Sensitization to Aspergillus fumigatus as a risk factor for bronchiectasis in COPD

[Take-home messages from the 2nd COPD 2023 Biennial of the French Society of Respiratory Diseases. Placing the patient at the center of the care pathway]

INTRODUCTION

The second COPD Biennial organized by the COPD working group of the French Society of Respiratory Diseases took place in Paris (Cochin) on 13th December 2023.

STATE OF THE ART

Major trends in 2023 were discussed; they encompassed concepts, definitions, biologics, care pathways, pulmonary rehabilitation and complex situations entailed by respiratory infections, cardiovascular comorbidities and pulmonary hypertension, and modalities of oxygen therapy and ventilation.

PERSPECTIVES

The different talks underlined major changes in COPD including the concepts of pre-COPD, etiotypes, health trajectories and new definitions of exacerbation. Recent results in biologics for COPD open the door to new pharmacological options. Assessment of current care pathways in France highlighted some causes for concern. For example, pulmonary rehabilitation is a key but insufficiently practiced element. Respiratory infections require careful assessment and treatments. Diagnosis and treatment of cardiovascular comorbidities and pulmonary hypertension are of paramount importance. As of late, oxygen therapy and ventilation modalities have evolved, and are beginning to afford more personalized options.

CONCLUSIONS

As regards COPD, a personalized approach is crucial, placing the patient at the center of the care pathway and facilitating coordination between healthcare providers.

Lung microbiome: new insights into the pathogenesis of respiratory diseases

The lungs were long thought to be sterile until technical advances uncovered the presence of the lung microbial community. The microbiome of healthy lungs is mainly derived from the upper respiratory tract (URT) microbiome but also has its own characteristic flora. The selection mechanisms in the lung, including clearance by coughing, pulmonary macrophages, the oscillation of respiratory cilia, and bacterial inhibition by alveolar surfactant, keep the microbiome transient and mobile, which is different from the microbiome in other organs. The pulmonary bacteriome has been intensively studied recently, but relatively little research has focused on the mycobiome and virome. This up-to-date review retrospectively summarizes the lung microbiome's history, composition, and function. We focus on the interaction of the lung microbiome with the oropharynx and gut microbiome and emphasize the role it plays in the innate and adaptive immune responses. More importantly, we focus on multiple respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD), fibrosis, bronchiectasis, and pneumonia. The impact of the lung microbiome on coronavirus disease 2019 (COVID-19) and lung cancer has also been comprehensively studied. Furthermore, by summarizing the therapeutic potential of the lung microbiome in lung diseases and examining the shortcomings of the field, we propose an outlook of the direction of lung microbiome research.

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.

The clinical spectrum of aspergillosis in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. In this review, we present the clinical spectrum and pathogenesis of syndromes caused by Aspergillus in COPD namely invasive aspergillosis (IA), community-acquired Aspergillus pneumonia, chronic pulmonary Aspergillosis and Aspergillus sensitisation. Some of these entities are clearly linked to COPD, while others may coexist, but are less clearly liked directly to COPD. We discuss current uncertainties as these pertain to IA in COPD cohorts and explore areas for future research in this field.

Sensitisation to recombinant Aspergillus fumigatus allergens and clinical outcomes in COPD

BACKGROUND

Variable clinical outcomes are reported with fungal sensitisation in chronic obstructive pulmonary disease (COPD), and it remains unclear which fungi and what allergens associate with the poorest outcomes. The use of recombinant as opposed to crude allergens for such assessment is unknown.

METHODS

A prospective multicentre assessment of stable COPD (n=614) was undertaken in five hospitals across three countries: Singapore, Malaysia and Hong Kong. Clinical and serological assessment was performed against a panel of 35 fungal allergens including crude and recombinant Aspergillus and non-Aspergillus allergens. Unsupervised clustering and topological data analysis (TDA) approaches were employed using the measured sensitisation responses to elucidate if sensitisation subgroups exist and their related clinical outcomes.

RESULTS

Aspergillus fumigatus sensitisation was associated with increased exacerbations in COPD. Unsupervised cluster analyses revealed two "fungal sensitisation" groups. The first was characterised by Aspergillus sensitisation and increased exacerbations, poorer lung function and worse prognosis. Polysensitisation in this group conferred even poorer outcome. The second group, characterised by Cladosporium sensitisation, was more symptomatic. Significant numbers of individuals demonstrated sensitisation responses to only recombinant (as opposed to crude) A. fumigatus allergens f 1, 3, 5 and 6, and exhibited increased exacerbations, poorer lung function and an overall worse prognosis. TDA validated these findings and additionally identified a subgroup within Aspergillus-sensitised COPD of patients with frequent exacerbations.

CONCLUSION

Aspergillus sensitisation is a treatable trait in COPD. Measuring sensitisation responses to recombinant Aspergillus allergens identifies an important patient subgroup with poor COPD outcomes that remains overlooked by assessment of only crude Aspergillus allergens.

