Environmental exposure to Aspergillus fumigatus allergen (Asp f I)

Residual profiles and health risk of indoor allergens in China

Exposure to indoor allergens is a principal risk factor for allergic diseases. However, most of the previous studies on indoor allergens focused on very limited kinds of allergens in China. Knowledge of the simultaneous exposure to multiple allergens is still lacking. In this study, the residual profiles of 8 allergens were investigated in 166 dust samples from 11 cities in China. The house dust mite allergens including Der p 1, Der f 1, and Der 2 were detected in the range of <0.02-283.83 μg/g dust. The concentrations of dog allergen Can f 1 and cat allergen Fel d 1 varied widely, from <0.84-22,896.46 μg/g dust for Can f 1 and from <0.02-6298.96 μg/g dust for Fel d 1. Cockroach allergen Bla g 2 was detected in 68% of the samples but at a low level with a maximum of 9.44 μg/g dust. Comparatively low detection frequencies were found for mouse allergen Mus m 1 as 37% and for fungi allergen Asp f 2 as 24%. The frequency of cleaning sheets/bedding was negatively correlated to the levels of house dust mite allergens. The presence of pets indoors was associated with higher levels of pet allergens and lower levels of house dust mite allergens and cockroach allergen. Risk evaluation reveals that at least 4 allergens were found in more than 80% of the rooms and more than 2 allergens with median/high risk were detected in 42% of the rooms, indicating that simultaneous exposure to multiple allergens is prevalent in China.

Aspergillus Conidia and Allergens in Outdoor Environment: A Health Hazard?

Aspergillus is a genus of saprophytic fungus widely distributed in the environment and associated with soil, decaying vegetation, or seeds. However, some species, such as A. fumigatus, are considered opportunistic pathogens in humans. Their conidia (asexual spores) and mycelia are associated with clinical diseases known as invasive aspergillosis (IA), mainly related to the respiratory tract, such as allergic asthma, allergic bronchopulmonary aspergillosis (ABPA), or hypersensitivity. However, they can also disseminate to other organs, particularly the central nervous system. Due to the dispersal mechanism of the conidia through the air, airborne fungal particle measurement should be used to prevent and control this mold. This study aims to measure the outdoor airborne concentration of Aspergillus conidia and the Asp f 1 allergen concentration in Bellaterra (Barcelona, Spain) during 2021 and 2022, and to compare their dynamics to improve the understanding of the biology of this genus and contribute to a better diagnosis, prevention, and therapeutic measures in the face of possible health problems. The results show that both particles were airborne nearly all year round, but their concentrations showed no correlation. Due to Asp f 1 not being present in the conidia itself but being detectable during their germination and in hyphal fragments, we report the relevance of the aero-immunological analysis as a methodology to detect the potential pathogenic hazard of this fungus.

Fungal Contamination of Building Materials and the Aerosolization of Particles and Toxins in Indoor Air and Their Associated Risks to Health: A Review

It is now well established that biological pollution is a major cause of the degradation of indoor air quality. It has been shown that microbial communities from the outdoors may significantly impact the communities detected indoors. One can reasonably assume that the fungal contamination of the surfaces of building materials and their release into indoor air may also significantly impact indoor air quality. Fungi are well known as common contaminants of the indoor environment with the ability to grow on many types of building materials and to subsequently release biological particles into the indoor air. The aerosolization of allergenic compounds or mycotoxins borne by fungal particles or vehiculated by dust may have a direct impact on the occupant’s health. However, to date, very few studies have investigated such an impact. The present paper reviewed the available data on indoor fungal contamination in different types of buildings with the aim of highlighting the direct connections between the growth on indoor building materials and the degradation of indoor air quality through the aerosolization of mycotoxins. Some studies showed that average airborne fungal spore concentrations were higher in buildings where mould was a contaminant than in normal buildings and that there was a strong association between fungal contamination and health problems for occupants. In addition, the most frequent fungal species on surfaces are also those most commonly identified in indoor air, regardless the geographical location in Europe or the USA. Some fungal species contaminating the indoors may be dangerous for human health as they produce mycotoxins. These contaminants, when aerosolized with fungal particles, can be inhaled and may endanger human health. However, it appears that more work is needed to characterize the direct impact of surface contamination on the airborne fungal particle concentration. In addition, fungal species growing in buildings and their known mycotoxins are different from those contaminating foods. This is why further in situ studies to identify fungal contaminants at the species level and to quantify their average concentration on both surfaces and in the air are needed to be better predict health risks due to mycotoxin aerosolization.

Atmospheric modelling of grass pollen rupturing mechanisms for thunderstorm asthma prediction

The world’s most severe thunderstorm asthma event occurred in Melbourne, Australia on 21 November 2016, coinciding with the peak of the grass pollen season. The aetiological role of thunderstorms in these events is thought to cause pollen to rupture in high humidity conditions, releasing large numbers of sub-pollen particles (SPPs) with sizes very easily inhaled deep into the lungs. The humidity hypothesis was implemented into a three-dimensional atmospheric model and driven by inputs from three meteorological models. However, the mechanism could not explain how the Melbourne event occurred as relative humidity was very low throughout the atmosphere, and most available grass pollen remained within 40 m of the surface. Our tests showed humidity induced rupturing occurred frequently at other times and would likely lead to recurrent false alarms if used in a predictive capacity. We used the model to investigate a range of other possible pollen rupturing mechanisms which could have produced high concentrations of SPPs in the atmosphere during the storm. The mechanisms studied involve mechanical friction from wind gusts, electrical build up and discharge incurred during conditions of low relative humidity, and lightning strikes. Our results suggest that these mechanisms likely operated in tandem with one another, but the lightning method was the only mechanism to generate a pattern in SPPs following the path of the storm. If humidity induced rupturing cannot explain the 2016 Melbourne event, then new targeted laboratory studies of alternative pollen rupture mechanisms would be of considerable value to help constrain the parameterisation of the pollen rupturing process.

Optimal Aspergillus fumigatus and Asp f 1 serum IgG cut-offs for the diagnosis of allergic bronchopulmonary aspergillosis

BACKGROUND

The presence of IgG antibodies (Abs) to Aspergillus fumigatus (Af) is a crucial diagnostic criterion for allergic bronchopulmonary aspergillosis (ABPA). Although precipitation is traditionally used to document IgG Abs, anti-Af serum IgG levels can also be measured by enzyme immunoassay (EIA). However, there are insufficient data on the optimal cut-offs to assess diagnostic performance of the EIA method. This study aimed to determine cut-off levels of IgG binding crude Af extracts or recombinant Asp f 1 (by ImmunoCAP®) and to compare their efficacy for ABPA diagnosis with Af-precipitating Abs.

METHODS

The age distribution of levels of IgG to crude extracts of Af (Af-IgG) and recombinant Asp f 1 (Asp f 1-IgG) was established using sera from 694 healthy controls (HC). Receiver operating characteristic analysis for Af-IgG and Asp f 1-IgG levels for the purpose of ABPA diagnosis was performed in 306 Af-sensitized asthma patients (including 49 ABPA), and cut-offs were determined.

