Detection of airborne Par j 1 and Par j 2 allergens in relation to Urticaceae pollen counts in different bioclimatic areas

What molecular allergy teaches us about genetics and epidemiology of allergies

PURPOSE OF REVIEW

To delineate pertinent information regarding the application of molecular allergology within the realm of both genetic and epidemiological facets of allergic diseases.

RECENT FINDINGS

The emergence of molecular allergy has facilitated the comprehension of the biochemical characteristics of allergens originating from diverse sources. It has allowed for the exploration of sensitization trajectories and provided novel insights into the influence of genetics and environmental exposure on the initiation and development of allergic diseases. This review delves into the primary discoveries related to the genetics and epidemiology of allergies, facilitated by the application of molecular allergy. It also scrutinizes the impact of environmental exposure across varied geoclimatic, socioeconomic, and lifestyle contexts. Additionally, the review introduces specific models of molecular allergy within the realms of plants and animals.

SUMMARY

The utilization of molecular allergy in clinical practice holds crucially acknowledged diagnostic and therapeutic implications. From a research standpoint, there is a growing need for the widespread adoption of molecular diagnostic tools to achieve a more profound understanding of the epidemiology and natural progression of allergic diseases.

Airborne Alt a 1 Dynamic and Its Relationship with the Airborne Dynamics of Alternaria Conidia and Pleosporales Spores

Fungal spores are universal atmospheric components associated to allergic reactions. Alternaria (Ascomycota) is considered the most allergenic spore taxa. Alt a 1 is the major allergen of Alternaria and is present also in other Pleosporales. In this study, standard Hirst-based sampling and analyzing methods for measuring spore daily concentrations of Alternaria, Curvularia, Drechslera-Helminthosporium, Epicoccum, Leptosphaeria, Pithomyces, Pleospora and Stemphylium (all included in the taxon Pleosporales) have been used as well as two high-volume samplers, Burkard Cyclone (2017) and MCV CAV-A/mb (2019–2020), and ELISA kits for measuring the allergen. The detection and quantification of Alt a 1 was only possible in the samples from the MCV sampler. Although Alt a 1 was better correlated with Alternaria spores than with Pleosporales spores, the three of them showed high correlations. It is shown that there is a high and significant correlation of Alt a 1 with temperature, a negative correlation with relative humidity and no correlation with precipitation. The aerobiological monitoring of these three elements ensures the best information for understanding the affectation to allergy sufferers, but, if this is not possible, as a minimum public health service aimed at the detection, treatment and prevention of allergies, the study of the airborne Alternaria spores should be ensured.

Influence of environmental drivers on allergy to pollen grains in a case study in Spain (Madrid): meteorological factors, pollutants, and airborne concentration of aeroallergens

The aim of this study was to compare airborne levels of Phl p 1 and Phl p 5, with Poaceae pollen concentrations inside and outside of the pollen season, and to evaluate their association with symptoms in grass allergic patients and the influence of climate and pollution. The Hirst and the Burkard Cyclone samplers were used for pollen and allergen quantification, respectively. The sampling period ran from 23 March 2009 to 27 July 2010. Twenty-three patients with seasonal allergic asthma and rhinitis used an electronic symptom card. The aerosol was extracted and quantified for Phl p 1 and Phl p 5 content. Descriptive statistics, non-parametric paired contrast of Wilcoxon, Spearman's correlations, and a categorical principal component analysis (CatPCA) were carried out. Significant variations in pollen, aeroallergen levels, pollen allergen potency, and symptoms score were observed in this study. Phl p 5 pollen allergen potency was higher at the beginning of the 2010 grass pollen season. Presence of Phl p 1 outside the pollen season with positive O₃ correlation was clinically relevant. 45.5% of the variance was explained by two dimensions in the CatPCA analysis, showing the symptom relationships dissociated in two dimensions. In the first one, the more important relationship was with grass pollen grains concentration and Phl p 5 and to a lesser extent with Phl p 1 and levels of NO₂ and O₃, and in the second dimension, symptoms were associated with humidity and SO₂. Clinically relevant out-season Phl p 1 was found with a positive O₃ correlation. The effect of climate and pollution may have contributed to the higher seasonal allergic rhinitis symptom score recorded in 2009.

Allergenicity at component level of sub-pollen particles from different sources obtained by osmolar shock: A molecular approach to thunderstorm-related asthma outbreaks

BACKGROUND

The so-called "thunderstorm asthma" (TA) is an uncommon but dramatic outbreak of asthma attacks occurring during a thunderstorm in the pollen and moulds season. Mechanisms which make the pollen able to enter the deeper airways and provoke severe asthma symptoms are still unclear.