Aspergillus-Specific IgG Antibodies are Associated With Fungal-Related Complications and Chronic Lung Allograft Dysfunction After Lung Transplantation

Fungal exposure and sensitization negatively affect outcomes in various respiratory diseases, however, the effect of fungal sensitization in lung transplant (LTx) recipients is still unknown. We performed a retrospective cohort study of prospectively collected data on circulating fungal specific IgG/IgE antibodies, and their correlation with fungal isolation, chronic lung allograft dysfunction (CLAD) and overall survival after LTx. 311 patients transplanted between 2014 and 2019 were included. Patients with elevated Aspergillus fumigatus or Aspergillus flavus IgG (10%) had more mold and Aspergillus species isolation (p = 0.0068 and p = 0.0047). Aspergillus fumigatus IgG was specifically associated with Aspergillus fumigatus isolation in the previous or consecutive year (AUC 0.60, p = 0.004 and AUC 0.63, p = 0.022, respectively). Elevated Aspergillus fumigatus or Aspergillus flavus IgG was associated with CLAD (p = 0.0355), but not with death. Aspergillus fumigatus, Aspergillus flavus or Aspergillus niger IgE was elevated in 19.3% of patients, but not associated with fungal isolation, CLAD or death. Mold isolation and Aspergillus species isolation from respiratory cultures were associated with CLAD occurrence (p = 0.0011 and p = 0.0005, respectively), and Aspergillus species isolation was also associated with impaired survival (p = 0.0424). Fungus-specific IgG could be useful in long-term follow-up post-LTx, as a non-invasive marker for fungal exposure, and thus a diagnostic tool for identifying patients at risk for fungal-related complications and CLAD.

Specific Focus on Antifungal Peptides against Azole Resistant Aspergillus fumigatus: Current Status, Challenges, and Future Perspectives

The prevalence of fungal infections is increasing worldwide, especially that of aspergillosis, which previously only affected people with immunosuppression. Aspergillus fumigatus can cause allergic bronchopulmonary aspergillosis and endangers public health due to resistance to azole-type antimycotics such as fluconazole. Antifungal peptides are viable alternatives that combat infection by forming pores in membranes through electrostatic interactions with the phospholipids as well as cell death to peptides that inhibit protein synthesis and inhibit cell replication. Engineering antifungal peptides with nanotechnology can enhance the efficacy of these therapeutics at lower doses and reduce immune responses. This manuscript explains how antifungal peptides combat antifungal-resistant aspergillosis and also how rational peptide design with nanotechnology and artificial intelligence can engineer peptides to be a feasible antifungal alternative.

Emerging cellular and molecular interactions between the lung microbiota and lung diseases

With the discovery of the lung microbiota, its study in both pulmonary health and disease has become a vibrant area of emerging research interest. Thus far, most studies have described the lung microbiota composition in lung disease quite well, and some of these studies indicated alterations in lung microbial communities related to the onset and development of lung disease and vice versa. However, the underlying mechanisms, particularly the cellular and molecular links, are still largely unknown. In this review, we highlight the current progress in the complex cellular and molecular mechanisms by which the lung microbiome interacts with immune homeostasis and pulmonary disease pathogenesis to advance our understanding of the elaborate function of the lung microbiota in lung disease. We hope that this work can attract more attention to this still-young yet very promising field to facilitate the identification of new therapeutic targets and provide more innovative therapies. Additional accurate standard-based methodologies and technological breakthroughs are critical to propel the field forward to ultimately achieve the goal of maintaining respiratory health.

HIGH FREQUENCY OF ALLERGIC BRONCHOPULMONARY ASPERGILLOSIS IN BRONCHIECTASIS-COPD OVERLAP

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) is associated with frequent exacerbations and poor outcomes in chronic respiratory disease but remains underdiagnosed. The role of fungal sensitization in bronchiectasis-COPD overlap (BCO) is unknown.

RESEARCH QUESTION

What is the occurrence and clinical relevance of Aspergillus sensitization and ABPA in BCO when compared to individuals with COPD or bronchiectasis without overlap?

STUDY DESIGN

Prospective, observational and cross-sectional.

METHODS

We prospectively recruited n=280 patients during periods of clinical stability with bronchiectasis (n=183), COPD (n=50) and BCO (n=47) from six hospitals across three countries (Singapore, Malaysia, and Scotland). We assessed sensitization responses (as specific IgE) to a panel of recombinant Aspergillus fumigatus (rAsp f) allergens and the occurrence of ABPA (ABPA) in relation to clinical outcomes.

RESULTS

Individuals with BCO illustrate an increased frequency and clinical severity of ABPA compared to COPD and bronchiectasis without overlap. BCO-associated ABPA demonstrates more severe disease, higher exacerbation rates and lower lung function when compared to ABPA occurring in the absence of overlap. BCO with a severe bronchiectasis severity index (BSI) (>9) significantly associates with the occurrence of ABPA that is unrelated to underlying COPD severity.

