Airborne house dust particles and diesel exhaust particles as allergen carriers

Bioaerosols in the atmosphere: A comprehensive review on detection methods, concentration and influencing factors

In the past few decades, especially since the outbreak of the coronavirus disease (COVID-19), the effects of atmospheric bioaerosols on human health, the environment, and climate have received great attention. To evaluate the impacts of bioaerosols quantitatively, it is crucial to determine the types of bioaerosols in the atmosphere and their spatial-temporal distribution. We provide a concise summary of the online and offline observation strategies employed by the global research community to sample and analyze atmospheric bioaerosols. In addition, the quantitative distribution of bioaerosols is described by considering the atmospheric bioaerosols concentrations at various time scales (daily and seasonal changes, for example), under various weather, and different underlying surfaces. Finally, a comprehensive summary of the reasons for the spatiotemporal distribution of bioaerosols is discussed, including differences in emission sources, the impact process of meteorological factors and environmental factors. This review of information on the latest research progress contributes to the emergence of further observation strategies that determine the quantitative dynamics of public health and ecological effects of bioaerosols.

Fine particulate matter contributes to COPD-like pathophysiology: experimental evidence from rats exposed to diesel exhaust particles

BACKGROUND

Ambient fine particulate matter (PM2.5) is considered a plausible contributor to the onset of chronic obstructive pulmonary disease (COPD). Mechanistic studies are needed to augment the causality of epidemiologic findings. In this study, we aimed to test the hypothesis that repeated exposure to diesel exhaust particles (DEP), a model PM2.5, causes COPD-like pathophysiologic alterations, consequently leading to the development of specific disease phenotypes. Sprague Dawley rats, representing healthy lungs, were randomly assigned to inhale filtered clean air or DEP at a steady-state concentration of 1.03 mg/m3 (mass concentration), 4 h per day, consecutively for 2, 4, and 8 weeks, respectively. Pulmonary inflammation, morphologies and function were examined.

RESULTS

Black carbon (a component of DEP) loading in bronchoalveolar lavage macrophages demonstrated a dose-dependent increase in rats following DEP exposures of different durations, indicating that DEP deposited and accumulated in the peripheral lung. Total wall areas (WAt) of small airways, but not of large airways, were significantly increased following DEP exposures, compared to those following filtered air exposures. Consistently, the expression of α-smooth muscle actin (α-SMA) in peripheral lung was elevated following DEP exposures. Fibrosis areas surrounding the small airways and content of hydroxyproline in lung tissue increased significantly following 4-week and 8-week DEP exposure as compared to the filtered air controls. In addition, goblet cell hyperplasia and mucus hypersecretions were evident in small airways following 4-week and 8-week DEP exposures. Lung resistance and total lung capacity were significantly increased following DEP exposures. Serum levels of two oxidative stress biomarkers (MDA and 8-OHdG) were significantly increased. A dramatical recruitment of eosinophils (14.0-fold increase over the control) and macrophages (3.2-fold increase) to the submucosa area of small airways was observed following DEP exposures.

CONCLUSIONS

DEP exposures over the courses of 2 to 8 weeks induced COPD-like pathophysiology in rats, with characteristic small airway remodeling, mucus hypersecretion, and eosinophilic inflammation. The results provide insights on the pathophysiologic mechanisms by which PM2.5 exposures cause COPD especially the eosinophilic phenotype.

Determination of ragweed allergen Amb a 1 distribution in aerosols using ELISA and immunogold scanning electron microscopy

Background

Ragweed as an invasive species in Europe has become more important for allergy sufferers in the last decade. Because pollen fractions can be found in the respirable fraction of aerosols, they can generate severe disease progressions.

Objective

To obtain information about the concentration and distribution of 1 of the main ragweed allergens Ambrosia artemisiifolia 1 in the air of Vienna, PM10 and PM2.5 fine dust filters were analyzed.

Methods

Standard fine dust filters used for air quality monitoring were analyzed via ELISA and immunogold scanning electron microscopy.

Results

Via ELISA it was possible to show that already at pollen season start in August a recognizably high A artemisiifolia 1 concentration can be found. In addition, the allergen concentration in the air stays comparatively high after the peak season has ended even when the pollen concentration drops to a moderate level. The immunogold electron microscopy investigation directly applied on filters shows that the allergen can be found on organic as well as on mixtures of organic and inorganic particles. A first semistatistical analysis of the labeled particle sizes indicates that a large number of the allergen carriers can be found within the smallest particle size range. Nevertheless, further investigations are needed to obtain enough particle counts for a significant statistical analysis.

Conclusions

It was possible to show that reliable results can be obtained from ELISA and immunogold scanning electron microscopy directly applied on filters that are used in air quality monitoring sites. By adaptation of the used protocols, it should be possible to obtain respective information about further allergens.

Mammalian derived lipocalin and secretoglobin respiratory allergens strongly bind ligands with potentially immune modulating properties

Allergens from furry animals frequently cause sensitization and respiratory allergic diseases. Most relevant mammalian respiratory allergens belong either to the protein family of lipocalins or secretoglobins. Their mechanism of sensitization remains largely unresolved. Mammalian lipocalin and secretoglobin allergens are associated with a function in chemical communication that involves abundant secretion into the environment, high stability and the ability to transport small volatile compounds. These properties are likely to contribute concomitantly to their allergenic potential. In this study, we aim to further elucidate the physiological function of lipocalin and secretoglobin allergens and link it to their sensitizing capacity, by analyzing their ligand-binding characteristics. We produced eight major mammalian respiratory allergens from four pet species in E.coli and compared their ligand-binding affinities to forty-nine ligands of different chemical classes by using a fluorescence-quenching assay. Furthermore, we solved the crystal-structure of the major guinea pig allergen Cav p 1, a typical lipocalin. Recombinant lipocalin and secretoglobin allergens are of high thermal stability with melting temperatures ranging from 65 to 90°C and strongly bind ligands with dissociation constants in the low micromolar range, particularly fatty acids, fatty alcohols and the terpene alcohol farnesol, that are associated with potential semiochemical and/or immune-modulating functions. Through the systematic screening of respiratory mammalian lipocalin and secretoglobin allergens with a large panel of potential ligands, we observed that total amino acid composition, as well as cavity shape and volume direct affinities to ligands of different chemical classes. Therefore, we were able to categorize lipocalin allergens over their ligand-binding profile into three sub-groups of a lipocalin clade that is associated with functions in chemical communication, thus strengthening the function of major mammalian respiratory allergens as semiochemical carriers. The promiscuous binding capability of hydrophobic ligands from environmental sources warrants further investigation regarding their impact on a molecule's allergenicity.

Investigation of indoor and outdoor air quality in a university campus during COVID-19 lock down period

The pandemic of COVID-19 currently shadows the world; the whole earth has been on an unprecedented lockdown. Social distancing among people interrupted domestic and international air traffic, suspended industrial productions and economic activities, and had various far-reaching and undetermined implications on air quality. Improvement in air quality has been reported in many cities during the lockdown. On March 22, 2020, the Turkish government enforced strict lockdown measures to reduce coronavirus disease transmission. This lockdown had a significant impact on the movement of people within the country, which resulted in a major drop in worldwide commercial activities. During this period, university campuses were emptied due to the transition to distance education. In this study, various air pollutants sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), fine particulate matter (PM2.5), total bacteria, and total fungi were measured in different indoor environments at Eskişehir Technical University Campus in Eskişehir, Turkey during COVID-19 lock down period. Also, to calculate the indoor and outdoor ratios (I/O) of the pollutants, simultaneous outdoor measurements were also carried out. The average indoor SO2, NO2, O3, and PM2.5 concentrations in different indoor environments ranged between 2.10 and 54.58, 1.36-30.89, 12.01-39.05, and 21-94 μg/m3, respectively. The total number of bacteria and fungi ranged between 21.83-514.15 and 13.10-83.36 CFU/m3, respectively. Our study intends to give a glimpse to quantify the impact of a pandemic on air quality in different indoor environments in a university campus in Eskişehir, Turkey and calls for follow-up studies. Indoor concentrations were evaluated together with outdoor concentrations. In general, it can be said that the calculated I/O ratios for SO2, NO2, O3, bacteria, and fungi were less than 1 in most indoor environments.

