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Rapid pollen rupture and release of pollen cytoplasmic granules upon hydration of allergenic grass and weed species commonly found in subtropical regions

Authors:
Umaporn Siriwattanakul at Mahidol University
Umaporn Siriwattanakul
Surapon Piboonpocanun
Surapon Piboonpocanun
Surapon Piboonpocanun
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Wisuwat Songnuan at Mahidol University
Wisuwat Songnuan
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Abstract and Figures

Airborne pollen is an important and potent source of allergens. Allergenic protein components located in the cytoplasm of pollen, so-called pollen cytoplasmic granules, are released upon contact with moisture, thereby inducing allergic symptoms. However, few studies have compared factors affecting pollen rupture and protein release from allergenic pollen. This study investigated the dynamics of pollen rupture and protein release upon hydration using common allergenic grass and weed species in subtropical regions. The three factors examined were incubation time, incubating solution, and pollen age after shedding. We found that pollen rupture and protein release occurred rapidly upon contact with solutions. The highest amount of protein was released within 15 min after incubation. As expected, pollen rupture increased as incubation time increased. Fresh pollen had higher rupture percentage and released a higher amount of protein than aged pollen. Rainwater caused more rupture and triggered more protein release than other tested solutions. The dynamics of rupture and the amount of released protein were drastically different among species. In conclusion, incubation time, incubating solution, and age of pollen significantly affected the amount of pollen rupture and protein release from allergenic pollen. This information provided better understanding of factors involving the release of allergenic protein from pollen in relation to its internal and external conditions, which could affect its allergenicity.
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ORIGINAL PAPER
Rapid pollen rupture and release of pollen cytoplasmic
granules upon hydration of allergenic grass and weed
species commonly found in subtropical regions
Umaporn Siriwattanakul .Surapon Piboonpocanun .Wisuwat Songnuan
Received: 23 December 2018 / Accepted: 4 September 2019 / Published online: 13 September 2019
ÓSpringer Nature B.V. 2019
Abstract Airborne pollen is an important and potent
source of allergens. Allergenic protein components
located in the cytoplasm of pollen, so-called pollen
cytoplasmic granules, are released upon contact with
moisture, thereby inducing allergic symptoms. How-
ever, few studies have compared factors affecting
pollen rupture and protein release from allergenic
pollen. This study investigated the dynamics of pollen
rupture and protein release upon hydration using
common allergenic grass and weed species in sub-
tropical regions. The three factors examined were
incubation time, incubating solution, and pollen age
after shedding. We found that pollen rupture and
protein release occurred rapidly upon contact with
solutions. The highest amount of protein was released
within 15 min after incubation. As expected, pollen
rupture increased as incubation time increased. Fresh
pollen had higher rupture percentage and released a
higher amount of protein than aged pollen. Rainwater
caused more rupture and triggered more protein
release than other tested solutions. The dynamics of
rupture and the amount of released protein were
drastically different among species. In conclusion,
incubation time, incubating solution, and age of pollen
significantly affected the amount of pollen rupture and
protein release from allergenic pollen. This informa-
tion provided better understanding of factors involving
the release of allergenic protein from pollen in relation
to its internal and external conditions, which could
affect its allergenicity.
Keywords Allergen Released protein Ruptured
pollen Pollen cytoplasmic granules Pollen allergy
1 Introduction
Airborne pollen is an abundant and potent source of
airborne allergens. Concentration of airborne pollen
and released allergens can help predict allergen dose
and improve management of allergy and asthma
attacks (Taylor et al. 2002; D’Amato et al. 2016).