CONCLUSIONS

BCO demonstrates a high frequency of ABPA that associates with a severe BSI (>9) and poor clinical outcomes. Clinicians should maintain a high index of suspicion for the potential development of ABPA in BCO patients with high BSI.

Aspergillus-Associated Endophenotypes in Bronchiectasis

Bronchiectasis is a chronic condition of global relevance resulting in permanent and irreversible structural airway damage. Bacterial infection in bronchiectasis is well studied; however, recent molecular studies identify fungi as important pathogens, either independently or in association with bacteria. Aspergillus species are established fungal pathogens in cystic fibrosis and their role is now increasingly being recognized in noncystic fibrosis bronchiectasis. While the healthy airway is constantly exposed to ubiquitously present Aspergillus conidia in the environment, anatomically damaged airways appear more prone to colonization and subsequent infection by this fungal group. Aspergilli possess diverse immunopathological mechanistic capabilities and when coupled with innate immune defects in a susceptible host, such as that observed in bronchiectasis, it may promote a range of clinical manifestations including sensitization, allergic bronchopulmonary aspergillosis, Aspergillus bronchitis, and/or invasive aspergillosis. How such clinical states influence "endophenotypes" in bronchiectasis is therefore of importance, as each Aspergillus-associated disease state has overlapping features with bronchiectasis itself, and can evolve, depending on underlying host immunity from one type into another. Concurrent Aspergillus infection complicates the clinical course and exacerbations in bronchiectasis and therefore dedicated research to better understand the Aspergillus-host interaction in the bronchiectasis airway is now warranted.

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.

Respiratory Aspergillus Colonization Was Associated With Relapse of Acute Exacerbation in Patients With Chronic Obstructive Pulmonary Disease: Analysis of Data From A Retrospective Cohort Study

Background: Patients with chronic obstructive pulmonary disease (COPD) are more susceptible to Aspergillus colonization or infection. Several studies have demonstrated that invasive pulmonary Aspergillosis (IPA) and Aspergillus hypersensitivity (AH) have a detrimental effect on COPD. However, it remains to be clarified whether Aspergillus colonization is associated with acute exacerbation of COPD (AECOPD). This study aimed to explore the impact of Aspergillus colonization in the lower respiratory tract on AECOPD.

Method: Patients with Aspergillus colonization were identified from a retrospective cohort of hospitalized AECOPD from 2011 to 2016 in eight centers in Shanghai, China. The demographic information, conditions of the stable stage, clinical characteristics during hospitalization, and 1-year follow-up information after discharge were collected and compared to participants without fungi colonization.

Result: Twenty-six hospitalized AECOPD patients with Aspergillus colonization and 72 controls were included in the final analysis after excluding patients with other fungi isolation and matching. The rates of recurrence of acute exacerbation within 90 days and 180 days after discharge in the patients with Aspergillus colonization were both significantly higher than that in the fungi negative patients (90 days: 19.2 vs. 4.2%, p = 0.029; 180 days: 23.1 vs. 4.2%, p = 0.010), and the all-cause mortality within 1 year was also higher (11.5 vs. 0.0%, p = 0.017). Multivariate logistic regression analysis showed that Aspergillus colonization was an independent risk factor for the recurrence of acute exacerbation within 90 days and 180 days (90 days: OR = 8.661, 95% CI: 1.496-50.159, p = 0.016; 180 days: OR =10.723, 95% CI: 1.936-59.394, p = 0.007).

Conclusion:Aspergillus colonization may predict poor prognosis of AECOPD while leading to an increased risk of recurrent AECOPD in a short period.

Impact of domestic mould exposure on Aspergillus biomarkers and lung function in patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) are frequently colonised or sensitised by Aspergillus, but clinical significance remains unclear. Furthermore, little is known on the impact of indoor mould exposure during COPD. In this study, we assessed the relationship between domestic mould exposure, Aspergillus biomarkers and COPD severity during acute exacerbation and at stable state. Aspergillus section Fumigati culture in sputum and anti-Aspergillus antibodies detection (IgG and precipitins) were followed up in COPD patients that were prospectively recruited during exacerbation (n = 62), and underwent a visit at stable state after 18 months (n = 33). Clinical characteristics were collected at inclusion. Electrostatic dust collectors (EDCs) were used to measure domestic mould contamination. Aspergillus section Fumigati was more frequently detected during exacerbation (16.9%) than at stable state (4.0%), but the frequency of patients presenting with anti-Aspergillus antibodies was similar (32.2% and 33.3%, respectively). Aspergillus section Fumigati detection was associated with a higher body-mass index (BMI) during exacerbation, whereas patients with anti-Aspergillus antibodies presented a lower BMI and forced expiratory volume in 1 s, as well as a higher frequency of inhaled corticoids and higher total mould and Penicillium exposure at final visit (P < 0.05). The frequency of patients with anti-Aspergillus antibodies was higher for total mould counts >30 CFU/cm² (P = 0.03). Aspergillosis was diagnosed in 2 patients (6.1%) who presented increased levels of antibodies. Our data suggest that anti-Aspergillus antibodies are associated with chronic lung function alteration and/or domestic mould exposure, thereby supporting the consideration of indoor mould contamination and anti-Aspergillus antibodies kinetics in COPD management.