The Contribution of Geogenic Particulate Matter to Lung Disease in Indigenous Children

Indigenous children have much higher rates of ear and lung disease than non-Indigenous children, which may be related to exposure to high levels of geogenic (earth-derived) particulate matter (PM). The aim of this study was to assess the relationship between dust levels and health in Indigenous children in Western Australia (W.A.). Data were from a population-based sample of 1077 Indigenous children living in 66 remote communities of W.A. (>2,000,000 km²), with information on health outcomes derived from carer reports and hospitalisation records. Associations between dust levels and health outcomes were assessed by multivariate logistic regression in a multi-level framework. We assessed the effect of exposure to community sampled PM on epithelial cell (NuLi-1) responses to non-typeable Haemophilus influenzae (NTHi) in vitro. High dust levels were associated with increased odds of hospitalisation for upper (OR 1.77 95% CI [1.02–3.06]) and lower (OR 1.99 95% CI [1.08–3.68]) respiratory tract infections and ear disease (OR 3.06 95% CI [1.20–7.80]). Exposure to PM enhanced NTHi adhesion and invasion of epithelial cells and impaired IL-8 production. Exposure to geogenic PM may be contributing to the poor respiratory health of disadvantaged communities in arid environments where geogenic PM levels are high.

Mechanisms and treatments for severe, steroid-resistant allergic airway disease and asthma

Severe, steroid-resistant asthma is clinically and economically important since affected individuals do not respond to mainstay corticosteroid treatments for asthma. Patients with this disease experience more frequent exacerbations of asthma, are more likely to be hospitalized, and have a poorer quality of life. Effective therapies are urgently required, however, their development has been hampered by a lack of understanding of the pathological processes that underpin disease. A major obstacle to understanding the processes that drive severe, steroid-resistant asthma is that the several endotypes of the disease have been described that are characterized by different inflammatory and immunological phenotypes. This heterogeneity makes pinpointing processes that drive disease difficult in humans. Clinical studies strongly associate specific respiratory infections with severe, steroid-resistant asthma. In this review, we discuss key findings from our studies where we describe the development of representative experimental models to improve our understanding of the links between infection and severe, steroid-resistant forms of this disease. We also discuss their use in elucidating the mechanisms, and their potential for developing effective therapeutic strategies, for severe, steroid-resistant asthma. Finally, we highlight how the immune mechanisms and therapeutic targets we have identified may be applicable to obesity-or pollution-associated asthma.

Flow Cytometric Analysis of Particle-bound Bet v 1 Allergen in PM10

Flow cytometry is a method widely used to quantify suspended solids such as cells or bacteria in a size range from 0.5 to several tens of micrometers in diameter. In addition to a characterization of forward and sideward scatter properties, it enables the use of fluorescent labeled markers like antibodies to detect respective structures. Using indirect antibody staining, flow cytometry is employed here to quantify birch pollen allergen (precisely Bet v 1)-loaded particles of 0.5 to 10 µm in diameter in inhalable particulate matter (PM10, particle size ≤10 µm in diameter). PM10 particles may act as carriers of adsorbed allergens possibly transporting them to the lower respiratory tract, where they could trigger allergic reactions.

So far the allergen content of PM10 has been studied by means of enzyme linked immunosorbent assays (ELISAs) and scanning electron microscopy. ELISA measures the dissolved and not the particle-bound allergen. Compared to scanning electron microscopy, which can visualize allergen-loaded particles, flow cytometry may additionally quantify them. As allergen content of ambient air can deviate from birch pollen count, allergic symptoms might perhaps correlate better with allergen exposure than with pollen count. In conjunction with clinical data, the presented method offers the opportunity to test in future experiments whether allergic reactions to birch pollen antigens are associated with the Bet v 1 allergen content of PM10 particles >0.5 µm.

Particulate matter properties and health effects: consistency of epidemiological and toxicological studies

Identifying the ambient particulate matter (PM) fractions or constituents, critically involved in eliciting adverse health effects, is crucial to the implementation of more cost-efficient abatement strategies to improve air quality. This review focuses on the importance of different particle properties for PM-induced effects, and whether there is consistency in the results from epidemiological and experimental studies. An evident problem for such comparisons is that epidemiological and experimental data on the effects of specific components of ambient PM are limited. Despite this, some conclusions can be drawn. With respect to the importance of the PM size-fractions, experimental and epidemiological studies are somewhat conflicting, but there seems to be a certain consistency in that the coarse fraction (PM10-2.5) has an effect that should not be neglected. Better exposure characterization may improve the consistency between the results from experimental and epidemiological studies, in particular for ultrafine particles. Experimental data indicate that surface area is an important metric, but composition may play an even greater role in eliciting effects. The consistency between epidemiological and experimental findings for specific PM-components appears most convincing for metals, which seem to be important for the development of both pulmonary and cardiovascular disease. Metals may also be involved in PM-induced allergic sensitization, but the epidemiological evidence for this is scarce. Soluble organic compounds appear to be implicated in PM-induced allergy and cancer, but the data from epidemiological studies are insufficient for any conclusions. The present review suggests that there may be a need for improvements in research designs. In particular, there is a need for better exposure assessments in epidemiological investigations, whereas experimental data would benefit from an improved comparability of studies. Combined experimental and epidemiological investigations may also help answer some of the unresolved issues.

Latex Allergy and Sensitization in Cities: A Survey in a Population at Risk

The constant increase in allergic diseases in western countries is correlated with changes in lifestyle and with the deterioration of the air inhaled by the inhabitants because of the growing concentrations of pollutant substances present. Within a population at risk, i.e., the inhabitants of cities, a group of subjects at even higher risk was selected, whose job exposes them to automobile exhaust fumes for many hours a day. All the study subjects underwent allergological screening and spirometry. The results obtained show an overall increase of respiratory allergic diseases but no increased sensitisation to latex. It therefore seems plausible that, besides social and lifestyle changes, the deterioration of the quality of the air could be considered responsible, at least in part, for the growing numbers of allergic subjects. This study offers an opportunity to reconsider the validity of the “hygiene hypothesis” as an explanation for the increase of allergic disease in western countries, although recent reports have indicated that a sedentary lifestyle may also contribute, together with environmental degradation, to the notably increased prevalence of allergic diseases in large cities in industrialized nations.

Health Outcomes of Exposure to Biological and Chemical Components of Inhalable and Respirable Particulate Matter

Particulate matter (PM) is a key indicator of air pollution and a significant risk factor for adverse health outcomes in humans. PM is not a self-contained pollutant but a mixture of different compounds including chemical and biological fractions. While several reviews have focused on the chemical components of PM and associated health effects, there is a dearth of review studies that holistically examine the role of biological and chemical components of inhalable and respirable PM in disease causation. A literature search using various search engines and (or) keywords was done. Articles selected for review were chosen following predefined criteria, to extract and analyze data. The results show that the biological and chemical components of inhalable and respirable PM play a significant role in the burden of health effects attributed to PM. These health outcomes include low birth weight, emergency room visit, hospital admission, respiratory and pulmonary diseases, cardiovascular disease, cancer, non-communicable diseases, and premature death, among others. This review justifies the importance of each or synergistic effects of the biological and chemical constituents of PM on health. It also provides information that informs policy on the establishment of exposure limits for PM composition metrics rather than the existing exposure limits of the total mass of PM. This will allow for more effective management strategies for improving outdoor air quality.

A Review of the Effects of Major Atmospheric Pollutants on Pollen Grains, Pollen Content, and Allergenicity

This review summarizes the available data related to the effects of air pollution on pollen grains from different plant species. Several studies carried out either on in situ harvested pollen or on pollen exposed in different places more or less polluted are presented and discussed. The different experimental procedures used to monitor the impact of pollution on pollen grains and on various produced external or internal subparticles are listed. Physicochemical and biological effects of artificial pollution (gaseous and particulate) on pollen from different plants, in different laboratory conditions, are considered. The effects of polluted pollen grains, subparticles, and derived aeroallergens in animal models, in in vitro cell culture, on healthy human and allergic patients are described. Combined effects of atmospheric pollutants and pollen grains-derived biological material on allergic population are specifically discussed. Within the notion of "polluen," some methodological biases are underlined and research tracks in this field are proposed.