RESULTS

An age-dependent decline in the levels of Af-IgG was observed in HC. Thus, cut-offs for Af-IgG levels were determined separately by age as 60 mg/L for patients aged <55 years, and 45 mg/L for those aged ≥55 years. For Asp f 1-IgG, 6.6 mg/L was set as the cut-off regardless of age. Although such IgG testing by EIA allowed a sufficiently good diagnostic performance, Af-precipitating Abs had better diagnostic applicability for ABPA.

CONCLUSIONS

We determined cut-offs for Af-IgG and Asp f 1-IgG measured by EIA, which can be useful in clinical settings where precipitating Abs are unavailable.

Value of Component Resolved Diagnostics to Aspergillus fumigatus in Patients with Upper Airway Complaints

INTRODUCTION

Sensitization to Aspergillus fumigatus is a risk factor for severe asthma. However, little is known about its presence, appearance, and impact on allergic rhinitis. Herein, we investigated the usefulness of component resolved diagnostics in patients sensitized to Aspergillus fumigatus protein extract.

METHODS

Seventy-eight patients with suspected allergic rhinitis and elevated IgE levels toward Aspergillus fumigatus protein extract were retrospectively evaluated regarding their total and Aspergillus-specific IgE levels and their skin prick test. Furthermore, they were tested for specific IgE antibodies against Asp f 1, 2, 3, 4, and 6.

RESULTS

Skin prick test missed 6 patients (7.7%) with elevated IgE toward Aspergillus fumigatus protein extract. Fifty percent of patients (n = 39) were sensitized to at least one component. Even though monosensitization affected all components, all patients with positivity toward more than one component were sensitized to Asp f 1. There was a statistically significant increase of Aspergillus-specific IgE with increasing number of components affected by sensitization. Many patients were oligo- (34.6%) or polysensitized (51.3%). There was a high prevalence of sinusitis (61.8%).

CONCLUSIONS

Component resolved diagnostic testing toward the major allergen Asp f 1 was less sensitive than skin prick test and serology to Aspergillus fumigatus protein extract. However, sensitivity of component resolved diagnostics might be underestimated. Diagnostics of the species-specific allergens Asp f 1, 2, and 4 might allow to differentiate between genuine and cross-reactive sensitization. In the clinical routine, skin prick test and serology to crude extract remain the methods of choice.

Serum IgE and IgG reactivity to Aspergillus recombinant antigens in patients with cystic fibrosis

PURPOSE

The diagnosis of aspergillosis in cystic fibrosis (CF) patients remains a challenge due to overlapping features of both diseases. This is further complicated by inconsistent antibody reactivity to the currently used crude antigen, which has led a more focused evaluation of the efficacy of IgE response to a number of pure Aspergillus fumigatus recombinant proteins in patients with CF and asthma. In this study, we dissected the IgE and IgG responses to multiple A. fumigatus recombinant antigens in CF patients with different Aspergillus diseases.

METHODOLOGY

Serum IgE and IgG antibodies were measured in 12 CF patients with allergic bronchopulmonary aspergillosis (ABPA), 12 with Aspergillus sensitization (AS) and 12 with Aspergillus bronchitis (AB) against recombinant antigens Asp f1, f2, f3, f4 and f6.

RESULTS

The ABPA group showed significantly greater IgE reactivity to Asp f1, f2, f3 and f4 compared to patients with AS. Patients with AB expressed higher IgG positivity to Asp f1 and Asp f2 compared with those with ABPA. There were very low IgE antibody levels against all recombinant antigens in patients with AS. Aspf1 IgG reactivity in ABPA patients correlated with positive culture.

CONCLUSION

The use of multiple recombinant antigens may improve the diagnostic accuracy in CF complicated with ABPA or AB. Asp f1 reactivity may relate to the presence of actively growing Aspergillus spp., which might be a useful marker for guiding antifungal therapy in ABPA.

Fungal Lanosterol 14α-demethylase: A target for next-generation antifungal design

The cytochrome P450 enzyme lanosterol 14α-demethylase (LDM) is the target of the azole antifungals used widely in medicine and agriculture as prophylaxis or treatments of infections or diseases caused by fungal pathogens. These drugs and agrochemicals contain an imidazole, triazole or tetrazole substituent, with one of the nitrogens in the azole ring coordinating as the sixth axial ligand to the LDM heme iron. Structural studies show that this membrane bound enzyme contains a relatively rigid ligand binding pocket comprised of a deeply buried heme-containing active site together with a substrate entry channel and putative product exit channel that reach to the membrane. Within the ligand binding pocket the azole antifungals have additional affinity determining interactions with hydrophobic side-chains, the polypeptide backbone and via water-mediated hydrogen bond networks. This review will describe the tools that can be used to identify and characterise the next generation of antifungals targeting LDM, with the goal of obtaining highly potent broad-spectrum fungicides that will be able to avoid target and drug efflux mediated antifungal resistance.

Allergic aspergillosis in asthmatic patients in a tertiary hospital in the Kingdom of Bahrain

BACKGROUND INFORMATION:

Aspergillosis is an alarming complication in asthma, leading to worsening symptoms and irreversible lung damage. It is underdiagnosed among asthmatics worldwide, especially in our geographical region.

AIM:

This research was aimed to shed some light on the prevalence of Aspergillus sensitization and allergic bronchopulmonary aspergillosis (ABPA) in asthmatic patients in the Kingdom of Bahrain.

IMPORTANCE:

This project has never been conducted in the region and hopefully will lead to a better care for asthmatics.

METHODOLOGY:

Our study population consisted of adult outpatients visiting the pulmonary and chest diseases clinic at Al-Salmaniya Medical Complex (SMC); the main inclusion condition was manifesting respiratory distress symptoms related to one or more respiratory tract diseases. 152 individuals were selected; the study group consisted of 119 asthmatic patients manifesting respiratory distress. The control group consisted of 33 nonasthmatic patients that manifested pulmonary distress symptoms due to respiratory tract diseases other than asthma like chronic obstructive pulmonary disease, bronchitis, among others. Sera samples were collected in SMC and analyzed via Phadia-250 fluoro-enzyme-immunoassay to determine the levels of Aspergillus fumigatus-specific IgE. The rAsp f1 antigen was used against IgE.

RESULTS:

Our results indicated a 16% prevalence of A. fumigatus sensitization in asthmatics; also, 75.6% of asthmatics were sensitized to pollen grains, and 22.3% reported one or many food allergies. Furthermore, details of patients with significant levels of A. fumigatus- specific IgE were analyzed, and ABPA prevalence was estimated to be 10.1% in asthmatics.

CONCLUSION:

Increasing awareness toward these indolent diseases is required, as well as, more efforts in determining the burden of aspergillosis in other parts of the region.