Respiratory Mycoses in COPD and Bronchiectasis

Chronic obstructive pulmonary disease (COPD) and bronchiectasis represent chronic airway diseases associated with significant morbidity and mortality. Bacteria and viruses are commonly implicated in acute exacerbations; however the significance of fungi in these airways remains poorly defined. While COPD and bronchiectasis remain recognized risk factors for the occurrence of Aspergillus-associated disease including chronic and invasive aspergillosis, underlying mechanisms that lead to the progression from colonization to invasive disease remain uncertain. Nonetheless, advances in molecular technologies have improved our detection, identification and understanding of resident fungi characterizing these airways. Mycobiome sequencing has revealed the complex varied and myriad profile of airway fungi in COPD and bronchiectasis, including their association with disease presentation, progression, and mortality. In this review, we outline the emerging evidence for the clinical importance of fungi in COPD and bronchiectasis, available diagnostic modalities, mycobiome sequencing approaches and association with clinical outcomes.

Manifesto on united airways diseases (UAD): an Interasma (global asthma association - GAA) document

OBJECTIVE

The large amount of evidence and the renewed interest in upper and lower airways involvement in infectious and inflammatory diseases has led Interasma (Global Asthma Association) to take a position on United Airways Diseases (UAD).

METHODS

Starting from an extensive literature review, Interasma executive committee discussed and approved this Manifesto developed by Interasma scientific network (INES) members.

RESULTS

The manifesto describes the evidence gathered to date and defines, states, advocates, and proposes issues on UAD (rhinitis, rhinosinusitis and nasal polyposis), and concomitant/comorbid lower airways disorders (asthma, chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis, obstructive sleep apnoea) with the aim of challenging assumptions, fostering commitment, and bringing about change. UAD refers to clinical pictures characterized by the coexistence of upper and lower airways involvement, driven by a common pathophysiological mechanism, leading to a greater burden on patient's health status and requiring an integrated diagnostic and therapeutic plan. The high prevalence of UAD must be taken into account. Upper and lower airways diseases influence disease control and patient's quality of life.

CONCLUSIONS

Patients with UAD need to have a timely and adequate diagnosis, treatment, and, when recommended, referral for management in a specialized center. Diagnostic testing including skin prick or serum specific IgE, lung function, fractional exhaled nitric oxide (FeNO), polysomnography, allergen-specific immunotherapies, biological therapies and home based continuous positive airway pressure (CPAP) whenever these are recommended, should be part of the management plan for UAD. Education of medical students, physicians, health professionals, patients and caregivers on the UAD is needed.

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.

Bacterial Interactions with Aspergillus fumigatus in the Immunocompromised Lung

The immunocompromised airways are susceptible to infections caused by a range of pathogens which increases the opportunity for polymicrobial interactions to occur. Pseudomonas aeruginosa and Staphylococcus aureus are the predominant causes of pulmonary infection for individuals with respiratory disorders such as cystic fibrosis (CF). The spore-forming fungus Aspergillus fumigatus, is most frequently isolated with P. aeruginosa, and co-infection results in poor outcomes for patients. It is therefore clinically important to understand how these pathogens interact with each other and how such interactions may contribute to disease progression so that appropriate therapeutic strategies may be developed. Despite its persistence in the airways throughout the life of a patient, A. fumigatus rarely becomes the dominant pathogen. In vitro interaction studies have revealed remarkable insights into the molecular mechanisms that drive agonistic and antagonistic interactions that occur between A. fumigatus and pulmonary bacterial pathogens such as P. aeruginosa. Crucially, these studies demonstrate that although bacteria may predominate in a competitive environment, A. fumigatus has the capacity to persist and contribute to disease.

Obstructive lung diseases and allergic bronchopulmonary aspergillosis

PURPOSE OF REVIEW

Allergic bronchopulmonary aspergillosis (ABPA) is a disease frequently complicating asthma and cystic fibrosis. ABPA is increasingly recognized in other obstructive lung diseases (OLDs), including chronic obstructive pulmonary disease (COPD) and noncystic fibrosis bronchiectasis. Herein, we summarize the recent developments in ABPA complicating OLDs.

RECENT FINDINGS

Recent research has described the clinical features and natural history of ABPA complicating asthma in children and the elderly. We have gained insights into the pathophysiology of ABPA, especially the role of eosinophil extracellular trap cell death and mucus plugs. The utility of recombinant fungal antigens in the diagnosis of ABPA has been established. Newer, more sensitive criteria for the diagnosis of ABPA have been proposed. Although ABPA is uncommon in COPD and noncystic fibrosis bronchiectasis, aspergillus sensitization is more common and is associated with a higher exacerbation rate.

