Isolation of filamentous fungi from sputum in asthma is associated with reduced post-bronchodilator FEV1

The effects of inhaled corticosteroids on healthy airways

BACKGROUND

The effects of inhaled corticosteroids (ICS) on healthy airways are poorly defined.

OBJECTIVES

To delineate the effects of ICS on gene expression in healthy airways, without confounding caused by changes in disease-related genes and disease-related alterations in ICS responsiveness.

METHODS

Randomized open-label bronchoscopy study of high-dose ICS therapy in 30 healthy adult volunteers randomized 2:1 to (i) fluticasone propionate 500 mcg bd daily or (ii) no treatment, for 4 weeks. Laboratory staff were blinded to allocation. Biopsies and brushings were analysed by immunohistochemistry, bulk RNA sequencing, DNA methylation array and metagenomics.

RESULTS

ICS induced small between-group differences in blood and lamina propria eosinophil numbers, but not in other immunopathological features, blood neutrophils, FeNO, FEV1, microbiome or DNA methylation. ICS treatment upregulated 72 genes in brushings and 53 genes in biopsies, and downregulated 82 genes in brushings and 416 genes in biopsies. The most downregulated genes in both tissues were canonical markers of type-2 inflammation (FCER1A, CPA3, IL33, CLEC10A, SERPINB10 and CCR5), T cell-mediated adaptive immunity (TARP, TRBC1, TRBC2, PTPN22, TRAC, CD2, CD8A, HLA-DQB2, CD96, PTPN7), B-cell immunity (CD20, immunoglobulin heavy and light chains) and innate immunity, including CD48, Hobit, RANTES, Langerin and GFI1. An IL-17-dependent gene signature was not upregulated by ICS.

CONCLUSIONS

In healthy airways, 4-week ICS exposure reduces gene expression related to both innate and adaptive immunity, and reduces markers of type-2 inflammation. This implies that homeostasis in health involves tonic type-2 signalling in the airway mucosa, which is exquisitely sensitive to ICS.

Identification of allergens from Aspergillus fumigatus-Potential association with lung damage in asthma

BACKGROUND

Component-resolved diagnosis allows detection of IgE sensitization having the advantage of reproducibility and standardization compared to crude extracts. The main disadvantage of the traditional allergen identification methods, 1- or 2-dimensional western blotting and screening of expression cDNA libraries with patients' IgEs, is that the native structure of the protein is not necessarily maintained.

METHODS

We used a novel immunoprecipitation technique in combination with mass spectrometry to identify new allergens of Aspergillus fumigatus. Magnetic Dynabeads coupled with anti-human IgE antibodies were used to purify human serum IgE and subsequently allergens from A. fumigatus protein extract.

RESULTS

Of the 184 proteins detected by subsequent mass peptide fingerprinting, a subset of 13 were recombinantly expressed and purified. In a panel of 52 A. fumigatus-sensitized people with asthma, 23 non-fungal-sensitized asthmatics and 18 healthy individuals, only the former showed an IgE reaction by immunoblotting and/or ELISA. We discovered 11 proteins not yet described as A. fumigatus allergens, with fructose-bisphosphate aldolase class II (FBA2) (33%), NAD-dependent malate dehydrogenase (31%) and Cu/Zn superoxide dismutase (27%) being the most prevalent. With respect to these three allergens, native versus denatured protein assays indicated a better recognition of the native proteins. Seven of 11 allergens fulfilled the WHO/IUIS criteria and were accepted as new A. fumigatus allergens.

CONCLUSION

In conclusion, we introduce a straightforward method of allergen identification from complex allergenic sources such as A. fumigatus by immunoprecipitation combined with mass spectrometry, which has the advantage over traditional methods of identifying allergens by maintaining the structure of the proteins.

Poorly controlled asthma - Easy wins and future prospects for addressing fungal allergy

Poorly controlled asthma is especially common in low resource countries. Aside from lack of access to, or poor technique with, inhaled beta-2 agonists and corticosteroids, the most problematic forms of asthma are frequently associated with both fungal allergy and exposure, especially in adults leading to more asthma exacerbations and worse asthma. The umbrella term 'fungal asthma' describes many disorders linked to fungal exposure and/or allergy to fungi. One fungal asthma endotype, ABPA, is usually marked by a very high IgE and its differential diagnosis is reviewed. Both ABPA and fungal bronchitis in bronchiectasis are marked by thick excess airway mucus production. Dermatophyte skin infection can worsen asthma and eradication of the skin infection improves asthma. Exposure to fungi in the workplace, home and schools, often in damp or water-damaged buildings worsens asthma, and remediation improves symptom control and reduces exacerbations. Antifungal therapy is beneficial for fungal asthma as demonstrated in nine of 13 randomised controlled studies, reducing symptoms, corticosteroid need and exacerbations while improving lung function. Other useful therapies include azithromycin and some biologics approved for the treatment of severe asthma. If all individuals with poorly controlled and severe asthma could be 'relieved' of their fungal allergy and infection through antifungal therapy without systemic corticosteroids, the health benefits would be enormous and relatively inexpensive, improving the long term health of over 20 million adults and many children. Antifungal therapy carries some toxicity, drug interactions and triazole resistance risks, and data are incomplete. Here we summarise what is known and what remains uncertain about this complex topic.

Relationship between Aspergillus and asthma

Fungal sensitization is highly prevalent in severe asthma. The relationship between fungus and asthma, especially Aspergillus fumigatus, has been the subject of extensive research. The ubiquitous presence of A. fumigatus, its thermotolerant nature, the respirable size of its conidia, and its ability to produce potent allergens are pivotal in worsening asthma control. Due to the diverse clinical manifestations of fungal asthma and the lack of specific biomarkers, its diagnosis remains intricate. Diagnosing fungal asthma requires carefully assessing the patient's clinical history, immunological tests, and imaging. Depending on the severity, patients with fungal asthma require personalized treatment plans, including inhaled corticosteroids and bronchodilators, and antifungal therapy. This review provides a comprehensive overview of the association between Aspergillus and asthma by reviewing the relevant literature and highlighting key findings. We discuss the diagnosis of various entities included in fungal asthma. We also debate whether newer definitions, including allergic fungal airway disease, offer any additional advantages over the existing ones. Finally, we provide the current treatment options for the individual entities, including A. fumigatus-associated asthma, severe asthma with fungal sensitization, and allergic bronchopulmonary mycoses.

Frequency and Distribution of Broncho-Alveolar Fungi in Lung Diseases in Martinique

The microbiota refers to all the microorganisms living in and on the human body; its fungal component is known as the mycobiota. The molecular component (mycobiome) has been linked to certain pulmonary diseases. Morphological fungal examination is still common practice and makes it possible to isolate fungi on direct examination or after sample culture. This study aimed to identify fungi via the genus colonising the respiratory tract in our environment and to evaluate the relationship between identified fungi and underlying diseases. We performed a retrospective study of patients who underwent bronchofiberoscopy and mycological analysis of fluid collected by broncho-alveolar lavage at our centre over a period of 5 years. During the study period, 1588 samples from 1547 patients were analysed (50.7% male, mean age 63.7 ± 14.8 years). Among the 1588 samples, 213 (13.4%) were positive on direct examination, and 1282 (80.8%) were positive after culture. The average number of species detected per sample was 1.4 ± 1.1. For patients with positive fungus, the median was two (ranging from one to seven). At least three fungal species were isolated in 14.4% of samples (17.9% of positive cultures), and at least two were isolated in 41.2% of samples (51.1% of positive cultures). Sterile mycelium was observed in 671 samples (42.28%), while Candida was identified in 607 samples (38.25%), and Geotrichum was identified in 271 samples (17.08%). Moulds were more frequently associated with bronchiectasis, while yeasts were associated with infectious pneumonia. Both moulds and yeasts were less frequent in diffuse interstitial lung disease, and yeast was less frequently present in chronic cough. Although overall, sterile mycelium and Candida were most frequently observed regardless of the underlying disease, there was nonetheless significant variability in the fungal genera between diseases. Fungal spores are highly prevalent in respiratory samples in Martinique. The species present in the samples varied according to the underlying respiratory disease.

