Detection of Filamentous Fungi in the Homes and Airways of Patients with Asthma

Asthma is a heterogeneous condition characterised by variable airflow obstruction, airway inflammation and hyper-responsiveness. Fungal sensitisation has been associated with asthma severity; and airways colonisation by the pathogenic fungus Aspergillus fumigatus has been associated with a progressive lung function decline in allergic bronchopulmonary aspergillosis. Interest in the home environment as a source of fungal exposure is increasing; however, there are still no accepted guidelines or standardised methods for the quantification of indoor fungal levels. We sought to i) investigate typical airborne fungal spore concentrations in homes and to compare exposure levels in asthma patients grouped according to either A. fumigatus sensitisation or sputum culture; ii) fully characterise the fungal biota capable of colonising the airways in patients with asthma; and iii) define the clinical characteristics of fungal colonisation. Aspergillus/Penicillium-type conidia exhibited indoor predominance and independence of season, and were highest in old, terraced, non-insulated properties. A. fumigatus was the predominant fungus isolated from sputum and IgE sensitisation to A. fumigatus was associated with reduced post-bronchodilator FEV1 in patients with asthma. Sputum culture of filamentous fungi was also associated with reduced lung function, with predominant fungi comprising Aspergillus and Penicillium species; notably Penicillium piceum and species of Aspergillus section Nigri. Higher levels of airborne A. fumigatus were detected in homes of asthmatics with a positive sputum culture for A. fumigatus. In conclusion, sensitisation to A. fumigatus and airways colonisation by fungi are associated with reduced lung function in moderate to severe asthma; and this study provides a direct link between home exposure and airways colonisation

Detection of filamentous fungi in the homes and airways of patients with asthma

Asthma is a heterogeneous condition characterised by variable airflow obstruction, airway inflammation and hyper-responsiveness. Fungal sensitisation has been associated with asthma severity; and airways colonisation by the pathogenic fungus Aspergillus fumigatus has been associated with a progressive lung function decline in allergic bronchopulmonary aspergillosis. Interest in the home environment as a source of fungal exposure is increasing; however, there are still no accepted guidelines or standardised methods for the quantification of indoor fungal levels. We sought to i) investigate typical airborne fungal spore concentrations in homes and to compare exposure levels in asthma patients grouped according to either A. fumigatus sensitisation or sputum culture; ii) fully characterise the fungal biota capable of colonising the airways in patients with asthma; and iii) define the clinical characteristics of fungal colonisation. Aspergillus/Penicillium-type conidia exhibited indoor predominance and independence of season, and were highest in old, terraced, non-insulated properties. A. fumigatus was the predominant fungus isolated from sputum and IgE sensitisation to A. fumigatus was associated with reduced post-bronchodilator FEV1 in patients with asthma. Sputum culture of filamentous fungi was also associated with reduced lung function, with predominant fungi comprising Aspergillus and Penicillium species; notably Penicillium piceum and species of Aspergillus section Nigri. Higher levels of airborne A. fumigatus were detected in homes of asthmatics with a positive sputum culture for A. fumigatus. In conclusion, sensitisation to A. fumigatus and airways colonisation by fungi are associated with reduced lung function in moderate to severe asthma; and this study provides a direct link between home exposure and airways colonisation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Allergic fungal airway disease: Pathophysiologic and diagnostic considerations

Purpose of review Fungal spores are ubiquitously present in indoor and outdoor air. A number can act as aeroallergens in Immunoglobulin E (IgE)-sensitized individuals and some thermotolerant fungi germinate in the lung where they can cause a combined allergic and infective stimulus leading to a number of clinical presentations characterized by evidence of lung damage. We discuss which biomarkers are useful in helping to guide diagnosis, prognosis and treatment of allergic fungal airway disease (AFAD). Recent findings Diagnostic biomarkers, such as specific IgEs and fungal culture, for AFAD are limited by sensitivity, although this may be improved with novel agents such as specific IgEs to fungal components and quantitative PCR. Total IgE and hypereosinophilia are nonspecific and do not clearly relate to disease activity. High attenuation mucus and proximal bronchiectasis are specific, albeit insensitive markers of AFAD. Biomarkers that predict prognosis and treatment response are yet to be defined. Summary This review summarizes the fungi involved and the current debate regarding the diagnostic criteria to define fungal-associated lung disease. We advocate the phasing out of the term allergic bronchopulmonary aspergillosis and the use of a more inclusive term such as AFAD, together with a more liberal set of criteria based largely on IgE sensitization to thermotolerant fungi, which identifies those patients at risk of developing lung damage