Air Pollution and Climate Change Effects on Allergies in the Anthropocene: Abundance, Interaction, and Modification of Allergens and Adjuvants

Air pollution and climate change are potential drivers for the increasing burden of allergic diseases. The molecular mechanisms by which air pollutants and climate parameters may influence allergic diseases, however, are complex and elusive. This article provides an overview of physical, chemical and biological interactions between air pollution, climate change, allergens, adjuvants and the immune system, addressing how these interactions may promote the development of allergies. We reviewed and synthesized key findings from atmospheric, climate, and biomedical research. The current state of knowledge, open questions, and future research perspectives are outlined and discussed. The Anthropocene, as the present era of globally pervasive anthropogenic influence on planet Earth and, thus, on the human environment, is characterized by a strong increase of carbon dioxide, ozone, nitrogen oxides, and combustion- or traffic-related particulate matter in the atmosphere. These environmental factors can enhance the abundance and induce chemical modifications of allergens, increase oxidative stress in the human body, and skew the immune system toward allergic reactions. In particular, air pollutants can act as adjuvants and alter the immunogenicity of allergenic proteins, while climate change affects the atmospheric abundance and human exposure to bioaerosols and aeroallergens. To fully understand and effectively mitigate the adverse effects of air pollution and climate change on allergic diseases, several challenges remain to be resolved. Among these are the identification and quantification of immunochemical reaction pathways involving allergens and adjuvants under relevant environmental and physiological conditions.

Molecular-based allergy diagnosis of allergic bronchopulmonary aspergillosis in Aspergillus fumigatus-sensitized Japanese patients

BACKGROUND

Distinguishing between patients with allergic bronchopulmonary aspergillosis (ABPA) and Aspergillus fumigatus (Af)-sensitized asthmatic patients without ABPA is sometimes difficult owing to the IgE-cross-reactivity between Af and other fungal allergens.

OBJECTIVE

To establish the usefulness of molecular-based allergy diagnostics using allergen components from Af in distinguishing ABPA from Af-sensitized asthma without ABPA.

METHODS

Sera from Japanese patients with ABPA (n = 53) and Af-sensitized asthma without ABPA (n = 253) were studied. The levels of IgE and IgG antibodies to allergen components from Af and IgE antibodies to different fugal allergen extracts were measured by ImmunoCAP. Comorbid atopic dermatitis (AD) was taken into consideration in the sensitization profile analysis.

RESULTS

Patients with ABPA possessed significantly higher levels of IgE antibodies to Asp f 1, and Asp f 2 than asthmatic patients without ABPA. The areas under the receiver operating characteristic curves for the levels of IgE to Asp f 1 and Asp f 2 as diagnostic markers of ABPA were 0.75 and 0.78, respectively. The presence of IgE positivity to Asp f 1 and/or Asp f 2 resulted in increased sensitivity while losing little specificity. Comorbid AD was associated with higher levels of IgE to Asp f 6 (manganese superoxide dismutase from Af, a ubiquitous pan-allergen in fungi) and low but positive levels of IgE to other Af-components, which hampered the serological discrimination of ABPA.

CONCLUSIONS AND CLINICAL RELEVANCE

The levels of IgE to Asp f 1 and/or Asp f 2 can effectively differentiate ABPA from Af-sensitized asthma, suggesting that the amounts of IgE specific for these molecules are markers for genuine Af-sensitization in ABPA. However, comorbid AD must be taken into consideration in the interpretation of high IgE to Asp f 6. Establishing of IgE-sensitization profiles using panel of Af-allergen components provides valuable information for distinguishing genuine vs. cross-reactive sensitization in Af-sensitized patients.

Serological diagnosis of allergic bronchopulmonary mycosis: Progress and challenges

Prompt diagnosis of allergic bronchopulmonary mycosis (ABPM) is an important clinical issue in preventing irreversible lung damage. Therefore, a good serological marker for the diagnosis of ABPM is desired in clinical practice. The measurement of IgE antibody to crude Aspergillus fumigatus allergen is considered the first step in screening asthmatic patients for allergic bronchopulmonary aspergillosis (ABPA). However, presence of IgE to A. fumigatus does not always indicate genuine sensitization to A. fumigatus because of cross-reactivity between crude extracts from different fungal sources. The application of molecular-based allergy diagnosis can solve this problem. The specificity of testing can be greatly improved by measuring the IgE antibody to Asp f 1 and f 2, specific allergen components for genuine A. fumigatus allergy. The problem of cross-reactivity between crude fungal extracts is also true for the identification of genuine causal fungi in each ABPM patient. Some patients with ABPM induced by fungi other than Aspergillus may be consistent with ABPA diagnostic criteria because current criteria depend on IgE/IgG reactivity to crude extracts. Accurate identification of genuine causal fungi for ABPM is of clinical importance, considering that clinical presentation, anti-fungal treatment strategies and disease prognosis can be influenced by different causal fungi. The diagnosis of causal fungi can be robustly validated by the confirmation of genuine sensitization to fungi after measuring IgE to specific allergen components, as well as repeated microbiological isolation of the fungi from their airway.

Blood basophil activation is a reliable biomarker of allergic bronchopulmonary aspergillosis in cystic fibrosis

The diagnosis of cystic fibrosis (CF) patients with allergic bronchopulmonary aspergillosis (ABPA) is clinically challenging, due to the absence of an objective biological test. Since blood basophils play a major role in allergic responses, we hypothesised that changes in their surface activation pattern discriminate between CF patients with and without ABPA.

We conducted a prospective longitudinal study (Stanford cohort) comparing basophil activation test CD203c levels by flow cytometry before and after activation withAspergillus fumigatusallergen extract or recombinantAspf1 in 20 CF patients with ABPA (CF-ABPA) and in two comparison groups: CF patients withA. fumigatuscolonisation (AC) but without ABPA (CF-AC; n=13) and CF patients without either AC or ABPA (CF; n=12). Patients were tested every 6 months and when ill with pulmonary exacerbation. We also conducted cross-sectional validation in a separate patient set (Dublin cohort).

Basophil CD203c surface expression reliably discriminated CF-ABPA from CF-AC and CF over time. Ex vivostimulation withA. fumigatusextract or recombinantAspf1 produced similar results within the Stanford (p<0.0001) and the Dublin cohorts. CF-ABPA patients were likelier to have elevated specific IgE toA. fumigatusand were less frequently co-infected withStaphylococcus aureus.

Basophil CD203c upregulation is a suitable diagnostic and stable monitoring biomarker of ABPA in CF.

Sensitization to fungal allergens: Resolved and unresolved issues

Exposure and sensitization to fungal allergens can promote the development and worsening of allergic diseases. Although numerous species of fungi have been associated with allergic diseases in the literature, the significance of fungi from the genera Alternaria, Cladosporium, Penicillium, Aspergillus, and Malassezia has been well documented. However, it should be emphasized that the contribution of different fungal allergens to allergic diseases is not identical, but species-specific. Alternaria and Cladosporium species are considered to be important outdoor allergens, and sensitization and exposure to species of these genera is related to the development of asthma and rhinitis, as well as epidemics of asthma exacerbation, including life-threatening asthma exacerbation. In contrast, xerophilic species of Penicillium and Aspergillus, excluding Aspergillus fumigatus, are implicated in allergic diseases as indoor allergens. A. fumigatus has a high capacity to colonize the bronchial tract of asthmatic patients, causing severe persistent asthma and low lung function, and sometimes leading to allergic bronchopulmonary aspergillosis. Malassezia are common commensals of healthy skin, although they are also associated with atopic dermatitis, especially on the head and neck, but not with respiratory allergies. Despite its importance in the management of allergic diseases, precise recognition of species-specific IgE sensitization to fungal allergens is often challenging because the majority of fungal extracts exhibit broad cross-reactivity with taxonomically unrelated fungi. Recent progress in gene technology has contributed to the identification of specific and cross-reactive allergen components from different fungal sources. However, data demonstrating the clinical relevance of IgE reactivity to these allergen components are still insufficient.