However, the amount of airborne pollen alone may not
correlate well with allergy symptoms. Pollen aller-
genicity is partly due to the combined immunoreac-
tivity of individual allergenic components, which has
been studied extensively in the past decades, and
bioavailability of allergenic components, a factor that
U. Siriwattanakul W. Songnuan (&)
Department of Plant Science, Faculty of Science, Mahidol
University, Bangkok 10400, Thailand
e-mail: wisuwat.son@mahidol.edu
U. Siriwattanakul W. Songnuan
Systems Biology of Diseases Research Unit, Faculty of
Science, Mahidol University, Bangkok 10400, Thailand
S. Piboonpocanun
Institute of Molecular Biosciences, Mahidol University,
Nakhon Pathom 73170, Thailand
123
Aerobiologia (2019) 35:719–730
https://doi.org/10.1007/s10453-019-09611-0(0123456789().,-volV)(0123456789().,-volV)
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... They had also reported that pollen from sour grasses and Birch did not rupture under hydration, which led them to assume that osmotically active compounds of polysaccharides (also known as p-particles) present in sweet grasses were responsible for the osmotic rupturing of pollen (Grote et al., 2001). Though most studies focus on temperate grasses commonly available in the northern hemisphere, a study done by Siriwattanakul et al. (2019) used sub-tropical grasses reported that around 50 % of pollen grains from these grass species ruptured immediately following hydration, which indicated the common pathway of pollen rupturing following hydration, that existed between the grass species. Contrary to the previous study discussed (Grote et al. (2001)), this study indicated that the pollen rupturing and allergen release were significantly increased when pollen was incubated with rainwater (p H ~ 4.6), especially in the first 30 min. ...
... Pollen from weeds, common in sub-tropical regions (T. latifolia and A. hybridus), experience varied degrees of rupturing following exposure to water, with only 20 % of grains rupturing for the former and 70 % grains rupturing for the latter even following overnight exposure (Siriwattanakul et al., 2019). The same study also indicated that water composition (rainwater, saline solution, artificial tears, and distilled water) had minimal effect on pollen rupturing and protein release. ...
... The same study also indicated that water composition (rainwater, saline solution, artificial tears, and distilled water) had minimal effect on pollen rupturing and protein release. The observed variation in the degree of pollen rupturing was speculated to be due to the differences in pollen exine thickness between the species used for the study, thereby indicating the need to investigate several other weed species to validate this claim (Siriwattanakul et al., 2019). Caronni et al. (2021) performed a study using pollen from three different species of Ambrosia genus to investigate the impact of rainwater composition and wind speed on the mechanism and the dynamics of SPP release. ...
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... SPPs release has been reported for species of very different genera (e.g., Schappi et al., 1999;De Linares et al., 2010) and has been studied in different allergenic species during thunderstorms (e.g., Taylor & Jonsson, 2004;D' Amato et al., 2007;D'Amato et al., 2017). Nevertheless, very scarce information about the main environmental factors affecting pollen grain rupture and SPPs release is still available in the literature for several extremely allergenic species (Siriwattanakul et al., 2019). ...
... In temperate regions of Europe, such as Italy and Croatia, it is known that the allergenic pathologies caused by A. artemisiifolia emerge between the end of August and the end of September, due to the seasonal release of its pollen in the atmosphere (Müller-Germann et al., 2017;Peternel et al., 2006). Anyway, a poor correlation between pollen grain counts and related allergic symptoms on atopic subjects has been observed in many areas (Bacsi et al., 2006;Siriwattanakul et al., 2019), suggesting that in those cases SPPs released in the air represent the major allergen source. Furthermore, it cannot be excluded that a fraction of SPPs carrying allergens could originate from other Ambrosia species. ...
... Each value represents the mean of the four independent counts performed artemisiifolia pollen grains some hours after hydration. Anyway, in agreement with authors, who consider the grain breakdown the cause of SPP release after hydration (De Linares et al., 2010;Knox et al., 1997;Siriwattanakul et al., 2019;Suphioglu et al., 1992), we also observed the rupture of some pollen grains after aqueous solution exposure. In fact, upon hydration, the water penetrates rapidly through the germinative pore of the more exposed grains, hydrating them in a few seconds causing an osmotic shock (Danti et al., 2011;Grote et al., 2001). ...