OBJECTIVE

To test the hypothesis that sub-pollen particles (SPPs) originated from the rupture by an osmotic shock of pollen associated with TA contain allergens.

METHODS

After hydration, SPPs released from pollen grains of grass, pellitory, olive, cypress, ragweed and birch were isolated and determined by microscopy. Allergens were determined by in vitro ELISA inhibition tests indirectly using the sera from 10 polyreactive patients. An inhibition <50% was considered as negative, 50%-75% moderate and > 75% complete.

RESULTS

The inhibition experiments showed that the SPPs from birch and cypress were unable to inhibit serum IgE reactivity to Bet v 1 and Cup a 1, respectively. Ragweed SPPs inhibited ragweed pollen extract and Amb a 1 by 75.8 ± 0.11% and 81.2 ± 0.15%, respectively. Olive and pellitory SPPs retained almost the whole IgE-binding capability in all cases tested. Grass SPPs inhibited 32 ± 0.06% of Lolium perenne Lol p 1 and 65% of Phleum pratense extracts, but results were highly variable for individual allergens (97.5%-0.03% for Phl p 2, 45.3 ± 0.12% for Phl p 5, 24.7 ± 0.22% for Phl p 6, and 38.3 ± 0.2% for Phl p 1).

CONCLUSIONS

Inhibition experiments confirm the hypothesis that SSPs obtained after the osmotic shock of pollen involved in TA, namely grass, pellitory and olive tree pollen, contain allergens and therefore they can induce severe asthma attacks during thunderstorms.

Identifying patterns of airborne pollen distribution using a synoptic climatology approach

Understanding the mechanisms of pollen release and dispersion in the atmosphere is of high importance, not only for getting an insight on the patterns of movement of these biological particles that are necessary for plants' reproduction, but also because exposure to airborne pollen is a major concern for respiratory allergies worldwide. In this work, a synoptic circulation-to-environment classification method was adopted to elucidate the relationship between distinct atmospheric patterns and pollen levels for the 11 most abundant but also allergenic taxa in Thessaloniki, Greece, for the 15-year period 1987-2001. It was found that the NW1 depressional weather type is associated with the "low winter pollen season" and high levels of pollen from Carpinus spp., Corylus spp., Cupressaceae, Platanus spp., Pinaceae, Quercus spp. and Urticaceae. In contrast, the SW1 cyclonic type is linked to the "high spring-summer pollen season" and high levels of pollen from Oleaceae and Urticaceae. On the other hand, anticyclonic weather is associated with the "summer-autumn pollen season" and high levels of Poaceae and Chenopodiaceae pollen in the atmosphere. Regional transport of Alnus pollen is linked to a strong high-pressure system centered over Italy, giving light NE winds over northern Greece. These findings shed light to the synoptic climatology of airborne pollen in Thessaloniki and could feed early-warning systems for alerting vulnerable groups of the allergic population.

Atmospheric exposure to the major Artemisia pollen allergen (Art v 1): Seasonality, impact of weather, and clinical implications

Artemisia pollen grains are important aeroallergens worldwide. The amount of allergenic proteins produced by pollen, or pollen allergenicity, is regulated by both genes and the environment. As a result, even closely related plant taxa may release pollen with distinctly different allergen contents. Here, we determined the variability in atmospheric exposure to the major Artemisia pollen allergen, Art v 1, during the pollination seasons of two common species, i.e., A. vulgaris (early flowering species) and A. campestris (late flowering species), in Poznań, Poland (2013-2015). Artemisia pollen grains were collected using Hirst-type volumetric trap, while Art v 1 was collected by a two-stage cascade impactor (PM₁₀ and PM_>10 air fractions) and quantified by immunoenzymatic analysis. The results showed that daily Art v 1 levels correlated significantly with mean daily concentrations of Artemisia pollen (from r = 0.426 to r = 0.949, depending on air fraction and peak of the season). Significant differences were observed between 1) the median pollen allergenicity in different seasons (from 2.5 to 4.7 pg Art v 1/pollen) and 2) the median pollen allergenicity in different peak periods of the season (from 1.8 to 6.7 pg Art v 1/pollen). During the late peak (flowering of A. campestris), the median pollen allergenicity was significantly higher (on average by 63%, p < 0.05) than that during A. vulgaris flowering. The highest mean seasonal pollen allergenicity was observed during the wettest season, while the lowest was observed during the driest season (from July-August). In summary, our study showed distinct differences in Artemisia pollen allergenicity, that were not only related to daily and seasonal variability, which may exceed 800% and 80%, respectively but also noticeable when two common Artemisia species were compared. Therefore, we argue that variability in pollen allergenicity (both seasonal and species-specific) should be considered in future studies assessing pollen exposure.