A new immunoassay to quantify fungal antigens from the indoor mould Aspergillus versicolor

Aspergillus versicolor is among the most commonly found moulds in moisture-damaged buildings and can be associated with adverse health effects in humans. This paper reports the development, validation and application of an enzyme immunoassay to quantify A. versicolor antigens. A sandwich ELISA was developed using polyclonal antibodies that recognize a broad range of A. versicolor proteins present in fungal spores and in mycelia fragments. To validate the new method, A. versicolor antigens were quantified in samples collected from homes with visible mould growth, including dust from vacuumed walls and bulk samples of building materials. Antigen concentrations were compared to the results of a commercial ELISA based on monoclonal antibodies (AveX ELISA, Indoor Biotechnologies, Charlottesville, USA) and correlated with colony forming units (CFU) of A. versicolor. The A. versicolor ELISA was very sensitive with a lower detection limit of 120 pg ml(-1). The assay also showed some reactivity to other moulds with strongest reactions with other Aspergillus species (1-3% reactivity). The new assay detected A. versicolor antigens in a much higher percentage of dust samples (88% vs. 27%) and bulk samples (89% vs. 24%) than the AveX assay. A significant correlation (r = 0.67, and p < 0.0001) was found between antigen concentrations and CFU of A. versicolor. Based on its low detection limit and good correlation with the culture-based method, this new immunoassay seems to be a useful tool for the measurement of A. versicolor exposure levels and a reliable complement to the traditional monitoring techniques, such as mould cultivation or microscopy.

Indoor Exposure to Mould Allergens

Humid indoor environments may be colonised by allergenic filamentous microfungi (moulds),Aspergillusspp.,Penicilliumspp.,Cladosporiumspp., andAlternariaspp. in particular. Mould-induced respiratory diseases are a worldwide problem. In the last two decades, mould allergens and glucans have been used as markers of indoor exposure to moulds. Recently, mould allergens Alt a 1 (Alternaria alternata) and Asp f 1 (Aspergillus fumigatus) have been analysed in various environments (residential and occupational) with enzyme-linked immunosorbent assays, which use monoclonal or polyclonal antibodies. Household Alt a 1 and Asp f 1 levels were usually under the limit of the method detection. By contrast, higher levels of mould allergens were found in environments with high levels of bioaerosols such as poultry farms and sawmills. Data on allergen Alt a 1 and Asp f 1 levels in agricultural settings may provide information on possible colonisation of respective moulds and point out to mould-related diseases in occupants.

Determination of Aspergillus fumigatus allergen 1 in poultry farms using the enzyme immunoassay

Poultry farms contain high levels of allergenic fungi, and Aspergillus spp. is the most common genus of moulds. Aspergillus fumigatus antigens are responsible for the development of several respiratory diseases including asthma. The aim of this study was to measure the mass fraction of Asp f 1, a major allergen of Asperillus fumigatus in 37 indoor dust samples collected from four poultry farms in a rural area of the Zagreb County (Croatia) using the enzyme-linked immunosorbent assay. More than 62 % of dust samples had detectable Asp f 1 levels (limit of detection 3.6 ng g(-1)). The overall mean Asp f 1 level was 17.9 ng g(-1) [range (3.8 to 72.4) ng g(-1)]. Satisfactory results were obtained for analytical within-run imprecision (6.7 %), between-run imprecision (10.5 %), and accuracy (91 % to 115 %). Microclimate parameters (air temperature, relative humidity, and velocity) were within the recommended ranges in all poultry farms. This study has shown that Asp f 1 settles on dust at poultry farms and that occupational exposure to this allergen deserves monitoring in livestock buildings.

Murine models of airway fungal exposure and allergic sensitization

Inhalation of common indoor filamentous fungi has been associated with the induction or exacerbation of allergic respiratory disease. The understanding of fungal inhalation and allergic sensitization has significantly advanced with the use of small animal models, especially mouse models. Numerous studies have employed different animal exposure and sensitization techniques, each with inherent advantages and disadvantages that are addressed in this review. In addition, most studies involve exposure of animals to fungal spores or spore extracts while neglecting the influence of hyphal or subcellular fragment exposures. Recent literature examining the potential for hyphae and fungal fragments to induce or exacerbate allergy is discussed. Innate immune recognition of fungal elements and their contribution to lung allergic inflammation in animal models are also reviewed. Though physical properties of fungi play an important role following exposure, host immune development is also critical in airway inflammation and allergy. We discuss the importance of environmental factors that influence early immune development and subsequent susceptibility to allergy. Murine studies that examine the role of intestinal microflora and prenatal or early life environmental factors that promote allergic sensitization are also evaluated. Future studies will require animal models that accurately reflect natural fungal exposures and identify environmental factors that influence immune development and thus promote respiratory fungal allergy and disease.

Surveillance of Fungal Allergic Sensitization Using the Fluorescent Halogen Immunoassay

OBJECTIVE: Conidia derived from a small number of common fungal genera are widely accepted as the etiological agents responsible for fungal allergic sensitization. The contribution of fungal conidia, spores, airborne hyphae, and subcellular fragments from other uncharacterized fungal genera remains unclear. In this proof-of-concept study, we examined the composition of mycoaerosols that atopic women were exposed and sensitized to in their own indoor environment using the fluorescent halogen immunoassay (fHIA). PATIENTS AND METHODS: Mycoaerosols were collected onto mixed cellulose ester protein binding membranes (PBMs) for 30 minutes with volumetric air sampling pumps. The PBMs were laminated with an adhesive cover slip and indirectly immunostained with individual patient serum IgE using the fHIA. Samples were examined using confocal laser scanning microscopy and immunostained particles were expressed as a percentage of total particles. RESULTS: All air samples contained a broad spectrum of fungal spores, conidia, hyphae, and other fungal particulates. Airborne concentrations varied between individual study participant environments. Positively immunostained conidia belonging to moniliaceous amerospores, Cladosporium, Alternaria, and many unknown species were observed in the majority of air samples. Other fungal genera including Bipolaris, Curvularia, Pithomyces, and Stachybotrys, in addition to, ascospore genera and dematiaceous hyphal fragments released detectable allergen. Twelve percent of all fHIA haloes quantified in the analysis were directed towards fungal particles. No immunostaining was detected to conidia belonging to Epicoccum, Fusarium, and Spegazzinia species. CONCLUSION: In addition to characterized fungal aeroallergens, we observed a wider composition of fungi that bound human IgE. Field surveillance studies that utilize immunodiagnostic techniques such as the fHIA will provide further insight into the diversity of fungi that function as aeroallergen sources in individual study participant environments.