Subpollen particle release from different species of the invasive allergenic genus Ambrosia: the effect of rainwater composition and wind speed
Article
Full-text available
  • Jul 2021
  • AEROBIOLOGIA
Allergen-containing subpollen particles (SPPs) are micrometric or sub-micrometric particles (0.12–5 µm) released from pollen. They are able to reach the lower airways, causing allergenic reactions. SPP release occurs through the pore of intact grains or by rupture of the whole grain. In this paper the results of two laboratory experiments investigating the dynamics of SPP release for three alien species of Ambrosia genus are shown. Rainwater composition and wind speed were considered, by simulating different conditions, in accordance with a fully orthogonal experimental design. The principle response variable was the total percentage of SPPs-releasing pollen grains; also the percentage of intact grains releasing SPPs through the pore and of broken SPPs-releasing grains were considered. Both osmotic and mechanical shock caused the discharge of SPPs but different results were observed. The highest number of releasing grains was recorded in case of acid solution and 20 knots wind speed. Moreover, wind and rainfalls caused SPPs release through different mechanisms. Wind mainly provoked a mechanical shock leading to grain rupture, whereas rainfall caused mainly SPPs release through the pore of intact grains. Comparing species, the effect of wind and at least in some cases also that of rainwater appeared to be less relevant for Ambrosia trifida than for Ambrosia psilostachya and Ambrosia artemisiifolia . The obtained results suggest a species-specific response of Ambrosia species to wind speed and rainwater that lead to a different release of SPPs and then to a species-specific impact on allergy according to the characteristics of their growth environment.
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... For FM4-64 staining, a third treatment group was added (PBShydrated kiwi pollen, PKP), by resuspending the rehydrated pollen in particle-free PBS (Dubecco's PBS 1x, Capricorn Scientific, Italy) at concentrations of 1 mg/mL, and incubating it in a Petri dish for 2 h at 30°C. PKP was used as control only in the FM4-64 experiment, since the extended incubation in a liquid medium without the promotion of germination represents a stressful condition for pollen grains (Siriwattanakul et al., 2019;Bozǐčand Sǐber, 2022), hence cannot be assumed as a neutral treatment for a negative control. For all groups, viability and germinability were estimated in bright field microscopy with a Leica DM750 microscope, equipped with a Leica ICC50 W camera, using Leica AirLab software. ...
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... For FM4-64 staining, a third treatment group was added (PBShydrated kiwi pollen, PKP), by resuspending the rehydrated pollen in particle-free PBS (Dubecco's PBS 1x, Capricorn Scientific, Italy) at concentrations of 1 mg/mL, and incubating it in a Petri dish for 2 h at 30°C. PKP was used as control only in the FM4-64 experiment, since the extended incubation in a liquid medium without the promotion of germination represents a stressful condition for pollen grains (Siriwattanakul et al., 2019;Bozǐčand Sǐber, 2022), hence cannot be assumed as a neutral treatment for a negative control. For all groups, viability and germinability were estimated in bright field microscopy with a Leica DM750 microscope, equipped with a Leica ICC50 W camera, using Leica AirLab software. ...
Small extracellular vesicles released from germinated kiwi pollen (pollensomes) present characteristics similar to mammalian exosomes and carry a plant homolog of ALIX
Article
Full-text available
  • Jan 2023
Introduction In the last decade, it has been discovered that allergen-bearing extracellular nanovesicles, termed “pollensomes”, are released by pollen during germination. These extracellular vesicles (EVs) may play an important role in pollen-pistil interaction during fertilization, stabilizing the secreted bioactive molecules and allowing long-distance signaling. However, the molecular composition and the biological role of these EVs are still unclear. The present study had two main aims: (I) to clarify whether pollen germination is needed to release pollensomes, or if they can be secreted also in high humidity conditions; and (II) to investigate the molecular features of pollensomes following the most recent guidelines for EVs isolation and identification. Methods To do so, pollensomes were isolated from hydrated and germinated kiwi (Actinidia chinensis Planch.) pollen, and characterized using imaging techniques, immunoblotting, and proteomics. Results These analyses revealed that only germinated kiwi pollen released detectable concentrations of nanoparticles compatible with small EVs for shape and protein content. Moreover, a plant homolog of ALIX, which is a well-recognized and accepted marker of small EVs and exosomes in mammals, was found in pollensomes. Discussion The presence of this protein, along with other proteins involved in endocytosis, is consistent with the hypothesis that pollensomes could comprehend a prominent subpopulation of plant exosome-like vesicles.
