High environmental ozone levels lead to enhanced allergenicity of birch pollen

Birch pollen-induced signatures in dendritic cells are maintained upon additional cytomegalovirus exposure

During the birch pollen season an enhanced incidence of virus infections is noticed, raising the question whether pollen can affect anti-viral responses independent of allergic reactions. We previously showed that birch pollen-treatment of monocyte-derived dendritic cells (moDC) enhances human cytomegalovirus (HCMV) infection. Here we addressed how in moDC the relatively weak pollen response can affect the comparably strong response to HCMV. To this end, moDC were stimulated with aqueous birch pollen extract (APE), HCMV, and APE with HCMV, and transcriptomic signatures were determined after 6 and 24 h of incubation. Infection was monitored upon exposure of moDC to GFP expressing HCMV by flow cytometric analysis of GFP expressing cells. Principle component analysis of RNA sequencing data revealed close clustering of mock and APE treated moDC, whereas HCMV as well as APE with HCMV treated moDC clustered separately after 6 and 24 h of incubation, respectively. Communally induced genes were detected in APE, HCMV and APE with HCMV treated moDC. In APE with HCMV treated moDC, the comparably weak APE induced signatures were maintained after HCMV exposure. In particular, NF-κB/RELA and PI3K/AKT/MAPK signaling were altered upon APE with HCMV exposure. Earlier, we discovered that NF-κB inhibition alleviated APE induced enhancement of HCMV infection. Here we additionally found that impairment of PI3K signaling reduced HCMV infection in HCMV and APE with HCMV treated moDC. APE treated moDC that were exposed to HCMV show a unique host gene signature, which to a large extent is regulated by NF-κB activation and PI3K/AKT/MAPK signaling.

The Relationship of Climate Change to Rhinitis

Evidence is mounting that climate change is having a significant impact on exacerbations of rhinitis. Concomitantly, the prevalence of allergic rhinitis is increasing at an accelerated rate. We herein explore the impact of carbon dioxide, barometric pressure and humidity changes, and anthropogenic pollutants on aeroallergens and rhinitis hypersensitivity. Important immune mechanisms underlying the climate-driven effects on rhinitis are discussed. Also, climate change is shifting ecological zones and seasons, increasing weather extremes, and altering regional atmospheric and environmental conditions. The direct impact of these factors on promoting allergic and nonallergic rhinitis is reviewed.

Biodiversity and human health: A scoping review and examples of underrepresented linkages

Mounting evidence supports the connections between exposure to environmental typologies(such as green and blue spaces)and human health. However, the mechanistic links that connect biodiversity (the variety of life) and human health, and the extent of supporting evidence remain less clear. Here, we undertook a scoping review to map the links between biodiversity and human health and summarise the levels of associated evidence using an established weight of evidence framework. Distinct from other reviews, we provide additional context regarding the environment-microbiome-health axis, evaluate the environmental buffering pathway (e.g., biodiversity impacts on air pollution), and provide examples of three under- or minimally-represented linkages. The examples are (1) biodiversity and Indigenous Peoples' health, (2) biodiversity and urban social equity, and (3) biodiversity and COVID-19. We observed a moderate level of evidence to support the environmental microbiota-human health pathway and a moderate-high level of evidence to support broader nature pathways (e.g., greenspace) to various health outcomes, from stress reduction to enhanced wellbeing and improved social cohesion. However, studies of broader nature pathways did not typically include specific biodiversity metrics, indicating clear research gaps. Further research is required to understand the connections and causative pathways between biodiversity (e.g., using metrics such as taxonomy, diversity/richness, structure, and function) and health outcomes. There are well-established frameworks to assess the effects of broad classifications of nature on human health. These can assist future research in linking biodiversity metrics to human health outcomes. Our examples of underrepresented linkages highlight the roles of biodiversity and its loss on urban lived experiences, infectious diseases, and Indigenous Peoples' sovereignty and livelihoods. More research and awareness of these socioecological interconnections are needed.

The importance of teaching climate-health literacy in psychotherapeutic training and continuing education

Climate-health literacy is the ability to find, access, understand, interpret, evaluate, and communicate information about the impact of climate change on human health and to make decisions and act accordingly to that information. Climate change affects people's health in numerous ways, both directly and indirectly, e.g., by increasing the risks of cardiovascular disease, infections, depression, anxiety disorders, and trauma. It is important for health professionals to understand the complex interaction between climate change and health. A teaching concept is presented that incorporates the core elements of climate-health literacy. On a first level, physical and climatological basics are taught, direct and indirect impacts of climate change on human health, climate protective measures, the psychological background of climate-protective behavior, and professional ethics. Furthermore, via self-awareness and self-reflection, the impact of climate change on the student's mental health should be evaluated. In an advanced level, the direct and indirect impacts of climate change on mental health are taught, coping strategies, resilience, and vulnerability, as well as the role of health-care professionals in the climate crisis. In expert-level lectures, the knowledge can be deepened, and special content like activist burnout can be addressed.

Outdoor airborne allergens: Characterization, behavior and monitoring in Europe

Aeroallergens or inhalant allergens, are proteins dispersed through the air and have the potential to induce allergic conditions such as rhinitis, conjunctivitis, and asthma. Outdoor aeroallergens are found predominantly in pollen grains and fungal spores, which are allergen carriers. Aeroallergens from pollen and fungi have seasonal emission patterns that correlate with plant pollination and fungal sporulation and are strongly associated with atmospheric weather conditions. They are released when allergen carriers come in contact with the respiratory system, e.g. the nasal mucosa. In addition, due to the rupture of allergen carriers, airborne allergen molecules may be released directly into the air in the form of micronic and submicronic particles (cytoplasmic debris, cell wall fragments, droplets etc.) or adhered onto other airborne particulate matter. Therefore, aeroallergen detection strategies must consider, in addition to the allergen carriers, the allergen molecules themselves. This review article aims to present the current knowledge on inhalant allergens in the outdoor environment, their structure, localization, and factors affecting their production, transformation, release or degradation. In addition, methods for collecting and quantifying aeroallergens are listed and thoroughly discussed. Finally, the knowledge gaps, challenges and implications associated with aeroallergen analysis are described.

How does pollen production of allergenic species differ between urban and rural environments?

Pollen production is one plant characteristic that is considered to be altered by changes in environmental conditions. In this study, we investigated pollen production of the three anemophilous species Betula pendula, Plantago lanceolata, and Dactylis glomerata along an urbanization gradient in Ingolstadt, Germany. We compared pollen production with the potential influencing factors urbanization, air temperature, and the air pollutants nitrogen dioxide (NO2) and ozone (O3). While we measured air temperature in the field, we computed concentration levels of NO2 and O3 from a land use regression model. The results showed that average pollen production (in million pollen grains) was 1.2 ± 1.0 per catkin of Betula pendula, 5.0 ± 2.4 per inflorescence of Plantago lanceolata, and 0.7 ± 0.5 per spikelet of Dactylis glomerata. Pollen production was higher in rural compared to urban locations on average for B. pendula (+ 73%) and P. lanceolata (+ 31%), while the opposite was the case for D. glomerata (- 14%). We found that there was substantial heterogeneity across the three species with respect to the association of pollen production and environmental influences. Pollen production decreased for all species with increasing temperature and urbanization, while for increasing pollutant concentrations, decreases were observed for B. pendula, P. lanceolata, and increases for D. glomerata. Additionally, pollen production was found to be highly variable across species and within species-even at small spatial distances. Experiments should be conducted to further explore plant responses to altering environmental conditions.

