Current and Future Effects of Climate Change on Airborne Allergens.

PURPOSE OF REVIEW: Delineation of the impact of elevated carbon dioxide and concomitant global warming on airborne allergens is performed. RECENT FINDINGS: European tree pollen trends in general showed earlier start and end dates and increased total pollen release, with some differences both in locale and among species. Earlier flowering was also seen with grasses and weeds. In the case of some boreal trees, flowering was delayed due to a pre-seasonal requirement for necessary accumulated chilling temperature to achieve bud-set. Anthropogenic climate change induced rise in temperature and CO2 levels has resulted in demonstrable increases in aeroallergens. This has been most dramatic in tree pollen annual load, but also seen with grasses and weeds. Collected data is greatest for the Northern Hemisphere, especially the European continent, with supporting data from North America and Australia.

Mapping pollen allergenicity from urban trees in Valencia: A tool for green infrastructure planning.

Urban trees provide many benefits to citizens but also have associated disservices such as pollen allergenicity. Pollen allergies affect 40% of the European population, a problem that will be exacerbated with climate change by lengthening the pollen season. The allergenic characteristics of the urban trees and urban parks of the city of Valencia (Spain) have been studied. The Value of Potential Allergenicity (VPA) was calculated for all species. The most abundant allergenic trees with a very high VPA were the cypresses, followed by Platanus x hispanica and species of genera Morus, Acer and Fraxinus, with a high VPA. On the contrary, Citrus x aurantium, Melia azedarach, Washingtonia spp., Brachychiton spp. and Jacaranda mimosifolia were among the most abundant low allergenic trees. VPA was mapped for the city and a hot spot analysis was applied to identify areas of clustering of high and low VPA values. This geostatistical analysis provides a comprehensive representation of the VPA patterns which is very useful for urban green infrastructure planning. The Index of Urban Green Zone Allergenicity (IUGZA) was calculated for the main parks of the city. The subtropical and tropical flora component included many entomophilous species and the lowest share of high and very high allergenic trees in comparison with the Mediterranean and Temperate components. Overall, a diversification of tree species avoiding clusters of high VPA trees, and the prioritization of species with low VPA are good strategies to minimize allergy-related impacts of urban trees on human health.

Tree pollen exposure is associated with reduced lung function in children.

BACKGROUND: Allergic disease is a recognized global epidemic and a significant cause of ill health and poor quality of life. The prevalence of pollen allergy is high throughout the world, and pollen exposure itself plays a role in emergency department presentations and hospitalizations for asthma. Lung function and airway inflammation are important measures of asthma activity and control. OBJECTIVE: To examine associations between exposure to multiple pollen types and lung function and markers of airway inflammation at 8 and 14 years of age, and to explore potential modification by residential greenness. METHODS: A cohort of high-risk children living in Sydney, Australia had spirometry and fractional exhaled nitric oxide (FeNO) measured at 8 and 14 years of age. Ambient pollen concentration on the day of lung function measurement and up to three days prior was used as the exposure measure. Residential greenness was derived from satellite imagery. We modelled the association between six pollen types and lung function and FeNO. We also assessed modifying effects of residential greenness. RESULTS: Casuarina, cypress and Pinus pollen in the air the day before measurement and 3 days prior respectively, were associated with reduced lung function in 8-year-olds. The pollen exposures were associated with decreases in FEV1 and FVC; however, the FEV1 /FVC ratio was not affected. Effect modification by greenness was not observed due to loss of power. CONCLUSIONS & CLINICAL RELEVANCE: Airborne tree pollen of cypress, Casuarina and Pinus and not grass in some regions may be detrimental to childhood lung function.

Tree defence and bark beetles in a drying world: carbon partitioning, functioning and modelling.