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... Third, airborne pollen could completely rupture and release cytoplasmic contents upon hydration, and thereby could not be counted in pollen surveys. The pollen rupture could be highly synchronized and releases allergenic content simultaneously, leading to the thunderstorm allergy and asthma attacks (56,57). The pollen grains and allergenic particles on the ground can become airborne again via a redeposition process by the wind (54). ...
Exploring the effects of seasons, diurnal cycle, and heights on airborne pollen load in a Southeast Asian atmospheric condition
Article
Full-text available
  • Dec 2022
Introduction Aeropollen can induce detrimental effects, particularly in respiratory airways. Monitoring local aeropollen is essential for the management of pollen allergic patients in each area. However, without resources for constant monitoring, pollen counts are subjected to biases imposed by the choices of sampling season, time of collection, and location. Therefore, the effects of these factors must be better understood. This study investigated the dynamics of aeropollen types through seasonal variation, diurnal cycle and different heights from the ground in Bangkok, Thailand. Methods Aeropollen samples were collected for 12 months at the Faculty of Science, Mahidol University in Bangkok, using a RotoRod Sampler®. For the investigation of diurnal effect, pollen was collected at 7 a.m., 10 a.m., 1 p.m., 4 p.m., and 7 p.m. For the study of height effect, data were collected at 2, 10, and 18 meters above ground. Results and discussion This is the first study of the effects of diurnal cycle and height variation on airborne pollen count in Southeast Asia. The results showed the highest concentration of aeropollen was observed in November, which was at the beginning of the northeast monsoon season in Bangkok, whereas the lowest concentration was recorded in July (rainy season). Interestingly, the lowest airborne pollen concentration recorded in July was greater than the high level of most standards. Grass pollen was found as the major aeropollen. The highest total pollen concentration was detected at 1 p.m. The maximum pollen quantity was detected at 10 meters from the ground. However, the total aeropollen concentration was extremely high (>130 grains/m³) at all elevated heights compared to other studies that mostly found at lower height (approximately 1–2 m above ground). The result suggested that pollen concentrations of most pollen types increased as height increased. This study also illustrated the correlation between aeropollen quantity and local meteorological factors. Conclusion This aeropollen survey reported that pollen concentration and diversity were affected by seasonal variation, diurnal cycle, and height from the ground. Understanding these relationships can help with predictions of aeropollen type and quantity.
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... Of note, we considered several aspects: In addition to the above-mentioned factors determining the allergenic potency of pollen, another important element is bioavailability of the allergenic components, for example, the efficiency of pollen grain rupture. 13 The rupture can occur within several minutes in hypotonic solutions such rainwater or tears, 14 or might take up to several hours, as shown for birch pollen in water. 13 This means that different proteins are released over time by pollen particles depending ...
