High ambient levels of grass, weed and other pollen are associated with asthma admissions in children and adolescents: A large 5-year case-crossover study.

BACKGROUND: Pollen is an important aeroallergen that triggers asthma exacerbations in children, but we know little about the impact of different pollen types in cities with varying climatic conditions and pollen seasons. OBJECTIVES: We aimed to assess the role of ambient level of different types of pollen on a large time series of child and adolescent asthma hospitalizations in Sydney, Australia. METHODS: Childhood asthma hospitalization and the daily ambient pollen concentrations of different species were collected in South-West Sydney. With a bidirectional case-crossover design, we fitted conditional logistic regression models to measure the associations between instantaneous and up to 3 days lagged effects of pollen concentrations on asthma hospitalizations after controlling for potential confounders and testing for interactions. RESULTS: A total of 2098 children, more boys (59.7%) and 2-5 years old (62.6%), were hospitalized due to asthma. The geometric mean concentration of Cupressus, 7.88 [5.02] grains/m3 , was the highest during the study period. The increase from 75th to 90th percentile of grass (OR = 1.037, 95% CI 1.005-1.070), weed other than Plantago species (OR = 1.053, 95% CI 1.009-1.098) and unclassified pollen (OR = 1.034, 95% CI 1.010-1.058) were significantly associated with the odds of asthma hospitalizations. Boys were at greater risk of asthma exacerbations associated with grass (OR = 1.046, 95% CI 1.003-1.090) and unclassified pollen (OR = 1.041, 95% CI 1.010-1.073). There was evidence of effect modification by age groups for Cupressus, conifer, total tree and total pollen. CONCLUSIONS: Although boys are more vulnerable to grass pollen, weed, and other pollen are also important triggers of asthma exacerbations in all children and adolescents. These findings are important for urban green space planning and the development of pollen monitoring systems for families with children at risk of asthma exacerbations during peak pollen seasons.

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.

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.

[Prevalence of sensitization to allergens in school children with asthma residents from Guadalajara metropolitan area]. / Prevalencia de sensibilización a alergenos en niños escolares con asma que viven en la zona metropolitana de Guadalajara.

BACKGROUND: Allergic sensitization is dependent on the geographical and climatic conditions in each region; therefore, identify agents most commonly sensitized children with asthma is important for planning prevention measures. OBJECTIVE: To determine the prevalence of the sensitization to allergens in children with asthma. MATERIAL AND METHOD: This cross-sectional and prolective study includes children from ages 6 to 14, who have asthma, attended for the first time in an allergy service. The patients were recruited consecutively between the months of January 1st 2014 to December 31st 2014. The frequency of the allergen sensitization was estimated. RESULTS: This study included 186 children, the median age was 7 years olds, the male group was 104/186 (55.9%) The median of the positive results was 5 and monosensitized were 47/186 (2.2%). The most common category of allergens was the indoor (90.3%), then trees (71.0%), and finally the fungi (9.7%). Individually, the house dust mites were more common in between the interior allergens, followed by the epithelial; in the tree pollen were oaks (31.7%) and ashes (28.0%), in weeds was mugwort (21.5%), in grasses was Zea mays (18.3%) and in the fungi was Cladosporium spp. (6.5%). CONCLUSION: The high prevalence of the sensitization to house dust mites and epithelial in children with asthma, stimulates to implement methods of environmental control for contributing a better control of the disease.