Impact of meteorological parameters and air pollutants on airborne concentration of Betula pollen and Bet v 1 allergen

The intensity of birch pollen season is expressed by seasonal pollen integral (SPIn, the sum of the mean daily pollen concentration during the birch pollination period) and the amount of Bet v 1 allergen released per birch pollen grain expressed by pollen allergen potency (PAP). Betula pollen and Bet v 1 allergen were simultaneously measured in the air of Bratislava from 2019 to 2022 by using two Burkard traps (Hirst-type and cyclone) in order to evaluate the causes of the seasonal variation in the SPIn and PAP levels. The highest SPIn (19,975 pollen/m3) was observed in 2022 and the lowest one (1484 pollen/m3) in 2021. The average daily PAP level (4.0 pg Bet v 1/pollen) was highest in 2019 and lowest (2.5 pg Bet v 1/pollen) in 2020. We found that seasonal variation in SPIn was associated mainly with the changes in environmental conditions during the pre-season period, whereas the year-to-year variation in PAP levels was attributed to environmental conditions during both pre- and in-season periods. Our results indicate that rainy weather in June 2020 and cold overcast weather in January‒February 2021 resulted in low SPIn in 2021. On the other hand, dry weather in June 2021 and warm weather in January‒February 2022 resulted in high SPIn in 2022. The low average daily PAP level in 2020 was associated with (1) low levels of gaseous air pollutants in March, when the ripening of pollen takes place; (2) an earlier start of the birch main pollen season (MPS); and (3) dry weather during the MPS. On the other hand, high PAP level in 2019 was associated with higher levels of air pollutants in March and during the MPS.

The Notorious Triumvirate in Pediatric Health: Air Pollution, Respiratory Allergy, and Infection

A plausible association is suspected among air pollution, respiratory allergic disorder, and infection. These three factors could cause uncontrollable chronic inflammation in the airway tract, creating a negative impact on the physiology of the respiratory system. This review aims to understand the underlying pathophysiology in explaining the association among air pollution, respiratory allergy, and infection in the pediatric population and to capture the public's attention regarding the interaction among these three factors, as they synergistically reduce the health status of children living in polluted countries globally, including Indonesia.

Betula pendula trees infected by birch idaeovirus and cherry leaf roll virus: Impacts of urbanisation and NO2 levels

Viruses are frequently a microbial biocontaminant of healthy plants. The occurrence of the infection can be also due to environmental stress, like urbanisation, air pollution and increased air temperature, especially under the ongoing climate change. The aim of the present study was to investigate the hypothesis that worsened air quality and fewer green areas may favour the higher frequency of common viral infections, particularly in a common tree in temperate and continental climates, Betula pendula ROTH. We examined 18 trees, during the years 2015-2017, the same always for each year, in the region of Augsburg, Germany. By specific PCR, the frequency of two viruses, Cherry leaf roll virus (CLRV, genus Nepovirus, family Secoviridae), which is frequent in birch trees, and a novel virus tentatively named birch idaeovirus (BIV), which has been only recently described, were determined in pollen samples. The occurrence of the viruses was examined against the variables of urban index, air pollution (O₃ and NO₂), air temperature, and tree morphometrics (trunk perimeter, tree height, crown height and diameter). Generalized Non-linear models (binomial logit with backward stepwise removal of independent variables) were employed. During the study period, both CLRV and BIV were distributed widely throughout the investigated birch individuals. CLRV seemed to be rather cosmopolitan and was present independent of any abiotic factor. BIV's occurrence was mostly determined by higher values of the urban index and of NO₂. Urban birch trees, located next to high-traffic roads with higher NO₂ levels, are more likely to be infected by BIV. Increased environmental stress may lead to more plant viral infections. Here we suggest that this is particularly true for urban spaces, near high-traffic roads, where plants may be more stressed, and we recommend taking mitigation measures for controlling negative human interventions.

Uptake of ozone by allergenic pollen grains

Ozone exacerbates allergy symptoms to certain pollens. The molecular mechanisms by which ozone affects pollen grains (PGs) and allergies are not fully understood, especially as the effects of pollutants may vary depending on the type of pollen. In this work, pollens of 22 different taxa were exposed under laboratory conditions to ozone (100 ppb) to quantify the ozone uptake by the PGs. The ozone uptake was highly variable among the 22 taxa tested. The highest ozone uptake per PG was measured on Acer negundo PGs (2.5 ± 0.2 pg. PG^-1). On average, tree pollens captured significantly more ozone than herbaceous pollens (average values of 0.5 and 0.02 pg. PG^-1, respectively). No single parameter (such as the number of apertures, time of the year for the pollen season, pollen size, or lipid fraction) could predict a pollen's ability to take up ozone. Lipids seem to act as a barrier to ozone uptake and play a protective role for some taxa. After inhalation of PGs, pollen-transported ozone could be transferred to mucous membranes and exacerbate symptoms through oxidative stress and local inflammation. Although the amount of ozone transported is small in absolute terms, it is significant compared to the antioxidant capacity of nasal mucus at a microscale. This mechanism of pollen-induced oxidative stress could explain the aggravation of allergic symptoms during ozone pollution episodes.

Birch pollen-The unpleasant herald of spring

Type I respiratory allergies to birch pollen and pollen from related trees of the order Fagales are increasing in industrialized countries, especially in the temperate zone of the Northern hemisphere, but the reasons for this increase are still debated and seem to be multifaceted. While the most important allergenic molecules of birch pollen have been identified and characterized, the contribution of other pollen components, such as lipids, non-allergenic immunomodulatory proteins, or the pollen microbiome, to the development of allergic reactions are sparsely known. Furthermore, what also needs to be considered is that pollen is exposed to external influences which can alter its allergenicity. These external influences include environmental factors such as gaseous pollutants like ozone or nitrogen oxides or particulate air pollutants, but also meteorological events like changes in temperature, humidity, or precipitation. In this review, we look at the birch pollen from different angles and summarize current knowledge on internal and external influences that have an impact on the allergenicity of birch pollen and its interactions with the epithelial barrier. We focus on epithelial cells since these cells are the first line of defense in respiratory disease and are increasingly considered to be a regulatory tissue for the protection against the development of respiratory allergies.

The Concept of One Health for Allergic Diseases and Asthma

The worldwide prevalence of allergic disease is rising as a result of complex gene-environment interactions that shape the immune system and host response. Climate change and loss of biodiversity are existential threats to humans, animals, plants, and ecosystems. While there is significant progress in the development of targeted therapeutic options to treat allergies and asthma, these approaches are inadequate to meet the challenges faced by climate change. The exposomic approach is needed with the recognition of the bidirectional effect between human beings and the environment. All stakeholders need to work together toward mitigating the effects of climate change and promoting a One Health concept in order to decrease the burden of asthma and allergy and to improve immune health. Healthcare professionals should strive to incorporate One Health counseling, environmental health precepts, and advocacy into their practice.