Drought has promoted large-scale, insect-induced tree mortality in recent years, with severe consequences for ecosystem function, atmospheric processes, sustainable resources and global biogeochemical cycles. However, the physiological linkages among drought, tree defences, and insect outbreaks are still uncertain, hindering our ability to accurately predict tree mortality under on-going climate change. Here we propose an interdisciplinary research agenda for addressing these crucial knowledge gaps. Our framework includes field manipulations, laboratory experiments, and modelling of insect and vegetation dynamics, and focuses on how drought affects interactions between conifer trees and bark beetles. We build upon existing theory and examine several key assumptions: (1) there is a trade-off in tree carbon investment between primary and secondary metabolites (e.g. growth vs defence); (2) secondary metabolites are one of the main component of tree defence against bark beetles and associated microbes; and (3) implementing conifer-bark beetle interactions in current models improves predictions of forest disturbance in a changing climate. Our framework provides guidance for addressing a major shortcoming in current implementations of large-scale vegetation models, the under-representation of insect-induced tree mortality.

Outdoor pollen is a trigger of child and adolescent asthma emergency department presentations: A systematic review and meta-analysis.

BACKGROUND: In the context of increased asthma exacerbations associated with climatic changes such as thunderstorm asthma, interest in establishing the link between pollen exposure and asthma hospital admissions has intensified. Here, we systematically reviewed and performed a meta-analysis of studies on pollen and emergency department (ED) attendance. METHODS: A search for studies with appropriate search strategy in MEDLINE, EMBASE, Web of Science and CINAHL was conducted. Each study was assessed for quality and risk of bias. The available evidence was summarized both qualitatively and meta-analysed using random-effects models when moderate heterogeneity was observed. RESULTS: Fourteen studies were included. The pollen taxa investigated differed between studies, allowing meta-analysis only of the effect of grass pollen. A statistically significant increase in the percentage change in the mean number of asthma ED presentations (MPC) (pooled results from 3 studies) was observed for an increase in 10 grass pollen grains per cubic metre of exposure 1.88% (95% CI = 0.94%, 2.82%). Time series studies showed positive correlations between pollen concentrations and ED presentations. Age-stratified studies found strongest associations in children aged 5-17 years old. CONCLUSION: Exposure to ambient grass pollen is an important trigger for childhood asthma exacerbations requiring ED attendance. As pollen exposure is increasingly a problem especially in relation to thunderstorm asthma, studies with uniform measures of pollen and similar analytical methods are necessary to fully understand its impact on human health.

Characterization of a Major Allergen from Mongolian Oak, Quercus mongolica, a Dominant Species of Oak in Korea.

BACKGROUND: Oaks are the most common trees in Korean forests, and Mongolian oak, Quercus mongolica, is the dominant species. However, no allergen has been characterized from Mongolian oak. In this study, we tried to characterize a major allergen from Mongolian oak. METHODS: A molecule homologous to pathogenesis-related 10 (PR-10)-like protein, Que m 1, was cloned by RT-PCR. Its recombinant protein, along with Que a 1, an allergen from white oak (Q. alba), was produced. The allergenicity and diagnostic value of recombinant Que m 1, Que a 1, and Bet v 1 proteins were compared by ELISA using sera from oak-sensitized subjects. A basophil activation test was also performed using CD63 expression as an activation marker. RESULTS: Que m 1 sequence shares 57.5-96.2% amino acid sequence identity with PR-10-like allergens from various plants. Specific IgE to recombinant Que m 1, Que a 1, and Bet v 1 were detected in 92.0, 74.0, and 38.0% of 50 serum samples from Korean tree pollinosis patients. Recombinant Que m 1 was able to inhibit IgE reactivity to Que a 1 and Bet v 1, indicating its strong cross-reactivity. The activation patterns of basophils from 5 patients were similar in terms of the CD63 expression and protein concentration of challenged Bet v 1 and Que m 1. CONCLUSIONS: A major allergen, Que m 1, was cloned, and its recombinant protein was produced from Mongolian oak, a dominant species in Korea. Recombinant Que m 1 is potentially useful for the diagnosis and treatment of tree pollinosis in Korea.

Determination of irritant threshold concentrations of multiple tree, grass, weed and mould allergens for intradermal testing of horses residing in the southern USA.