Antecedentes: la prevalencia de rinosinusitis crónica en pacientes adultos con inmunodeficiencia común variable (IDCV) es de 52%. Los pacientes con esta enfermedad tienen mayor frecuencia de rinosinusitis crónica, enfermedad inflamatoria que afecta a la mucosa de uno o más senos paranasales y la cavidad nasal. Objetivo: identificar los microorganismos de secreción del meato medio obtenida por endoscopia asociados con rinosinusitis crónica en pacientes adultos con inmunodeficiencia común variable (IDCV). Material y método: estudio descriptivo, transversal, que incluyó a pacientes adultos con inmunodeficiencia común variable, de quienes se obtuvo una muestra vía endoscópica de secreción del meato medio de ambas fosas nasales, que se envió a cultivo para bacterias aerobias, anaerobias y hongos. Se obtuvo consentimiento informado de todos los pacientes. Resultados: se estudiaron 29 pacientes: 18 mujeres y 11 hombres, con edad promedio de 40±13 años. Los resultados obtenidos fueron: 2 muestras de pacientes no tuvieron desarrollo microbiano, 24 tuvieron desarrollo de bacterias aerobias, en 3 casos hubo crecimiento fúngico sin desarrollo de bacterias anaerobias. Conclusiones: nuestros resultados muestran que los microorganismos asociados con rinosinusitis crónica en pacientes adultos con inmunodeficiencia común variable más comunes son: Moraxella catarrhalis, Staphylococcus, Sphingomonas paucimobilis y Citrobacter koseri; los agentes micóticos asociados fueron: Candida albicans y Aspergillus fumigatus.

Allergens of weed pollen: an overview on recombinant and natural molecules.

Weeds represent a botanically unrelated group of plants that usually lack commercial or aesthetical value. Pollen of allergenic weeds are able to trigger type I reactions in allergic patients and can be found in the plant families of Asteraceae, Amaranthaceae, Plantaginaceae, Urticaceae, and Euphorbiaceae. To date, 34 weed pollen allergens are listed in the IUIS allergen nomenclature database, which were physicochemically and immunologically characterized to varying degrees. Relevant allergens of weeds belong to the pectate lyase family, defensin-like family, Ole e 1-like family, non-specific lipid transfer protein 1 family and the pan-allergens profilin and polcalcins. This review provides an overview on weed pollen allergens primarily focusing on the molecular level. In particular, the characteristics and properties of purified recombinant allergens and hypoallergenic derivatives are described and their potential use in diagnosis and therapy of weed pollen allergy is discussed.

Cross allergic reactions in infants and toddlers with atopic dermatitis.

PURPOSE: Prevalence and clinical significance of cross sensitization in children up to 3 years old, diagnosed with atopic dermatitis. MATERIAL AND METHOD: The retrospective study included 69 children up to 3 years old with atopic dermatitis. Allergological diagnostics was performed based on skin tests, determination of total IgE concentration and allergen-specific IgE. RESULTS: Cross sensitization was found in 26% of children. Other patients were qualified to the control group. The sensitization to trees pollen and fruits as well as grass pollen and vegetables were the most frequent types of cross allergy. The patient's family history was positive with regard to atopy in 72% of children from the study group vs. 31% of children from the control group. The statistically higher prevalence of allergic rhinitis and bronchial asthma as well as co-existence of sensitization to house dust mite and animal dander were revealed in the study group. The total concentration of IgE, eosinophilia and SCORAD values were statistically higher in the study group. Children with cross sensitization required systemic steroid therapy more frequently. CONCLUSION: In children up to 3 years with atopic dermatitis and sensitization to plant pollen, the role of a pollen-food allergy syndrome must be taken into account in the pathogenesis of the disease. In children with cross sensitization, the course of atopic dermatitis is more severe; the symptoms from the respiratory and digestive system co-exist. The positive family history is a factor, predisposing to the development of cross sensitization in infants and toddlers.

Recombinant allergens for pollen immunotherapy.

Specific immunotherapy (IT) represents the only potentially curative therapeutic intervention of allergic diseases capable of suppressing allergy-associated symptoms not only during treatment, but also after its cessation. Presently, IT is performed with allergen extracts, which represent a heterogeneous mixture of allergenic, as well as nonallergenic, compounds of a given allergen source. To overcome many of the problems associated with extract-based IT, strategies based on the use of recombinant allergens or derivatives thereof have been developed. This review focuses on recombinant technologies to produce allergy therapeuticals, especially for allergies caused by tree, grass and weed pollen, as they are among the most prevalent allergic disorders affecting the population of industrialized societies. The reduction of IgE-binding of recombinant allergen derivatives appears to be mandatory to increase the safety profile of vaccine candidates. Moreover, increased immunogenicity is expected to reduce the dosage regimes of the presently cumbersome treatment. In this regard, it has been convincingly demonstrated in animal models that hypoallergenic molecules can be engineered to harbor inherent antiallergenic immunologic properties. Thus, strategies to modulate the allergenic and immunogenic properties of recombinant allergens will be discussed in detail. In recent years, several successful clinical studies using recombinant wild-type or hypoallergens as active ingredients have been published and, currently, novel treatment forms with higher safety and efficacy profiles are under investigation in clinical trials. These recent developments are summarized and discussed.