Skin Physiology, Mucosal Functions, and Symptoms Are Modulated by Grass Pollen and Ozone Double Exposure in Allergic Patients

INTRODUCTION

Along with climate changes, we see an increase in allergic symptoms and the number of pollen-allergic patients in many countries. Increased allergic symptoms are associated with an elevated ozone exposure which may be linked by impaired epithelial barrier function. This study aimed to quantify the clinical effect of ozone and pollen double exposure (DE). We tested whether ozone impairs barrier-related skin physiology and mucosal functions under DE with pollen in grass pollen-allergic patients versus healthy controls.

METHODS

This case-control study included 8 grass pollen-allergic patients and 8 non-allergic healthy subjects exposed to grass pollen and ozone in the GA2LEN pollen chamber, comparing shorter and longer DE duration. Non-invasive skin physiological parameters were assessed, including stratum corneum hydration, skin redness, surface pH, and basal transepidermal water loss as a parameter for epidermal barrier function. The subjects' general well-being, bronchial, nasal, and ocular symptoms were documented.

RESULTS

Skin physiology tests revealed that DE in allergic patients deteriorates the epidermal barrier function and increases the surface pH and skin redness. DE significantly induced nasal secretion in pollen-allergic versus healthy subjects, which was more pronounced with longer DE. The general well-being was significantly impaired under DE versus pollen or ozone alone, with a negative influence of DE duration. No relevant bronchial symptoms were recorded.

CONCLUSION

Skin physiology and nasal mucosal symptoms are negatively affected by ozone and grass pollen DE in allergic patients. The negative effects showed, in some parameters, a dose (time)-response relationship. The pH can be regarded as a possible modulatory mechanism.

Pollen, respiratory viruses, and climate change: Synergistic effects on human health

In recent years, evidence of the synergistic effects of pollen and viruses on respiratory health has begun to accumulate. Pollen exposure is a known risk factor for the incidence and severity of respiratory viral infections. However, recent evidence suggests that pollen exposure may also inhibit or weaken viral infections. A comprehensive summary has not been made and a consensus on the synergistic health effects has not been reached. It is highly possible that climate change will increase the significance of pollen exposure as a cause of respiratory problems and, at the same time, affect the risk of infectious disease outbreaks. It is important to accurately assess how these two factors affect human health separately and concurrently. In this review article, for the first time, the data from previous studies are combined and reviewed and potential research gaps concerning the synergistic effects of pollen and viral exposure are identified.

The differential impact of air pollutants on acute urticaria and chronic urticaria: a time series analysis

Several studies have revealed a relationship between short-term exposure to air pollution and the exacerbation of certain skin conditions. This study was developed to expand on these findings by exploring the potential association between exposure to air pollutants including particulate matter, sulfur dioxide, and ozone and the incidence of acute and chronic urticaria in Shenyang, China, from 2016 to 2018. Exposure-response relationships between daily mean concentrations of these airborne pollutants and visits to outpatient dermatological clinics for acute urticaria and chronic urticaria were evaluated via a time series analysis approach using a generalized additive model. This analysis revealed that a 10 μg/m³ increase in daily mean O₃_8h concentrations was associated with a 0.36% (95% CI, 0.31-0.41%), 0.35% (95% CI, 0.30-0.40%), and 0.34% (95% CI, 0.29-0.39%) increase in the number of outpatient visits for acute urticaria on that day (lag0), lagging day 1 (lag1), and lagging day 2 (lag2), respectively. O3 levels also had a similar but weaker effect on the frequency of patients seeking outpatient care for chronic urticaria. These analyses also revealed that estimated 0.47% (95% CI, 0.41-0.52%) and 0.46% (95% CI, 0.40-0.51%) increases in dermatological outpatient acute urticaria visits were observed for every 10μg/m3 rise in O3_8h concentrations on cumulative lagging days (lag01 and lag02). Increases in particulate matter (PM_2.5, PM₁₀) levels had a similar cumulative effect on patients with chronic urticaria. In summary, these results suggest that short-term O₃, PM_2.5, and PM₁₀ exposure can increase the risk of acute urticaria and chronic urticaria.

Assessment and potential of ecosystem services of ornamental dendroflora in public green areas

The green infrastructure of the city of Novi Sad is characterized by a significant presence of ornamental invasive alien species, which might lead to their uncontrolled spread and suppression of autochthonous dendroflora. This study aimed to determine the ecosystem services and disservices of ornamental dendroflora in Novi Sad, as well as how they can affect urban green areas. Of the total ornamental dendroflora in Novi Sad, 88.33% of species with a good adaptation were determined, while 10% had a medium and 1.67% had a very good adaptation. Thirty-four allochthonous species showed very high (38.24%), moderate (47.06%), and low (14.71%) invasive potential according to the conducted invasiveness risk assessment. These species are also characterized by high (2.94%), moderate (67.65%), and low (29.41%) allergenic potential. On the contrary, 26 ornamental autochthonous species are characterized by moderate (38.46%) and low (61.54%) rates of spread on public green areas, while also characterized by high (26.92%), moderate (50%), and weak (23.08%) allergenic potential. Ornamental dendroflora provides many more positive ecosystem services, such as urban afforestation, climate regulation, decorative-aesthetic value, air and water purification, ecotourism and recreation, and other services that are of great benefit to the residents of that city. The highest calculated values of ecosystem services in allochthonous and autochthonous species were 27 and 26.5 (out of possible maximal value 40), while ecosystem disservices accounted down to the value of - 13.5 (out of possible minimal value - 22). Therefore, intrinsic disservices such as the production of large amounts of green waste of ornamental dendroflora can be shifted into a novel ecosystem service-green solutions based on nature, to avoid unsuitable deposition of seeds in the soil and creation of suitable vegetation on public green areas.

Short-Term Exposure of Dactylis glomerata Pollen to Atmospheric Gaseous Pollutants Is Related to an Increase in IgE Binding in Patients with Grass Pollen Allergies

The concentrations of nitrogen dioxide (NO₂) and tropospheric ozone (O₃) in urban and industrial site atmospheres are considered key factors associated with pollen-related respiratory allergies. This work studies the effects of NO₂ and O₃ on the protein expression profile and IgE binding in patients with grass allergies to Dactylis glomerata pollen extracts. Pollens were collected during the flowering season and were exposed to NO₂ and O₃ in a controlled environmental chamber. The amount of soluble protein was examined using the Bradford method, and the protein expression profile and antigenic properties were analysed using the immunoblotting and enzyme-linked immunosorbent assay (ELISA), respectively. Our results showed apparent inter-sera differences concerning the number and intensity of IgE reactivity, with the most prominent at bands of 55 kDa, 35, 33, and 13 kDa. In the 13 kDa band, both gases tend to induce an increase in IgE binding, the band at 33 kDa showed a tendency towards a reduction, particularly pollen exposed to O₃. Reactive bands at 55 and 35 kDa presented an increase in the IgE binding pattern for all the patient sera samples exposed to NO₂, but the samples exposed to O₃ showed an increase in some sera and in others a decrease. Regarding the ELISA results, out of the 21 tested samples, only 9 showed a statistically significant increase in total IgE reactivity after pollen exposure to the pollutants. Our study revealed that although airborne pollen allergens might be affected by air pollution, the possible impacts on allergy symptoms might vary depending on the type of pollutant and the patient's sensitisation profile.