Comparative proteomics of common allergenic tree pollens of birch, alder, and hazel
Article
Full-text available
Background In addition to known allergens, other proteins in pollen can aid the development of an immune response in allergic individuals. The contribution of the “unknown” protein allergens is apparent in phylogenetically related species where, despite of high homology of the lead allergens, the degree of allergenic potential can vary greatly. The aim of this study was to identify other potentially allergenic proteins in pollen of three common and highly related allergenic tree species: birch (Betula pendula), hazel (Corylus avellana) and alder (Alnus glutinosa). Methods For that purpose, we carried out a comprehensive, comparative proteomic screening of the pollen from the three species. In order to maximize protein recovery and coverage, different protein extraction and isolation strategies during sample preparation were employed. Results As a result, we report 2500–3000 identified proteins per each of the pollen species. Identified proteins were further used for a number of annotation steps, providing insight into differential distribution of peptidases, peptidase inhibitors and other potential allergenic proteins across the three species. Moreover, we carried out functional enrichment analyses that, interestingly, corroborated high species similarity in spite of their relatively distinct protein profiles. Conclusion We provide to our knowledge first insight into proteomes of two very important allergenic pollen types, hazel and alder, where not even transcriptomics data are available, and compared them to birch. Datasets from this study can be readily used as protein databases and as such serve as basis for further functional studies.
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Pollen Overload: Seasonal Allergies in a Changing Climate
Article
Full-text available
  • Apr 2016
  • ENVIRON HEALTH PERSP
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Variation of the group 5 grass pollen allergen content of airborne pollen in relation to geographic location and time in season
Article
Full-text available
  • May 2015
Allergies to grass pollen are the number one cause of outdoor hay fever. The human immune system reacts with symptoms to allergen from pollen. We investigated the natural variability in release of the major group 5 allergen from grass pollen across Europe. Airborne pollen and allergens were simultaneously collected daily with a volumetric spore trap and a high-volume cascade impactor at 10 sites across Europe for 3 consecutive years. Group 5 allergen levels were determined with a Phl p 5-specific ELISA in 2 fractions of ambient air: particulate matter of greater than 10 μm in diameter and particulate matter greater than 2.5 μm and less than 10 μm in diameter. Mediator release by ambient air was determined in FcεRI-humanized basophils. The origin of pollen was modeled and condensed to pollen potency maps. On average, grass pollen released 2.3 pg of Phl p 5 per pollen. Allergen release per pollen (potency) varied substantially, ranging from less than 1 to 9 pg of Phl p 5 per pollen (5% to 95% percentile). The main variation was locally day to day. Average potency maps across Europe varied between years. Mediator release from basophilic granulocytes correlated better with allergen levels per cubic meter (r(2) = 0.80, P < .001) than with pollen grains per cubic meter (r(2) = 0.61, P < .001). In addition, pollen released different amounts of allergen in the non-pollen-bearing fraction of ambient air, depending on humidity. Across Europe, the same amount of pollen released substantially different amounts of group 5 grass pollen allergen. This variation in allergen release is in addition to variations in pollen counts. Molecular aerobiology (ie, determining allergen in ambient air) might be a valuable addition to pollen counting. Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.
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Glutathione-S-Transferase: A Minor Allergen in Birch Pollen due to Limited Release from Hydrated Pollen
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Full-text available
Background Recently, a protein homologous to glutathione-S-transferases (GST) was detected in prominent amounts in birch pollen by proteomic profiling. As members of the GST family are relevant allergens in mites, cockroach and fungi we investigated the allergenic relevance of GST from birch (bGST). Methodology bGST was expressed in Escherichia coli, purified and characterized by mass spectrometry. Sera from 217 birch pollen-allergic patients were tested for IgE-reactivity to bGST by ELISA. The mediator-releasing activity of bGST was analysed with IgE-loaded rat basophil leukaemia cells (RBL) expressing human FcεRI. BALB/c mice were immunized with bGST or Bet v 1. Antibody and T cell responses to either protein were assessed. IgE-cross-reactivity between bGST with GST from house dust mite, Der p 8, was studied with murine and human sera in ELISA. The release kinetics of bGST and Bet v 1 from birch pollen were assessed in water, simulated lung fluid, 0.9% NaCl and PBS. Eluted proteins were quantified by ELISA and analysed by immunoblotting. Principle findings Only 13% of 217 birch pollen-allergic patients showed IgE-reactivity to bGST. In RBL assays bGST induced mediator release. Immunization of mice with bGST induced specific IgE and a Th2-dominated cellular immune response comparably to immunization with Bet v 1. bGST did not cross-react with Der p 8. In contrast to Bet v 1, only low amounts of bGST were released from pollen grains upon incubation in water and the different physiological solutions. Conclusion/Significance Although bGST is abundant in birch pollen, immunogenic in mice and able to induce mediator release from effector cells passively loaded with specific IgE, it is a minor allergen for birch pollen-allergic patients. We refer this discrepancy to its limited release from hydrated pollen. Hence, bGST is an example demonstrating that allergenicity depends mainly on rapid elution from airborne particles.
