Specific IgE is better than skin testing for detecting Aspergillus sensitization and allergic bronchopulmonary aspergillosis in asthma

EQUAL ABPA Score 2024: A Tool to Measure Guideline Adherence for Managing Allergic Bronchopulmonary Aspergillosis

OBJECTIVES

Allergic bronchopulmonary aspergillosis (ABPA) is a complex lung disease associated with significant morbidity. The ABPA Working Group (AWG) of the International Society for Human and Animal Mycology (ISHAM) revised their management guidelines in 2024, but there is currently no standardised tool to assess adherence to these recommendations.

METHODS

We extracted key recommendations from the updated 2024 ISHAM-AWG guidelines, focusing on critical areas: screening and diagnosis of ABPA, managing acute and treatment-dependent ABPA, and monitoring treatment response. Each item was assigned a score ranging from zero to three. We assigned negative scores to interventions not recommended by the guidelines.

RESULTS

We identified 38 items indicative of optimal clinical care for patients with ABPA. The score for screening asthmatics for ABPA was set at three points. For diagnosing ABPA, 16 items were included, with a score ranging from 12 to 16 points, depending on the specific components used (predisposing conditions, serum A. fumigatus-specific IgE and IgG, serum total IgE, blood eosinophil count and chest computed tomography). The management of acute ABPA comprised 11 items, with a maximum score of three points. For treatment-dependent ABPA, there were nine items (scores ranging from -3 to 6). Follow-up care comprised 10 items with a maximum score of 10-13 points, covering imaging, spirometry, testing serum total IgE levels and therapeutic drug monitoring.

CONCLUSIONS

The EQUAL ABPA score has been developed as a comprehensive tool to quantify guideline adherence. Future studies will evaluate to which extent guideline adherence is associated with improved clinical outcomes for patients with ABPA.

Population prevalence of aspergillus sensitization and allergic bronchopulmonary aspergillosis in COPD subjects in North India

BACKGROUND

Sensitization to Aspergillus fumigatus (AS) has been recently described in chronic obstructive pulmonary disease (COPD) patients. However, there is no data on the community prevalence of AS in COPD.

OBJECTIVES

To assess the prevalence of AS among COPD subjects. The secondary objectives were to (1) assess the prevalence of allergic bronchopulmonary aspergillosis (ABPA) in COPD and (2) compare the lung function in COPD subjects with and without AS.

METHODS

We conducted a cross-sectional study in rural (29 villages) and urban (20 wards) communities in North India. We identified individuals with respiratory symptoms (IRS) through a house-to-house survey using a modified IUATLD questionnaire. We then diagnosed COPD through specialist assessment and spirometry using the GOLD criteria. We assayed A.fumigatus-specific IgE in COPD subjects. In those with A. fumigatus-specific IgE ≥0.35 kUA/L (AS), ABPA was diagnosed with raised serum total IgE and raised A.fumigatus-specific IgG or blood eosinophil count.

RESULTS

We found 1315 (8.2%) IRS among 16,071 participants >40 years and diagnosed COPD in 355 (2.2%) subjects. 291 (82.0%) were men and 259 (73.0%) resided in rural areas. The prevalence of AS and ABPA was 17.7% (95% CI, 13.9-21.8) and 6.6% (95% CI, 4.4-8.8). We found a lower percentage predicted FEV1 in COPD subjects with AS than those without (p =.042).

CONCLUSIONS

We found an 18% community prevalence of AS in COPD subjects in a specific area in North India. Studies from different geographical areas are required to confirm our findings. The impact of AS and ABPA on COPD requires further research.