SUMMARY

Several advances have occurred in the diagnosis and treatment of ABPA in recent years. However, there is an unmet need for research into the genetic predisposition, pathophysiology, and treatment of ABPA. Apart from asthma and cystic fibrosis, patients with other OLDs also require evaluation for Aspergillus sensitization and ABPA.

Consensus Document on the Diagnosis and Treatment of Chronic Bronchial Infection in Chronic Obstructive Pulmonary Disease

Although the chronic presence of microorganisms in the airways of patients with stable chronic obstructive pulmonary disease (COPD) confers a poor outcome, no recommendations have been established in disease management guidelines on how to diagnose and treat these cases. In order to guide professionals, the Spanish Society of Pulmonology and Thoracic Surgery (SEPAR) has prepared a document which aims to answer questions on the clinical management of COPD patients in whom microorganisms are occasionally or habitually isolated. Since the available scientific evidence is too heterogeneous to use in the creation of a clinical practice guideline, we have drawn up a document based on existing scientific literature and clinical experience, addressing the definition of different clinical situations and their diagnosis and management. The text was drawn up by consensus and approved by a large group of respiratory medicine experts with extensive clinical and scientific experience in the field, and has been endorsed by the SEPAR Scientific Committee.

The global impact of Aspergillus infection on COPD

Background

Advanced chronic obstructive pulmonary disease (COPD) often leads to hospitalisation and invasive aspergillosis (IA) is a serious complication. Aspergillus sensitisation may worsen symptoms in COPD.

Methods

We identified published papers between January 2000 and May 2019 with > 50 subjects and GOLD criteria for grade II, III or IV (FEV1/FVC < 70% and FEV1 < 80%) using standardised criteria in multiple countries, to re-estimate the prevalence of COPD. Hospitalised COPD patients develop IA in 1.3–3.9%, based on positive cultures of Aspergillus spp. and radiological findings. Given limited data on per-patient annual hospitalisation rates, we assumed a conservative 10.5% estimate. Annual IA mortality in COPD was estimated using the literature rates of 43–72%. A separate literature search assessed the impact of Aspergillus sensitisation on severity of COPD (by FEV1).

Results

We re-estimated the global prevalence of COPD GOLD stages II-IV at 552,300,599 people (7.39% of the population) with 339,206,893 (8.58%) in Asia, 85,278,783 (8.52%) in the Americas, 64,298,051 (5.37%) in Africa, 59,484,329 (7.77%) in Europe and 4,032,543 (10.86%) in Oceania. An estimated 57,991,563 (10.5%) people with COPD are admitted to hospital annually and of these 753,073 (1.3%) – 2,272,322 (3.9%) develop IA and 540,451–977,082 deaths are predicted annually. Aspergillus sensitisation prevalence in COPD was 13.6% (7.0–18.3%) and not related to lower predicted FEV1% (P > 0.05).

Conclusions

The prevalence of COPD is much higher than previously estimated. Overall COPD mortality may be higher than estimated and IA probably contributes to many deaths. Improved rapid diagnosis of IA using culture and non-culture based techniques is required in COPD hospital admissions to reduce mortality.

Environmental fungal sensitisation associates with poorer clinical outcomes in COPD

Introduction

Allergic sensitisation to fungi such as Aspergillus are associated to poor clinical outcomes in asthma, bronchiectasis and cystic fibrosis; however, clinical relevance in COPD remains unclear.

Methods

Patients with stable COPD (n=446) and nondiseased controls (n=51) were prospectively recruited across three countries (Singapore, Malaysia and Hong Kong) and screened against a comprehensive allergen panel including house dust mites, pollens, cockroach and fungi. For the first time, using a metagenomics approach, we assessed outdoor and indoor environmental allergen exposure in COPD. We identified key fungi in outdoor air and developed specific-IgE assays against the top culturable fungi, linking sensitisation responses to COPD outcomes. Indoor air and surface allergens were prospectively evaluated by metagenomics in the homes of 11 COPD patients and linked to clinical outcome.

Results

High frequencies of sensitisation to a broad range of allergens occur in COPD. Fungal sensitisation associates with frequent exacerbations, and unsupervised clustering reveals a “highly sensitised fungal predominant” subgroup demonstrating significant symptomatology, frequent exacerbations and poor lung function. Outdoor and indoor environments serve as important reservoirs of fungal allergen exposure in COPD and promote a sensitisation response to outdoor air fungi. Indoor (home) environments with high fungal allergens associate with greater COPD symptoms and poorer lung function, illustrating the importance of environmental exposures on clinical outcomes in COPD.

Conclusion

Fungal sensitisation is prevalent in COPD and associates with frequent exacerbations representing a potential treatable trait. Outdoor and indoor (home) environments represent a key source of fungal allergen exposure, amenable to intervention, in “sensitised” COPD.