BACKGROUND: Appropriate allergen threshold concentrations (TCs) for intradermal testing (IDT) have not been established in horses for many pollen and mould allergens. OBJECTIVES: To determine the TCs in non-allergic horses and describe the frequency of late phase reactions for 26 allergens, including trees, grasses, weeds and moulds in horses residing in the southern Unites States. ANIMALS: Twenty four clinically normal horses in the southern United States. METHODS: Threshold concentrations for different allergens were determined using IDT subjective measurements at 30 minutes. Delayed reactions were evaluated at 4 and 24 h. RESULTS: Threshold concentrations (all PNU/mL) were established for eight tree allergens (black willow 1,000, box elder 1,000, live oak 1,000, pecan 2,000, white ash 4,000, red oak 4,000, red mulberry 2,000 and green ash 2,000); two grass allergens (Johnson grass 250 PNU/mL and Kentucky blue grass 500 PNU/mL); two weeds (carelessweed 1,000 PNU/mL, great ragweed 500 PNU/mL) and one mould (Curvularia 8,000 PNU/mL). The TC was not determined due to excessive reactivity at the lowest concentration tested (1,000 PNU/mL) for bahia and perennial rye grass. Eleven other allergens did not meet the criteria to establish a TC when evaluated at 30 min due to lack of positive reactions. Multiple allergens caused positive reactions in ≥10% of horses at 4 h. Reactions at 24 h were rare with the exception of one horse. CONCLUSIONS AND CLINICAL IMPORTANCE: This study identified intradermal TC for multiple pollen and mould allergens in horses. These values may prove useful for optimizing allergen concentrations for IDT of allergic horses.

Is the ISAC 112 Microarray Useful in the Diagnosis of Pollinosis in Spain?

BACKGROUND: Multiple sensitization is frequent among pollen-allergic patients. The goal of this study was to determine the diagnostic accuracy of the ImmunoCAP ISAC 112 (ISAC112) microarray in allergy to pollen from several taxa and its clinical utility in a Spanish population. METHODS: Specific IgE was determined in 390 pollen-allergic patients using the ISAC112 microarray. Diagnostic accuracy (sensitivity, specificity, predictive values, and area under the ROC curve) was calculated for the diagnosis of allergy to pollen from grass (n=49), cypress (n=75), olive tree (n=33), plane tree (n=63), and pellitory of the wall (n=17) and compared with that of the singleplex ImmunoCAP immunoassay. RESULTS: The sensitivity of the ISAC112 microarray ranged from 68.2% for allergy to plane tree pollen to 93.9% for allergy to grass pollen. The specificity was >90%. The AUC for the diagnosis of allergy to plane tree pollen was 0.798, whereas the AUC for the remaining cases was ≥0.876. The accuracy of ISAC112 was higher than that of ImmunoCAP for plane tree pollen and similar for the remaining pollens. The frequency of sensitization to most species-specific allergenic components and profilins varied between the different geographical regions studied. A total of 73% of pollen-allergic patients were sensitized to species-specific components of more than 1 pollen type. CONCLUSIONS: The ISAC112 microarray is an accurate tool for the diagnosis of allergy to pollen from grass, cypress, olive tree, plane tree, and pellitory of the wall. The features of the ISAC112 microarray are similar or superior (in the case of plane tree pollen) to those of ImmunoCAP. This microarray is particularly useful for the etiologic diagnosis of pollinosis in patients sensitized to multiple pollen species whose pollination periods overlap.

Induced plant defenses, host-pathogen interactions, and forest insect outbreaks.

Cyclic outbreaks of defoliating insects devastate forests, but their causes are poorly understood. Outbreak cycles are often assumed to be driven by density-dependent mortality due to natural enemies, because pathogens and predators cause high mortality and because natural-enemy models reproduce fluctuations in defoliation data. The role of induced defenses is in contrast often dismissed, because toxic effects of defenses are often weak and because induced-defense models explain defoliation data no better than natural-enemy models. Natural-enemy models, however, fail to explain gypsy moth outbreaks in North America, in which outbreaks in forests with a higher percentage of oaks have alternated between severe and mild, whereas outbreaks in forests with a lower percentage of oaks have been uniformly moderate. Here we show that this pattern can be explained by an interaction between induced defenses and a natural enemy. We experimentally induced hydrolyzable-tannin defenses in red oak, to show that induction reduces variability in a gypsy moth's risk of baculovirus infection. Because this effect can modulate outbreak severity and because oaks are the only genus of gypsy moth host tree that can be induced, we extended a natural-enemy model to allow for spatial variability in inducibility. Our model shows alternating outbreaks in forests with a high frequency of oaks, and uniform outbreaks in forests with a low frequency of oaks, matching the data. The complexity of this effect suggests that detecting effects of induced defenses on defoliator cycles requires a combination of experiments and models.