Pollution of the Environment and Pollen: A Review

Bioindication of the environment is one of the actively developing directions of ecology. Information about pollutants and the level of environmental pollution can be obtained as a result of studying the biological reaction of plants to pollution. Ecological palynology is a new direction, when pollen of various woody and herbaceous species is used for bioindication of the level of environmental pollution and the presence of mutagens. The review considers the morphological variability of pollen, its fertility and viability under the influence of pollutants, the possibility of its use as a bioindicator of pollution of urban areas by emissions of vehicle transport and industry.

Drivers of the release of the allergens Bet v 1 and Phl p 5 from birch and grass pollen

The drivers affecting the Pollen Allergen Potency (PAP, amount of allergen released per pollen) are sparsely known. Betula and Poaceae airborne pollen are the two main allergenic pollen in the World. Airborne pollen and their allergens Bet v 1 and Phl p 5 were simultaneously measured from 2010 to 2015 in Davos (Switzerland) and Munich (Germany) by using volumetric traps and ChemVol cascade impactors. Daily variations in PAP were analysed in PM_>10 and PM_2.5-10 air fractions and generalized additive models were created to explain which factors determine PAP, including meteorological parameters and inorganic pollutants. 87.1 ± 13.9% of Bet v 1 and 88.8 ± 15.5% of Phl p 5 was detected in the fraction PM_>10 where most pollen grains were collected. Significantly higher PAP for grasses (3.5 ± 1.9 pg Phl p 5/pollen grain) were observed in Munich than in Davos (2.4 ± 1.5 pg/pollen grain, p < 0.001), but not for Betula (2.5 ± 1.6 pg Bet v 1/pollen grain in Munich and 2.3 ± 1.7 in Davos, N.S.). PAP varied between days, years and location, and increased along the pollen season for Poaceae, but remaining constant for Betula. Free allergens (allergens observed in the fraction with limited pollen, PM_{2.5- 10}) were recorded mostly at the beginning or at the end of the pollen season, being linked to higher humidity and rainy days. Also, PAP was higher when the airborne pollen concentrations increased rapidly after one day of low/moderate levels. Our findings show that pollen exposure explains allergen exposure only to a limited extend, and that day in the season, geographic location and some weather conditions need to be considered also to explain symptoms of allergic individuals.

Influence of the environment on ragweed pollen and their sensitizing capacity in a mouse model of allergic lung inflammation

Common ragweed (Ambrosia artemisiifolia) is an invasive plant with allergenic pollen. Due to environmental changes, ragweed pollen (RWP) airborne concentrations are predicted to quadruple in Europe by 2050 and more than double allergic sensitization of Europeans by 2060. We developed an experimental RWP model of allergy in BALB/c mice to evaluate how the number of RWP and how RWP collected from different geographical environments influence disease. We administered RWP six times over 3 weeks intranasally to the mice and then evaluated disease parameters 72 h later or allowed the mice to recover for at least 90 days before rechallenging them with RWP to elicit a disease relapse. Doses over 300 pollen grains induced lung eosinophilia. Higher doses of 3,000 and 30,000 pollen grains increased both eosinophils and neutrophils and induced disease relapses. RWP harvested from diverse geographical regions induced a spectrum of allergic lung disease from mild inflammation to moderate eosinophilic and severe mixed eosinophilic-neutrophilic lung infiltrates. After a recovery period, mice rechallenged with pollen developed a robust disease relapse. We found no correlation between Amb a 1 content, the major immunodominant allergen, endotoxin content, or RWP structure with disease severity. These results demonstrate that there is an environmental impact on RWP with clinical consequences that may underlie the increasing sensitization rates and the severity of pollen-induced disease exacerbation in patients. The multitude of diverse environmental factors governing distinctive patterns of disease induced by RWP remains unclear. Further studies are necessary to elucidate how the environment influences the complex interaction between RWP and human health.

The priming effect of diesel exhaust on native pollen exposure at the air-liquid interface

Pollen related allergic diseases have been increasing for decades. The reasons for this increase are unknown, but environmental pollution like diesel exhaust seem to play a role. While previous studies explored the effects of pollen extracts, we studied here for the first time priming effects of diesel exhaust on native pollen exposure using a novel experimental setup.

METHODS

Human bronchial epithelial BEAS-2B cells were exposed to native birch pollen (real life intact pollen, not pollen extracts) at the air-liquid interface (pollen-ALI). BEAS-2B cells were also pre-exposed in a diesel-ALI to diesel CAST for 2 h (a model for diesel exhaust) and then to pollen in the pollen-ALI 24 h later. Effects were analysed by genome wide transcriptome analysis after 2 h 25 min, 6 h 50 min and 24 h. Selected genes were confirmed by qRT-PCR.

RESULTS

Bronchial epithelial cells exposed to native pollen showed the highest transcriptomic changes after about 24 h. About 3157 genes were significantly up- or down-regulated for all time points combined. After pre-exposure to diesel exhaust the maximum reaction to pollen had shifted to about 2.5 h after exposure, plus the reaction to pollen was desensitised as only 560 genes were differentially regulated. Only 97 genes were affected synergistically. Of these, enrichment analysis showed that genes involved in immune and inflammatory response were involved.

CONCLUSION

Diesel exhaust seems to prime cells to react more rapidly to native pollen exposure, especially inflammation related genes, a factor known to facilitate the development of allergic sensitization. The marker genes here detected could guide studies in humans when investigating whether modern and outdoor diesel exhaust exposure is still detrimental for the development of allergic disease.

Birch pollen, air pollution and their interactive effects on airway symptoms and peak expiratory flow in allergic asthma during pollen season - a panel study in Northern and Southern Sweden

BACKGROUND

Evidence of the role of interactions between air pollution and pollen exposure in subjects with allergic asthma is limited and need further exploration to promote adequate preventive measures. The objective of this study was to assess effects of exposure to ambient air pollution and birch pollen on exacerbation of respiratory symptoms in subjects with asthma and allergy to birch.

METHODS

Thirty-seven subjects from two Swedish cities (Gothenburg and Umeå) with large variation in exposure to both birch-pollen and air pollutants, participated in the study. All subjects had confirmed allergy to birch and self-reported physician-diagnosed asthma. The subjects recorded respiratory symptoms such as rhinitis or eye irritation, dry cough, dyspnoea, the use of any asthma or allergy medication and peak respiratory flow (PEF), daily for five consecutive weeks during two separate pollen seasons and a control season without pollen. Nitrogen oxides (NO_x), ozone (O₃), particulate matter (PM_2.5), birch pollen counts, and meteorological data were obtained from an urban background monitoring stations in the study city centres. The data were analysed using linear mixed effects models.

RESULTS

During pollen seasons all symptoms and medication use were higher, and PEF was reduced in the subjects. In regression analysis, exposure to pollen at lags 0 to 2 days, and lags 0 to 6 days was associated with increased ORs of symptoms and decreased RRs for PEF. Pollen and air pollution interacted in some cases; during low pollen exposure, there were no associations between air pollution and symptoms, but during high pollen exposure, O₃ concentrations were associated with increased OR of rhinitis or eye irritation, and PM_2.5 concentrations were associated with increased ORs of rhinitis or eye irritation, dyspnea and increased use of allergy medication.