Fungal sensitisation associates with frequent exacerbations in COPD, and represents a treatable trait. Outdoor and indoor environments represent a key source of fungal allergen exposure, amenable to intervention, in “sensitised” COPD patients.https://bit.ly/2Vw3kHi

Role of Type2 Inflammatory Biomarkers in Chronic Obstructive Pulmonary Disease

Airway inflammation in chronic obstructive pulmonary disease (COPD) is typically thought to be driven by Type1 immune responses, while Type2 inflammation appears to be present in definite proportions in the stable state and during exacerbations. In fact, some COPD patients showed gene expression of Type2 inflammation in the airway, and this subset was associated with the inhaled corticosteroid (ICS) response. Interestingly enough, the relationship between COPD and diseases associated with Type2 inflammation from the perspective of impaired lung development is increasingly highlighted by recent epidemiologic studies on the origin of COPD. Therefore, many researchers have shown an interest in the prevalence and the role of existent Type2 biomarkers such as sputum and blood eosinophils, exhaled nitric oxide fraction, and atopy, not only in asthma but also in COPD. Although the evidence about Type2 biomarkers in COPD is inconsistent and less robust, Type2 biomarkers have shown some potential when analyzing various clinical outcomes or therapeutic response to ICS. In this article, we review the existent and emerging Type2 biomarkers with clinically higher applicability in the management of COPD.

Vitamin D reduces autophagy by regulating NF-κB resistance to Aspergillus fumigatus infection

Vitamin D is one of the indispensable nutrients of human body. When vitamin D is deficient, it can cause a series of related diseases, such as respiratory tract infection. The regulatory role of vitamin D in inflammatory immune response and defense has attracted more and more attention. However, few studies have shown that vitamin D regulates inflammation and autophagy in Aspergillus fumigatus infected lungs. In this study, we will explain the mechanism of vitamin D regulating inflammation and autophagy in Aspergillus fumigatus infected lungs.

METHODS

Different concentrations of Aspergillus fumigatus spores were injected into mice with deficien diets (VitD-) or sufficient vitamin D (VitD + ) , and the survival rates were recorded. Then, the weight changes of rats were measured every other time. At the same time, a gauze was used to filter the lapped lung tissue to get the pulmonary spores and measured the amount of the spores. The mice with the same concentration of Aspergillus fumigatus infected were cut off and the lung tissue for pathological examination in the deficien diets (VitD-) group or sufficient vitamin D (VitD + ) group. Moreover, the expression of inflammation related factors TNF-α, IL-1β, IL-6 in lung was measured by immunohistochemical method. The expression of TNF-α, IL-1β, IL-6 in the serum of vitamin D deficiency and sufficient mice were measured by ELISA. In vitro, we obtained macrophages from healthy mice and mixed cultures of Aspergillus fumigatus spores and lung macrophages in medium with or without vitamin D. After the cells were infected with Aspergillus fumigatus spores, the expressions of NF-κB and IL-8 were detected by RT-PCR and Western blot. The RAW264.7 cells transfected with GFP-LC3BII were mixed with Aspergillus fumigatus spores, and the expression of cell fluorescence was observed by the fluorescence microscope with or without chloroquine and rapamycin , and the autophagy flow of the cells was measured by Western blot. In the RAW264.7 cells, Lentivirus transfection and SiRNA technologies were used to enhance or reduce the expression of the NF-κB gene (siNF-κB) for investgating the influence of high or low expression of NF-κB in the autophagic flow of vitamin D + or vitamin D-treated RAW264.7 cells.

RESULTS

The survival rate of vitamin D deficient mice infected Aspergillus fumigatus was significantly lower than that of vitamin D sufficient mice, while the number of spores, spore activity, pathological changes of lungs and inflammation in the lungs of vitamin D deficient mice were more severe than that of vitamin D sufficient mice. In vitro cell experiments, when cell was stimulated with vitamin D, the expressions of NF-κB and IL-8 in cells were lower. The autophagic flux and TNF-α, IL-1β, IL-6 and LC3BII in vitamin D group were significantly lower than those in vitamin D deficiency group.

CONCLUSIONS

Vitamin D deficiency can aggravate the inflammatory damage in the lungs of Aspergillus fumigatus. When the body is sufficient in vitamin D, if the lungs infect Aspergillus fumigatus spores, the body may resist the infection of Aspergillus fumigatus by reducing the expression of NF-κB, inflammatory factors and autophagy.

Distinct "Immunoallertypes" of Disease and High Frequencies of Sensitization in Non-Cystic Fibrosis Bronchiectasis

RATIONALE

Allergic sensitization is associated with poor clinical outcomes in asthma, chronic obstructive pulmonary disease, and cystic fibrosis; however, its presence, frequency, and clinical significance in non-cystic fibrosis bronchiectasis remain unclear.

OBJECTIVES

To determine the frequency and geographic variability that exists in a sensitization pattern to common and specific allergens, including house dust mite and fungi, and to correlate such patterns to airway immune-inflammatory status and clinical outcomes in bronchiectasis.