Real-life compliance and persistence among users of subcutaneous and sublingual allergen immunotherapy.

BACKGROUND: Subcutaneous allergen immunotherapy (SCIT) and sublingual allergen immunotherapy (SLIT) are safe and effective treatments of allergic rhinitis, but high levels of compliance and persistence are crucial to achieving the desired clinical effects. OBJECTIVE: Our objective was to assess levels and predictors of compliance and persistence among grass pollen, tree pollen, and house dust mite immunotherapy users in real life and to estimate the costs of premature discontinuation. METHODS: We performed a retrospective analysis of a community pharmacy database from The Netherlands containing data from 6486 patients starting immunotherapy for 1 or more of the allergens of interest between 1994 and 2009. Two thousand seven hundred ninety-six patients received SCIT, and 3690 received SLIT. Time to treatment discontinuation was analyzed and included Cox proportional hazard models with time-dependent covariates, where appropriate. RESULTS: Overall, only 18% of users reached the minimally required duration of treatment of 3 years (SCIT, 23%; SLIT, 7%). Median durations for SCIT and SLIT users were 1.7 and 0.6 years, respectively (P < .001). Other independent predictors of premature discontinuation were prescriber, with patients of general practitioners demonstrating longer persistence than those of allergologists and other medical specialists; single-allergen immunotherapy, lower socioeconomic status; and younger age. Of the persistent patients, 56% were never late in picking up their medication from the pharmacy. Direct medication costs per nonpersistent patient discontinuing in the third year of treatment were €3800, an amount that was largely misspent. CONCLUSION: Real-life persistence is better in SCIT users than in SLIT users, although it is low overall. There is an urgent need for further identification of potential barriers and measures that will enhance persistence and compliance.

Sublingual Tablet Immunotherapy Improves Quality of Life in Adults With Allergic Rhinoconjunctivitis.

BACKGROUND: Allergic rhinitis with or without conjunctivitis can negatively impact many aspects of quality of life (QoL). The efficacy and safety of standardized quality (SQ) sublingual immunotherapy (SLIT) tablets have been confirmed across large clinical trials in adults with grass, tree, ragweed, and house dust mite (HDM) allergic rhinitis with or without conjunctivitis. OBJECTIVE: This pooled analysis investigates whether the reduction in symptom burden found across the clinical trials is supported by improvements in QoL. METHODS: A total of 11 phase II/III randomized placebo-controlled trials across the SQ grass, tree, ragweed, and HDM SLIT tablets (grass: N = 3179; ragweed: N = 767; tree: N = 634; HDM: N = 2221) were included. QoL was assessed using the standardized Rhinitis Quality of Life Questionnaire (RQLQ), with the exception of 3 grass trials, which used the nonstandardized version. The overall RQLQ scores were expressed as a mean of 7 domains. In the pooled analysis, treatment was used as fixed effect; and the trial, and the interaction between region/country and trial as random effects. RESULTS: The pooled analysis showed consistent and statistically significant improvements in overall RQLQ scores across all 4 SQ SLIT tablets versus placebo (pooled estimate [95% CI], P value-grass: -0.20 [-0.28 to -0.12], P < .001; tree: -0.42 [-0.58 to -0.26], P < .001; ragweed: -0.36 [-0.55 to -0.17], P < .001; HDM: -0.28 [-0.39 to -0.17], P < .001). Furthermore, significant improvements versus placebo for all 4 SQ SLIT tablets were seen across the 7 individual domains. CONCLUSIONS: The proven efficacy of SQ SLIT tablets to reduce symptoms across 4 of the most common respiratory allergens is supported by concurrent significant improvements in RQLQ scores overall and for all 7 domains.

Variation in carbon availability, defense chemistry and susceptibility to fungal invasion along the stems of mature trees.