Airway epithelium interactions with aeroallergens: role of secreted cytokines and chemokines in innate immunity

Airway epithelial cells are the first line of defense against the constituents of the inhaled air, which include allergens, pathogens, pollutants, and toxic compounds. The epithelium not only prevents the penetration of these foreign substances into the interstitium, but also senses their presence and informs the organism’s immune system of the impending assault. The epithelium accomplishes the latter through the release of inflammatory cytokines and chemokines that recruit and activate innate immune cells at the site of assault. These epithelial responses aim to eliminate the inhaled foreign substances and minimize their detrimental effects to the organism. Quite frequently, however, the innate immune responses of the epithelium to inhaled substances lead to chronic and high level release of pro-inflammatory mediators that may mediate the lung pathology seen in asthma. The interactions of airway epithelial cells with allergens will be discussed with particular focus on interactions-mediated epithelial release of cytokines and chemokines and their role in the immune response. As pollutants are other major constituents of inhaled air, we will also discuss how pollutants may alter the responses of airway epithelial cells to allergens.

Alveolar T-helper type-2 immunity in atopic asthma is associated with poor clinical control

Real-world evaluation studies have shown that many patients with asthma remain symptomatic despite treatment with inhaled corticosteroids (ICSs). As conventional ICSs have poor access to the peripheral airways, the aim of the present paper was to study the relationship between peripheral airway inflammation and clinical control in allergic asthma. Consequently, bronchial and transbronchial biopsies were obtained from patients with poorly controlled asthma [n=12, asthma control test (ACT) score<20], patients with well-controlled asthma (n=12, ACT score≥20) and healthy controls (n=8). Tissue sections were immunostained to assess multiple leucocyte populations. To determine the degree of T-helper type-2 (Th2) immunity, the logarithmic value of the ratio between Th2 cells/mm2 and Th1 cells/mm2 was used as a surrogate score for Th2-skewed immunity. In the bronchi, the leucocyte infiltration pattern and the Th2-score were similar between patients with well-controlled asthma and those with poorly controlled asthma. In contrast, in the alveolar parenchyma, the expression of T-helper cells was significantly higher in patients with poorly controlled asthma than in patients with well-controlled asthma (P<0.01). Furthermore, the alveolar Th2-score was significantly higher in patients with poorly controlled asthma (median 0.4) than in the controlled patients (median -0.10, P<0.05). In addition, in contrast with bronchial Th2-score, the alveolar Th2-score correlated significantly with ACT score (rs=-0.62, P<0.01) in the pooled asthma group. Collectively, our data reveal an alveolar Th2-skewed inflammation, specifically in asthmatic patients who are poorly controlled with ICSs, and suggest that pharmacological targeting of the peripheral airways may be beneficial in this large patient category.

Indoor pollutant exposure is associated with heightened respiratory symptoms in atopic compared to non-atopic individuals with COPD

Background

Indoor particulate matter (PM) has been linked to respiratory symptoms in former smokers with COPD. While subjects with COPD and atopy have also been shown to have more frequent respiratory symptoms, whether they exhibit increased susceptibility to PM as compared to their non-atopic counterparts remains unclear. The aim of this study was to determine whether atopic individuals with COPD have greater susceptibility to PM compared to non-atopic individuals with COPD.

Methods

Former smokers with moderate to severe COPD were enrolled (n = 77). PM_2.5, PM with diameter <2.5 micrometers, was measured in the main living area over three one-week monitoring periods at baseline, 3, and 6 months. Quality of life, respiratory symptoms and medication use were assessed by questionnaires. Serum was analyzed for specific IgE for mouse, cockroach, cat, dog and dust mite allergens. Atopy was established if at least one test was positive. Interaction terms between PM and atopy were tested and generalized estimating equation analysis determined the effect of PM concentrations on health outcomes. Multivariate models were adjusted for age, sex, education, race, season, and baseline lung function and stratified by atopic status.

Results

Among atopic individuals, each 10 μg/m³ increase in PM was associated with higher risk of nocturnal symptoms (OR, 1.95; P = 0.02), frequent wheezing (OR, 2.49; P = 0.02), increased rescue medication use (β = 0.14; P = 0.02), dyspnea (β = 0.23; P < 0.001), higher St. George’s Respiratory Quality of Life score (β = 2.55; P = 0.01), and higher breathlessness, cough, and sputum score (BCSS) (β = 0.44; P = 0.01). There was no association between PM and health outcomes among the non-atopic individuals. Interaction terms between PM_2.5 and atopy were statistically significant for nocturnal symptoms, frequency of rescue medication use, and BCSS (all P < 0.1).

Conclusions

Individuals with COPD and atopy appear to be at higher risk of adverse respiratory health effects of PM exposure compared to non-atopic individuals with COPD.

Urban particulate matter suppresses priming of T helper type 1 cells by granulocyte/macrophage colony-stimulating factor-activated human dendritic cells

Urban particulate matter (UPM) exacerbates asthmatic lung inflammation and depresses lung immunity. Lung dendritic cells (DCs) react to airway particulates, and have a critical role in linking innate and adaptive immunity, but the direct effects of UPM on DCs, that have been activated by granulocyte/macrophage colony-stimulating factor (GM-CSF), a product of stimulated normal human bronchial epithelial cells, has not been investigated. Human blood CD1c(+) DCs were purified and activated with UPM in the presence or absence of GM-CSF with and without LPS, and DC maturation was assessed by flow cytometry. DC stimulatory capacity and priming of 5-(and -6)-carboxyfluorescein diacetate succinimidyl ester-labeled naive CD4 T cells was investigated using the allogeneic mixed lymphocyte reaction. T cell proliferation and effector function were assessed using flow cytometry and secreted cytokines were measured by combined bead array. UPM enhanced DC maturation in an LPS-independent manner. DCs activated by UPM plus GM-CSF (UPM + GM-CSF DCs) induced higher naive CD4 T cell proliferation in the allogeneic mixed lymphocyte reaction than DCs pretreated by GM-CSF alone (GM-CSF DCs), and elicited both substantially lower levels of IFN-γ, IL-13, and IL-5 secretion, and lower frequencies of alloantigen-specific T helper (Th) type 1 effector cells than naive CD4 T cells primed by GM-CSF DCs. UPM-stimulated DCs produced IL-6 and TNF-α. Neutralization of IL-6 decreased naive CD4 T cell proliferation stimulated by UPM + GM-CSF DCs, and significantly increased the frequency of alloantigen-specific Th1 effector cells, but did not reverse UPM-induced inhibition of IFN-γ secretion. We conclude that UPM enhances GM-CSF-induced DC maturation and stimulatory capacity, but inhibits the generation of Th1 cells. Thus, UPM exposure may impair Th1 responses to pulmonary pathogens.

Particles influence allergic responses in mice--role of gender and particle size

Epidemiological evidence suggesting that exposure to traffic air pollution may enhance sensitization to common allergens in children is increasing, and animal studies support biological plausibility and causality. The effect of air pollution on respiratory symptoms was suggested to be gender dependent. Previous studies showed that allergy-promoting activity of polystyrene particles (PSP) increased with decreasing particle size after footpad injection of mice. The primary aim of this study was to confirm the influence of particle size on the immunoglobulin E (IgE)-promoting capacity of particles in an airway allergy model. A second aim was to examine whether the allergy-promoting capacity of particles was influenced by gender. Female and male mice were intranasally exposed to the allergen ovalbumin (OVA) with or without ultrafine, fine, or coarse PSP modeling the core of ambient air particles. After intranasal booster immunizations with OVA, serum levels of OVA-specific IgE antibodies, and also markers of airway inflammation and cellular responses in the lung-draining mediastinal lymph nodes (MLN), were determined. PSP of all sizes promoted allergic responses, measured as increased serum concentrations of OVA-specific IgE antibodies. Further, PSP produced eosinophilic airway inflammation and elevated MLN cell numbers as well as numerically reducing the percentage of regulatory T cells. Ultrafine PSP produced stronger allergic responses to OVA than fine and coarse PSP. Although PSP enhanced sensitization in both female and male mice, significantly higher IgE levels and numbers of eosinophils were observed in females than males. However, the allergy-promoting effect of PSP was apparently independent of gender. Thus, our data support the notion that ambient air particle pollution may affect development of allergy in both female and male individuals.