METHODS

Patients with bronchiectasis were recruited in Asia (Singapore and Malaysia) and the United Kingdom (Scotland) (n = 238), forming the Cohort of Asian and Matched European Bronchiectasis, which matched recruited patients on age, sex, and bronchiectasis severity. Specific IgE response against a range of common allergens was determined, combined with airway immune-inflammatory status and correlated to clinical outcomes. Clinically relevant patient clusters, based on sensitization pattern and airway immune profiles ("immunoallertypes"), were determined.

MEASUREMENTS AND MAIN RESULTS

A high frequency of sensitization to multiple allergens was detected in bronchiectasis, exceeding that in a comparator cohort with allergic rhinitis (n = 149). Sensitization was associated with poor clinical outcomes, including decreased pulmonary function and more severe disease. "Sensitized bronchiectasis" was classified into two immunoallertypes: one fungal driven and proinflammatory, the other house dust mite driven and chemokine dominant, with the former demonstrating poorer clinical outcome.

CONCLUSIONS

Allergic sensitization occurs at high frequency in patients with bronchiectasis recruited from different global centers. Improving endophenotyping of sensitized bronchiectasis, a clinically significant state, and a "treatable trait" permits therapeutic intervention in appropriate patients, and may allow improved stratification in future bronchiectasis research and clinical trials.

Functional effects of the microbiota in chronic respiratory disease

The composition of the lung microbiome is increasingly well characterised, with changes in microbial diversity or abundance observed in association with several chronic respiratory diseases such as asthma, cystic fibrosis, bronchiectasis, and chronic obstructive pulmonary disease. However, the precise effects of the microbiome on pulmonary health and the functional mechanisms by which it regulates host immunity are only now beginning to be elucidated. Bacteria, viruses, and fungi from both the upper and lower respiratory tract produce structural ligands and metabolites that interact with the host and alter the development and progression of chronic respiratory diseases. Here, we review recent advances in our understanding of the composition of the lung microbiome, including the virome and mycobiome, the mechanisms by which these microbes interact with host immunity, and their functional effects on the pathogenesis, exacerbations, and comorbidities of chronic respiratory diseases. We also describe the present understanding of how respiratory microbiota can influence the efficacy of common therapies for chronic respiratory disease, and the potential of manipulation of the microbiome as a therapeutic strategy. Finally, we highlight some of the limitations in the field and propose how these could be addressed in future research.

Diagnostic Cutoffs and Clinical Utility of Recombinant Aspergillus fumigatus Antigens in the Diagnosis of Allergic Bronchopulmonary Aspergillosis

BACKGROUND

The clinical utility of IgE against recombinant Aspergillus fumigatus (rAsp)-specific antigens in allergic bronchopulmonary aspergillosis (ABPA) remains unclear.

OBJECTIVE

To identify the optimal diagnostic cutoffs of rAsp-specific IgE in differentiating ABPA from A fumigatus-sensitized asthma (ASA), and define their utility in the diagnosis of ABPA.

METHODS

We enrolled consecutive subjects with ASA and ABPA. IgE against rAsp f1, f2, f3, f4, and f6 was assayed in all the subjects. We evaluated 3 fixed cutoffs (0.35, 0.5, and 1.0 kU_A/L) for their diagnostic performance in the entire cohort. We also divided the study population into derivation and validation cohorts. Cutoffs for rAsp-specific IgE were obtained using the receiver-operating characteristic analysis in the derivation cohort. We then evaluated the diagnostic performance of these cutoffs in the validation cohort. We further correlated rAsp-specific IgE levels in ABPA with asthma control, spirometry, imaging, and immunologic markers.

RESULTS

We included 194 subjects (123 ABPA and 71 ASA). The statistically derived cutoffs proved superior to fixed cutoffs. IgE against rAsp f1 yielded the best combination of sensitivity (89%) and specificity (100%). The sensitivity and specificity of IgE against either rAsp f1 (cutoff, 4.465 kU_A/L) or f2 (cutoff, 1.300 kU_A/L) for diagnosing ABPA were 100% and 81%, respectively. The correlation between rAsp-specific IgE and most clinical parameters of ABPA was weak.

CONCLUSIONS

IgE against rAsp f1 and f2 (using receiver-operating characteristic-derived cutoffs) were found to be the most useful in differentiating ABPA from ASA. Because this study was conducted at a single center, our results require further validation.

Prospective study of the serum Aspergillus-specific IgG, IgA and IgM assays for chronic pulmonary aspergillosis diagnosis

Background

Chronic pulmonary aspergillosis (CPA) is an underdiagnosed and misdiagnosed disease and now increasingly recognised. However, the diagnosis of CPA remains challenging. In this study, we aimed to investigate the diagnostic values of serum Aspergillus-specific IgG, IgA and IgM antibodies in patients with CPA.

Methods

The prospective study was performed at Chinese People’s Liberation Army General Hospital in Beijing, from January 2017 to December 2017. Adult patients with lung lesions presented as cavity, nodule, mass, bronchiectasis or severe fibrotic destruction with at least two lobes in CT imaging were enrolled. One hundred healthy persons were also enrolled as additional controls. The serum levels of Aspergillus-specific IgG, IgA and IgM antibodies and galactomannan (GM) levels were measured simultaneously by plate ELISA kit.