Inhaled antifungal therapy: benefits, challenges, and clinical applications

INTRODUCTION

Disease due to pulmonary infection with Aspergillus, and other emerging opportunistic fungi remains a significant unmet need. Existing antifungal medicines are predominantly dosed either orally or systemically, but because of limited exposure to the lung lumen, adverse events, and problematic drug-drug interactions, inhaled treatment could provide an attractive option.

AREA COVERED

This review summarizes 1) the limitations of current antifungal therapy, 2) the beneficial effects of inhaled antifungal agents, 3) the clinical development of inhaled antifungal triazoles (repurposed with an innovative inhalation system or a novel inhaled agent) for the treatment of pulmonary fungal infections, and 4) the difficulties and challenges of inhaled antifungal agent development. Regrettably, details of novel inhaled devices or formulations were not covered.

EXPERT OPINION

Inhaled antifungal treatment could provide an attractive option by shifting the risk benefit ratio of treatment favorably. Preclinical and clinical studies with inhaled antifungal agents (off-label use) are encouraging so far. New inhaled antifungal triazoles are well tolerated in early clinical studies and warrant further clinical development. However, challenges remain and many unaddressed issues including required preclinical studies, appropriate clinical design, pharmacokinetics, delivery system(s) and regulatory process need to be resolved. Early communication with regulatory authorities is therefore recommended.

Novel acute hypersensitivity pneumonitis model induced by airway mycosis and high dose lipopolysaccharide

BACKGROUND

Inhalation of fungal spores is a strong risk factor for severe asthma and experimentally leads to development of airway mycosis and asthma-like disease in mice. However, in addition to fungal spores, humans are simultaneously exposed to other inflammatory agents such as lipopolysaccharide (LPS), with uncertain relevance to disease expression. To determine how high dose inhalation of LPS influences the expression of allergic airway disease induced by the allergenic mold Aspergillus niger (A. niger).

METHODS

C57BL/6J mice were intranasally challenged with the viable spores of A. niger with and without 1 μg of LPS over two weeks. Changes in airway hyperreactivity, airway and lung inflammatory cell recruitment, antigen-specific immunoglobulins, and histopathology were determined.

RESULTS

In comparison to mice challenged only with A. niger, addition of LPS (1 μg) to A. niger abrogated airway hyperresponsiveness and strongly attenuated airway eosinophilia, PAS+ goblet cells and TH2 responses while enhancing TH1 and TH17 cell recruitment to lung. Addition of LPS resulted in more severe, diffuse lung inflammation with scattered, loosely-formed parenchymal granulomas, but failed to alter fungus-induced IgE and IgG antibodies.

CONCLUSIONS

In contrast to the strongly allergic lung phenotype induced by fungal spores alone, addition of a relatively high dose of LPS abrogates asthma-like features, replacing them with a phenotype more consistent with acute hypersensitivity pneumonitis (HP). These findings extend the already established link between airway mycosis and asthma to HP and describe a robust model for further dissecting the pathophysiology of HP.

Microbiota Emergencies in the Diagnosis of Lung Diseases: A Meta-Analysis

Although many studies have reported that microbiota emergencies are deeply involved in the occurrence and subsequent progression of lung diseases, the present diagnosis of lung disease depends on microbiota markers, which is still poorly understood. Therefore, a meta-analysis was performed to confirm lung microbiota markers for the diagnosis of lung diseases. Literature databases were searched following the inclusion and exclusion criteria. There are 6 studies including 1347 patients and 26 comparisons to be enrolled, and then the diagnostic effect was evaluated using Stata 14.0 and Meta-disc 1.4 software. The pooled sensitivity (SEN), specificity (SPE), diagnostic likelihood ratio positive (DLR+), diagnostic likelihood ratio negative (DLR-), and diagnostic OR (DOR), as well as area under the curve (AUC) of microbiota markers in the diagnosis of lung diseases were 0.90 (95% CI: 0.83-0.94), 0.89 (95% CI: 0.76-0.95), 7.86 (95% CI: 3.39-18.21), 0.12 (95% CI: 0.06-0.21), 22.254 (95% CI: 12.83-39.59.14), and 0.95 (95% CI: 0.93-0.97), respectively. Subgroup analysis revealed that research based on Caucasian, adult, BAL fluid, PCR, pneumonia obtained higher AUC values. The microbiota markers have shown potential diagnosis value for lung diseases. But further large-scale clinical studies are still needed to verify and replicate the diagnostic value of lung microbiota markers.

Allergic fungal airways disease (AFAD): an under-recognised asthma endotype

The term allergic fungal airways disease has a liberal definition based on IgE sensitisation to thermotolerant fungi and evidence of fungal-related lung damage. It arose from a body of work looking into the role of fungi in asthma. Historically fungi were considered a rare complication of asthma, exemplified by allergic bronchopulmonary aspergillosis; however, there is a significant proportion of individuals with Aspergillus fumigatus sensitisation who do not meet these criteria, who are at high risk for the development of lung damage. The fungi that play a role in asthma can be divided into two groups; those that can grow at body temperature referred to as thermotolerant, which are capable of both infection and allergy, and those that cannot but can still act as allergens in IgE sensitised individuals. Sensitisation to thermotolerant filamentous fungi (Aspergillus and Penicillium), and not non-thermotolerant fungi (Alternaria and Cladosporium) is associated with lower lung function and radiological abnormalities (bronchiectasis, tree-in-bud, fleeting shadows, collapse/consolidation and fibrosis). For antifungals to play a role in treatment, the focus should be on fungi capable of growing in the airways thereby causing a persistent chronic allergenic stimulus and releasing tissue damaging proteases and other enzymes which may disrupt the airway epithelial barrier and cause mucosal damage and airway remodelling. All patients with IgE sensitisation to thermotolerant fungi in the context of asthma and other airway disease are at risk of progressive lung damage, and as such should be monitored closely.

New Perspectives in the Diagnosis and Management of Allergic Fungal Airway Disease

Allergy to airway-colonising, thermotolerant, filamentous fungi represents a distinct eosinophilic endotype of often severe lung disease. This endotype, which particularly affects adult asthma, but also complicates other airway diseases and sometimes occurs de novo, has a heterogeneous presentation ranging from severe eosinophilic asthma to lobar collapse. Its hallmark is lung damage, characterised by fixed airflow obstruction (FAO), bronchiectasis and lung fibrosis. It has a number of monikers including severe asthma with fungal sensitisation (SAFS) and allergic bronchopulmonary aspergillosis/mycosis (ABPA/M), but these exclusive terms constitute only sub-sets of the condition. In order to capture the full extent of the syndrome we prefer the inclusive term allergic fungal airway disease (AFAD), the criteria for which are IgE sensitisation to relevant fungi in association with airway disease. The primary fungus involved is Aspergillus fumigatus, but a number of other thermotolerant species from several genera have been implicated. The unifying mechanism involves germination of inhaled fungal spores in the lung in the context of IgE sensitisation, leading to a persistent and vigorous eosinophilic inflammatory response in association with release of fungal proteases. Most allergenic fungi, including Alternaria and Cladosporium species, are not thermotolerant and cannot germinate in the airways so only act as aeroallergens and do not cause AFAD. Studies of the airway mycobiome have shown that A. fumigatus colonises the normal as much as the asthmatic airway, suggesting it is the tendency to become IgE-sensitised that is the critical triggering factor for AFAD rather than colonisation per se. Treatment is aimed at preventing exacerbations with glucocorticoids and increasingly by the use of anti-T2 biological therapies. Anti-fungal therapy has a limited place in management, but is an effective treatment for fungal bronchitis which complicates AFAD in about 10% of cases.