Carbon nanofibers have IgE adjuvant capacity but are less potent than nanotubes in promoting allergic airway responses

There is a growing concern for the possible health impact of nanoparticles. The main objective of this study was to investigate the allergy-promoting capacity of four different carbon nanofiber (CNF) samples in an injection and an airway mouse model of allergy. Secondly, the potency of the CNF was compared to the previously reported allergy-promoting capacity of carbon nanotubes (CNT) in the airway model. Ultrafine carbon black particles (ufCBP) were used as a positive control. Particles were given together with the allergen ovalbumin (OVA) either by subcutaneous injection into the footpad or intranasally to BALB/cA mice. After allergen booster, OVA-specific IgE, IgG1, and IgG2a in serum were measured. In the airway model, inflammation was determined as influx of inflammatory cells (eosinophils, neutrophils, lymphocytes, and macrophages) and by mediators (MCP-1 and TNF-α present in bronchoalveolar fluid (BALF)). CNF and CNT both increased OVA-specific IgE levels in the two models, but in the airway model, the CNT gave a significantly stronger IgE response than the CNF. Furthermore, the CNT and not the CNF promoted eosinophil lung inflammation. Our data therefore suggest that nanotube-associated properties are particularly potent in promoting allergic responses.

Exposure to multiwalled carbon nanotubes and allergen promotes early- and late-phase increases in airway resistance in mice

The facilitating effects of multiwalled carbon nanotubes (MWCNT) on allergic asthma have not been sufficiently examined, although MWCNT appear to significantly increase the risk of health problems from occupational or environmental exposure. In this study, we examined whether sensitization by the combination of MWCNT with ovalbumin (OVA) promotes allergic asthmatic responses. BALB/c mice administered vehicle, MWCNT, OVA, or MWCNT+OVA through an intranasal route were challenged with OVA intratracheally four times. In the MWCNT+OVA group, the fourth challenge caused not only early- but also late-phase increases in airway resistance, although these responses were not observed in the vehicle, MWCNT, or OVA group; furthermore, the extents of the early and late responses were comparable to those in mice systemically sensitized with OVA+alum. Sensitization with MWCNT and OVA promoted airway inflammation and goblet cell hyperplasia in the lung compared with the vehicle, MWCNT or OVA group. In addition, adjuvant activity for OVA-specific immunoglobulin E (IgE), IgG1, and IgG2a production in serum and increased levels of interleukin-4 (IL-4), IL-5, IL-13, and IL-17 in the lung tissue were observed. In conclusion, these results suggest that exposure to MWCNT and antigen can induce a biphasic increase in airway resistance, airway inflammation, goblet cell hyperplasia, and the production of antigen-specific antibodies. This study highlights the risk of exposure to a combination of MWCNT with antigen.

Dual role of Toll-like receptors in asthma and chronic obstructive pulmonary disease

During the last decade, significant research has been focused on Toll-like receptors (TLRs) in the pathogenesis of airway diseases. TLRs are pattern recognition receptors that play pivotal roles in the detection of and response to pathogens. Because of the involvement of TLRs in innate and adaptive immunity, these receptors are currently being exploited as possible targets for drug development. Asthma and chronic obstructive pulmonary disease (COPD) are chronic inflammatory airway diseases in which innate and adaptive immunity play an important role. To date, asthma is the most common chronic disease in children aged 5 years and older. COPD is prevalent amongst the elderly and is currently the fifth-leading cause of death worldwide with still-growing prevalence. Both of these inflammatory diseases result in shortness of breath, which is treated, often ineffectively, with bronchodilators and glucocorticosteroids. Symptomatic treatment approaches are similar for both diseases; however, the underlying immunological mechanisms differ greatly. There is a clear need for improved treatment specific for asthma and for COPD. This review provides an update on the role of TLRs in asthma and in COPD and discusses the merits and difficulties of targeting these proteins as novel treatment strategies for airway diseases. TLR agonist, TLR adjuvant, and TLR antagonist therapies could all be argued to be effective in airway disease management. Because of a possible dual role of TLRs in airway diseases with shared symptoms and risk factors but different immunological mechanisms, caution should be taken while designing pulmonary TLR-based therapies.

Study on some factors affecting survivability of airborne fungi

The aim of the present study was to investigate the effect of some air pollutants and meteorological parameters on the survivability of airborne fungi. Fungi were collected by using a slit impactor sampler calibrated to draw 20 L/min, for 3 min. Nitrogen dioxide (NO(2)), sulfur dioxide (SO(2)), particulate matter (PM), relative humidity (RH %), temperature (T °C) and wind speed (WS) were also measured. Air samples were taken during the period from March 2006 to February 2007. Fungal concentrations ranged between 45 and 451 CFU/m(3) with an annual mean concentration of 216 CFU/m(3). The lowest fungal concentration was found in the summer, however the highest one was found in the autumn. NO(2,) SO(2) and PM averaged 83.66 μg/m(3), 67.01 μg/m(3), and 237.69 μg/m(3), respectively. T °C was positively and negatively correlated with Aspergillus (P = 0.000) and Penicillium (P = 0.007), respectively. RH% was positively correlated with total fungi (P = 0.001), Aspergillus (P = 0.002) and Cladosporium (P = 0.047). Multiple regression analysis showed that T °C and RH% were the most predicted variants. Non-significant correlations were found between fungal concentrations and air pollutants. Meteorological parameters were the critical factors affecting fungal survivability.

Threat of allergenic airborne grass pollen in Szczecin, NW Poland: the dynamics of pollen seasons, effect of meteorological variables and air pollution

The dynamics of Poaceae pollen season, in particularly that of the Secale genus, in Szczecin (western Poland) 2004-2008 was analysed to establish a relationship between the meteorological variables, air pollution and the pollen count of the taxa studied. Consecutive phases during the pollen season were defined for each taxon (1, 2.5, 5, 25, 50, 75, 95, 97.5, 99% of annual total), and duration of the season was determined using the 98% method. On the basis of this analysis, the temporary differences in the dynamics of the seasons were most evident for Secale in 2005 and 2006 with the longest main pollen season (90% total pollen). The pollen season of Poaceae started the earliest in 2007, when thermal conditions were the most favourable. Correlation analysis with meteorological factors demonstrated that the relative humidity, mean and maximum air temperature, and rainfall were the factors influencing the average daily pollen concentrations in the atmosphere; also, the presence of air pollutants such as ozone, PM(10) and SO(2) was statistically related to the pollen count in the air. However, multiple regression models explained little part of the total variance. Atmospheric pollution induces aggravation of symptoms of grass pollen allergy.

Particulate allergens potentiate allergic asthma in mice through sustained IgE-mediated mast cell activation

Allergic asthma is characterized by airway hyperresponsiveness, inflammation, and a cellular infiltrate dominated by eosinophils. Numerous epidemiological studies have related the exacerbation of allergic asthma with an increase in ambient inhalable particulate matter from air pollutants. This is because inhalable particles efficiently deliver airborne allergens deep into the airways, where they can aggravate allergic asthma symptoms. However, the cellular mechanisms by which inhalable particulate allergens (pAgs) potentiate asthmatic symptoms remain unknown, in part because most in vivo and in vitro studies exploring the pathogenesis of allergic asthma use soluble allergens (sAgs). Using a mouse model of allergic asthma, we found that, compared with their sAg counterparts, pAgs triggered markedly heightened airway hyperresponsiveness and pulmonary eosinophilia in allergen-sensitized mice. Mast cells (MCs) were implicated in this divergent response, as the differences in airway inflammatory responses provoked by the physical nature of the allergens were attenuated in MC-deficient mice. The pAgs were found to mediate MC-dependent responses by enhancing retention of pAg/IgE/FcεRI complexes within lipid raft–enriched, CD63(+) endocytic compartments, which prolonged IgE/FcεRI-initiated signaling and resulted in heightened cytokine responses. These results reveal how the physical attributes of allergens can co-opt MC endocytic circuitry and signaling responses to aggravate pathological responses of allergic asthma in mice.