Results

A total of 202 patients were enrolled in this study, including 42 CPA patients, 60 non-CPA patients and 100 healthy persons. The most common underlying lung diseases in CPA patients were bronchiectasis (28.6%) and COPD (19.0%). The most common symptoms in the CPA patients were cough (76.2%), sputum (71.4%), and fever (45.2%); chest pain (4.8%) was infrequent. Receiver operating characteristic (ROC) curve analysis revealed that the optimal CPA diagnostic cut-off of Aspergillus-specific IgG, IgA and IgM assays and GM test were 89.3 AU/mL, 8.2 U/mL, 73.3 AU/mL and 0.5μg/L, respectively. The serum levels of Aspergillus-specific IgG and IgA in CPA patients were higher than these in non-CPA patients or healthy persons. The sensitivities and specificities of Aspergillus-specific IgG, IgA, IgM tests and GM test were 78.6 and 94.4%, 64.3 and 89.4%, 50.0 and 53.7% and 71.4 and 58.1%, respectively.

Conclusions

The sensitivity and specificity of serum Aspergillus-specific IgG assay are satisfactory for diagnosing CPA, while the performance of Aspergillus-specific IgA assay is moderate. Aspergillus-specific IgM assay and serum GM test have limited value for CPA diagnosis.

Trial registration

NCT03027089. Registered 20 January 2017.

Microbial exposure to dairy farmers' dwellings and COPD occurrence

Dairy farming is a risk factor for chronic obstructive pulmonary disease (COPD). The aim was to determine predictive markers either in blood samples or in dwelling dust samples by comparing COPD and healthy controls with or without farming activity. Dust was collected and analyzed by real-time quantitative PCR. ELISA and DELFIA® were performed to assay the level of specific IgG and IgE of 10 targeted microorganisms. The dwelling exposure of farmers was higher than in the non-farmers (Especially Eurotium amstelodami and Lichtheimia corymbifera). The IgG response against Wallemia sebi and Saccharopolyspora rectivirgula was more often higher in the farmers than the non-farmers. However, exposure and sensitization to the microorganisms tested cannot explain the occurrence of COPD in the dairy farmers' population. COPD development is probably caused by multiple factors associated with exposure over a period of several years.

Paediatric and adult bronchiectasis: Vaccination in prevention and management

Bronchiectasis has received increased attention recently, including an emphasis on preventing infective exacerbations that are associated with disease progression and lung function decline. While there are several bacteria and viruses associated with bronchiectasis, licensed vaccines are only currently available for Streptococcus pneumoniae, Haemophilus influenzae (H. influenzae protein D as a conjugate in a pneumococcal vaccine), Mycobacterium tuberculosis, Bordetella pertussis and influenza virus. The evidence for the efficacy and effectiveness of these vaccines in both preventing and managing bronchiectasis in children and adults is limited with the focus of most research being on other chronic lung disorders, such as chronic obstructive pulmonary diseases, asthma and cystic fibrosis. We review the existing evidence for these vaccines in bronchiectasis and highlight the existing gaps in knowledge. High-quality experimental and non-experimental studies using current state-of-the-art microbiological methods and validated, standardised case definitions are needed across the depth and breadth of the vaccine development pathway.

Immunological corollary of the pulmonary mycobiome in bronchiectasis: the CAMEB study

Understanding the composition and clinical importance of the fungal mycobiome was recently identified as a key topic in a “research priorities” consensus statement for bronchiectasis.

Patients were recruited as part of the CAMEB study: an international multicentre cross-sectional Cohort of Asian and Matched European Bronchiectasis patients. The mycobiome was determined in 238 patients by targeted amplicon shotgun sequencing of the 18S–28S rRNA internally transcribed spacer regions ITS1 and ITS2. Specific quantitative PCR for detection of and conidial quantification for a range of airway Aspergillus species was performed. Sputum galactomannan, Aspergillus specific IgE, IgG and TARC (thymus and activation regulated chemokine) levels were measured systemically and associated to clinical outcomes.

The bronchiectasis mycobiome is distinct and characterised by specific fungal genera, including Aspergillus, Cryptococcus and Clavispora. Aspergillus fumigatus (in Singapore/Kuala Lumpur) and Aspergillus terreus (in Dundee) dominated profiles, the latter associating with exacerbations. High frequencies of Aspergillus-associated disease including sensitisation and allergic bronchopulmonary aspergillosis were detected. Each revealed distinct mycobiome profiles, and associated with more severe disease, poorer pulmonary function and increased exacerbations.

The pulmonary mycobiome is of clinical relevance in bronchiectasis. Screening for Aspergillus-associated disease should be considered even in apparently stable patients.

The airway mycobiome in bronchiectasis is associated with clinically significant diseasehttp://ow.ly/MCKj30knVrn

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.