Determinants of indoor allergens in tropical child care centers

Limited data are available about indoor allergen determinants in child care centers (CCCs) especially in the tropics. This information is important epidemiologically and clinically considering many children attend CCCs. The purpose of this study was to determine the allergen concentrations in CCCs and their associations with CCC characteristics and indoor air quality (IAQ). A panel of indoor allergens including Der p 1, Blo t 5, Fel d 1, Can f 1, Mus m 1, Bla g 1 and Asp f 1 were evaluated from dusts vacuumed from classroom floors of CCCs. Allergen levels were assayed with antibody-based bioplex array or enzyme-linked immunosorbent assays. Indoor temperature, relative humidity and air exchange rates were measured and CCC characteristics inspected. Allergen levels were linearly regressed with CCC characteristics and IAQ. The dominant allergens found in classroom floors were Der p 1, Blo t 5 and Fel d 1. Lower indoor temperatures were associated with higher Der p 1 while lower ventilation rates were associated with higher Blo t 5 concentrations. Prevalence of cat owners was found to be a predictor for Fel d 1 concentrations. Full or partial carpeting is associated with higher dust mite allergen levels. These findings provide information for future indoor allergen exposure assessment studies in CCCs and can be used for intervention with regard to allergen avoidance.

Seasonal variability of culturable fungal genera in the house dust of inner-city residences

House dust samples were collected up to six times over a 1-year period to explore seasonal variability of individual fungal genera in inner-city households in Minneapolis, Minnesota. General linear mixed-effects models were used to explore the variability of 13 fungal genera (Cladosporium, yeasts, Aureobasidium, Alternaria, Penicillium, Epicoccum, Mucor, Rhodotorula, Aspergillus, sterile fungi, Phoma, Pithomyces, and Fusarium) found in more than 20% of total dust samples. The five most common fungi (% of samples detected) were Cladosporium (81%), yeasts (63%), Aureobasidium (57%), Alternaria (56%), and Penicillium (55%), with the remaining genera found in 20-50% of the samples. When expressed as frequency of occurrence (%), genus fraction of total fungal concentration (%), or concentration of individual genera (CFU/g), these five genera also varied substantially by season. In contrast, Aureobasidium, Fusarium, and Mucor levels remained relatively constant throughout the year. The observed concentrations of the five most common fungal genera were higher than levels associated with increased respiratory symptoms reported in previous studies. Our results indicate that seasonal variability in common fungal genera is large: within-home to between-home variance ratios of Penicillium (4.1), Alternaria (4.9), Cladosporium (7.1), and yeasts (20.3) were substantially larger than that observed for total fungi (2.5). These results suggest that future studies attempting to link individual fungal genera to health effects need to characterize and control for this seasonal variability.

Identification of spore allergens from the indoor mould Aspergillus versicolor

BACKGROUND

Indoor mould growth and dampness are associated with respiratory health effects and allergies and several studies demonstrated that mainly Aspergillus versicolor and Penicillium expansum are responsible for indoor mould exposure. In contrast, commercialized test systems to diagnose allergic reactions to this mould species are not available. In this study, allergenic proteins from spores of the indoor relevant species A. versicolor and P. expansum should get detected and identified.

METHODS

We used two-dimensional (2D)-gel electrophoresis of spore proteins and immunoblotting with sera from patients participating in an epidemiologic study about indoor exposure of moulds and their influence on the development of allergies (ESTERSPEGA). Sera were screened for IgE antibodies specific for proteins from A. versicolor, A. fumigatus and P. expansum in one-dimensional blots and in 2D immunoblots. From the 2D gels, the corresponding spots were picked and identified by mass spectrometry.

RESULTS

More than 20 allergens from A. versicolor were identified; in particular, seven major allergens were selected, which were detected by more than 90% of the positive sera. The most abundant allergen was glyceraldehyde-3-phosphate dehydrogenase, followed by an unnamed protein, which displays a high homology to sobitol/xylose reductase. The other allergens were identified as catalase A, hypothetical protein AN6918.2, enolase, hypothetical protein AN0297.2 and a protein with homology to a fungal malate dehydrogenase.

CONCLUSIONS

The results indicate an important role of spore proteins from A. versicolor for sensitization against indoor moulds and identification of the major allergens might enable species-specific diagnosis of allergic reactions.

Comparison of detection methods for Aspergillus fumigatus in environmental air samples in an occupational environment

Methods to study occupational exposures to fungi and fungal materials in facilities where the dominant exposure is the pathogenic and allergenic fungus Aspergillus fumigatus are lacking. Air samples were collected near a conveyor in a wood chip recycling plant to compare methods that might be used to assess exposure to A. fumigatus or suitable proxies. These included total dust mass, total intact spores, culturable propagules growing > 35 degrees C, ergosterol, A. fumigatus allergen Asp f1, and quantitative polymerase chain reaction for A. fumigatus. Of these measurements, Asp f1 showed the most promise based on its relative response to measurements where there is a long history of use in industrial hygiene practice (total mass, ergosterol, total intact spores, culturable propagules).

Quantification and characterisation of IgG binding to mould spores by flow cytometry and scanning electron microscopy

The concentration of mould-specific IgG antibodies in serum may objectively indicate mould exposure and can help identifying exposed individuals. Although inhaled spores probably are the most important source of mould exposure, the commonly used methods for detecting mould-specific IgG antibodies are based on extracts from all mould components, with only low contribution from spores. We have developed a flow cytometric method using surface antigens on mould spores for quantifying mould-specific IgG antibodies in serum. Flow cytometric results were evaluated by comparison with ImmunoCap and ELISA measurements. The flow cytometric assay showed a broad linear dose-dependency and correlated moderately to strongly (r=0.41-0.97) with ImmunoCap and ELISA measurements. The IgG antibody binding was studied in detail by immunolabelling in scanning electron microscopy (SEM), revealing that morphology and IgG antibody binding differed among spores, both within and between mould strains. Germination studies by flow cytometry and SEM showed that IgG antibody binding to mould spores was altered during germination due to loss of coat. The present spore based antibody assay are simple and suitable for quantification of mould-specific IgG antibodies in serum, and includes specificity to other and possibly more relevant antigens than existing methods.

Halogen immunoassay, a new method for the detection of sensitization to fungal allergens; comparisons with conventional techniques

BACKGROUND

Accurate diagnosis of allergy to specific fungal species is confounded by the variability in allergens occurring with different diagnostic systems. We compared the halogen immunoassay (HIA), which uses allergens expressed by freshly germinated spores that are bound to protein binding membranes (PBM), with the commercial Pharmacia UniCap assay (CAP) and with skin prick tests (SPT).

METHODS

Serum from 60 subjects was used; 30 were SPT positive and sensitized to at least one of Alternaria alternata or Aspergillus fumigatus and the other 30 were SPT negative to these fungi but known to be sensitized to non-fungal allergens. All sera were analyzed by CAP against A. alternata, A. fumigatus, Cladosporium herbarum and Epicoccum purpurascens. For HIA, spores from reference cultures belonging to these four species were germinated on PBM, laminated and then probed with each serum. Two independent observers using an ordinal ranking system quantified the intensity and occurrence of the resultant immunoglobulin E (IgE) immunostained haloes around spores and this was statistically compared with the results of the two conventional immunodiagnostic techniques.