If carbon (C) sinks withdraw carbohydrates as they are transported along tree stems, carbohydrate availability may depend on local sink strength and distance from sources. Defenses, including monoterpenes--a major component of resin--limit the invasibility of pines. Since carbohydrate reserves fund monoterpene synthesis, we hypothesized that monoterpene concentrations in pine stems would decrease from the crown to the lower stem, and susceptibility to fungal infection would increase. Here, we measured carbohydrate and monoterpene concentrations along the stems of lodgepole pine trees (Pinus contorta var. latifolia) before inoculating with a blue-stain fungus at different heights. After 6 wk, we assessed tree responses to fungal infection based on lesion length and carbohydrate mobilization. Concentrations of carbohydrates and monoterpenes in the phloem before inoculation decreased with distance from the crown, whereas lesion lengths after inoculation increased. However, trees mobilized sugars in response to fungal infection such that carbohydrate reserves near lesions were similar at all heights. Despite C mobilization, the lower stem was more vulnerable than the upper stem. Consistent with predictions based on sink-source relationships, vulnerability occurred where carbohydrates were less available, and likely resulted from C withdrawal by sinks higher in the supply chain.

A systematic review of the effect of thermal processing on the allergenicity of tree nuts.

BACKGROUND: Allergenicity of foods can be influenced by processing. Tree nuts are an important source of nutrition and increasingly consumed; however, processing methods are quite variable and data are currently lacking on the effects of processing on allergenicity. OBJECTIVE: To perform a systematic literature review on the effects of food processing on the allergenicity of tree nuts. METHODS: A systematic literature search of PubMed and Embase databases was performed, with screening of references, related articles and citations. Studies were included if they assessed the allergenicity or immunogenicity of processed nuts. RESULTS: The search resulted in 32 articles suitable for analysis. Clinical studies indicate that roasting reduces the allergenicity of hazelnut in individuals with a birch pollen allergy and reactivity to raw hazelnut. Thermal processing may reduce the allergenicity of the PR-10 protein in hazelnut and almond in vitro. The majority of the in vitro studies investigating the allergenicity of nonspecific lipid transfer proteins (nsLTPs) and seed storage proteins in hazelnut, almond, cashew nut, Brazil nut, walnut, pecan nut and pistachio nut show heat stability towards different thermal processing methods. CONCLUSION: Thermal processing may reduce allergenicity of PR-10 proteins in hazelnut and almond, in contrast to nsLTPs and seed storage proteins. This has important implications for source materials used for IgE testing and food challenges and diet advice.

Increased susceptibility to drought-induced mortality in Sequoia sempervirens (Cupressaceae) trees under Cenozoic atmospheric carbon dioxide starvation.

PREMISE OF THE STUDY: Climate-induced forest retreat has profound ecological and biogeochemical impacts, but the physiological mechanisms underlying past tree mortality are poorly understood, limiting prediction of vegetation shifts with climate variation. Climate, drought, fire, and grazing represent agents of tree mortality during the late Cenozoic, but the interaction between drought and declining atmospheric carbon dioxide ([CO2]a) from high to near-starvation levels ∼34 million years (Ma) ago has been overlooked. Here, this interaction frames our investigation of sapling mortality through the interdependence of hydraulic function, carbon limitation, and defense metabolism. • METHODS: We recreated a changing Cenozoic [CO2]a regime by growing Sequoia sempervirens trees within climate-controlled growth chambers at 1500, 500, or 200 ppm [CO2]a, capturing the decline toward minimum concentrations from 34 Ma. After 7 months, we imposed drought conditions and measured key physiological components linking carbon utilization, hydraulics, and defense metabolism as hypothesized interdependent mechanisms of tree mortality. • KEY RESULTS: Catastrophic failure of hydraulic conductivity, carbohydrate starvation, and tree death occurred at 200 ppm, but not 500 or 1500 ppm [CO2]a. Furthermore, declining [CO2]a reduced investment in carbon-rich foliar defense compounds that would diminish resistance to biotic attack, likely exacerbating mortality. • CONCLUSIONS: Low-[CO2]a-driven tree mortality under drought is consistent with Pleistocene pollen records charting repeated Californian Sequoia forest contraction during glacial periods (180-200 ppm [CO2]a) and may even have contributed to forest retreat as grasslands expanded on multiple continents under low [CO2]a over the past 10 Ma. In this way, geologic intervals of low [CO2]a coupled with drought could impose a demographic bottleneck in tree recruitment, driving vegetation shifts through forest mortality.