CONCLUSIONS

Pollen and air pollutants interacted to increase the effect of air pollution on respiratory symptoms in allergic asthma. Implementing the results from this study, advisories for individuals with allergic asthma could be improved, minimizing the morbidities associated with the condition.

A Review of the Respiratory Health Burden Attributable to Short-Term Exposure to Pollen

Respiratory diseases such as asthma, allergic rhinitis (AR) and chronic obstructive pulmonary disease (COPD) affect millions worldwide and pose a significant global public health burden. Over the years, changes in land use and climate have increased pollen quantity, allergenicity and duration of the pollen season, thus increasing its impact on respiratory disease. Many studies have investigated the associations between short-term ambient pollen (i.e., within days or weeks of exposure) and respiratory outcomes. Here, we reviewed the current evidence on the association between short-term outdoor pollen exposure and thunderstorm asthma (TA), asthma and COPD hospital presentations, general practice (GP) consultations, self-reported respiratory symptoms, lung function changes and their potential effect modifiers. The literature suggests strong evidence of an association between ambient pollen concentrations and almost all respiratory outcomes mentioned above, especially in people with pre-existing respiratory diseases. However, the evidence on sub-clinical lung function changes, COPD, and effect modifiers other than asthma, hay fever and pollen sensitisation are still scarce and requires further exploration. Better understanding of the implications of pollen on respiratory health can aid healthcare professionals to implement appropriate management strategies.

Climate change and allergies

The climate crisis poses a major challenge to human health as well as the healthcare system and threatens to jeopardize the medical progress made in recent decades. However, addressing climate change may also be the greatest opportunity for global health in the 21st century. The climate crisis and its consequences, such as rising temperatures, forest fires, floods, droughts, and changes in the quality and quantity of food and water, directly and indirectly affect human physical and mental health. More intense and frequent heat waves and declining air quality have been shown to increase all-cause mortality, especially among the most vulnerable. Climate warming alters existing ecosystems and favors biological invasions by species that better tolerate heat and drought. Pathogen profiles are changing, and the transmission and spread of vector-borne diseases are increasing. The spread of neophytes in Europe, such as ragweed, is creating new pollen sources that increase allergen exposure for allergy sufferers. In addition, the overall milder weather, especially in combination with air pollution and increased CO₂ levels, is changing the production and allergenicity of pollen. The phenomenon of thunderstorm asthma is also occurring more frequently. In view of the increasing prevalence of allergic diseases due to climate change, early causal immunomodulatory therapy is therefore all the more important. During a climate consultation, patients can receive individual advice on climate adaptation and resilience and the benefits of CO₂ reduction-for their own and the planet's health. Almost 5% of all greenhouse gas emissions in Europe come from the healthcare sector. It thus has a central responsibility for a climate-neutral and sustainable transformation.

Klimawandel und Allergien

Die Klimakrise stellt eine große Herausforderung für die menschliche Gesundheit sowie das Gesundheitssystem dar und droht, den medizinischen Fortschritt der letzten Jahrzehnte zu gefährden. In der Bewältigung des Klimawandels könnte jedoch auch die größte Chance für die globale Gesundheit im 21. Jahrhundert liegen.

Die Klimakrise und ihre Folgen, wie steigende Temperaturen, Waldbrände, Überschwemmungen, Dürren, Veränderungen in der Qualität und Quantität von Nahrungsmitteln und des Wassers wirken sich direkt und indirekt auf die physische und psychische Gesundheit des Menschen aus. Intensivere und häufigere Hitzewellen und die abnehmende Luftqualität erhöhen nachweislich die Gesamtmortalität, insbesondere bei den am meisten vulnerablen Personen. Die Klimaerwärmung verändert die bestehenden Ökosysteme und begünstigt biologische Invasionen von Arten, die Wärme und Trockenheit besser tolerieren. Die Erregerprofile verändern sich, die Übertragung und Verbreitung von durch Vektoren übertragene Krankheiten nehmen zu. Durch die Ausbreitung von Neophyten in Europa, wie beispielsweise der Ambrosiapflanze, entstehen neue Pollenquellen, die die Allergenexposition für Allergiker*innen erhöhen. Darüber hinaus verändert die insgesamt mildere Witterung, gerade in Kombination mit der Luftverschmutzung und einem erhöhten CO₂-Gehalt, die Produktion und Allergenität von Pollen. Das Phänomen Thunderstorm-Asthma tritt zudem häufiger auf. Angesichts der durch den Klimawandel zunehmenden Prävalenz von allergischen Erkrankungen ist eine frühzeitige kausale immunmodulierende Therapie umso wichtiger.

Im Rahmen einer Klimasprechstunde können Patient*innen individuell bezüglich einer Klimaadaption und -resilienz und der Vorteile einer CO₂-Reduzierung beraten werden - für die eigene und die planetare Gesundheit. Fast 5 % aller Treibhausgasemissionen in Europa stammen aus dem Gesundheitssektor. Er hat damit eine zentrale Verantwortung für eine klimaneutrale und nachhaltige Transformation.

Zitierweise: Luschkova D, Traidl-Hoffmann C, Ludwig A. Climate change and allergies. Allergo J Int 2022;31:114-20

https://doi.org/10.1007/s40629-022-00212-x

Food allergy in early childhood increases the risk of oral allergy syndrome in schoolchildren: A birth cohort study

BACKGROUND

The level of pollen in Korea has increased over recent decades. Research suggests that oral allergy syndrome (OAS) may be more frequent in childhood than previously recognized. We aimed to investigate the prevalence and characteristics of OAS in children aged 6-10 years from a general-population-based birth cohort.

METHODS

We analyzed 930 children from the cohort for childhood origin of asthma and allergic diseases (COCOA). Allergic diseases were diagnosed annually by pediatric allergists. The skin prick tests were performed with 14 common inhalant allergens and four food allergens for the general population of children aged 3 and 7 years.

RESULTS

Of the 930 eligible children, 44 (4.7%) aged 6-10 years were diagnosed with OAS. The mean age at onset was 6.74 years. OAS prevalence was 7.2% among children with allergic rhinitis (AR) and 19.1% among those with pollinosis, depending on comorbidity. OAS was more prevalent in schoolchildren with atopic dermatitis, food allergy, and sensitization to food allergens and grass pollen in early childhood. In schoolchildren with AR, only a history of food allergy until the age of 3 years increased the risk of OAS (aOR 2.971, 95% CI: 1.159-7.615).

CONCLUSION

Food allergy and food sensitization in early childhood were associated with OAS in schoolchildren with AR. Further study is required to elucidate the mechanism by which food allergy in early childhood affects the development of OAS.