Relationship between anti-fungal effects and lung exposure of PC945, a novel inhaled antifungal agent, in Aspergillus fumigatus infected mice: Pulmonary PK-PD analysis of anti-fungal PC945

PC945 is a novel antifungal agent, optimised for inhaled treatment. In this study, the relationship between antifungal effects of PC945 and its exposure in the lungs was investigated in Aspergillus fumigatus intranasally infected, temporarily neutropenic mice. Mice were given prophylactic PC945 intranasally once daily (0.56 µg/mouse) on either Day -7 to 0 (8 doses) or Day -1 to 0 (2 doses). Lung tissue, plasma and bronchoalveolar lavage (BAL) fluid were collected 24 or 72 h post A. fumigatus inoculation for biomarker and pharmacokinetic analyses. BAL cell pellets and supernatants were prepared separately by centrifugation. 8 prophylactic doses of PC945 were found to demonstrate significantly stronger antifungal effects (lung fungal burden and galactomannan (GM) in BAL and plasma) than prophylaxis with 2 doses. PC945 concentrations were below the limit of detection in plasma but readily measured in lung extracts. The concentrations were much higher after extended prophylaxis (709 and 312 ng/g of lung) than short prophylaxis (301 and 195 ng/g of lung) at 24 and 72 h post last dose, respectively, suggesting PC945 accumulation in whole lung after repeat dosing although it was likely to be a mixture of dissolved and undissolved PC945, meaning that the data should be interpreted with caution. Interestingly, low concentrations of PC945 were detected in BAL supernatant (6.6 and 1.9 ng/ml) whereas high levels of PC945 were measured in BAL cell pellets (626 and 406 ng/ml) at 24 and 72 h post last dose, respectively, in extended prophylaxis. In addition, the PC945 concentrations in BAL cells showed a statistically significant correlation with measured anti-fungal activities. These observations will be pursued, and it is intended that BAL cell concentrations of PC945 be measured in future clinical studies rather than standard measurement in BAL itself. Thus, PC945's profile makes it an attractive potential prophylactic agent for the prevention of pulmonary fungal infections.

A high-risk airway mycobiome is associated with frequent exacerbation and mortality in COPD

INTRODUCTION

The chronic obstructive pulmonary disease (COPD) bacteriome associates with disease severity, exacerbations and mortality. While COPD patients are susceptible to fungal sensitisation, the role of the fungal mycobiome remains uncertain.

METHODS

We report the largest multicentre evaluation of the COPD airway mycobiome to date, including participants from Asia (Singapore and Malaysia) and the UK (Scotland) when stable (n=337) and during exacerbations (n=66) as well as nondiseased (healthy) controls (n=47). Longitudinal mycobiome analysis was performed during and following COPD exacerbations (n=34), and examined in terms of exacerbation frequency, 2-year mortality and occurrence of serum specific IgE (sIgE) against selected fungi.

RESULTS

A distinct mycobiome profile is observed in COPD compared with controls as evidenced by increased α-diversity (Shannon index; p<0.001). Significant airway mycobiome differences, including greater interfungal interaction (by co-occurrence), characterise very frequent COPD exacerbators (three or more exacerbations per year) (permutational multivariate ANOVA; adjusted p<0.001). Longitudinal analyses during exacerbations and following treatment with antibiotics and corticosteroids did not reveal any significant change in airway mycobiome profile. Unsupervised clustering resulted in two clinically distinct COPD groups: one with increased symptoms (COPD Assessment Test score) and Saccharomyces dominance, and another with very frequent exacerbations and higher mortality characterised by Aspergillus, Curvularia and Penicillium with a concomitant increase in serum sIgE levels against the same fungi. During acute exacerbations of COPD, lower fungal diversity associates with higher 2-year mortality.

CONCLUSION

The airway mycobiome in COPD is characterised by specific fungal genera associated with exacerbations and increased mortality.

Comparative Analysis of Clinical Parameters and Sputum Biomarkers in Establishing the Relevance of Filamentous Fungi in Cystic Fibrosis

Background

The relationship between fungal culture (FC) positivity and airway inflammation in CF is largely unknown. Identifying the clinical significance of filamentous fungi in CF using both clinical parameters and biomarkers may change our antimicrobial therapeutic strategies.

Objectives

To investigate the clinical characteristics and airway biomarker profile in relation to the detection of filamentous fungi in respiratory samples obtained from CF patients.

Methods

A prospective cohort study over 24 months, including children and adults with CF. Participants provided sputum and/or bronchoalveolar lavage samples, which underwent processing for bacterial and fungal culture, leukocyte differential cell count and biomarker analysis for neutrophil elastase (NE), interleukin-8 (IL-8), galactomannan and tumor necrosis factor receptor type 2 (TNF-R2). We performed FC using neat sputum plugs, an approach shown to be more sensitive compared to routine laboratory testing.

Results

Sixty-one patients provided 76 respiratory samples (72 sputum and 4 BAL). Median age was 17 years (range 6 months-59 years). FC positivity was noted in 49% of the cohort. FC positivity was greater during pulmonary exacerbation compared to the stable state (67 versus 50%). Participants aged 5-30 years had a lower FEV1 within the FC positive group. A significant association between FC positivity and non-tuberculosis mycobacterial (NTM) culture was observed on non-parametric testing (p = 0.022) and regression analysis (p = 0.007). Exposure to indoor mold was a predictor for FC positivity (p = 0.047). There was a trend towards increased lung clearance index (LCI), bronchiectasis and intravenous antibiotic use in the FC positive group. There was no significant difference in biomarkers between FC positive and negative patients.

Conclusion

Aspergillus. fumigatus is the commonest filamentous fungi cultured from CF airways. We found no difference in the airway biomarker profile between FC positive and negative patients. The role of galactomannan and TNFR2 as fungal specific biomarkers in CF remains uncertain. FC positivity is associated with a lower FEV₁ in younger patients, a lower LCI, NTM positivity, bronchiectasis, and intravenous antibiotic exposure. Larger trials are needed to determine the role of galactomannan and TNF-R2 as potential fungal biomarkers in CF.

Fungal sensitization and positive fungal culture from sputum in children with asthma are associated with reduced lung function and acute asthma attacks respectively

BACKGROUND

Sensitization to thermotolerant fungi, including filamentous fungi and Candida albicans, is associated with poor lung function in adults with severe asthma. Data in children are lacking. Environmental exposure to fungi is linked with acute severe asthma attacks, but there are few studies reporting the presence of fungi in the airways during asthma attacks.

METHODS

We investigated the association between fungal sensitization and/or positive fungal sputum culture and markers of asthma severity in children with chronic and acute asthma. Sensitization was determined using serum-specific IgE and skin prick testing against a panel of five fungi. Fungal culture was focused towards detection of filamentous fungi from sputum samples.

RESULTS

We obtained sensitization data and/or sputum from 175 children: 99 with chronic asthma, 39 with acute asthma and 37 controls. 34.1% of children with chronic asthma were sensitized to thermotolerant fungi compared with no children without asthma (p =< 0.001). These children had worse pre-bronchodilator lung function compared with asthmatics without sensitization including a lower FEV₁ /FVC ratio (p < .05). The isolation rate of filamentous fungi from sputum was higher in children with acute compared with chronic asthma.