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Wind-pollination and the roles of pollen allergenic proteins
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Full-text available
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Over the past few decades, there has been an explosion of understanding of the molecular nature of major allergens contained within pollens from the most important allergenic plant species. Most major allergens belong to only a few protein families. Protein characteristics, cross-reactivity, structures, and IgE binding epitopes have been determined for several allergens. These efforts have led to significant improvements in specific immunotherapy, yet there has been little discussion about the physiological functions of these proteins. Even with large amounts of available information about allergenic proteins from pollens, the incidence of pollen allergy continuously increases worldwide. The reason for this increase is unclear and is most likely due to a combination of factors. One important culprit might be a change in the pollen itself. Knowledge about pollen biology and how pollen is changing as a result of more extreme environmental conditions might improve our understanding of the disease. This review focuses on the characteristics of plants producing allergenic pollens that are relevant to pollen allergy, including the phylogenetic relationships, pollen dispersal distances, amounts of pollen produced, amounts of protein in each type of pollen, and how allergenic proteins are released from pollens. In addition, the physiological roles of major allergenic protein families will be discussed to help us understand why some of these proteins become allergens and why GMO plants with hypoallergenic pollens may not be successful.
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Beta-Expansin of Bermuda, Johnson, and Para grass pollens, is a major cross-reactive allergen for Allergic Rhinitis patients in subtropical climate
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  • Mar 2018
Background: Subtropical grass pollens of Bermuda (BGP), Johnson (JGP), and Para or buffalo grass (PGP), are common causes of pollen allergies in warm climate area. Allergic rhinitis (AR) patients had positive skin prick test (SPT) to extract of these 3 grass pollens. However, no allergenic proteins of 3 grass pollens have never been studied. Objective: To identify major allergens of BGP, JGP, and PGP in Thai grass pollen-allergic patients and to examine their sIgE cross-reactivity. Methods: Serum of nine AR patients with positive SPT to at least 2 of 3 studied pollens were collected. Based on availability, only ImmunoCAP of BGP and JGP were available to determine a level of sIgE. Profiles of sIgE bound proteins from BGP, JGP, and PGP, were obtained by immunoblot. Major IgE bound protein was identified by liquid chromatography-tandem mass spectrophotometry (LC-MS/MS). Cross-reactivity of purified major allergen of the 3 grass pollens was determined by inhibition of sIgE in both ELISA and immunoblot. Results: AR patients who have positive SPT to extract of BGP, JGP, and PGP, were 9, 8, and 6, respectively. Positive sIgE (> 0.35 kUA/L) to BGP and JGP were found in 9 and 8 patients, respectively. Eight profiles of IgE bound proteins of the 3 grass pollens showed 29-30 kDa pollen protein as major allergen and was identified as beta-expansin (ExpB). Moreover, purified ExpB of the 3 grass pollens cross-inhibited serum sIgE. Conclusion: ~30 kDa ExpB of BGP, JGP, and PGP, is major cross-reactive allergen for AR Thai patients.