Influence of meteorological parameters and air pollutants on the airborne pollen of city Chandigarh, India

Pollen, climatic variables and air pollutants coexist in nature with the potential to interact with one another and play a crucial role in increasing allergic diseases. The current study evaluates the influence of meteorological parameters and air pollutants on the airborne pollen in an urban city, Chandigarh, situated in the Indo-Gangetic Plains. Airborne pollen monitoring was done following Spanish Aerobiological Network guidelines and dynamics of daily total pollen and six most abundant taxa were studied from June 2018 to June 2020. Among meteorological parameters, temperature and wind were the most correlated and influential parameters to airborne pollen concentration. Annual Pollen Integral (APIn) of Cannabis sativa (r = 0.52), Parthenium hysterophorus (r = 0.27), Poaceae (r = 0.32) and total pollen concentration (r = 0.30) showed a statistically significant positive correlation with temperature. In contrast, precipitation and relative humidity negatively correlated with APIn of total pollen concentration, Eucalyptus sp. and Poaceae except for Parthenium hysterophorus and Celtis occidentalis. Similar results were found with Seasonal Pollen Integral (SPIn) of total pollen concentration, six major taxa and meteorological variables. Spearman correlation performed for NOx showed a significant positive correlation among APIn and SPIn of Celtis occidentalis and insignificant among APIn and SPIn of Eucalyptus sp. and Morus alba. In contrast, except for Eucalyptus sp., PM₁₀ and PM_2.5 were negatively correlated among APIn and SPIn of total pollen concentration and other major taxa. Spearman's correlation of APIn and SPIn for each pollen taxon, meteorological parameters and air pollutants suggests that each taxon has a different pattern in response to all parameters. The study findings suggest that pollen response must be examined at the taxon level, not the assemblage level, having long time-series data. This will help to compute future scenarios of changing environmental factors and comprehend the relationships and trends among meteorology, air pollutants and aerobiology.

Pollen allergy: Developing multi-sectorial strategies for its prevention and control in lower and middle-income countries

Pollen allergy is considered a major public health problem that causes morbidity and subsequently affects a patient's quality of life. Pollen due to their large size cannot enter the thoracic regions of the respiratory tract but can affect the nasopharyngeal mucous membrane. At the same time, the submicronic-pollen particles can act as respirable particles reaching deeper into the upper airways leading to exacerbation of asthma, chronic obstructive pulmonary disease (COPD) and other allergic reactions. Based on the existing literature, expanding evidence shows that climate change and air pollutants could affect the pollen number, morphology, season, allergen content, and distribution pattern. Hence, this will influence the prevalence and occurrence of allergies linked to pollen exposure. Being a part of biogenic pollutants, pollen allergens are not expected to diminish in the foreseeable future. Therefore, it is imperative that steps need to be strengthened to improve and optimize preventive/adaptive strategies. This paper aims to review the major causes of widespread allergy, identify the major gaps, and suggest key preventive/adaptive measures to address the onset and exacerbation of pollen-related allergic diseases with a major focus on lower and middle-income countries. The study also discusses how-to implement the prevention and control measures at the individual, health care communities and organizations, Local Governments, National/International Governments levels to decrease the risk of illnesses associated with pollen allergy.

[Not Available]

Die Klimakrise stellt eine große Herausforderung für die menschliche Gesundheit sowie das Gesundheitssystem dar und droht, den medizinischen Fortschritt der letzten Jahrzehnte zu gefährden. In der Bewältigung des Klimawandels könnte jedoch auch die größte Chance für die globale Gesundheit im 21. Jahrhundert liegen.

[Climate crisis and its impact on human health]

The climate crisis and its consequences represent the greatest challenge facing human health and health care system in the 21st century. It threatens to undermine the last decades of health gains. Rising temperatures, fires, floods and droughts can directly and indirectly cause human pathologies, that are physical and mental. Extreme weather events lead to loss of life, basic life resources and cause severe mental burden. More intense and frequent heat waves due to global warming impact human health and increase mortality, especially for those most vulnerable. The heat-related health risk depends on individual state of health as well as environmental and socioeconomic characteristics of residential areas. Increasing exposure to air pollutants, due to wildfires and anthropogenic emissions, raises respiratory and cardiovascular mortality. Climate warming changes ecosystems and enhances biological invasions that can better adapt to warm environments. Pathogen profiles are changing, transmission and spread of vector-borne diseases as Malaria or Dengue are increasing. Further, rising temperatures and air pollution increase the production and allergenicity of pollen, associated with higher prevalence of allergic diseases. Protective environmental factors, as biodiversity or diverse microbiome, should be given greater consideration in future research.Health sector has the central responsibility as the fifth-largest greenhouse gas emitter to transform in a climate-neutral and sustainable way, e. g. by efficient use of resources. Further education and training in this area should be intensified and included in curricula for medical staff. Furthermore, medical professionals must educate patients about the burden of climate change, climate resilience, and the benefits of CO2 reduction - for human but also for planetary health.

A systematic review of the effects of temperature and precipitation on pollen concentrations and season timing, and implications for human health

Climate and weather directly impact plant phenology, affecting airborne pollen. The objective of this systematic review is to examine the impacts of meteorological variables on airborne pollen concentrations and pollen season timing. Using PRISMA methodology, we reviewed literature that assessed whether there was a relationship between local temperature and precipitation and measured airborne pollen. The search strategy included terms related to pollen, trends or measurements, and season timing. For inclusion, studies must have conducted a correlation analysis of at least 5 years of airborne pollen data to local meteorological data and report quantitative results. Data from peer-reviewed articles were extracted on the correlations between seven pollen indicators (main pollen season start date, end date, peak date, and length, annual pollen integral, average daily pollen concentration, and peak pollen concentration), and two meteorological variables (temperature and precipitation). Ninety-three articles were included in the analysis out of 9,679 articles screened. Overall, warmer temperatures correlated with earlier and longer pollen seasons and higher pollen concentrations. Precipitation had varying effects on pollen concentration and pollen season timing indicators. Increased precipitation may have a short-term effect causing low pollen concentrations potentially due to "wash out" effect. Long-term effects of precipitation varied for trees and weeds and had a positive correlation with grass pollen levels. With increases in temperature due to climate change, pollen seasons for some taxa in some regions may start earlier, last longer, and be more intense, which may be associated with adverse health impacts, as pollen exposure has well-known health effects in sensitized individuals.

A Satellite-Based Model for Estimating Latent Heat Flux From Urban Vegetation

The impacts of extreme heat events are amplified in cities due to unique urban thermal properties. Urban greenspace mitigates high temperatures through evapotranspiration and shading; however, quantification of vegetative cooling potential in cities is often limited to simple remote sensing greenness indices or sparse, in situ measurements. Here, we develop a spatially explicit, high-resolution model of urban latent heat flux from vegetation. The model iterates through three core equations that consider urban climatological and physiological characteristics, producing estimates of latent heat flux at 30-m spatial resolution and hourly temporal resolution. We find strong agreement between field observations and model estimates of latent heat flux across a range of ecosystem types, including cities. This model introduces a valuable tool to quantify the spatial heterogeneity of vegetation cooling benefits across the complex landscape of cities at an adequate resolution to inform policies addressing the effects of extreme heat events.