CONCLUSIONS

Fungal sensitization is a feature of children with chronic asthma. Children sensitized to thermotolerant fungi have worse lung function, require more courses of systemic corticosteroids and have greater limitation of activities due to asthma. Asthma attacks in children were associated with the presence of filamentous fungi positive sputum culture. Mechanistic studies are required to establish whether fungi contribute directly to the development of acute asthma.

The role of antifungals in the management of patients with severe asthma

In patients with asthma, the inhalation of elevated amounts of fungal spores and hyphae may precipitate the onset of asthma or worsen control to the extent of being life-threatening. Sensitisation to fungi, especially Aspergillus fumigatus, is found in 15% to 48% of asthmatics in secondary care and is linked to worse asthma control, hospitalisation, bronchiectasis and fixed airflow obstruction, irrespective of whether allergic bronchopulmonary aspergillosis (ABPA) is diagnosed. ABPA represents a florid response to the presence of Aspergillus spp. but up to 70% of patients with severe asthma exhibit sensitisation to different fungi without meeting the diagnostic criteria for ABPA. The presence of persistent endobronchial colonisation with fungi, especially A. fumigatus, is linked to significantly higher rates of radiological abnormalities, lower post-bronchodilator FEV1 and significantly less reversibility to short acting bronchodilators. The therapeutic benefit for antifungal intervention in severe asthma is based on the assumption that reductions in airway fungal burden may result in improvements in asthma control, lung function and symptoms (especially cough). This contention is supported by several prospective studies which demonstrate the effectiveness of antifungals for the treatment of ABPA. Significantly, these studies confirm lower toxicity of treatment with azoles versus high dose oral corticosteroid dosing regimens for ABPA. Here we review recent evidence for the role of fungi in the progression of severe asthma and provide recommendations for the use of antifungal agents in patients with severe asthma, airways fungal infection (mycosis) and fungal colonisation. Documenting fungal airways colonisation and sensitisation in those with severe asthma opens up alternative therapy options of antifungal therapy, which may be particularly valuable in low resource settings.

Fungal and bacterial microbiome dysbiosis and imbalance of trans-kingdom network in asthma

Background

Fungal and bacterial microbiota play an important role in development of asthma. We aim to characterize airway microbiome (mycobiome, bacteriome) and functional genes in asthmatics and controls.

Methods

Sputum microbiome of controls, untreated asthma patients and inhaled corticosteroid (ICS) receiving patients was detected using high throughput sequencing. Metagenomic sequencing was used to examine the functional genes of microbiome.

Results

1. Mycobiome: α diversity was lower in untreated asthma group than that in controls. Mycobiome compositions differed among the three groups. Compared with controls, untreated asthma group has higher abundance of Wallemia, Mortierella and Fusarium. Compared with untreated asthma patients, ICS receiving patients has higher abundance of Fusarium and Mortierella, lower frequency of Wallemia, Alternaria and Aspergillus. 2. Bacteriome: α diversity was lower in untreated asthma group than that in controls. There are some overlaps of bacteriome compositions between controls and untreated asthma patients which were distinct from ICS receiving patients. Untreated asthma group has higher Streptococcus than controls. 3. Potential fungal and bacterial biomarkers of asthma: Trametes, Aspergillus, Streptococcus, Gemella, Neisseria, etc. 4. Correlation network: There are dense and homogenous correlations in controls but a dramatically unbalanced network in untreated asthma and ICS receiving patients, which suggested the existence of disease-specific inter-kingdom and intra-kingdom alterations. 5. Metagenomic analysis: functional pathways were associated with the status of asthma, microbiome and functional genes showed different correlations in different environment.

Conclusion

We showed mycobiome and bacteriome dysbiosis in asthma featured by alterations in biodiversity, community composition, inter-kingdom and intra-kingdom network. We also observed several functional genes associated with asthma.

Role of pulmonary microorganisms in the development of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic obstructive respiratory disease characterized by irreversible airway limitation and persistent respiratory symptoms. The main clinical symptoms of COPD are dyspnoea, chronic cough, and sputum. COPD is often accompanied by other respiratory diseases, which can cause worsening of the disease. COPD patients with dyspnoea and aggravation of cough and sputum symptoms represent acute exacerbations of COPD (AECOPD). There is mounting evidence suggesting that dysbiosis of pulmonary microbiota participates in the disease. However, investigations of dysbiosis of pulmonary microbiota and the disease are still in initial phases. To screen, diagnose, and treat this respiratory disease, integrating data from different studies can improve our understanding of the occurrence and development of COPD and AECOPD. In this review, COPD epidemiology and the primary triggering mechanism are explored. Emerging knowledge regarding the association of inflammation, caused by pulmonary microbiome imbalance, and changes in lung microbiome flora species involved in the development of the disease are also highlighted. These data will further our understanding of the pathogenesis of COPD and AECOPD and may yield novel strategies for the use of pulmonary microbiota as a potential therapeutic intervention.

Effectiveness of Low-Dose Itraconazole in Fungal-Associated Severe Asthma: A Retrospective Study

Background

The efficacy of antifungal therapy in fungal-associated severe asthma remains controversial.

Objective

We aimed to evaluate the differences in the clinical presentation and response to antifungal therapy between severe asthmatics with fungal sensitization and positive fungal isolates.

Methods

This retrospective study included 73 patients with severe asthma from January 2004 to December 2017. We examined the presentation, medication, exacerbations, pulmonary function, serum IgE, blood eosinophils, and sputum culture results. Follow-up care was provided to each patient for minimum 3 years.

Results

We classified the patients into four groups: group 1, neither fungal sensitization nor fungal isolates in the sputum (n=16); group 2, positive fungal sensitization (n=16); group 3, positive fungal isolates (n=31); and group 4, concomitant positive fungal sensitization and positive fungal isolates (n=10). There were four participants in group 2, 15 in group 3, and 6 in group 4 had received itraconazole therapy for 3 months. Patients in group 3 presented with lower serum IgE level than those in groups 2 and 4. Antifungal therapy significantly improved ACT score during the first year in groups 3 (from 18 [15–22] to 24 [23–24], p=0.0004) and resulted in a long-lasting ACT improvement till the third year in group 3 (from 18 [15–22] to 24 [22–24], p=0.0013).

Conclusion

Antifungal therapy could effectively control the symptoms in patients with severe asthma with positive fungal isolates, contrary to those with merely fungal sensitization; therefore, highlighting the need for a more precise treatment strategy in future for fungal-associated severe asthma.

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 sensitization and healthy controls; to compare samples representing different airway compartments; to determine whether 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 A. niger and C. humicola species complexes may play unexpected roles in the pathogenesis of asthma.

Relationship between spirometry results and colonisation of Aspergillus species in allergic asthma

INTRODUCTION AND OBJECTIVES

Exposure to fungi in patients with asthma leads to the release of various fungal antigens, which can increase the severity of asthma. Regarding this, the present study was conducted to evaluate the relationship between the colonisation of Aspergillus species and spirometry results in allergic asthma.

MATERIALS AND METHODS

Two hundred sixteen patients with mild to severe asthma and 30 healthy controls were included. All participants underwent pulmonary function tests. Furthermore, sputum samples were collected from each subject. Each sputum sample was subjected to direct microscopic examination and fungal culture. All cultured Aspergillus colonies were identified at species level by molecular methods. Finally, all available data from sputum culture and spirometry test were analysed.