Gender differences in indoor allergen exposure and association with current rhinitis

BACKGROUND

Differences between boys and girls in allergic manifestations are well known, and this difference is possibly not attributed to physiological differences alone.

OBJECTIVE

We, therefore, investigated whether boys and girls could be exposed to different allergen levels at home and whether indoor allergen levels could be differently associated with rhinitis in boys and girls at 10 years of age.

METHODS

Cat, dog and house dust mite (HDM) allergen levels in mattress dust and interview data regarding current allergic disease were available for 797 10-year-old children (360 girls) in The Environment and Childhood Asthma Study in Oslo.

RESULTS

Girls had higher concentrations of cat and dog allergens in their mattresses compared with boys, also in homes without cats [geometric mean 95% confidence intervals (95% CI): 0.37 (0.31, 0.44) for girls and 0.26 (0.23, 0.30) microg cat allergen/g dust for boys, P=0.002], and without dogs [girls: 0.74 (0.63, 0.86) and boys: 0.55 (0.48, 0.62) microg dog allergen/g dust, P=0.003]. No difference was observed for HDM allergen (Der p 1) levels. Of the 190 (23.8%) children reporting current rhinitis, 144 (75.8%) were sensitized to at least one allergen. The adjusted odds ratio for current rhinitis increased with 1.20 (95% CI: 1.01, 1.42) per 1 microg/g dust increase in Der p 1 for girls (P=0.037), but not for boys (P=0.91).

CONCLUSION

Girls had higher levels of cat and dog allergens in mattress dust compared with boys, whereas no difference was observed for Der p 1 allergen. Nevertheless, only increasing levels of Der p 1 and not cat and dog allergens significantly increased the risk of current rhinitis in girls, whereas no significant association was observed for boys.

Effect of diesel exhaust particles on house dust mite-induced airway eosinophilic inflammation and remodeling in mice

Recent research has focused on the effects of ambient particulate pollution and much evidence has indicated that particulate pollution is associated with the onset of asthma and allergy; however, the effect of diesel exhaust particles (DEP) on the development of allergen-induced airway remodeling has not been fully investigated in vivo. In the present study, we examined the effects of DEP on Dermatophagoides farinae allergens (Der f)-induced asthma-like phenotypes in mice. Mice were administered i.t. 8 times with Der f. DEP were injected i.t. with Der f 4 times throughout the experiment or twice at the sensitization period. In both cases, DEP aggravated Der f-induced increases in airway responsiveness to acetylcholine, the number of eosinophils and neutrophils in the bronchoalveolar lavage fluid (BALF), serum Der f-specific IgG1 levels, Th2 cytokines and transforming growth factor-beta1 levels in BALF, and amount of hydroxyproline in the right lungs. Furthermore, goblet cell hyperplasia and subepithelial fibrosis were also markedly aggravated. These findings indicate that DEP can potentiate airway remodeling induced by repeated allergen challenge as well as Th2-drived airway hyperresponsiveness, eosinophilic inflammation, and IgG1 production and that DEP can exhibit adjuvant activity for airway remodeling, probably due to the enhancement of allergen sensitization and/or of Th2 polarizing pathways.

Nasal complaints and signs of disease in farmers--a methodological study

CONCLUSION

The methods used in this study are suitable for field studies that involve examinations of groups of workers. For individual examinations, there is no gold standard method that can discriminate work-related discomfort from other causes of rhinitis.

OBJECTIVES

Studies of the effects of occupation on farmers' health have mainly focused on lower airways; few studies have examined effects on upper airways. This study investigated nasal functions in three groups of farmers (swine, milk and grain producers) and a control group using different methods, suitable for field studies.

SUBJECTS AND METHODS

Health-related complaints were examined and several functional tests, such as expirogram, olfactory threshold test, acoustic rhinometry, nasal lavage with biomarkers of inflammation (eosinophilic cationic proteins (ECP), myeloperoxidase (MPO), tryptase, albumin) and allergy tests were performed. The different tests were correlated to nasal complaints and to each other.

RESULTS

Nasal blockage complaints were more common among farmers; overall, nasal polyps were more frequent in grain producers. Objective parameters showed more pronounced mucosal swelling in farmers and higher concentrations of ECP in nasal lavage compared with controls. Lung function, olfactory threshold, atopy frequency and allergen-specific IgE to the storage mite Lepidoglyphus destructor did not differ between farmers and controls. Mucosal swelling measured with acoustic rhinometry was more pronounced in subjects with nasal complaints, hypersensitivity, nasal polyps and symptoms from lower airways. There was a correlation between biomarkers in nasal lavage (MPO, albumin and ECP).

Advancing a multilevel framework for epidemiologic research on asthma disparities

Our understanding of asthma epidemiology is growing increasingly complex. Asthma outcomes are clearly socially patterned, with asthma ranking as a leading cause of health disparities among minority and low socioeconomic groups. Yet, the increasing prevalence and marked disparities in asthma remain largely unexplained by known risk factors. In the United States, asthma disproportionately affects nonwhite children living in urban areas and children living in poverty. Low socioeconomic status (SES), ethnic minority group status, and residence in an inner-city environment are closely intertwined in the United States, making it a challenge to fully disentangle the independent effects of each of these characteristics on asthma morbidity. In addition, studies show geographic variation in asthma outcomes across large cities and neighborhoods within cities that cannot be explained by economic factors alone. Although more limited data are available, studies in rural areas also suggest the stratification of risk based on SES and the proportion of minorities. Among low-SES areas, those with predominantly minority, segregated populations seem especially burdened. Marginalized populations of lower socioeconomic position are disproportionately exposed to irritants (eg, tobacco smoke), pollutants (eg, diesel-related particles), and indoor allergens (eg, cockroach and mouse allergen). Moreover, these marginalized individuals may also live in communities that are increasingly socially toxic, which, in turn, may be related to the increased experience of psychosocial stress that may influence asthma morbidity. Epidemiologic trends suggest that asthma may provide an excellent paradigm for understanding the role of community-level contextual factors in disease. Specifically, a multilevel approach that includes an ecological perspective may help to explain heterogeneities in asthma expression across socioeconomic and geographic boundaries that, to date, remain largely unexplained. Traditionally, asthma epidemiology has focused on individual-level risk factors and family factors. Far less attention has been given to the broader social context in which individuals live. A multilevel approach that explicitly recognizes the embedding of asthma within its biological, psycho-socioeconomic, environmental, and community contexts, is likely to provide a better understanding of asthma disparities at different stages in the life course. Is it simply asthma disparities or is it social disparities in asthma?

Do indoor chemicals promote development of airway allergy?

Allergic asthma has increased worldwide in the industrialized countries. This review evaluates whether the major groups of indoor chemical exposures possess allergy-promoting (adjuvant) effects; formaldehyde was excluded, because of the size of the literature. Volatile organic compounds (VOCs) are used as an example of gases and vapors. The precipitation of asthmatic symptoms by VOC exposures is probably because of VOC levels considerably above typical indoor levels, or VOCs may be a surrogate for exposure to allergens, combustion products or dampness. Indoor particles possessed adjuvant effects in animal studies and allergy-promoting effects in humans. Quaternary ammonium compounds may possess adjuvant effects in animal studies and promoted sensitization in humans in occupational settings. The use of cleaning agents, anionic and non-ionic surfactants are not considered to possess an important adjuvant effect in the general population. Regarding phthalate exposures, results from animal and epidemiological studies were found to be discordant. There is little evidence that the indoor chemicals evaluated possess important adjuvant effects. If buildings are kept clean, dry and free of combustion products, the important question may be would it be profitable to look for lifestyle factors and non-chemical indoor exposures in order to abate airway allergy?

PRACTICAL IMPLICATIONS

Indoor chemicals (pollutants) have been accused to promote development of airway allergy by adjuvant effects. In this review, we evaluated the scientific literature and found little support for the supposition that indoor chemicals possess important adjuvant effects. This rises the question: would it be profitable for abatement of airway allergy to look for non-chemical indoor exposures, including lifestyle factors, and exposures to allergens, microorganisms, including vira, and their interactions?