Analysis of changes in Betula pollen season start including the cycle of pollen concentration in atmospheric air

Birch belongs to the most important allergenic taxa in Europe, therefore information on the start dates of the pollen season is very important for allergists and their patients as well as for climatologists. The study examined changes in the start of the birch pollen season as well as determined the trend of these changes. Pollen monitoring was performed in Lublin (eastern Poland) in the period 2001-2019 using the volumetric method. The Makra-test was used to detect periods with significantly higher or lower average of the onset than the average for the whole dataset. Two significant falls in the average of the pollen season start were found in 2007 and 2014. Besides, taking into account the 2-3-year rhythm of high and low concentrations of birch pollen in the atmospheric air, linear trends were fitted for the subsets of high and low abundance seasons. Significant changes in Betula pollen season start dates were only determined for the highly abundance seasons, while the results for seasons with a low concentration did not allow rejecting the hypothesis about the lack of a linear trend in the changes in the studied parameter. Moreover, a significant polynomial relationship was found between the beginning of a pollen season and the average values of monthly temperatures preceded a season. These analyses show that the start dates of the Betula pollen season are getting significantly earlier. The dynamics of changes differ between seasons with high and low concentrations of pollen.

Atopic eczema is an environmental disease

It is obvious that social, biogenic, and anthropogenic environmental factors, as well as nutrition contribute to the development and course of atopic eczema. Social deprivation and stress have a negative impact on atopic eczema symptoms, and social change in recent decades has led to a "westernized" lifestyle associated with high prevalence of atopic eczema in industrialized countries. Urbanization leads to an increase in air pollution and a decrease in biodiversity, which negatively affects atopic eczema. Climate change alters the allergenicity of pollen, which increases atopic eczema symptoms in some patients during the pollen season. Protective natural and social factors for the prevention of atopic eczema and for the promotion of "climate resilience" should be given greater consideration in future research.

Exposure to green space and pollen allergy symptom severity: A case-crossover study in Belgium

BACKGROUND

The prevalence of pollen allergy has increased due to urbanization, climate change and air pollution. The effects of green space and air pollution on respiratory health of pollen allergy patients are complex and best studied in spatio-temporal detail.

METHODS

We tracked 144 adults sensitized to Betulaceae pollen during the tree pollen season (January-May) of 2017 and 2018 and assessed their spatio-temporal exposure to green space, allergenic trees, air pollutants and birch pollen. Participants reported daily symptom severity scores. We extracted 404 case days with high symptom severity scores and matched these to 404 control days. The data were analyzed using conditional logistic regression with a 1:1 case-crossover design.

RESULTS

Case days were associated with exposure to birch pollen concentration (100 grains/m³) [adjusted odds ratio 1.045 and 95% confidence interval (1.014-1.078)], O₃ concentration (10 μg/m³) [1.504 (1.281-1.766)] and PM₁₀ concentration (10 μg/m³) [1.255 (1.007-1.565)] on the day of the severe allergy event and with the cumulative exposure of one and two days before. Exposure to grass cover (10% area fraction) [0.655 (0.446-0.960)], forest cover (10% area fraction) [0.543 (0.303-0.973)] and density of Alnus (10%) [0.622 (0.411-0.942)] were protective for severe allergy, but only on the day of the severe allergy event. Increased densities of Betula trees (10%) were a risk factor [unadjusted OR: 2.014 (1.162-3.490)].

CONCLUSION

Exposure to green space may mitigate tree pollen allergy symptom severity but only when the density of allergenic trees is low. Air pollutants contribute to more severe allergy symptoms. Spatio-temporal tracking allows for a more realistic exposure assessment.

Climate Effect, Globalization, and Ethics in Allergy

The prevalence of allergic diseases is increasing rapidly and has already reached an epidemic level. Two major drivers of this development are climate change and globalization, which both induce an increase in allergens. Concomitant climate change fosters the spreading of the latter on a global scale. The increase in allergens not only aggravates the symptoms and the degree of suffering for patients who already are allergic, but also gives rise to new cases of allergies. The distribution of allergies in society follows a steep socioeconomic gradient worldwide. According to well-established theories of justice such a distribution of the allergy burden is unfair. This fact adds a major ethical dimension and challenge to the allergy epidemic. This chapter draws on the key points of policies for allergy prevention and treatment. It shows how related programs and measures can be conceptualized and prioritized according to the principles of distributional justice.

Organic and aqueous extraction of lipids from birch pollen grains exposed to gaseous pollutants

The lipid fraction of birch pollen grains (BPGs) is not yet fully described, although pollen lipid molecules may play a role in the allergic immune response. The mechanisms by which atmospheric pollutants modify allergenic pollen grains (PGs) are also far from being elucidated despite high potential effects on allergic sensitization. This work is a contribution to a better description of the lipid profile (both external and cytoplasmic) of BPGs and of alterations induced by gaseous air pollutants. Several lipid extractions were performed using organic and aqueous solvents on BPGs following exposure to ozone and/or nitrogen dioxide and under conditions favoring the release of internal lipids. Ozone reacted with alkenes to produce aldehydes and saturated fatty acids, while nitrogen dioxide was shown to be unreactive with lipids. NO₂ exhibited a protective effect against the reactivity of alkenes with ozone, probably by competition for adsorption sites. The decreased reactivity of ozone during simultaneous exposure to NO₂/O₃ raised the possibility of a Langmuir-Hinshelwood mechanism. Oxidation reactions induced by exposure of BPGs to ozone did not substantially modify the extraction of lipids by aqueous solvent, suggesting that the bioaccessibility of lipids was not modified by oxidation. On the contrary, the rupture of PGs appeared to be a key factor in enhancing the bioaccessibility of bioactive lipid mediators (linoleic and α-linolenic acids) in an aqueous solution. The internal lipid fraction of BPGs has specific characteristics compared with external lipids, with more abundant hexadecanoic acid, tricosanol, and particularly unsaturated fatty acids (linoleic and α-linolenic acids). Several mechanisms of action of gaseous pollutants on allergenic pollen were identified in this study: gaseous air pollutants can (i) modify the external lipid fraction by reactivity of alkenes, (ii) adsorb on the surface of PGs and be a source of oxidative stress after inhalation of PGs, and (iii) promote the release of cytoplasmic bioactive lipids by facilitating pollen rupture.

Indoor and Outdoor Pollution as Risk Factor for Allergic Diseases of the Skin and Lungs

Air pollution is worldwide a major public health problem and affects large part of the population. Air pollution does not only harm the respiratory tract system but also the other organs of the body. The damage may result directly from the pollutants toxicity, because the pollutant enters into the organs through a direct route or indirectly through systemic inflammation. There is accumulating evidence suggesting that ambient air pollution not only affects the human lung and the cardiovascular system, but also has negative effects on allergic diseases. In this regard, it has been shown that exposure increases the risk of allergies and eczema in children and adults. However, the mechanism how ambient air pollution affects the skin is not well investigated up to now and needs further research.

Rationale and Design of a Panel Study Investigating Six Health Effects of Airborne Pollen: The EPOCHAL Study

Background: While airborne pollen is widely recognized as a seasonal cause of sneezing and itchy eyes, its effects on pulmonary function, cardiovascular health, sleep quality, and cognitive performance are less well-established. It is likely that the public health impact of pollen may increase in the future due to a higher population prevalence of pollen sensitization as well as earlier, longer, and more intense pollen seasons, trends attributed to climate change. The effects of pollen on health outcomes have previously been studied through cross-sectional design or at two time points, namely preceding and within the period of pollen exposure. We are not aware of any observational study in adults that has analyzed the dose-response relationship between daily ambient pollen concentration and cardiovascular, pulmonary, cognitive, sleep, or quality of life outcomes. Many studies have relied on self-reported pollen allergy status rather than objectively confirming pollen sensitization. In addition, many studies lacked statistical power due to small sample sizes or were highly restrictive with their inclusion criteria, making the findings less transferable to the “real world.”