RESULTS

Out of 216 sputum samples, 145 (67.1%) were positive for fungal growth. Furthermore, out of 264 grown fungal colonies, 137 (51.9%) were Aspergillus species. Among the Aspergillus isolates, A. flavus (29.2%) was the most prevalent species, followed by A. fumigatus (27.7%). The mean forced expiratory volume in one second (FEV1) in the mild, moderate and severe asthmatic patients with a positive sputum culture for fungi were obtained as 90.0 ± 11.1, 71.1 ± 15.9 and 54.9 ± 16.4, respectively. In general, Aspergillus species colonisation had no statistically significant effect on spirometry results of study patients.

CONCLUSION

Our results showed that there is no difference in the FEV1 and forced vital capacity between Aspergillus positive and negative patients in any asthma severity group.

Aspergillus fumigatus Protease Alkaline Protease 1 (Alp1): A New Therapeutic Target for Fungal Asthma

We review three recent findings that have fundamentally altered our understanding of causative mechanisms underlying fungal-related asthma. These mechanisms may be partially independent of host inflammatory processes but are strongly dependent upon the actions of Alp1 on lung structural cells. They entail (i) bronchial epithelial sensing of Alp1; (ii) Alp1-induced airway smooth muscle (ASM) contraction; (iii) Alp1-induced airflow obstruction. Collectively, these mechanisms point to Alp1 as a new target for intervention in fungal asthma.

Regional differences in the prevalence of sensitization to environmental allergens: Analysis on IgE antibody testing conducted at major clinical testing laboratories throughout Japan from 2002 to 2011

BACKGROUND

Identification of sensitized allergens for patients with respiratory allergy is an important step in disease care and environmental allergen control. The Japanese archipelago belongs to various climate categories due to its length from north to south which transverse the subarctic in the north to the subtropical in the south, suggesting substantial regional differences in dominant environmental allergens. However, few studies have assessed the regional differences in the prevalence of sensitization to environmental allergens.

METHODS

We requested three major clinical testing laboratories to provide us with summarized results of antigen-specific IgE-antibody (Ab) measurements. These measurements were collected for clinical purposes throughout Japan from 2002 through 2011. The prevalence of positivity for IgE-Ab against 19 environmental allergens was calculated for each prefecture in order to evaluate regional differences.

RESULTS

Test data on specific IgE-Ab of 19,969,753 orders were analyzed. The prevalence of positivity for house dust mites was high and the regional difference was low, whereas apparent regional differences were found for pollen, insects, and fungi. The prevalence of positivity for Japanese cedar was low in Hokkaido and Okinawa, while those to alder was highest in Hokkaido. Higher prevalence for insects was observed in southern areas (Okinawa and prefectures in Kyusyu).

CONCLUSIONS

Findings of this study clearly demonstrated regional differences in the prevalence of sensitization to environmental allergens in Japan and the study also provides useful information for the clinician when deciding which allergens should preferentially be measured for IgE-Ab after considering regional difference.

Smoking and microbiome in oral, airway, gut and some systemic diseases

The human microbiome harbors a diverse array of microbes which establishes a mutually beneficial relation with the host in healthy conditions, however, the dynamic homeostasis is influenced by both host and environmental factors. Smoking contributes to modifications of the oral, lung and gut microbiome, leading to various diseases, such as periodontitis, asthma, chronic obstructive pulmonary disease, Crohn’s disease, ulcerative colitis and cancers. However, the exact causal relationship between smoking and microbiome alteration remains to be further explored.

Airway mycosis in allergic airway disease

The allergic airway diseases, including chronic rhinosinusitis (CRS), asthma, allergic bronchopulmonary mycosis (ABPM) and many others, comprise a heterogeneous collection of inflammatory disorders affecting the upper and lower airways and lung parenchyma that represent the most common chronic diseases of humanity. In addition to their shared tissue tropism, the allergic airway diseases are characterized by a distinct pattern of inflammation involving the accumulation of eosinophils, type 2 macrophages, innate lymphoid cells type 2 (ILC2), IgE-secreting B cells, and T helper type 2 (Th2) cells in airway tissues, and the prominent production of type 2 cytokines including interleukin (IL-) 33, IL-4, IL-5, IL-13, and many others. These factors and related inflammatory molecules induce characteristic remodeling and other changes of the airways that include goblet cell metaplasia, enhanced mucus secretion, smooth muscle hypertrophy, tissue swelling and polyp formation that account for the major clinical manifestations of nasal obstruction, headache, hyposmia, cough, shortness of breath, chest pain, wheezing, and, in the most severe cases of lower airway disease, death due to respiratory failure or disseminated, systemic disease. The syndromic nature of the allergic airway diseases that now include many physiological variants or endotypes suggests that distinct endogenous or environmental factors underlie their expression. However, findings from different perspectives now collectively link these disorders to a single infectious source, the fungi, and a molecular pathogenesis that involves the local production of airway proteinases by these organisms. In this review, we discuss the evidence linking fungi and their proteinases to the surprisingly wide variety of chronic airway and systemic disorders and the immune pathogenesis of these conditions as they relate to environmental fungi. We further discuss the important implications these new findings have for the diagnosis and future therapy of these common conditions.

IFN-stimulated Gene Expression, Type 2 Inflammation, and Endoplasmic Reticulum Stress in Asthma

RATIONALE

Quantification of type 2 inflammation provided a molecular basis for heterogeneity in asthma. Non-type 2 pathways that contribute to asthma pathogenesis are not well understood.

OBJECTIVES

To identify dysregulated pathways beyond type 2 inflammation.

METHODS

We applied RNA sequencing to airway epithelial brushings obtained from subjects with stable mild asthma not on corticosteroids (n = 19) and healthy control subjects (n = 16). Sequencing reads were mapped to human and viral genomes. In the same cohort, and in a separate group with severe asthma (n = 301), we profiled blood gene expression with microarrays.

MEASUREMENTS AND MAIN RESULTS

In airway brushings from mild asthma on inhaled corticosteroids, RNA sequencing yielded 1,379 differentially expressed genes (false discovery rate < 0.01). Pathway analysis revealed increased expression of type 2 markers, IFN-stimulated genes (ISGs), and endoplasmic reticulum (ER) stress-related genes. Airway epithelial ISG expression was not associated with type 2 inflammation in asthma or with viral transcripts but was associated with reduced lung function by FEV₁ (ρ = -0.72; P = 0.0004). ER stress was confirmed by an increase in XBP1 (X-box binding protein 1) splicing in mild asthma and was associated with both type 2 inflammation and ISG expression. ISGs were also the most activated genes in blood cells in asthma and were correlated with airway ISG expression (ρ = 0.55; P = 0.030). High blood ISG expression in severe asthma was similarly unrelated to type 2 inflammation.

CONCLUSIONS

ISG activation is prominent in asthma, independent of viral transcripts, orthogonal to type 2 inflammation, and associated with distinct clinical features. ER stress is associated with both type 2 inflammation and ISG expression.

Characterizing the Human Mycobiota: A Comparison of Small Subunit rRNA, ITS1, ITS2, and Large Subunit rRNA Genomic Targets

Interest in the human microbiome has increased dramatically in the last decade. However, much of this research has focused on bacteria, while the composition and roles of their fungal counterparts remain less understood. Furthermore, a variety of methodological approaches have been applied, and the comparability between studies is unclear. This study compared four primer pairs targeting the small subunit (SSU) rRNA (18S), ITS1, ITS2, and large subunit (LSU) rRNA (26S) genomic regions for their ability to accurately characterize fungal communities typical of the human mycobiota. All four target regions of 21 individual fungal mock community taxa were capable of being amplified adequately and sequenced. Mixed mock community analyses revealed marked variability in the ability of each primer pair to accurately characterize a complex community. ITS target regions outperformed LSU and SSU. Of the ITS regions, ITS1 failed to generate sequences for Yarrowia lipolytica and all three Malassezia species when in a mixed community. These findings were further supported in studies of human sinonasal and mouse fecal samples. Based on these analyses, previous studies using ITS1, SSU, or LSU markers may omit key taxa that are identified by the ITS2 marker. Of methods commonly used in human mycobiota studies to date, we recommend selection of the ITS2 marker. Further investigation of more recently developed fungal primer options will be essential to ultimately determine the optimal methodological approach by which future human mycobiota studies ought to be standardized.

