak presentation times during the rye grass pollination season (October-November) and at other times of the year.

METHODS

Data describing over 13 years of daily emergency department presentations with a provisional diagnosis of asthma at nine inland NSW base hospitals were assembled. Days of counts in the top 0.1 percentile for each emergency department were classified as peak asthma count days.

RESULTS

While the rye grass pollen season accounts for only 17% of days in the year, 53% of peak asthma count days fell within that period. Patients aged over 14 years represented 74% of visits on peak asthma count days during the pollen season and 50% on peak days at other times of the year.

DISCUSSION

Under the right climatic conditions, rye grass pollen may be responsible for presentations for acute asthma to emergency departments in inland NSW.