Reproducibility between counts of airborne allergenic pollen from two cities in the East Midlands, UK

Historically in the East Midlands, UK, airborne pollen has been monitored in two cities, Derby and Leicester, situated 41 km (25 miles) apart. The aim of the present study was to compare aerobiological data from both sites to determine if a forecast based on data from one site would be sufficient for both, and to address the wider issue of reproducibility between geographically separated sites. Pollen types recorded could be split into two groups according to annual abundance, maximum daily concentration and the number of high count days. Six taxa made up the abundant group; ash, birch, grass, oak, nettle-type and yew-type, representing 90 and 88% of the total air spora for Derby and Leicester, respectively. Three consecutive years of grass and nettle pollen data are presented, supported by one year of abundant tree pollen data. There were highly significant positive correlations between the counts obtained. Line charts showing the average number of pollen grains m−3 air day−1 show similar trends, and Bland–Altman plots show little discrepancy between the amounts of pollen counted on any given day. Each day was classified according to the UK accepted threshold levels for grass. Weighted kappa statistics showed substantial or almost perfect agreement between the forecast classifications. With the caveat that this would not apply in a region with restrictions to air flow such as a mountain range or with extreme fluctuations such as a coastline site, this study suggests that data from a single site is suitable for forecasting a distance of up to 41 km

IgE Sensitization to Aspergillus fumigatus Is Associated with Reduced Lung Function in Asthma

Rationale: The importance of Aspergillus fumigatus sensitization and colonization of the airways in patients with asthma is unclear

The airway fungal microbiome in asthma.

BACKGROUND:Fungal involvement in asthma is associated with severe disease. The full spectrum of fungal species in asthma is not well described and is derived largely from insensitive culture techniques. OBJECTIVES:To use high-throughput sequencing to describe the airway mycobiota in asthmatics with and without fungal-sensitisation and healthy controls; to compare samples representing different airway compartments; to determine if the mycobiota was influenced by the fungal composition of outdoor air, and to compare findings with clinically relevant outcomes. METHODS:We amplified the internal transcribed spacer region 2 of the nuclear ribosomal operon to identify the fungal species present. Ninety-seven subjects were recruited and provided sputum (83 asthmatics; 14 healthy subjects), with 29 also undergoing a bronchoscopy. A subset of airway samples were compared with matched outdoor air and mouthwash samples. RESULTS:Two hundred and six taxa at the species level were identified in sputum, most at low relative abundance. Aspergillus fumigatus, Candida albicans and Mycosphaerella tassiana had the highest relative abundances and were the most prevalent species across all subjects. The airway mycobiota consisted of a complex community with high diversity between individuals. Notable shifts in the balance of fungi detected in the lung were associated with asthma status, asthma duration and biomarkers of inflammation. Aspergillus tubingensis, a member of the Aspergillus niger species complex, was most prevalent from bronchoscopic protected brush samples and significantly associated with a low sputum neutrophilia. Cryptococcus pseudolongus, from the Cryptococcus humicola species complex, was more abundant from bronchoscopy samples than sputum, and differentially more abundant in asthma than health. CONCLUSIONS AND CLINICAL RELEVANCE:The airway mycobiota was dominated by a relatively small number of species, but was distinct from the oropharyngeal mycobiota and air samples. Members of the Aspergillus niger and Cryptococus humicola species complexes may play unexpected roles in the pathogenesis of asthma