Utility of serum Aspergillus-galactomannan antigen to evaluate the risk of severe acute exacerbation in chronic obstructive pulmonary disease

Background

Recent studies have shown that the microbiome, namely Aspergillus species, play a previously unrecognized role in both stable and exacerbated chronic obstructive pulmonary disease (COPD). Galactomannan is a major component of the Aspergillus cell wall that has been widely used as a diagnostic marker.

Objectives

To explore whether serum levels of Aspergillus-galactomannan antigen could be used to evaluate the risk of severe acute exacerbation of COPD (AE-COPD).

Methods

We measured the Aspergillus-galactomannan antigen levels of 191 patients with stable COPD, and examined its clinical relevance including AE-COPD.

Results

There were 77 (40.3%) patients who were positive for serum Aspergillus-galactomannan antigen (≥0.5). High Aspergillus-galactomannan antigen level (≥0.7) was associated with older age and presence of bronchiectasis and cysts on computed tomography images. Compared to patients with low Aspergillus-galactomannan antigen level (<0.7), patients with high Aspergillus-galactomannan antigen level had significantly higher incidence of severe AE-COPD (P = 0.0039, Gray’s test) and respiratory-related mortality (P = 0.0176, log-rank test). Multivariate analysis showed that high Aspergillus-galactomannan antigen level was independently associated with severe AE-COPD (hazard ratio, 2.162; 95% confidence interval, 1.267−3.692; P = 0.005).

Conclusion

Serum Aspergillus-galactomannan antigen was detected in patients with COPD, and elevated serum Aspergillus-galactomannan antigen was associated with severe AE-COPD.

In Vitro and In Vivo Efficacy of a Novel and Long-Acting Fungicidal Azole, PC1244, on Aspergillus fumigatus Infection

The antifungal effects of the novel triazole PC1244, designed for topical or inhaled administration, against Aspergillus fumigatus were tested in a range of in vitro and in vivo studies. PC1244 demonstrated potent antifungal activities against clinical A. fumigatus isolates (n = 96) with a MIC range of 0.016 to 0.25 μg/ml, whereas the MIC range for voriconazole was 0.25 to 0.5 μg/ml. PC1244 was a strong tight-binding inhibitor of recombinant A. fumigatus CYP51A and CYP51B (sterol 14α-demethylase) enzymes and strongly inhibited ergosterol synthesis in A. fumigatus with a 50% inhibitory concentration of 8 nM. PC1244 was effective against a broad spectrum of pathogenic fungi (MIC range, <0.0078 to 2 μg/ml), especially Aspergillus terreus, Trichophyton rubrum, Candida albicans, Candida glabrata, Candida krusei, Cryptococcus gattii, Cryptococcus neoformans, and Rhizopus oryzae. PC1244 also proved to be quickly absorbed into both A. fumigatus hyphae and bronchial epithelial cells, producing persistent antifungal effects. In addition, PC1244 showed fungicidal activity (minimum fungicidal concentration, 2 μg/ml) which indicated that it was 8-fold more potent than voriconazole. In vivo, once-daily intranasal administration of PC1244 (3.2 to 80 μg/ml) to temporarily neutropenic, immunocompromised mice 24 h after inoculation with itraconazole-susceptible A. fumigatus substantially reduced the fungal load in the lung, the galactomannan concentration in serum, and circulating inflammatory cytokine levels. Furthermore, 7 days of extended prophylaxis with PC1244 showed in vivo effects superior to those of 1 day of prophylactic treatment, suggesting accumulation of the effects of PC1244. Thus, PC1244 has the potential to be a novel therapy for the treatment of A. fumigatus infection in the lungs of humans.

High burden of Aspergillus fumigatus infection among chronic respiratory diseases

Aspergillus fumigatus (AF) is a ubiquitous fungus in our environment and causes severe airway disorders. Chronic respiratory diseases (CRDs) are a series of chronic airway and lung diseases. Although both are chronic disorders, however, the relationships between AF and CRDs are still unclear. Therefore, we examined 104 Aspergillus species (spp.) isolated samples in our hospital during three consecutive years to further elucidate the relationships between Aspergillus spp. and CRDs. Based on sample isolates, we then grouped these into two groups, AF and non-AF, to retrospectively analyse the clinical features and to clarify the relationships between AF and CRDs. Importantly, the manifestation of CRD was more frequent in the AF group than in the non-AF group (p = 0.035). Among CRDs, lung fibrosis was more evident in the AF group (p = 0.025). Moreover, diabetes mellitus was tended to be evident in AF group than non-AF group (p = 0.035). In conclusion, CRDs, especially lung fibrosis, were highly prevalent in AF group than non-AF group.

Aspergillus fumigatus Detection and Risk Factors in Patients with COPD-Bronchiectasis Overlap

The role of Aspergillus fumigatus in the airways of chronic obstructive pulmonary disease (COPD) patients with bronchiectasis is currently unclear. We searched for a sensitive and noninvasive method for A. fumigatus detection in the sputum of COPD patients and addressed potential risk factors for its presence. Induced sputum samples of 18 COPD patients and 17 COPD patients with bronchiectasis were analyzed for the presence of A. fumigatus by culture, galactomannan detection, and PCR. Of the patients with COPD–bronchiectasis overlap, 23.5% had a positive culture for A. fumigatus versus 10.5% of COPD patients without bronchiectasis (p = 0.39). The median sputum galactomannan optical density index was significantly higher in patients with COPD and bronchiectasis compared with patients with COPD alone (p = 0.026) and ranged between the levels of healthy controls and A. fumigatus-colonized cystic fibrosis patients. Both the presence of bronchiectasis and the administration of systemic corticosteroids were associated with sputum galactomannan (p = 0.0028 and p = 0.0044, respectively) and showed significant interaction (p interaction = 0.022). PCR for Aspergillus was found to be a less sensitive method, but was critically dependent on the extraction technique. The higher sputum galactomannan levels suggest a more abundant presence of A. fumigatus in the airways of patients with COPD–bronchiectasis overlap compared with patients with COPD without bronchiectasis, particularly when systemic corticosteroids are administered.

Aspergillus fumigatus-sensitive IgE is associated with bronchial hypersensitivity in a murine model of neutrophilic airway inflammation

Neutrophils are the predominant inflammatory cells that infiltrate airways during acute exacerbation of asthma. The importance of A. fumigatus sensitization, and IgE response in the airways in patients with acute asthma is unclear. Rockefeller (RK) mice were sensitized with A. fumigatus extract protein. The animals were subsequently challenged with different degrees of A. fumigatus contamination in the cage bedding. All groups of mice were euthanized to obtain bronchoalveolar lavage fluid (BALF) for cytological and Elisa assays, and lung tissue for histological analysis. Moreover, several bioassays were conducted to determine whether BALF IgE antibodies can activate mast cells. In this study, we demonstrated that exposure of sensitized mice to a known concentration of A. fumigatus conidia produces bronchial hyperreactivity with marked neutrophilic bronchial infiltration and increased BALF IgE, capable of triggering mast cell degranulation. This study suggests that IgE may play a role in bronchial hyperreactivity associated to A. fumigatus exposure in mice. Mice sensitized and challenged with this fungus showed characteristics of severe asthma, with an increase of BALF neutrophils, histological changes consistent with severe asthma and an increase of IgE capable of triggering type I hypersensitivity.