Correlation of ambient inhalable bioaerosols with particulate matter and ozone: a two-year study

In this study, we have examined the relationships between the concentrations of ambient inhalable airborne fungi and pollen with PM10, PM2.5, ozone, organic carbon, selected trace metals (cadmium, copper, lead, and zinc), temperature, and relative humidity. The database was collected in Cincinnati, Ohio, USA, during two consecutive years. Measurements of all environmental variables were performed at the same site continuously 5 days a week except during winter months. The airborne concentrations of biological and non-biological pollutants ranged as follows: total fungi: 184-16 979 spores m(-3); total pollen: 0-6692 pollen m(-3); PM10: 6.70-65.38 microg m(-3); PM2.5: 5.04-45.02 microg m(-3); and ozone: 2.54-64.17 ppb. Higher levels of total inhalable fungi and particulate matter were found during fall and summer months. In contrast, total pollen concentration showed elevated levels in spring. Peak concentrations of ozone were observed during summer and beginning of fall. Our study concluded that several types of inhalable airborne fungi and pollen, particulate matter, and ozone could be positively correlated as a result of the atmospheric temperature influence.

Initial high-dose nasal allergen exposure prevents allergic sensitization to a neoantigen

Primary allergic sensitization--IgE formation after Ag exposure--is fundamental in the development of allergic respiratory disease. With the rising prevalence of asthma and allergic rhinitis, improved understanding of the determining factors for allergic sensitization is needed. Human epidemiologic studies suggest high-dose allergen exposure may paradoxically protect against sensitization. Prospective human studies of allergen dose effect on primary allergic sensitization are lacking. We prospectively examined the effect of respiratory Ag dose exposure on the rate of primary allergic sensitization to a neoantigen, keyhole limpet hemocyanin, using a unique model of human nasal allergic sensitization. Atopic human subjects were exposed to 0.1-, 10-, 1,000-, or 100,000-mug doses of intranasal keyhole limpet hemocyanin in conjunction with adjuvant intranasal diesel exhaust particles. Ag-specific IgE, IgG, and IgG4 were measured in nasal lavage samples at the conclusion of the sensitization protocol. Allergic sensitization rates for the 0.1-, 10-, 1,000-, and 100,000-mug dose groups were 0, 100, 57, and 11%, respectively. All subjects produced Ag-specific IgG with the highest levels observed in the high-dose group. These results provide direct evidence that primary allergic sensitization may be prevented by initial high levels of respiratory Ag exposure through induction of a modified, nonallergic immune response. This Ag dose effect was capable of overcoming the well-established allergic adjuvant effects of diesel exhaust particle exposure. Whether this immune response represents durable allergic tolerance is not yet known. Studies investigating the molecular mechanisms of this non-IgE response may be useful in developing therapy to prevent allergic sensitization.

The allergy adjuvant effect of particles - genetic factors influence antibody and cytokine responses

BACKGROUND

There is increasing epidemiological and experimental evidence for an aggravating effect of particulate air pollution on asthma and allergic symptoms and, to a lesser extent, on allergic sensitization. Genetic factors appear to influence not only the magnitude, but also the quality of the adjuvant effect of particles with respect to allergen-specific IgE (Th2-associated) and IgG2a (Th1-associated) responses. In the present study, we aimed to investigate how the genetic background influences the responses to the allergen and particles alone and in combination. We examined how polystyrene particles (PSP) affected the IgE and IgG2a responses against the model allergen ovalbumin (OVA), after subcutaneous injection into the footpad of BALB/cA, BALB/cJ, NIH and C3H/HeN mice, Further, ex vivo IL-4, IFN-gamma and IL-10 cytokine secretion by Con A-stimulated cells from the draining popliteal lymph node (PLN) five days after injection of OVA and PSP separately or in combination was determined.

RESULTS

PSP injected with OVA increased the levels of OVA-specific IgE antibodies in all strains examined. In contrast, the IgG2a levels were significantly increased only in NIH and C3H/HeN mice. PSP in the presence of OVA increased cell numbers and IL-4, IL-10 and IFN-gamma levels in BALB/cA, NIH and C3H/HeN mice, with the exception of IFN-gamma in NIH mice. However, each mouse strain had their unique pattern of response to OVA+PSP, OVA and PSP, and also their unique background cytokine response (i.e. the cytokine response in cells from mice injected with buffer only).

CONCLUSION

Genetic factors (i.e. the strain of mice) influenced the susceptibility to the adjuvant effect of PSP on both secondary antibody responses and primary cellular responses in the lymph node, as well as the cellular responses to both OVA and PSP given separately. Interestingly, PSP alone induced cytokine responses in the lymph node in some of the mouse strains. Furthermore, we found that the ex vivo cytokine patterns did not predict the in vivo Th2- and Th1-associated antibody response patterns in the different mouse strains. The results indicate that insoluble particles act by increasing the inherent response to the allergen, and that the genetic background may determine whether an additional Th1-associated component is added to the response.

Ambient air pollution and respiratory emergency department visits

BACKGROUND

A number of emergency department studies have corroborated findings from mortality and hospital admission studies regarding an association of ambient air pollution and respiratory outcomes. More refined assessment has been limited by study size and available air quality data.

METHODS

Measurements of 5 pollutants (particulate matter [PM10], ozone, nitrogen dioxide [NO2], carbon monoxide [CO], and sulfur dioxide [SO2]) were available for the entire study period (1 January 1993 to 31 August 2000); detailed measurements of particulate matter were available for 25 months. We obtained data on 4 million emergency department visits from 31 hospitals in Atlanta. Visits for asthma, chronic obstructive pulmonary disease, upper respiratory infection, and pneumonia were assessed in relation to air pollutants using Poisson generalized estimating equations.

RESULTS

In single-pollutant models examining 3-day moving averages of pollutants (lags 0, 1, and 2): standard deviation increases of ozone, NO2, CO, and PM10 were associated with 1-3% increases in URI visits; a 2 microg/m increase of PM2.5 organic carbon was associated with a 3% increase in pneumonia visits; and standard deviation increases of NO2 and CO were associated with 2-3% increases in chronic obstructive pulmonary disease visits. Positive associations persisted beyond 3 days for several of the outcomes, and over a week for asthma.

CONCLUSIONS

The results of this study contribute to the evidence of an association of several correlated gaseous and particulate pollutants, including ozone, NO2, CO, PM, and organic carbon, with specific respiratory conditions.

Atopic dermatitis and respiratory symptoms in Russian and northern Norwegian school children: a comparison study in two arctic areas and the impact of environmental factors

BACKGROUND

The increase in atopic diseases during recent decades has been related to environmental factors such as indoor and outdoor pollution and the ingestion of certain foods. On the other hand, studies from Eastern Europe (with heavy air pollution) have reported a lower prevalence of atopic diseases and sensitization in their schoolchildren than in children living in Western Europe.

OBJECTIVES

This study compares the frequency of atopic diseases and respiratory symptoms in two geographically close arctic areas and points to possible risk factors for development of the diseases.

METHODS

A total of 1734 schoolchildren (1183 in Nikel and 551 in Sør-Varanger) were studied using identical, four-page, self-administered questionnaires.

RESULTS

Atopic diseases were reported in 38.7% of Norwegian and in 24.2% of Russian children (P < 0.001). Atopic dermatitis (AD) (23.6% vs 7.9%; P < 0.001) and allergic rhinoconjunctivitis (AR) (20.6% vs 14.7%; P < 0.001) occurred more frequently in Sør-Varanger, whereas 'self-reported' asthma (12.3% vs 13.1%) was similar in both areas. However, respiratory symptoms such as coughing, wheezing, breathlessness and bronchitis were 3-4 times more frequent in Nikel (P < 0.001).

CONCLUSION

This study disproves a previous hypothesis, i.e. that air pollution must be a major risk factor for the development of atopic diseases. Nevertheless, respiratory tract symptoms may be provoked by environmental pollution. Possible explanations for the higher frequency of atopic diseases in Sør-Varanger may be found in socio-economic and lifestyle differences between the two populations.