RESULTS

Germinated conidia of each species expressed detectable allergen in the HIA. The agreement between the ordinal rank scores assigned by the pair of observers was very good (k >or= 0.8) and only differed for A. fumigatus (k = 0.66) . Between 3% and 7% of SPT negative sera was identified by HIA to have specific IgE towards A. fumigatus and A. alternata. For all four species tested there were strong correlations between HIA and CAP (P < 0.0001). However the correlation of both HIA and CAP to SPT was weaker for A. alternata (r(s) = 0.44, P < 0.0153) and absent for A. fumigatus.

CONCLUSIONS

Overall, the HIA is a new immunodiagnostic technique for the detection of sensitization to fungal allergens that correlates significantly with CAP and to a lesser extent with SPT. This may be due to extract variability and system differences. The significance of this derives from the unique ability of the HIA to measure IgE antibodies to the undegraded allergens that are actively secreted by germinating conidia and hyphae. These are the natural agents of exposure to fungi, and as such, are most likely to be relevant to clinical disease.

Alternaria aerosol during a bovine respiratory syncytial virus infection alters the severity of subsequent re-infection and enhances IgE production

BACKGROUND

Previous studies with cattle and rodent models have shown that bovine and human RSV infections influence the immune response to inhaled allergen. In the present study, we extended these observations to examine the effect of fungal allergen Alternaria alternata aerosol exposure (prior to and during BRSV infection) on the immune response and clinical outcome of a secondary BRSV infection.

METHODS

Calves were either Alternaria (Alt)/mock Alt (mAlt) and BRSV/mBRSV exposed. Exposures began on day -6 and continued every other day until day 6 post infection. A second set of aerosols/infection began on day 103 and continued as before. Clinical outcome during infections was measured in each group. IgG1, IgA, and IgE responses to Alternaria were measured in serum or bronchiolar alveolar lavage fluid (BALF). Cytokine responses, including IL-4, were also measured.

RESULTS

Alternaria did not influence primary infection; however, the Alt/BRSV group had less disease than mAlt/BRSV group (median clinical score 8 vs 476.5; p<or=0.01) after secondary infection. Exposure to Alternaria facilitated IgE antibody production in BRSV infected calves. IgE responses to Alternaria were higher in Alt/BRSV than Alt/mBRSV animals on day 10 (mean baseline fold increase 1.97 vs 1.06; p=0.013) and 109 (1.40 vs 0.810; p=0.008). Comparatively, Alt/BRSV calves had less Alternaria specific IgG1 than Alt/mBRSV calves on days 0, 107, 109, 113, 115, and 120 (p<or=0.05) with more lung eosinophils and IL-4 secreting PBMCs.

CONCLUSION

Alternaria aerosols during primary and secondary BRSV infections decreased disease in secondary infections; however, BRSV infection enhanced Th2 responses against inhaled Alternaria.

Enumeration and detection of aerosolized Aspergillus fumigatus and Penicillium chrysogenum conidia and hyphae using a novel double immunostaining technique

The identification of collected airborne unicellular fungal conidia and hyphae using nonviable techniques is subjective and an imprecise process. Similarly, to determine whether an individual is allergic to a particular genus requires a separate immunodiagnostic analysis. This study demonstrates the development of a novel double immunostaining halogen assay, which enables (1) the simultaneous identification of collected airborne fungal conidia and hyphae of Aspergillus fumigatus and Penicillium chrysogenum using monoclonal antibodies and (2) the demonstration of patient-specific allergy to the same particles using human serum IgE. The results demonstrate that when conidia were ungerminated the binding of antibodies was homogeneous and localized in close proximity around the entire conidia for both species. However, when conidia were germinated, the proportion expressing antigen increased (P < 0.0001) for both species and the sites of binding of the two antibodies changed with double immunostaining restricted to the hyphal tips for A. fumigatus, in addition to the sites of germination for P. chrysogenum. The described immunoassay has the potential to identify fungal particles in personal environmental air samples, provided species-specific monoclonal antibodies are available, while simultaneously demonstrating allergic sensitization to the same particles by co-staining the samples with the patient's own serum. Such an immunoassay can use those fungi that the patient is actually exposed to and potentially avoids many problems associated with extract variability based on the performance of current diagnostic techniques for fungal allergy.

Detection of aerosolized Alternaria alternata conidia, hyphae, and fragments by using a novel double-immunostaining technique

A double-immunostaining halogen immunoassay was developed to identify aerosolized conidia, hyphae, and fragments of Alternaria alternata by using an anti-Alternaria polyclonal antiserum, while, simultaneously, allergy to these components was concurrently determined by using human immunoglobulin E antibodies.

Prevention of systemic mycoses by reducing exposure to fungal pathogens in hospitalized and ambulatory neutropenic patients

PURPOSE/OBJECTIVES

To describe sources of fungal contamination that can incite invasive mycoses in hospitalized and ambulatory neutropenic patients and to discuss approaches to reduce exposure to pathogens.

DATA SOURCES

Published articles, books, and brochures.

DATA SYNTHESIS

Modifications of patient environments and lifestyles include hand hygiene for patients and healthcare workers, air filtration in hospitals, and reduction in exposure to plants, soil, standing water, and dusty environments. The effectiveness of dietary restrictions is controversial, although avoidance of pepper is recommended. These restrictions should be implemented prior to, during, and following neutropenia.

CONCLUSIONS

Mycoses can be hospital or community acquired; however, although guidelines for environmental and lifestyle modifications are well documented for the institutional setting, they are more limited for ambulatory patients.

IMPLICATIONS FOR NURSING

Nurses have a key role in the early identification of outbreaks of fungal infections, evaluation of hospital and home environments for sources of pathogens, education of patients on preventive measures, and research on neutropenic diets and improved technology to reduce exposure to fungal pathogens.

Production profile of the major allergen Alt a 1 in Alternaria alternata cultures

BACKGROUND

The fungus Alternaria is strongly associated with asthma, but the importance of fungal allergen products is frequently underestimated. The profile of allergen release from fungal material is poorly understood.

OBJECTIVE

To investigate expression of the major allergen of Alternaria alternata, Alt a 1, during its growth in culture conditions for allergen extract production.

METHODS

Allergen expression was examined by Alt a 1-specific 2-site monoclonal antibody enzyme-linked immunosorbent assay, immunoblotting, and potency assays. The release of Alt a 1 was studied by transmission electron microscopy in conjunction with immunogold staining by using antibodies with specificity for Alt a 1.

RESULTS

A maximum amount of Alt a 1 was obtained after 4.5 weeks of growing, and it was found predominantly in the spent culture medium. In the same way, total IgE binding activity showed 15-fold more activity in the spent culture medium than in the buffer-extractable antigen fraction. Immunogold electron microscopy provided evidence that Alt a 1 is released from spores and mycelia.