Interplay between the lung microbiome and lung cancer

The human microbiome confers benefits or disease susceptibility to the human body through multiple pathways. Disruption of the symbiotic balance of the human microbiome is commonly found in systematic diseases such as diabetes, obesity, and chronic gastric diseases. Emerging evidence has suggested that dysbiosis of the microbiota may also play vital roles in carcinogenesis at multiple levels, e.g., by affecting metabolic, inflammatory, or immune pathways. Although the impact of the gut microbiome on the digestive cancer has been widely explored, few studies have investigated the interplay between the microbiome and lung cancer. Some recent studies have shown that certain microbes and microbiota dysbiosis are correlated with development of lung cancer. In this mini-review, we briefly summarize current research findings describing the relationship between the lung microbiome and lung cancer. We further discuss the potential mechanisms through which the lung microbiome may play a role in lung carcinogenesis and impact lung cancer treatment. A better knowledge of the interplay between the lung microbiome and lung cancer may promote the development of innovative strategies for early prevention and personalized treatment in lung cancer.

Environmental and molecular study of fungal flora in asthmatic patients

The aim of the present study was to investigate the epidemiological and fungal environmental profile in asthmatic patients. We conducted a prospective study involving 49 patients with allergic asthma. One hundred and forty-five clinical samples and 289 environmental samples were performed. Only 30 patients accepted to participate to the environmental study at their home. For specific IgE antibodies, ELISA assay was conducted for 21 patients. Molecular ITS sequencing was performed for 37 isolates. The frequency of attacks was significantly associated with the seasonality, which was closely related to climate (P=0.024), exposure to animals (cats, P=0.025), plants (olive, P=0.018), physical effort (P=0.04) and the number of permanent occupants in house (>6) (P=0.026). Fungal contaminants were detected from 78.6% of biological samples and 97.8% of environmental samples. Antibodies corresponding to the studied allergens were detected in 10 patients (10/21). PCR sequencing allowed as rectified morphological identification for 27.02% (10/37) strains of Aspergillus. The allergy in molds is an indisputable reality that is necessary to look for in front of any severe asthma. So, it is important to establish clearly a relationship between exposure to fungi and health disorders in order to set up specific and effective preventive measures.

In Vivo Biomarker Analysis of the Effects of Intranasally Dosed PC945, a Novel Antifungal Triazole, on Aspergillus fumigatus Infection in Immunocompromised Mice

PC945 is a novel triazole optimized for lung delivery, and the objective of this study is to determine the effects of intranasally dosed PC945 on Aspergillus fumigatus infection and associated biomarkers in immunocompromised mice. PC945, posaconazole, or voriconazole was administered intranasally once daily on days 0 to 3 (early intervention) or days 1 to 3 (late intervention) postinfection in temporarily neutropenic A/J mice infected intranasally with A. fumigatus, and bronchoalveolar lavage fluid (BALF) and serum were collected on day 3. The effects of extended prophylaxis treatment (daily from days −7 to +3 or days −7 to 0) were also compared with those of the shorter treatment regimens (days −1 to +3 or days −1 and 0). Early and late interventions with PC945 (2.8 to 350 μg/mouse; approximately 0.11 to ∼14 mg/kg of body weight) were found to inhibit lung fungal loads and to decrease the concentrations of galactomannan (GM) in both BALF and serum as well as several biomarkers in BALF (interferon gamma [IFN-γ], interleukin-17 [IL-17], and malondialdehyde) and serum (tumor necrosis factor alpha [TNF-α] and IL-6) in a dose-dependent manner and were >3- and >47-fold more potent than intranasally dosed posaconazole and voriconazole, respectively. Furthermore, extended prophylaxis with low-dose PC945 (0.56 μg/mouse; 0.022 mg/kg) was found to inhibit fungal loads and to decrease the concentrations biomarkers more potently than did the shorter treatment regimens. Thus, PC945 dosed intranasally once daily showed potent antifungal effects, and the effects of PC945 accumulated upon repeat dosing and were persistent. Therefore, PC945 has the potential to be a novel inhaled therapy for the treatment of A. fumigatus infection in humans.

Allergic and Noninvasive Infectious Pulmonary Aspergillosis Syndromes

Aspergillus spp are ubiquitous in the environment, and inhalation of Aspergillus spores is unavoidable. An intact immune system, with normal airway function, protects most people from disease. Globally, however, the toll from aspergillosis is high. The literature has largely focused on invasive aspergillosis, yet the burden in terms of chronicity and prevalence is higher for noninvasive Aspergillus conditions. This article discusses allergic aspergilloses and provides an update on the diagnosis and management of allergic bronchopulmonary aspergillosis, including in patients with cystic fibrosis, and an update on severe asthma with fungal sensitization. In addition, the presentation, investigation, and management of noninvasive infectious aspergilloses are reviewed.

Successful long-term terbinafine therapy in an asthmatic patient with Aspergillus sensitization and bronchiectasis

Severe asthma with fungal sensitization (SAFS) is estimated to affect ~25% of patients with poorly controlled asthma. Tri-azole therapy is effective in only 60-80% and side effects are common. We report a 25 years-old woman with severe asthma, Aspergillus sensitization and marked bronchiectasis that developed a rare Achilles-tendinopathy with both itraconazole and voriconazole. She started a trial with terbinafine as salvage therapy that led to a striking improvement and long-term control of her respiratory disease.

Microbiome effects on immunity, health and disease in the lung

Chronic respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF), are among the leading causes of mortality and morbidity worldwide. In the past decade, the interest in the role of microbiome in maintaining lung health and in respiratory diseases has grown exponentially. The advent of sophisticated multiomics techniques has enabled the identification and characterisation of microbiota and their roles in respiratory health and disease. Furthermore, associations between the microbiome of the lung and gut, as well as the immune cells and mediators that may link these two mucosal sites, appear to be important in the pathogenesis of lung conditions. Here we review the recent evidence of the role of normal gastrointestinal and respiratory microbiome in health and how dysbiosis affects chronic pulmonary diseases. The potential implications of host and environmental factors such as age, gender, diet and use of antibiotics on the composition and overall functionality of microbiome are also discussed. We summarise how microbiota may mediate the dynamic process of immune development and/or regulation focusing on recent data from both clinical human studies and translational animal studies. This furthers the understanding of the pathogenesis of chronic pulmonary diseases and may yield novel avenues for the utilisation of microbiota as potential therapeutic interventions.

Sputum Inflammatory Mediators Are Increased in Aspergillus fumigatus Culture-Positive Asthmatics

Aspergillus fumigatus sensitization and culture in asthma are associated with disease severity and lung function impairment, but their relationship with airway inflammation is poorly understood. We investigated the profile of 24 sputum inflammatory mediators in A. fumigatus culture-positive or-negative moderate-to-severe asthmatics. Fifty-two subjects were recruited from a single center. A. fumigatus was cultured from 19 asthmatics. Asthma control, symptom score, lung function, and sputum cell count were not significantly different between the asthmatics with and without a positive A. fumigatus culture. All of the sputum mediators were numerically increased in subjects with a positive versus negative sputum A. fumigatus culture. Sputum TNF-R2 was significantly elevated (P=0.03) and the mediator that best distinguished A. fumigatus culture-positive from culture-negative subjects (receiver-operator characteristic area under the curve 0.66 [95% CI: 0.51 to 0.82, P=0.045]). A. fumigates-positive culture in moderate-to-severe asthma is associated with increased inflammatory sputum mediators.