Diesel exhaust, solvents, and other occupational exposures as risk factors for wheeze among farmers

Farmers engage in activities that result in exposure to diesel exhaust, solvents, welding fumes, and other respiratory irritants. Using the Agricultural Health Study, a cohort of pesticide applicators in Iowa and North Carolina, we evaluated the odds of wheeze associated with nonpesticide occupational exposures. We used logistic regression models controlling for age, state, smoking, and history of asthma or atopy to evaluate odds of wheeze in the past year among the 20898 farmers who provided complete information on all covariates. Driving diesel tractors was associated with elevated odds of wheeze (odds ratio = 1.31; 95% confidence interval = 1.13, 1.52); the odds ratio for driving gasoline tractors was 1.11 (95% confidence interval = 1.02, 1.21). A duration-response relationship was observed for driving diesel tractors but not for driving gasoline tractors. Activities involving solvent exposure, including painting and use of solvents for cleaning, were associated with an increased odds of wheeze in a duration-dependent fashion. The highest odds of wheeze for farm activities were for daily painting (odds ratio = 1.82; 95% confidence interval = 0.89, 3.73), an indication of daily solvent exposure. These results add to the growing body of evidence of adverse respiratory effects of diesel exposure on the lung and suggest exposure to solvents may contribute as well.

A pilot investigation into associations between indoor airborne fungal and non-biological particle concentrations in residential houses in Brisbane, Australia

Indoor air contains a complex mixture of bioaerosols such as fungi, bacteria and allergens, as well as non-biological particles including products from various combustion processes. To date little work has been done to investigate the interactions and associations between particles of biological and non-biological origin, however, any occurring interactions could affect pollutant behaviour in the air and ultimately the effect they have on health. The aim of this work was to examine associations between the concentration levels of airborne particles and fungi measured in 14 residential suburban houses in Brisbane. The most frequently isolated fungal genus was Cladosporium, Curvularia, Alternaria, Fusarium and Penicillium. The average outdoor and indoor (living room) concentrations of fungal colony forming units were 1133+/-759 and 810+/-389, respectively. Average outdoor and indoor (normal ventilation) concentrations of submicrometre and supermicrometre particles were 23.8 x 10(3) and 21.7 x 10(3) (particles/cm(3)), 1.78 and 1.74 (particles/cm(3)), respectively. The study showed that no statistically significant associations between the fungal spore and submicrometre particle concentrations or PM(2.5) were present, while a weak but statistically significant relationship was found between fungal and supermicrometre particle concentrations (for the outdoors R(2)=0.4, P=0.03 and for a living room R(2)=0.3, P=0.04). A similarity in behaviour between the submicrometre particle and fungal spore concentrations was that the fungal spore concentrations were related directly to the distance from the source (a nearby park), in a very similar way in which the submicrometre particles originating from vehicle emissions from a road, were dependent on the distance to the road. In the immediate proximity to the park, fungal concentrations rose up to approximately 3100 CFU/m(3), whereas for houses more than 150 m away from the park the concentrations of fungi were below 1000 CFU/m(3). Recommendations have been provided as the future study designs to gain a deeper insight into the relationships between biological and non-biological particles.

A screening assessment of emissions of volatile organic compounds and particles from heated indoor dust samples

This paper characterizes and compares emissions during heating of different dust samples relevant to the indoor environment. Characterization includes emission of volatile organic compounds when dust samples were heated to 150 and 250 degrees C (gas chromatograph-mass spectrometer), weight loss during heating to 450 degrees C (thermogravimetric analysis), and the number of particles emitted during heating towards 200 degrees C (condensation nucleus counting). Element analyses were performed for non-heated dust (inductively coupled plasma discharge instrument). Emissions of volatile organic compounds from heated dust from different sources were surprisingly similar. However, the temperature at which the emission of volatiles started varied with the dust source. For most of the samples studied, the emissions were considerable already at 150 degrees C, and increased in number of peaks and peak area at 250 degrees C. Particle emissions started around 70 degrees C regardless of the dust source. Particle emissions seemed to be affected by the content of organic material.

Acute effect of air pollution on respiratory complaints, exhaled NO and biomarkers in nasal lavages of allergic children during the pollen season

During 2 months of the pollen season, the acute and putative adjuvant effect of traffic-related air pollution on respiratory health was investigated in children sensitised to grass pollen or house dust mite (HDM). Respiratory complaints were objectified via measurement of exhaled NO and inflammatory mediators in nasal lavage (NAL). During the study children, skin prick negative (n = 31) or positive to grass pollen (n = 22), HDM (n = 34) or grass pollen + HDM (n = 32), kept a daily diary on respiratory symptoms, and NAL and exhaled air was sampled twice a week. The level of air pollutants and pollen was monitored continuously. Like children sensitised to HDM, those sensitised to pollen reported respiratory complaints (shortness of breath, itchy eyes or blocked nose) more frequently than non-sensitised children during (but not before) the pollen season; the respiratory complaints of sensitised children were independent of the pollen level. In addition, exposure to increased levels of PM(10) induces 'shortness of breath' in pollen- and HDM-sensitised children, whereas ozone induces a blocked nose in HDM-sensitised children. Combined exposure to PM(10) + pollen and O(3) + pollen induces a blocked nose in both HDM-sensitised children and children sensitised to pollen + HDM. Significant positive associations were found between eNO and the levels of NO(2), CO, PM(2.5) and pollen in both sensitised and non-sensitised children. At the start of the pollen season, the NAL concentration of eosinophils and ECP in pollen-sensitised children was increased compared to winter, but their levels were not further affected by increased exposure to pollen or air pollution. In conclusion, during the pollen season, sensitised children continuously report a high prevalence of respiratory complaints which coincides with increased levels of upper and lower airway inflammatory markers. No additional pro-inflammatory effect of air pollution was observed, which indicates that air pollution does not facilitate allergen-induced inflammatory responses.

Relationship of outdoor air quality to pediatric asthma exacerbations

BACKGROUND

Although exposure to outdoor air pollutants has been shown to be associated with exacerbations of asthma, there are relatively few admissions for asthma to Cincinnati Children's Hospital, Cincinnati, OH during the summer months when air quality tends to be worst.

OBJECTIVE

The objective of this study was to determine the relationship of outdoor air quality parameters to asthma exacerbations in children.

METHODS

The number of emergency room visits and hospitalizations for asthma were determined by review of emergency department logs and the hospital computer database. Outdoor air concentrations of ozone, particulates of < 10 microm diameter (PM-10), pollens, and fungal spores were obtained from the Hamilton County Department of Environmental Services. Multiple regression analysis was performed, looking for relationships between the daily number of asthma visits and the air quality data for the same day and for 1 through 5 days before the visits.

RESULTS

A significant association was found between the number of asthma visits and the daily pollen count (P = 0.014, SE = 0.001). The effect was stronger for visits 1, 2, and 3 days after the pollen count (P < 0.001 for pollen count lagged 3 days). High PM-10 counts were synergistic with the pollen count as a predictor of asthma visits. There was no association between asthma visits and the ozone concentration or fungal spore count.

CONCLUSIONS

Exacerbations of asthma severe enough to require visits to the hospital were associated with elevated concentrations of airborne pollens and particulates, with a significant delayed effect. Ozone, in the concentrations measured here, was not a risk factor for severe asthma exacerbations in children.

Pollen and spores in the air of a hospital out-patient ward

BACKGROUND

Aerobiological studies of interest to the allergy specialist are routinely carried out using information from outdoor traps. However, most of our time is spent indoors and it is often the content of this air that is responsible for allergic phenomena.

MATERIAL AND METHODS

The air of a hospital outpatient ward was analyzed using two portable volumetric aerobiological traps, one at floor level and the other at a height of 1 meter. Both spores and pollen grains were counted and their values were compared with those outside the building.