CONCLUSIONS

Alternaria alternata allergenic proteins were constantly released into the culture medium, where they accumulated. Alt a 1 was a good marker for checking optimal culture conditions for A alternata extract production intended for clinical use.

Indoor fungal exposure

Fungi affect humans in complex ways and are capable of eliciting a number of disease responses, such as infectious, allergic, and irritant and toxic effects. Fungal exposure is unequivocally associated with exacerbations of asthma, although the role of fungi in causing the disease is yet to be determined. The association between home dampness and respiratory health effects is strong, and fungal exposure is suspected to be associated with this linkage. Fear of toxin exposures has generated debate over the possible toxic health effects of airborne fungi; however, several recent reviews discount the health impacts of mycotoxin through indoor exposures. Nevertheless, fungal contamination of indoor environments is undesirable. Knowledge of sources and characteristics of fungal spore release and dispersal are important for understanding the processes of exposure. Environmental monitoring for fungi and their disease agents are important aspects of exposure assessment, but few guidelines exist for interpreting their health impacts. Much work is needed in isolating, characterizing and standardizing fungal disease agents to properly assess the prevalence of fungal health effects.

Exposure, sensitization, and mechanisms of fungus-induced asthma

Healthy individuals are continuously exposed to fungal biomass, which includes live and dead spores and fungal debris that is entrapped in the airways. In patients with asthma and/or atopy, exposure to fungal biomass might result in age-dependent sensitization and asthmatic reactions. Interaction with Toll-like receptors (TLRs) of the innate immune defense (alveolar macrophages and epithelial cells) and protease-activated receptors (PARs) determine the effectiveness of elimination of fungal material. The association of sensitization to Alternaria with severe asthma is discussed in relation to the age-dependent sensitization, rate of release of allergens from spores, and activity of its proteases. A model is described concerning the influence of polymorphic genes for airway hyperresponsiveness (AHR) and atopy, showing a cumulating influence on susceptibility for allergen-induced asthma, and explaining that fungus-induced airway obstruction is mainly associated with more severe asthma.

Assessment of the indoor environment

Much attention has been focused on indoor molds; resulting in modest amounts of new research. There is strong evidence of respiratory effects. Although mechanisms are disputed, some of the effect (but not all) is likely to be allergy related. There is some evidence that atopic individuals may be more affected, but many nonatopic individuals also are affected. This area needs more general research and specific research on exposure measures (such as what fungal components should be measured) and on health-effect mechanisms. It is worthwhile to emphasize the practical knowledge that is readily available. Buildings should be designed, built, operated, and occupied so that the buildings stay dry. When this situation does not occur, the environmental and clinical aspects that are observed by competent professionals should both be considered when determining causal relationships.

Cloning of a gene encoding an Alt a 1 isoallergen differentially expressed by the necrotrophic fungus Alternaria brassicicola during Arabidopsis infection

Alternaria species are considered some of the most important fungi responsible for allergenic morbidity in humans. The Alternaria protein that elicits the most intense allergic reaction in humans is Alt a 1, yet no biological function has been identified for this protein. In this study, suppression subtractive hybridization and virtual Northern blots were used to identify and characterize an Alt a 1 homolog in the phytopathogenic fungus Alternaria brassicicola. RNA was extracted from A. brassicicola spores germinated in water and on leaf surfaces of the Arabidopsis ecotype Landsberg for 24 h and used to create cDNA by PCR. Double-stranded cDNA was then used in suppression subtractive hybridization to identify differentially expressed genes. mRNA transcript levels were assessed by virtual Northern blotting. A sequence with significant homology (90% amino acid, 92% cDNA) to the Alt a 1 subunit from Alternaria alternata was identified. Virtual Northern blots demonstrated that this homolog, designated Alt b 1 precursor, was highly up-regulated during the infection process of A. brassicicola on Arabidopsis: The full-length cDNA sequence of Alt b 1 was 815 bp, with an open reading frame of 477 bp. In this preliminary study, we identified a homolog of the major Alternaria allergen precursor, Alt a 1, in A. brassicicola, designated Alt b 1. This isoallergen is differentially expressed during fungal pathogenesis on Arabidopsis, suggesting a possible biological role in pathogenesis.

Allergen detection from 11 fungal species before and after germination

BACKGROUND

Allergens dispersed by airborne fungal spores play an important but poorly understood role in the underlying cause and exacerbation of asthma. Previous studies suggest that spores of Alternaria and Aspergillus release greater quantities of allergen after germination than before germination. It is unknown whether this is true of other allergenic fungi.

OBJECTIVE

Our purpose was to investigate the release of allergen from a range of individual fungal spores before and after germination.

METHODS

Allergen expression from spores of Alternaria alternata, Cladosporium herbarum, Aspergillus fumigatus, Botrytis cinerea, Epicoccum nigrum, Exserohilum rostratum, Penicillium chrysogenum, Stemphylium botryosum, Curvularia lunata, Trichoderma viride, and Bipolaris spicifera was examined by halogen immunoassays through the use of pooled serum IgE from patients allergic to fungus. Spores were deposited onto protein-binding membranes direct from culture. To germinate spores, samples were incubated in high humidity at room temperature for 48 hours. Ungerminated and germinated samples were then laminated with an adhesive film and immunostained by the halogen assay. The samples were examined by light microscopy, and positive counts (haloed particles) were expressed as percentages of total spores.

RESULTS

For 9 of 11 species, between 5.7% and 92% of spores released allergen before germination. Spores of Penicillium and Trichoderma did not release detectable allergen. After germination, all spores that germinated had allergen elution from their hyphae. Eight of 11 species showed a significant increase (P <.05) in the percentage of spores eluting detectable allergen. Localization of allergen along the hyphae varied with species, such that some eluted allergen mainly from hyphal tips and septal junctions whereas others eluted allergen along the entire length.

CONCLUSIONS

Increased elution of allergen after germination might be a common feature of many species of allergenic fungi. Although allergens from both spores and hyphae were recognized by human IgE, the extent to which human exposure occurs to allergens eluted from inhaled spores or from hyphae that germinate after deposition in the respiratory tract remains to be explored. The patterns of allergen expression might affect the clinical response to such exposure.

Dustborne and airborne fungal propagules represent a different spectrum of fungi with differing relations to home characteristics

BACKGROUND

Exposure to fungi is often assessed by culturing floor dust or air samples. Our objective was to evaluate the relationships between dustborne and airborne fungi and to identify factors that modify these relationships.

METHODS

From November 1994 to September 1996 sequential duplicate 45-l air samples were collected in bedrooms of 496 homes in the Boston area, using a Burkard culture plate sampler. After air sampling, bedroom floors were sampled with a vacuum cleaner that was modified to collect dust in a cellulose extraction thimble. Dust was sieved, and the fine dust was dilution-plated onto DG-18 media.