Pollen count and presentation of angiotensin-converting enzyme inhibitor-associated angioedema.

BACKGROUND: The incidence of angiotensin-converting enzyme (ACE) inhibitor-associated angioedema is increased in patients with seasonal allergies. OBJECTIVE: We tested the hypothesis that patients with ACE inhibitor-associated angioedema present during months when pollen counts are increased. METHODS: Cohort analysis examined the month of presentation of ACE inhibitor-associated angioedema and pollen counts in the ambulatory and hospital setting. Patients with ACE inhibitor-associated angioedema were ascertained through (1) an observational study of patients presenting to Vanderbilt University Medical Center, (2) patients presenting to the Marshfield Clinic and participating in the Marshfield Clinic Personalized Medicine Research Project, and (3) patients enrolled in The Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET). Measurements include date of presentation of ACE inhibitor-associated angioedema, population exposure to ACE inhibitor by date, and local pollen counts by date. RESULTS: At Vanderbilt, the rate of angioedema was significantly associated with tree pollen months (P = .01 from χ(2) test). When separate analyses were conducted in patients with a history of seasonal allergies and patients without, the rate of ACE inhibitor-associated angioedema was increased during tree pollen months only in patients with a history of seasonal allergies (P = .002). In Marshfield, the rate of angioedema was significantly associated with ragweed pollen months (P = .025). In ONTARGET, a positive trend was observed between the ACE inhibitor-associated angioedema rate and grass season, although it was not statistically significant (P = .057). CONCLUSIONS: Patients with ACE inhibitor-associated angioedema are more likely to present with this adverse drug event during months when pollen counts are increased.

The specific IgE reactivity pattern of weed pollen-induced allergic rhinitis patients.

CONCLUSION: Specific immunoglobulin E (IgE) reactivity towards the major mugwort allergen Art v 1 is a good indicator for Art v sensitization. Allergens from the ragweed species Amb t and Amb a possibly share common IgE-binding epitopes. OBJECTIVE: The aim of this study was to investigate the reactivity pattern of IgE in Chinese patients with weed pollen-induced allergic rhinitis. METHODS: Sera from 50 weed pollen-induced allergic rhinitis patients were tested for specific serum IgE reactivity against allergenic extracts of mugwort (Artemisia vulgaris, Art v), short ragweed (Ambrosia artemisiifolia, Amb a), giant ragweed (Ambrosia trifida, Amb t), and single allergens of Art v 1, Art v 3, Amb a 1, and profilin. RESULTS: Sera from 88% of the patients demonstrated positive specific IgE reactivity to Art v, and of these 82% were positive to Art v 1. Sera from 38% of the patients showed positive specific IgE reactivity to both ragweed species Amb t and Amb a. A strong correlation was found between the specific IgE levels of Amb t and Amb a. Of the Amb a IgE-positive patients, 38% were positive for Amb a 1. Of all patient sera tested, 12% were specific IgE-positive to profilin.

Important Florida botanical aeroallergens.

Florida is home to approximately 4 million allergy sufferers and almost 15,000 individual species of plants. Only a few of these plants produce pollen with documented allergenicity via in vivo/in vitro testing and provocation challenges. Many plant species with proven allergenicity are present only to a limited degree. Furthermore, allergenic plants in Florida do not follow the same pollinating patterns as the rest of the country, i.e., trees in the spring, grasses in the summer, and weeds in the fall. Media outlets that report pollen counts to the general public may mislead patients without appropriate interpretation. This review highlights clinical studies that document the allergenicity of some pollens and summarizes expert opinion regarding other prevalent and allergenic pollens throughout the state.