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Correlation between airborne Olea europaea pollen concentrations and levels of the major allergen Ole e 1 in Crdoba, Spain, 2012-2014
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  • Apr 2016
Olea europaea L. pollen is the second-largest cause of pollinosis in the southern Iberian Peninsula. Airborne-pollen monitoring networks provide essential data on pollen dynamics over a given study area. Recent research, however, has shown that airborne pollen levels alone do not always provide a clear indicator of actual exposure to aeroallergens. This study sought to evaluate correlations between airborne concentrations of olive pollen and Ole e 1 allergen levels in Córdoba (southern Spain), in order to determine whether atmospheric pollen concentrations alone are sufficient to chart changes in hay fever symptoms. The influence of major weather-related variables on local airborne pollen and allergen levels was also examined. Monitoring was carried out from 2012 to 2014. Pollen sampling was performed using a Hirst-type sampler, following the protocol recommended by the Spanish Aerobiology Network. A multi-vial cyclone sampler was used to collect aeroallergens, and allergenic particles were quantified by ELISA assay. Significant positive correlations were found between daily airborne allergen levels and atmospheric pollen concentrations, although there were occasions when allergen was detected before and after the pollen season and in the absence of airborne pollen. The correlation between the two was irregular, and pollen potency displayed year-on-year variations and did not necessarily match pollen-season-intensity.
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Airborne pollen survey in Bangkok, Thailand: A 35-year update
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  • Sep 2015
Background: Pollen allergy is a growing global health issue. While airborne pollen counts are reported daily in several countries, such information is lacking in Thailand. Objective: This study aimed to survey airborne pollens at five sites in Bangkok, comparing data with the previous study performed 35 years ago in 1980. Methods: Sample collection was done using the ROTOROD (R) sampler by exposing the rods for one hour each day twice a week from May 2012 April 2013. Results: Overall, we found that the average pollen count was relatively high throughout the year, at an average of 242 grains/m(3). The highest peak was found in September (700 grains/m(3)). Interestingly, we found that the pollen count was noticeably lower in 2012-2013 when compared to the 1980 study. We also observed the approximate shift of pollen peaks about one to two months earlier in the 2012-2013 study. However, the major groups of airborne pollens did not change significantly. Grass, sedge, amaranthus pollens and fern spores still dominated. The unidentified pollen group was the only group with a higher pollen count when compared to the previous study.
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Nasal and ocular responses after specific and nonspecific nasal challenges in seasonal allergic rhinitis
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  • Jan 2016
Background: Different nasal challenges induce neural and immune response leading to nasal and ocular symptoms in patients with seasonal allergic rhinitis (SAR). The release of neural mediators from nasal mucosa and conjunctiva after no-specific challenges in patients with SAR remains unknown. Objectives: To compare the release of mediators from the nose and conjunctiva with symptoms after different nasal challenges in patients with SAR. Methods: Three types of consecutive nasal challenges were performed outside the pollen season in 25 patients with SAR. Challenges consisted of 500 biological units (BU) of allergen, 80 μg of histamine, and 1 mL of 2% hypertonic saline per nostril, within 24-hour and 72-hour intervals, respectively. Before and 15 minutes after challenges, evaluation of symptoms was performed with a visual analog scale. Concentrations of tryptase, eosinophil cationic protein in nasal lavages after 15 minutes, and substance P in tears after 5 minutes were measured with enzyme immunoassays. Results: Concentrations of substance P in tears were significantly higher after nonspecific challenges. Substance P concentration in tears significantly correlated with eye itchiness after histamine and hypertonic saline and with tearing after allergen. Ocular symptoms correlated significantly with tryptase concentration in nasal lavage collected 15 minutes after allergen challenge. There is a significant correlation in tear volume comparing different nasal challenges. Conclusions: Nasal challenges with allergen, histamine, or irritants outside the pollen season induce a significant increase in nasal and ocular symptoms in patients with SAR. Interaction of the early-phase response and neurogenic inflammation define the pattern and severity of eye symptoms.
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Thunderstorm-related asthma: What happens and why
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The fifth report issued by the Intergovernmental Panel on Climate Change forecasts that greenhouse gases will increase 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 minutes 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 the light of these observations, it is useful to predict thunderstorms and thus minimise thunderstorm-related events. This article is protected by copyright. All rights reserved.
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