Genetic and hormonal regulation of cambial development.

The stems and roots of most dicot plants increase in diameter by radial growth, due to the activity of secondary meristems. Two types of meristems function in secondary plant body formation: the vascular cambium, which gives rise to secondary xylem and phloem, and the cork cambium, which produces a bark layer that replaces the epidermis and protects the plant stem from mechanical damage and pathogens. Cambial development, the initiation and activity of the vascular cambium, leads to an accumulation of wood, the secondary xylem tissue. The thick, cellulose-rich cell walls of wood provide a source of cellulose and have the potential to be used as a raw material for sustainable and renewable energy production. In this review, we will discuss what is known about the mechanisms regulating the cambium and secondary tissue development.

The spectrum of aeroallergen sensitization in children diagnosed with asthma during first 2 years of life.

Aeroallergens may trigger symptoms in sensitized children with asthma. Documentation of sensitization is crucial to enable effective implementation of measures to prevent asthma exacerbations. To document the sensitization patterns of very young children (≤2 years) with asthma, we retrospectively analyzed the skin-prick test (SPT) results of the largest referral center in the country. During a 4-year period, 432 children (median age, 1.21 years; male/female, 2.35) were referred. All patients had recurrent wheezing attacks and good response to inhaled bronchodilators and were diagnosed with asthma by their referring physician. SPT with eight aeroallergens (grass mix, weed mix, tree mix, mold mix, house-dust mite, cockroach, cat, and dog) was performed in 209 patients (full panel group) and the remaining 223 were tested only with a mixture of two house-dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae; house-dust mite group). The sensitization rates in house-dust mite and full panel groups were 3.2% (7/223) and 3.3% (7/209), respectively. Univariate and multivariate modeling was unable to identify a predictor for the presence of aeroallergen sensitization. During first 2 years of life, low rates of aeroallergen sensitization and lack of predictors of sensitization in children with asthma suggest that skin testing for aeroallergens may not be a routine procedure. When there is a high index of suspicion, testing only for indoor aeroallergens including house-dust mites, molds, and pets may identify the majority of sensitized children.

[About forest allergens]. / Jos metsään haluat mennä nyt.

In the summer forest there are allergens and irritating substances that cause respiratory or cutaneous symptoms. Birch and alder pollen allergy is common in Finland. Pollens of other trees cause sensitization only sporadically. Spores of molds and mushrooms cause allergic reactions, but the means to study spore allergy are inadequate. Even edible mushrooms may cause allergic abdominal discomforts, and trehalose intolerance is supposed to be present in a small percentage of the population. Lichen allergens may bring about IgE-mediated reactions, contact allergy and photoallergic reactions.

Plant food allergy in patients with pollinosis from the Mediterranean area.

BACKGROUND: Patients with pollinosis develop symptoms after intake of plant food more often than the general population. In order to study the prevalence of the presentation of allergic symptoms to plant foods in pollinosis, we selected a representative sample of the population from our Mediterranean area. METHODS: All patients completed a questionnaire, provided a blood sample and underwent a battery of skin and other complementary tests (prick-prick, oral challenge test) when necessary. The pollen counts were obtained from the Elche pollen station. In addition, sera from a subgroup of patients were checked with an allergen molecule panel on an Advia Centaur XP platform. RESULTS: Of the final sample (n = 233), 39.9% of the patients with pollinosis were sensitized and 30.9% had clinical allergy to at least one of the plant foods studied. Regression analysis showed that age and sensitization to the extracts of Platanus acerifolia and Artemisia vulgaris were the most important variables for discriminating between groups. Patients with pollinosis at a risk of allergy to plant foods had significantly higher Pru p 3 values [odds ratio (OR) 3.3; 95% confidence interval (95% CI) 2.3-4.8], and the value increased according to the number of plant food sensitizations. CONCLUSION: Plant food allergy is more common in patients with pollinosis than in the general population. The use of the London plain tree (P. acerifolia) and mugwort (A. vulgaris) in the skin tests may help identify such patients in our Mediterranean area, but determination of rPru p 3 could also be very useful in patients suspected of having plant food allergy.