Variable risk of atopic disease due to indoor fungal exposure in NHANES 2005-2006.

BACKGROUND: Exposure to damp indoor environments is associated with increased risk of eczema, allergy and asthma. The role of dampness-related exposures and risk of allergic diseases are yet to be fully explored in the US population. OBJECTIVE: We assess whether exposure to fungi, house dust mites and endotoxin increases the risk of eczema, allergy and asthma in children and adults participating in NHANES 2005-2006. METHODS: A total of 8412 participants (2849 were children aged between 6 and 17 years) were recruited in the 2005-2006 survey. We used multiple logistic regression to investigate whether mildew/musty odour and increased concentrations of Alternaria alternata allergen, Aspergillus fumigatus antigens, house dust mite and endotoxin antigens increase the risk of eczema, allergy and asthma. We stratified models by total IgE < 170 and ≥ 170 KU/L to assess allergic and non-allergic asthma outcomes. Exposure to multiple biological agents and risk of reporting eczema, allergy and asthma were also investigated. RESULTS: Reporting of a mildew/musty odour was associated with increased risk of childhood asthma (OR 1.60; 95% CI 1.17-2.19), and adult eczema, allergy and asthma (OR 1.92; 95% CI 1.39-2.63, OR 1.59 95% CI 1.26-2.02 and OR 1.61 95% CI 1.00-2.57, respectively). Risk of asthma was associated with total IgE ≥ 170 KU/L in children (OR 1.81; 95% CI 1.01-3.25) and total IgE < 170 KU/L in adults (OR 1.91; 95% CI 1.07-3.42). Children and adults exposed to more than eight biological agents present in the home were at reduced risk of eczema (OR 0.17; 95% CI 0.04-0.77) and asthma (OR 0.49; 95% CI 0.25-0.97), respectively. CONCLUSION: Exposure to a mildew/musty odour, as a proxy for exposure to fungus, was implicated in an increased risk of atopic diseases. Sensitisation may play a different role in children and adults, and exposure to multiple allergens may reduce the risk of atopic disease.

Performance of galactomannan, beta-d-glucan, Aspergillus lateral-flow device, conventional culture, and PCR tests with bronchoalveolar lavage fluid for diagnosis of invasive pulmonary aspergillosis.

Galactomannan detection in bronchoalveolar lavage (BAL) fluid samples (GM test) is currently considered the gold standard test for diagnosing invasive pulmonary aspergillosis (IPA). The limitations, however, are the various turnaround times and availability of testing. We compared the performance of GM testing with that of conventional culture, an Aspergillus lateral-flow-device (LFD) test, a beta-d-glucan (BDG) test, and an Aspergillus PCR assay by using BAL fluid samples from immunocompromised patients. A total of 78 BAL fluid samples from 78 patients at risk for IPA (74 samples from Graz and 4 from Mannheim) collected between December 2012 and May 2013 at two university hospitals in Austria and Germany were included. Three patients had proven IPA, 14 probable IPA, and 17 possible IPA, and 44 patients had no IPA. The diagnostic accuracies of the different methods for probable/proven IPA were evaluated. The diagnostic odds ratios were the highest for the GM, PCR, and LFD tests. The sensitivities for the four methods (except culture) were between 70 and 88%. The combination of the GM (cutoff optical density index [ODI], >1.0) and LFD tests increased the sensitivity to 94%, while the combination of the GM test (>1.0) and PCR resulted in 100% sensitivity (specificity for probable/proven IPA, 95 to 98%). The performance of conventional culture was limited by low sensitivity, while that of the BDG test was limited by low specificity. We evaluated established and novel diagnostic methods for IPA and found that the Aspergillus PCR, LFD, and GM tests were the most useful methods for diagnosing the disease by using BAL fluid samples. In particular, the combination of the GM test and PCR or, if PCR is not available, the LFD test, allows for sensitive and specific diagnosis of IPA.

Modifiable factors governing indoor fungal diversity and risk of asthma.

Exposure to dampness and fungi in the home is a known risk factor for individuals with allergic asthma. Inadequate heating and ventilation may lead to dampness and concomitant increased exposure to spores of allergenic fungi such as Aspergillus and Penicillium. These fungi have been cultured from sputum of asthmatic and non-asthmatic individuals, and implicated in the initiation or exacerbation of asthma. Indoor environmental factors influence the presence and concentrations of fungal propagules and, in turn, risk of asthma outcomes. This review aims to identify modifiable risk factors in the built environment that have been shown to influence fungal composition indoors, and to examine this association with the risk of asthma development and/or exacerbation. A complex interaction between residential characteristics, the built environment and the behaviour of people regulate the diversity and concentrations of indoor fungi. Modifiable factors include build age, architectural design, level of maintenance, variations in construction materials, presence of pets, heating and ventilation patterns. Risk of fungal contamination and asthma outcomes are also influenced by low occupant awareness concerning potential health effects and socio-economic factors. Addressing these factors provides an opportunity to improve future housing interventions, though it is not clear how the built environment and occupant behaviours interact to modify the diversity of indoor fungi and resultant risk of asthma. A combination of housing improvements combined with awareness programmes and the alleviation of fuel poverty can be used to lower the allergen burden associated with damp homes. Further research is needed to identify factors that regulate the concentration and diversity of indoor fungi and how this may act as a modifier for asthma outcomes.

Comparison of a novel Aspergillus lateral-flow device and the Platelia® galactomannan assay for the diagnosis of invasive aspergillosis following haematopoietic stem cell transplantation.