Mast cells in asthma--state of the art

Mast cells (MCs) play a central role in tissue homoeostasis, sensing the local environment through numerous innate cell surface receptors. This enables them to respond rapidly to perceived tissue insults with a view to initiating a co-ordinated programme of inflammation and repair. However, when the tissue insult is chronic, the ongoing release of multiple pro-inflammatory mediators, proteases, cytokines and chemokines leads to tissue damage and remodelling. In asthma, there is strong evidence of ongoing MC activation, and their mediators and cell-cell signals are capable of regulating many facets of asthma pathophysiology. This article reviews the evidence behind this.

Subchronic exposures to fungal bioaerosols promotes allergic pulmonary inflammation in naïve mice

BACKGROUND

Epidemiological surveys indicate that occupants of mold contaminated environments are at increased risk of respiratory symptoms. The immunological mechanisms associated with these responses require further characterization.

OBJECTIVE

The aim of this study was to characterize the immunotoxicological outcomes following repeated inhalation of dry Aspergillus fumigatus spores aerosolized at concentrations potentially encountered in contaminated indoor environments.

METHODS

Aspergillus fumigatus spores were delivered to the lungs of naïve BALB/cJ mice housed in a multi-animal nose-only chamber twice a week for a period of 13 weeks. Mice were evaluated at 24 and 48 h post-exposure for histopathological changes in lung architecture, recruitment of specific immune cells to the airways, and serum antibody responses.

RESULT

Germinating A. fumigatus spores were observed in lungs along with persistent fungal debris in the perivascular regions of the lungs. Repeated exposures promoted pleocellular infiltration with concomitant epithelial mucus hypersecretion, goblet cell metaplasia, subepithelial fibrosis and enhanced airway hyperreactivity. Cellular infiltration in airways was predominated by CD4(+) T cells expressing the pro-allergic cytokine IL-13. Furthermore, our studies show that antifungal T cell responses (IFN-γ(+) or IL-17A(+) ) co-expressed IL-13, revealing a novel mechanism for the dysregulated immune response to inhaled fungi. Total IgE production was augmented in animals repeatedly exposed to A. fumigatus.

CONCLUSIONS & CLINICAL RELEVANCE

Repeated inhalation of fungal aerosols resulted in significant pulmonary pathology mediated by dynamic shifts in specific immune populations and their cytokines. These studies provide novel insights into the immunological mechanisms and targets that govern the health outcomes that result from repeated inhalation of fungal bioaerosols in contaminated environments.

The spectrum of allergic fungal diseases of the upper and lower airways

Fungi cause a wide spectrum of fungal diseases of the upper and lower airways. There are three main phyla involved in allergic fungal disease: (1) Ascomycota (2) Basidiomycota (3) Zygomycota. Allergic fungal rhinosinusitis (AFRS) causes chronic rhinosinusitis symptoms and is caused predominantly by Aspergillus fumigatus in India and Bipolaris in the United States. The recommended treatment approach for AFRS is surgical intervention and systemic steroids. Allergic bronchopulmonary aspergillosis (APBA) is most commonly diagnosed in patients with asthma or cystic fibrosis. Long term systemic steroids are the mainstay treatment option for ABPA with the addition of an antifungal medication. Fungal sensitization or exposure increases a patient's risk of developing severe asthma and has been termed severe asthma associated with fungal sensitivity (SAFS). Investigating for triggers and causes of a patient's asthma should be sought to decrease worsening progression of the disease.

Identifying risk factors for exposure to culturable allergenic moulds in energy efficient homes by using highly specific monoclonal antibodies

The aim of this study was to determine the accuracy of monoclonal antibodies (mAbs) in identifying culturable allergenic fungi present in visible mould growth in energy efficient homes, and to identify risk factors for exposure to these known allergenic fungi. Swabs were taken from fungal contaminated surfaces and culturable yeasts and moulds isolated by using mycological culture. Soluble antigens from cultures were tested by ELISA using mAbs specific to the culturable allergenic fungi Aspergillus and Penicillium spp., Ulocladium, Alternaria, and Epicoccum spp., Cladosporium spp., Fusarium spp., and Trichoderma spp. Diagnostic accuracies of the ELISA tests were determined by sequencing of the internally transcribed spacer 1 (ITS1)-5.8S-ITS2-encoding regions of recovered fungi following ELISA. There was 100% concordance between the two methods, with ELISAs providing genus-level identity and ITS sequencing providing species-level identities (210 out of 210 tested). Species of Aspergillus/Penicillium, Cladosporium, Ulocladium/Alternaria/Epicoccum, Fusarium and Trichoderma were detected in 82% of the samples. The presence of condensation was associated with an increased risk of surfaces being contaminated by Aspergillus/Penicillium spp. and Cladosporium spp., whereas moisture within the building fabric (water ingress/rising damp) was only associated with increased risk of Aspergillus/Penicillium spp. Property type and energy efficiency levels were found to moderate the risk of indoor surfaces becoming contaminated with Aspergillus/Penicillium and Cladosporium which in turn was modified by the presence of condensation, water ingress and rising damp, consistent with previous literature.

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.

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.

Antifungals in severe asthma

PURPOSE OF REVIEW

Despite guideline-based treatment, many patients with severe asthma continue to have uncontrolled disease. Fungal allergy is being increasingly recognized in the pathogenesis of severe asthma. Limited data exist on the approach to treatment of fungal asthma. This review summarizes existing evidence on the use of antifungal agents in allergic bronchopulmonary aspergillosis (ABPA) and severe asthma with fungal sensitization (SAFS), and highlights needed areas of future investigation.

RECENT FINDINGS

Recent studies evaluating oral triazole therapy in ABPA appear to support triazole use in a carefully considered clinical setting, whereas studies assessing triazole use in SAFS have yielded mixed results. Despite early encouraging findings that oral triazole use may improve asthma symptoms, stabilize lung function, decrease inhaled and systemic corticosteroid requirements, and alter serum biomarkers, overall data are limited. Appropriate patient selection, as well as choice of the optimal drug, dose, frequency, and duration of therapy, remains poorly defined.

SUMMARY

The role of antifungal therapy in severe asthma remains unclear. Early studies have suggested a possible benefit of some antifungal agents, such as oral triazoles in ABPA and SAFS; however, routine clinical use of these agents in severe asthma without ABPA is not currently recommended. Further research is needed to better delineate the potential utility of antifungal medications in severe asthma and identify the asthma populations who benefit from such treatment.

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.

Developments in the field of allergy in 2013 through the eyes of Clinical and Experimental Allergy

2013 was another exciting year for allergy in general and Clinical and Experimental Allergy in particular. In the field of asthma and rhinitis, there continued to be a focus on heterogeneity and phenotypes with increasing use of biostatistical techniques to determine clusters of similar populations. Obesity- and aspirin-associated disease are intriguing associations with asthma which were explored in a number of papers. We published a number of excellent papers on mechanisms of airway inflammation and how this relates to physiology, pathology, genetics and biomarkers in both human and experimental model systems. In terms of mechanisms, there is less on individual cell types in allergic disease at the moment, but the immunology of allergic disease continued to fascinate our authors. Another area that was popular both in the mechanisms and in the epidemiology sections was early life events and how these lead to allergic disease, with an increasing focus on the role of the microbiome and how this influences immune tolerance. In the clinical allergy section, oral immunotherapy for food allergy is clearly a major topic of interest at the moment as was in vitro testing to distinguish between sensitization and allergic disease. There was less on inhalant allergy this year, but a good representation from the drug allergy community including some interesting work on non-IgE-mediated mechanisms. In the allergen section, important new allergens continue to be discovered, but the major focus as in the last couple of years was on working out how component-resolved approaches can improve diagnosis and management of food and venom allergy.