Parietaria major allergens vs pollen in the air we breathe

BACKGROUND

Parietaria and Urtica are the genera from the Urticaceae family more frequent in Mediterranean and Atlantic areas. Moreover, both genera share pollination periods, and their pollen (of the main species) is so similar that there is no aerobiological evidence of the proportion of each of them in the airborne pollen identification, except in the case of U. membranacea. However, Parietaria is one of the most important causes of pollinosis and Urtica is not. Our aim is determine if airborne Urticaceae pollen concentrations show the aerodynamics of the two major allergens of Parietaria (Par j 1 and Par j 2) as well as the allergen distribution in the different-sized particles.

METHODS

The air was sampled during the pollination period of Urticaceae using Hirst Volumetric Sampler and Andersen Cascade Impactor in two cities of Southern Spain (Córdoba and Granada). The samples were analysed by the methodology proposed by the Spanish Aerobiology Network (REA) and the minimum requirements of the European Aeroallergen Society (EAS) for pollen, and by ELISA immunoassay for allergens.

RESULTS

The patterns of airborne pollen and Par j 1-Par j 2 were present in the air during the studied period, although with irregular oscillations. Urticaceae pollen and Par j 1-Par j 2 allergens located in PM2.5 showed positive and significant correlation during the period with maximum concentrations (March to April).

CONCLUSION

Parietaria aeroallergens show similar pattern of Urticaceae airborne pollen. Urticaceae pollen calendar is as a good tool for allergy prevention. On the other hand, important concentrations of Par j 1 and Par j 2 were located in the breathable fraction (PM2.5), which could explain the asthmatic symptoms in the allergic population to Parietaria.

Assessment of the potential real pollen related allergenic load on the atmosphere of Porto city

The knowledge of the allergen content in the atmosphere is a useful tool to stablish the risk allergy warnings for the sensitive people. In Portugal the main airborne allergenic pollen come from trees (such as Betula or Olea), grasses or weeds (mainly Urticaceae). The present study sought the quantification of the Bet v 1, Ole e 1, Lol p1 and Par j1-2 aeroallergen concentration as well as how weather variables influence in the pollen and allergen concentration in Porto city. Aerobiological study was carried out by a Hirst-type volumetric sampler for pollen collection and a Burkard Cyclone sampler for the aeroallergens. A regression analysis between pollen and allergens was conducted for the identification the allergenic risk days. High Pollen Allergen Potency in the atmosphere was observed considering the low levels of airborne pollen detected. A significant and positive correlation has been obtained between pollen and aeroallergen values with the temperatures whereas the correlation was negative with relative humidity, rainfall and wind speed. Back trajectory methodology was applied in order to analyse the discordances between pollen and allergen maximum concentrations. The analysis showed that when the pollen and allergen peaks were registered on the same day, air masses always comes from the continent. However, when the peaks do not coincide, the air mass comes from the continent in the case of the pollen peak and from the sea for the allergen peak. This behaviour can be a consequence of the high humidity in the air masses from the sea, which can benefit the allergen release from pollen grains. In our study it was observed that the available traditional information for allergenic Type I patients, corresponding to the amount of pollen grains in the bioaerosol, do not accurately identify the real allergenic load in the air.

Extraction and quantification of Ole e 1 from atmospheric air samples: An optimized protocol

Olive pollen is the main cause of pollinosis in Mediterranean countries. The immunological analysis of Ole e 1, the major allergen of Olea europaea, has usually carried out by means of ELISA (Enzyme-Linked ImmunoSorbent Assay). However, most published works only specify the methodology related to antigen quantifications, but not the related to protein extraction. Furthermore, the results obtained are not compared with different buffers or modifications of them. The main aim of this study is to obtain an optimized and reproducible ELISA protocol for quantifications of Ole e 1 in the atmosphere. The study of Ole e 1 allergen and olive pollen in the atmosphere of Malaga (Spain) was carried out by means of an automatic multi-vial cyclonic sampler and a Hirst volumetric pollen trap, respectively. ELISA was tuned up on the basis of previously published protocols to quantify this allergen. Variations in the concentrations of capture and detection antibodies, as well as in the buffers used to carry out the extraction, were evaluated. The highest protein extraction was obtained when a modified buffer was applied. The correlation analysis between daily pollen concentrations and allergen quantifications showed highly significant values. The ELISA protocol, together with the buffer combination proposed in this work, considerably reduced the concentrations of capture and detection antibodies used for quantifying Ole e 1 in the atmosphere, allowing detect this allergen even in days in which the airborne pollen concentration was very low or null.