PURPOSE: The detection of galactomannan in serum is a cornerstone for the diagnosis of invasive fungal disease (IFD). Because a delay in treatment initiation is associated with a poor outcome, the results have to be available promptly. However, due to methodological and economic reasons, the test frequencies of the commonly used galactomannan assays vary between daily to weekly, meaning that results may be available too late to be clinically useful. The novel Aspergillus lateral-flow device (Aspergillus-LFD) is a rapid test that may overcome these limitations. METHODS: We compared the diagnostic performance of the Aspergillus-LFD and the Platelia® Aspergillus EIA (GM-EIA) in serum from 101 patients during and after allogeneic haematopoietic stem cell transplantation (HSCT). Clinical data and sera were collected prospectively and patients classified according to the European Organisation for Research and Treatment of Cancer (EORTC)/Mycoses Study Group (MSG) 2008 guidelines. RESULTS: By the end of hospitalisation, one proven, nine probable and 20 possible cases of IFD were identified. Depending on the number of positive serum samples required for test positivity, the sensitivities, specificities and diagnostic odds ratios in patients with proven and probable IFD were as follows. One positive serum required: Aspergillus-LFD 40.0 %, 86.8 % and 3.03; GM-EIA 40.0 %, 89.0 % and 3.64. Two positive sera required: Aspergillus-LFD 20.0 %, 97.8 % and 11.13; GM-EIA 30.0 %, 98.9 % and 38.57. Although the GM-EIA was positive in a higher percentage of samples, this did not result in an earlier diagnosis. CONCLUSIONS: If used as a screening test (one positive serum required for test positivity) or to rule out IFD, the Aspergillus-LFD has shown a comparable diagnostic performance to the GM-EIA. However, if the results have to be confirmed by a second positive serum, the GM-EIA exhibited superior sensitivity. In terms of practicability, the Aspergillus-LFD has demonstrated to be a quick (15 min) and easy-to-use test for single-patient detection of Aspergillus antigens.

Quantification of Fungal Antigens in Soil with a Monoclonal Antibody-Based ELISA: Analysis and Reduction of Soil-Specific Bias.

ABSTRACT This paper describes methods to improve the use of immunoassays for quantification of soilborne fungal antigens. Calibration curves, prepared by diluting known quantities of an antigen into soil extracts and into soil, were described by a four-parameter logistic curve from which two principal criteria, the lower detection limit and the horizontal locational parameter, were used to summarize the sensitivity and bias of an immuno-assay. We identify two sources of bias, retention of the antigen in soil due to bonding and interference of soluble soil components in plate-trapped-antigen, enzyme-linked immunosorbent assays. Using a monoclonal antibody that recognizes a putative catechol oxidase secreted by hyphae of Rhizoctonia solani, we show that bias due to retention of the antigen in soil is substantially greater than bias due to interference. Three soils were compared: a sand, a clay, and a loam. The degree of retention varied with soil type, with more than a 1,000-fold reduction in sensitivity in the clay soil. Addition of CuSO(4) to the extraction solution and optimizing the volume of extractant reduced the bias and increased the sensitivity of the assay for all three soils. Possible mechanisms for the effect due to Cu(2+) and the implications for the design and use of calibration curves for assays involving quantification of fungal antigens in soil are discussed.

Production and Characterization of a Monoclonal Antibody Raised Against Surface Antigens from Mycelium of Gaeumannomyces graminis var. tritici: Evidence for an Extracellular Polyphenol Oxidase.

ABSTRACT A murine monoclonal antibody (MAb) of immunoglobulin class M (IgM) was raised against surface antigens from Gaeumannomyces graminis var. tritici and, by enzyme-linked immunosorbent assay, recognized isolates of G. graminis var. tritici, G. graminis var. avenae and G. graminis var. graminis. Characterization of the antigen by heat and protease treatments showed that the epitope recognized by the MAb was a protein. Antigen production was detected only in live mycelia. Immunofluorescence studies showed that the antigen was associated with both the broad melanized macrohyphae and hyaline mycelia of G. graminis var. tritici. Secretion of antigen into an aqueous minimal medium was promoted only by exposure of live mycelia to certain phenolic substrates, including monophenols ortho-, para-, and meta-cresol; 3,4,5-trihydroxybenzoic acid (gallic acid); and phenolic amino acid L-3-(3,4-dihydroxyphenyl) alanine (L-DOPA). Antigen secretion was not promoted by 3-(4-hydroxyphenyl) alanine (L-tyrosine). The MAb reacted strongly with purified enzyme laccase (polyphenol oxidase, EC 1.10.3.2) but did not recognize purified tyrosinase (monophenol oxidase, EC 1.14.18.1). Moreover, chemicals that bind to copper and inhibit copper-containing enzymes such as laccase completely inhibited antigen secretion in response to L-DOPA. The MAb was tested for specificity against a wide range of fungi, common yeast species, and gram positive and negative bacteria. It did not recognize antigens from a broad range of unrelated fungi, including Gliocladium roseum, Fusarium sp., Phoma exigua, Phialophora fastigiata, Penicillium crustosum, Pythium ultimum, Rhizopus stolonifer, Rhizoctonia carotae, R. oryzae, R. tuliparum, and Trichoderma viride, nor did it recognize surface antigens from yeasts or bacteria. The MAb cross-reacted with antigens from Botrytis spp., Chaetomium globosum, R. cerealis, and R. solani. However, secretion of antigen by R. solani and R. cerealis was not promoted by L-DOPA, and secretion by C. globosum in response to the phenolic amino acid was significantly less compared to G. graminis var. tritici.