RESULTS AND CONCLUSIONS

Twenty types of pollen grains were found. Their concentrations ranged from 2.7 and 25.1 grains/m3, with the most frequent being (in order) grasses, evergreen oak (holm and cork oaks), water plantain, and olive. Twenty two different types of spores were found with concentrations of between 175.0 and 1395.8 spores/m3 and the most frequent were Cladosporium, Ustilago and basidiospores. No significant differences were found between the floor level and the meter-high measurements. Comparison with outdoor levels showed that the three most abundant pollen types were correlated, with a ratio of 30:1 between indoor and outdoor levels. For the spores and fungi propagules, the indoor:outdoor ratio was highly variable, depending on the type. Thus, for Aspergillus-Penicillium spores, the concentration was even higher indoors than outdoors, although for most types, lower levels were found indoors, with a mean outdoor:indoor ratio of 4:1. We argue that this relationship reflects the presence of indoor spore sources. Rainfall was correlated with a decline in pollen levels and a rise in spore levels.

Effects of birch pollen and traffic particulate matter on Th2 cytokines, immunoglobulin E levels and bronchial hyper-responsiveness in mice

BACKGROUND

Health effects due to air pollution arising from motor vehicles are a major public and political concern world-wide. Epidemiological studies have shown that the manifestations of asthma are increased by air pollution in already affected individuals.

OBJECTIVE

To investigate the potential role of air-polluted tunnel dust (traffic particulate matter, TPM) or pure carbon core particles in the initiation and persistence of experimental allergic inflammation.

METHODS

BP2 mice were immunized with birch pollen alone (group B) or pollen together with TPM (group A), or with birch pollen and Al(OH)3 (group C), or with birch pollen and carbon core particles (group D). Before methacholine challenge they were challenged intranasally and thereafter bronchial hyper-reactivity (BHR) was evaluated in a whole-body plethysmograph. Levels of Th2 cytokines, fibronectin and lactate dehydrogenase (LDH) were determined, and differential counts were performed in the bronchoalveolar lavage (BAL) fluid. Sera were collected for determination of antibody titres and cytokine levels.

RESULTS

Specific IgE titres, BHR, the number of recruited eosinophils and levels of fibronectin and LDH in BAL were increased in mice immunized and challenged with a mixture of birch pollen and TPM. However, mice immunized with birch pollen alone and challenged intranasally with pollen or a mixture of pollen and TPM demonstrated the highest levels of IL-4 and IL-5.

CONCLUSION

This study highlights the importance of the exposure to a combination of particulate matters and pollen allergens, in the induction of allergic disease in the airways, and we have demonstrated that polluted tunnel dust has an effect on both the inflammatory and immunological components of experimental allergy. Immunization and challenge with carbon core particles together with birch pollen increased neither the BHR nor the specific IgE production significantly. Our results therefore strongly suggest that it is most likely to be the organic phase bound to the carbon core of the diesel exhaust particles that might have an important adjuvant effect in the induction of experimental allergy.

Increased HLA-DR expression after exposure of human monocytic cells to air particulates

BACKGROUND

The expression of HLA-DR on the cell membrane of antigen-presenting cells is of major importance for the induction of an allergic response in the airways. Environmental particulates are thought to play an important role in inducing or enhancing allergic sensitization, possibly by increasing the expression of HLA-DR on the cell membrane of antigen-presenting cells. In addition, these particulates may synergize with common sensitizing agents in inducing or enhancing HLA-DR and thus antigen presentation.

OBJECTIVE

In this study, we investigated the potential of three particle types, namely carbon black, diesel exhaust particles and urban air particulates (0.1-1000 ng/cm(2)), to induce the expression of HLA-DR on differentiated THP-1 cells, taken as a model for alveolar macrophages. We also assessed the "adjuvant" potential of the particles on interferon (IFN)-gamma, a known enhancer of HLA-DR.

RESULTS

By themselves, the particles (0.1-1000 ng/cm(2)) were not able to induce HLA-DR on the THP-1 cells after an incubation of 48 h. However, even at very low concentrations, carbon black (from 1 ng/cm(2) on) and diesel exhaust particles (from 0.1 ng/cm(2) on), interacted with IFN-gamma (100 U/mL) to enhance HLA-DR expression (up to 2.5-fold increase).

CONCLUSION

This finding may reflect in vitro one of the mechanisms by which pollutant particles exert an "adjuvant" activity and may partially explain how exposure to particles can be related to the enhancement of allergic sensitization.

Coadministration of antigen and particles optimally stimulates the immune response in an intranasal administration model in mice

Some particulate matter is known to affect human health, yet the mechanism(s) by which it acts is largely unknown. One of the factors that may play a role in the immune- stimulating activity of particles is binding of allergen to particles. This may turn the particles into allergen carriers, resulting in antigen deposition within the altered inflammatory microenvironment created by the particles. We compared the efficacy of simultaneous versus separate administration of antigen and particles during sensitization in an intranasal exposure model in BALB/c mice. Sensitization consisted of three separate doses (10 microg) of TNP-OVA at Days 1, 2, and 3. Two hundred micrograms of carbon black particles (CBP) were administered either 1 day before sensitization (Day 0), 1 day after sensitization (Day 4), or during sensitization. The latter was performed either at Day 1 (200 microg) or at Days 1, 2, and 3 (67 microg/day). At Day 10 a challenge with 10 microg of TNP-OVA was performed, and at Day 15 the immune response was assessed. The total number of cells as well as antibody-forming cells (AFC) in lymph nodes draining the lung (peribronchial lymph nodes [PBLN]) were determined, and immunoglobulin levels in blood were assessed. Cell numbers of PBLN increased significantly in all particle-treated groups compared to controls. The number of TNP-specific IgG1-forming cells in the groups receiving particles during sensitization was significantly higher than control level. Only groups receiving particles during or before sensitization displayed significantly higher IgG1 levels than controls, in contrast to the group receiving particles after sensitization. Only in animals receiving three doses of 67 microg during sensitization did TNP-specific IgE increase significantly compared to controls. IgG2a did not show significant differences compared to controls, indicating that the response is predominantly Th2 mediated. These data indicate that coadministration of particles at all time points of antigen dosing is the most effective way to stimulate an immune response in our model compared to separate particle and antigen dosing. Also, administration shortly before antigen administration was effective in stimulating an immune response, suggesting that time-dependent processes are involved in immune-stimulating activity of particles, supporting the important role of the altered inflammatory microenvironment created by the particles.

The influence of diesel exhaust particles on mononuclear phagocytic cell-derived cytokines: IL-10, TGF-beta and IL-1 beta

Diesel exhaust particles (DEP) are known to modulate the production of cytokines associated with acute and chronic respiratory symptoms and allergic respiratory disease. Tolerance is an important mechanism through which the immune system can maintain nonresponsiveness to common environmental antigens. We examined the effect of DEP on IL-10 and TGF-beta, cytokines produced by macrophages and repressor (Tr-like) lymphocytes which influence tolerance. Human PBMCs (n = 22) were incubated with 1-100 ng/ml of DEP, and suboptimally primed with LPS. IL-10 gene expression was assessed by the S1 nuclease protection assay, and production of IL-10, TGF-beta, TNF-alpha, IL-1 beta and IL-4 stimulated CD23 was evaluated by ELISA after 24 and 48 h. The effect of the order of exposure to DEP and LPS was evaluated on IL-10 protein and mRNA in cells (1) preincubated with LPS followed by DEP, or (2) exposed first to DEP followed by LPS. IL-10 was further evaluated using benzo[a]pyrene and [alpha]naphthoflavone as a surrogate for the polyaromatic hydrocarbons (PAHs) adsorbed to DEP. Control cells were incubated with carbon black, without PAHs. In PBMCs exposed to DEP with LPS, or preincubated with LPS before DEP, IL-10 production and mRNA fall significantly. TGF-beta is similarly suppressed, IL-1 beta secretion is significantly stimulated, and IL-4 stimulated CD23 release rises in the atopic subjects. In contrast, when DEP is added prior to LPS, IL-10 production rises, and IL-1 beta falls to zero. These effects on IL-10 are reproduced with benzo[a]pyrene and reversed by the coaddition of [alpha]naphthoflavone, its known antagonist. The carbon black fraction has no effect on IL-10 production. The effect of DEP on IL-10 can be inhibitory or stimulatory, depending on the order of exposure to DEP and LPS. Pro-inflammatory cytokines and factors rise when IL-10 is inhibited, and are suppressed when IL-10 is stimulated. These results are duplicated with benzo[a]pyrene, suggesting that the PAH portion of the DEP is the active agent.