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.

Meteorological conditions, climate change, new emerging factors, and asthma and related allergic disorders. A statement of the World Allergy Organization

The prevalence of allergic airway diseases such as asthma and rhinitis has increased dramatically to epidemic proportions worldwide. Besides air pollution from industry derived emissions and motor vehicles, the rising trend can only be explained by gross changes in the environments where we live. The world economy has been transformed over the last 25 years with developing countries being at the core of these changes. Around the planet, in both developed and developing countries, environments are undergoing profound changes. Many of these changes are considered to have negative effects on respiratory health and to enhance the frequency and severity of respiratory diseases such as asthma in the general population.

Increased concentrations of greenhouse gases, and especially carbon dioxide (CO₂), in the atmosphere have already warmed the planet substantially, causing more severe and prolonged heat waves, variability in temperature, increased air pollution, forest fires, droughts, and floods – all of which can put the respiratory health of the public at risk. These changes in climate and air quality have a measurable impact not only on the morbidity but also the mortality of patients with asthma and other respiratory diseases. The massive increase in emissions of air pollutants due to economic and industrial growth in the last century has made air quality an environmental problem of the first order in a large number of regions of the world. A body of evidence suggests that major changes to our world are occurring and involve the atmosphere and its associated climate. These changes, including global warming induced by human activity, have an impact on the biosphere, biodiversity, and the human environment. Mitigating this huge health impact and reversing the effects of these changes are major challenges.

This statement of the World Allergy Organization (WAO) raises the importance of this health hazard and highlights the facts on climate-related health impacts, including: deaths and acute morbidity due to heat waves and extreme meteorological events; increased frequency of acute cardio-respiratory events due to higher concentrations of ground level ozone; changes in the frequency of respiratory diseases due to trans-boundary particle pollution; altered spatial and temporal distribution of allergens (pollens, molds, and mites); and some infectious disease vectors. According to this report, these impacts will not only affect those with current asthma but also increase the incidence and prevalence of allergic respiratory conditions and of asthma. The effects of climate change on respiratory allergy are still not well defined, and more studies addressing this topic are needed. Global warming is expected to affect the start, duration, and intensity of the pollen season on the one hand, and the rate of asthma exacerbations due to air pollution, respiratory infections, and/or cold air inhalation, and other conditions on the other hand.

Airborne pollen levels and drug consumption for seasonal allergic rhinoconjunctivitis: a 10-year study in France

BACKGROUND

Few time-series studies, and none lasting longer than 4 years, have investigated the etiology of treated seasonal allergic rhinoconjunctivitis (SAR) on the basis of anti-allergic medication prescriptions. The aim of this article was to study the short-term relationship between pollen exposure and drug-treated SAR over 10 years in an urban area in central France.

METHODS

A SAR case was defined as the association between an oral antihistamine and a local anti-allergic drug on the same prescription. The relationship between daily changes in pollen concentrations and daily changes in the number of treated SAR cases was analysed using generalized additive models, taking into account confounding factors such as air pollution, weather and days of the week.

RESULTS

Between 2003 and 2012, the total yearly number of treated SAR cases rose from 7265 to 11 315. The relative risk of treated SAR associated with an interquartile increase in pollen concentration increased significantly for Fraxinus, Betula, Carpinus, Platanus, Poaceae and Urticaceae for the whole pollen season, and for Urticaceae in the first semester.

CONCLUSIONS

The prevalence of treated SAR cases rose by about 55% in 10 years. The study not only confirmed the highly allergenic role of Fraxinus, Betula and Poaceae pollens but also showed a relatively unknown association between treated SAR and Carpinus and Platanus pollens, despite their pollen counts being <1% of overall pollen concentration. It also showed robust correlations with Urticaceae pollens, especially during the first semester, suggesting a potential allergenic role of Parietaria pollination in this non-Mediterranean area.