RESULTS

Concentrations of total culturable fungi per gram of bedroom-floor dust were correlated weakly, but significantly, with those of indoor air (r = 0.13, P < 0.05). Concentrations of some individual taxa in the dust and indoor air were also weakly associated. Adjusting for the concentrations of fungi in outdoor air, dustborne fungal concentrations were positively associated with those in indoor air for the taxa Cladosporium and Penicillium, but not for total fungi. The indoor air fungal levels were often predicted by different covariates to those predicting fungal levels in dust. The type of housing (house or apartment) and the presence of carpeting were often predictive factors for dust fungi. In contrast, outdoor fungal levels were often predictive of the indoor air fungal levels.

CONCLUSIONS

Because our data do not indicate a strong overall relationship between culturable fungi in dust and indoor air, the results from these two methods (dust and air sampling) likely represent different types of potential fungal exposures to residents. It may be essential to collect both air and dust samples, as well as information on housing characteristics, as indicators for fungal exposure.

The role of allergens in the induction of asthma

Despite the strong and consistent association between immediate hypersensitivity and asthma, there is still controversy about the role inhaled allergens play and about the timing of events related to sensitization. Recent studies have provided further evidence on the nature of the immune response to allergens, the timing of this response, and, in particular, whether any response to allergens occurs in utero. Some of the studies also provide a better explanation for why there is not a simple dose response relationship between allergens and asthma. The new studies also raise major issues about the nature of the immune response in nonallergic individuals. Taken together, the findings do not support a simple view about the balance between TH1 and TH2 responses, but strongly support the relevance of IgE to the risk of asthma.

Spore germination increases allergen release from Alternaria

Allergen released from individual spores of the fungus Alternaria has not been investigated. Germination of spores has been suggested to increase allergen release. This study examined allergen released from individual spores and the effect of germination on allergen availability. Allergen release was determined with the Halogen (Inhalix, Sydney, Australia) immunoassay, by use of serum IgE from Alternaria -sensitized subjects and 3 Alt a 1-specific antibodies. Not all spores released allergen. Germination of the spores significantly increased the proportion that released allergen (P < .0001 for all antibodies). Alt a 1 may be a minor contributor to the total allergen released from spores except when spores have germinated. How these results reflect the allergen content of spores in the air that we breathe requires investigation.

Effect of tree and grass pollens and fungal spores on spring allergic rhinitis: a comparative study

BACKGROUND

Current literature indicates tree pollen is less important than grass pollen as the cause of spring allergic rhinitis. The role of fungal spores is secondary and uncertain.

OBJECTIVE

To assess the relative allergenicity of tree and grass pollen and fungal spores as the cause of spring allergic rhinitis in central Indiana.

METHODS

(1) Chart review of 189 Indiana natives with seasonal allergic rhinitis to ascertain clinical sensitivity to tree or grass pollens. (2) A prospective study conducted in the spring of 1997 in 51 patients, correlating patients' symptom and medication scores with daily pollen and spore counts, obtained with a Burkard spore trap.

RESULTS

One hundred thirty of 189 patients (69%) reported symptoms before May with positive prick test to at least one tree pollen. One hundred thirty-four patients (71%) had symptoms in May and June with positive test to grass pollen. The ratio between the two groups is 1:1, in contrast to a ratio of 1:4 derived from the literature. The prospective study revealed a symptom score increase parallel to the rise of tree pollen counts beginning in mid-March and reaching a plateau in early May prior to the onset of grass season. Medication use continued to increase and peaked at the height of grass pollination. Spore counts increased in late May and stayed at high levels throughout June, yet symptom and medication scores steadily declined following the peak of grass pollination in early June.

CONCLUSIONS

This study suggests that in central Indiana, tree pollen is more important as the cause of spring allergic rhinitis than that suggested by the literature. This study confirmed previous observations that fungal spores are substantially less allergenic than pollens.

Fungal extracellular polysaccharides in house dust as a marker for exposure to fungi: relations with culturable fungi, reported home dampness, and respiratory symptoms

BACKGROUND

Epidemiologic studies have demonstrated an association between indoor fungal growth and respiratory symptoms. However, in only a few studies was fungal exposure actually measured.

OBJECTIVE

The purpose of this study was to evaluate the measurement by enzyme immunoassay of extracellular polysaccharides of Aspergillus and Penicillium species (EPS-Asp/Pen ) in house dust as a marker for fungal exposure and to study the relations between EPS-Asp/Pen levels and home dampness and respiratory symptoms in children.

METHODS

Extracts of house dust samples from bedroom and living room floors and mattresses from homes of 31 children with chronic respiratory symptoms and 29 children with no chronic respiratory symptoms were analyzed for EPS-Asp/Pen.

RESULTS

EPS-Asp/Pen were readily detectable (40 to 46,513 nanogram equivalent/g dust) in 161 house dust extracts, with highest concentrations in living room floor dust. EPS-Asp/Pen levels were 2 to 3 times higher on carpeted floors than on smooth floors. EPS-Asp/Pen were significantly correlated with total culturable fungi (r = 0.3 to 0.5) and with house dust mite allergens (r = 0.3 to 0.5). EPS-Asp/Pen levels in living room floor dust were positively associated with occupant-reported home dampness. This was not observed for EPS-Asp/Pen in bedroom floor and mattress dust. EPS-Asp/Pen levels in living room floor dust were positively associated with respiratory symptoms. EPS-Asp/Pen in bedroom floor and mattress dust showed a reversed association with respiratory symptoms, possibly because of allergen-avoidance measures taken in the bedroom.

CONCLUSION

The enzyme immunoassay for fungal EPS-Asp/Pen may be a useful method for exposure assessment of indoor fungi.

Indoor survey of moulds and prevalence of mould atopy in Israel

BACKGROUND

Moulds are ubiquitous indoor as well as outdoor allergens and therefore potential candidates for indoor environmental control measures. However, very few studies have been performed to examine the significance of indoor moulds in allergic diseases and the effectiveness of measures to reduce the quantity of indoor moulds has not been established.

OBJECTIVE

To determine the significance and the contribution of moulds to allergic manifestations.

METHODS

Prevalence of allergic rhinitis and asthma in 395 members of a rural community were examined by questionnaire and examination of medical files. The atopic status in general and allergy to moulds was determined by skin-prick tests (SPTs) to a panel of aeroallergens including Aspergillus, Penicillium, Alternaria and Cladosporium. A study of indoor mould levels was performed by placing SDA plates in 59 houses. The type of fungi and the number of colonies from each species were recorded.

RESULTS

Forty-two subjects, comprising 10.9% of the study group had positive SPT to moulds, 61.9% of those were classified as symptomatic. When taking into account individuals with a borderline positive SPT to moulds, an additional 23 had positive results. Of the 65 mould-positive subjects, 48% were symptomatic and of the 13 who were allergic to moulds alone, only two had allergic symptoms. Viable moulds were recovered from all 59 houses examined. The most common isolated genus was Aspergillus, followed by Penicillium, Alternaria and Cladosporium. Aspergillus was also the most abundant mould in houses. There was no significant correlation between the abundance of moulds, positive SPT to that mould and symptomatology.

CONCLUSIONS

Viable moulds are common in houses in temperate climates. Allergy to moulds itself has a low predictive value to development of allergic symptoms, but allergy to moulds in otherwise atopic subjects increases the risk of symptomatic allergic disease.