Methods: The EPOCHAL study is an observational panel study which aims to relate ambient pollen concentration to six specific health domains: (1) pulmonary function and inflammation; (2) cardiovascular outcomes (blood pressure and heart rate variability); (3) cognitive performance; (4) sleep; (5) health-related quality of life (HRQoL); and (6) allergic rhinitis symptom severity. Our goal is to enroll 400 individuals with diverse allergen sensitization profiles. The six health domains will be assessed while ambient exposure to pollen of different plants naturally varies. Health data will be collected through six home nurse visits (at approximately weekly intervals) as well as 10 days of independent tracking of blood pressure, sleep, cognitive performance, HRQoL, and symptom severity by participants. Through repeated health assessments, we aim to uncover and characterize dose-response relationships between exposure to different species of pollen and numerous acute health effects, considering (non-)linearity, thresholds, plateaus and slopes.

Conclusion: A gain of knowledge in pollen-health outcome relationships is critical to inform future public health policies and will ultimately lead toward better symptom forecasts and improved personalized prevention and treatment.

Characterization of allergenicity of Platanus pollen allergen a 3 (Pla a 3) after exposure to NO2 and O3

Pollen allergens, widely present in the atmosphere, are the main cause of seasonal respiratory diseases that affect millions of people worldwide. Although previous studies have reported that nitrogen dioxide (NO₂) and ozone (O₃) promote pollen allergy, the specific biological processes and underlying mechanisms remain less understood. In this study, Platanus pollen grains were exposed to gaseous pollutants (NO₂ and O₃). We employed environmental electron microscopy, flow cytometry, western blot assay, enzyme-linked immunoassay, ultraviolet absorption spectrometry, circular dichroism, and protein mass spectrometry to characterise the subpollen particles (SPPs) released from pollen grains. Furthermore, we determined the immunogenicity and pathogenicity induced by Platanus pollen allergen a 3 (Pla a 3). Our results demonstrated that NO₂ and O₃ could damage the pollen cell membranes in SPPs and increase the amount of Pla a 3 allergen released into the atmosphere. Additionally, NO₂ and O₃ altered the structure of Pla a3 protein through nitrification and oxidation, which not only enhanced the immunogenicity of allergens but also increased the stability of the protein. In vivo analysis using an animal model indicated that NO₂ and O₃ greatly aggravated pollen-induced pneumonia. Thus, our study provides guidance for the prevention of pollen allergic diseases.

Ragweed plants grown under elevated CO2 levels produce pollen which elicit stronger allergic lung inflammation

BACKGROUND

Common ragweed has been spreading as a neophyte in Europe. Elevated CO₂ levels, a hallmark of global climate change, have been shown to increase ragweed pollen production, but their effects on pollen allergenicity remain to be elucidated.

METHODS

Ragweed was grown in climate-controlled chambers under normal (380 ppm, control) or elevated (700 ppm, based on RCP4.5 scenario) CO₂ levels. Aqueous pollen extracts (RWE) from control- or CO₂ -pollen were administered in vivo in a mouse model for allergic disease (daily for 3-11 days, n = 5) and employed in human in vitro systems of nasal epithelial cells (HNECs), monocyte-derived dendritic cells (DCs), and HNEC-DC co-cultures. Additionally, adjuvant factors and metabolites in control- and CO₂ -RWE were investigated using ELISA and untargeted metabolomics.

RESULTS

In vivo, CO₂ -RWE induced stronger allergic lung inflammation compared to control-RWE, as indicated by lung inflammatory cell infiltrate and mediators, mucus hypersecretion, and serum total IgE. In vitro, HNECs stimulated with RWE increased indistinctively the production of pro-inflammatory cytokines (IL-8, IL-1β, and IL-6). In contrast, supernatants from CO₂ -RWE-stimulated HNECs, compared to control-RWE-stimulated HNECS, significantly increased TNF and decreased IL-10 production in DCs. Comparable results were obtained by stimulating DCs directly with RWEs. The metabolome analysis revealed differential expression of secondary plant metabolites in control- vs CO₂ -RWE. Mixes of these metabolites elicited similar responses in DCs as compared to respective RWEs.

CONCLUSION

Our results indicate that elevated ambient CO₂ levels elicit a stronger RWE-induced allergic response in vivo and in vitro and that RWE increased allergenicity depends on the interplay of multiple metabolites.

Climate change, air pollution, and allergic respiratory diseases: a call to action for health professionals

Rising emissions of greenhouse gases in the atmosphere have warmed the planet substantially and are also accompanied by poor air quality. The increased prevalence of allergic airway disease worldwide can be partially attributed to those global environmental changes. Climate change and air pollution pose adverse impacts on respiratory allergies, and that the mechanisms are complex and interactive. Adverse weather conditions, such as extreme temperatures, can act directly on the respiratory tract to induce allergic respiratory illnesses. Thunderstorms and floods can alter the production and distribution of aeroallergens while wildfires and dust storms increase air pollution, and therefore indirectly enhance health risks. Concentrations of particulate matter and ozone in the air have been projected to increase with climate warming and air stagnation, and the rising temperatures and CO₂ increase pollen, molds, and spores, which escalate the risk of allergic respiratory diseases. The synergistic effects of extreme heat and aeroallergens intensify the toxic effect of air pollutants, which in turn augment the allergenicity of aeroallergens. With the Earth's climate change, migration of humans and plants shift the living environments and allergens of susceptible people. Urban residents are exposed to multiple factors while children are sensitive to environmental exposure. Since climate change may pose many unexpected and persistent effects on allergic respiratory diseases, health professionals should advocate for effective mitigation and adaptation strategies to minimize its respiratory health effects.

Emergence of pollen food allergy syndrome in asthmatic children in Paris

BACKGROUND

Over the last few decades, the level of pollen from birch and homologous trees has increased in parts of Europe. Sensitization to birch pollen allergens (principally Bet v 1) has been associated with food cross-reactivity called pollen food allergy syndrome (PFAS).

OBJECTIVE

To evaluate changes in allergic diseases due to IgE sensitization over 25 years in asthmatic children.

METHODS

This was a cross-sectional retrospective study conducted in Paris. We analyzed two cohorts of asthmatic children with similar characteristics explored between 1993-1999 (old cohort = OC) and 2012-2018 (recent cohort = RC).

RESULTS

121 children were in the OC and 120 in the RC. An increase in sensitization to tree pollens was found especially for birch pollen, which was 11.6% in the OC and 31% in the RC (P = .0002). Allergic rhinitis prevalence was significantly higher in the RC than in the OC (96% vs 52%, respectively, P < .0001). IgE-mediated food allergy increased from 6% to 16% in the OC and RC, respectively, (P = .01) mainly due to PFAS. In the RC, a higher mean Bet v 1-specific IgE level was observed in children with PFAS compared to children without (105.7 KU/L ± 17.8 and 48.9 kU/L ± 15.7, respectively, P < .05).

CONCLUSION

Allergic rhinitis and food allergy with tree pollen sensitization have increased in Paris over 25 years mainly due to PFAS. Environmental factors could be responsible for these modifications as described in the literature.