Clinical Manifestation and Treatment of Allergic Bronchopulmonary Aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is a complex hypersensitivity reaction to airway colonization by Aspergillus fumigatus in patients with asthma and cystic fibrosis. The pathophysiology of ABPA involves a complex interplay between the fungus and the host immune response, which causes persistent inflammation and tissue damage. Patients present with chronic cough, wheezing, and dyspnea due to uncontrolled asthma. Characteristic symptoms include the expectoration of brownish mucus plugs. Radiographic findings often reveal fleeting pulmonary infiltrates, bronchiectasis, and mucus impaction. However, the definitive diagnosis of ABPA requires a combination of clinical, radiological, and immunological findings. The management of ABPA aims to reduce symptoms, prevent disease progression, and minimize the future risk of exacerbations. The treatment approach involves systemic glucocorticoids or antifungal agents to suppress the inflammatory response or fungal growth and prevent exacerbations. Biological agents may be used in patients with severe disease or glucocorticoid dependence. This review provides an overview of the clinical manifestations and current treatment options for ABPA.

Prevalence of Aspergillus sensitization and Allergic Bronchopulmonary Aspergillosis in bronchial asthma: A systematic review of Indian studies

Background

The prevalence of allergic bronchopulmonary aspergillosis (ABPA) in Indian asthmatic patients remains unknown. We systematically reviewed the literature for estimating the prevalence of Aspergillus sensitization (AS) and ABPA in Indian subjects with bronchial asthma.

Methods

We searched the PubMed and Embase databases for studies from India reporting the prevalence of AS or ABPA in at least 50 asthmatics. The primary outcome of our study was to assess the prevalence of ABPA. The secondary outcomes were to evaluate the prevalence of AS in asthma and ABPA in Aspergillus-sensitized asthma. We pooled the prevalence estimates using a random effects model and examined the factors influencing the prevalence using multivariate meta-regression.

Results

Of the 8,383 records retrieved, 34 studies with 14,580 asthmatics met the inclusion criteria. All the studies were from tertiary centers. The pooled prevalence of ABPA in asthmatics (26 studies; 5,554 asthmatics) was 16.2% [95% confidence interval (CI), 12.5-20.4]. The pooled prevalence of AS in asthma (29 studies; 13,405 asthmatics) was 30.9% (95% CI, 25.3-36.6), while the prevalence of ABPA in AS (20 studies; 1,493 asthmatics) was 48.2% (95% CI, 39.6-56.8). Meta-regression identified studies published after 2009 (OR 1.14; 95% CI, 1.02-1.28) and studies with severe asthmatics (OR 1.12; 95% CI, 1.00-1.26) as the only factors associated with higher ABPA prevalence.

Conclusions

There is a high prevalence of ABPA in Indian asthmatic subjects at tertiary centers, underscoring the need for screening all asthmatic subjects in special asthma and chest clinics for ABPA.

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.

Prevalence of Aspergillus Sensitization and Allergic Bronchopulmonary Aspergillosis in Adults With Bronchial Asthma: A Systematic Review of Global Data

BACKGROUND

The prevalence of allergic bronchopulmonary aspergillosis (ABPA) in asthmatic patients remains unclear and is likely different across geographic locales.

OBJECTIVE

To systematically review the literature for estimating the prevalence of Aspergillus sensitization (AS) and ABPA in adults with bronchial asthma.

METHODS

We searched the PubMed and Embase databases for studies reporting the prevalence of AS or ABPA in at least 50 asthmatic subjects. The primary outcome was to assess the prevalence of ABPA. The secondary outcome was to evaluate the prevalence of AS in asthma and that of ABPA in asthma with AS. We pooled the prevalence estimates using a random-effects model and examined the factors influencing the prevalence using multivariate meta-regression.

RESULTS

Of the 11,801 records retrieved, 86 studies with 25,770 asthmatic subjects met the inclusion criteria. Most of the studies were from tertiary care centers. The pooled prevalence of ABPA in asthma (47 studies; 9822 asthmatic subjects) was 11.3% (95% CI, 8.7-14.2). The pooled prevalence of AS in asthma (73 studies; 23,003 asthmatic subjects) was 25.1% (95% CI, 20.5-30.0), whereas the prevalence of ABPA in AS (36 studies; 2954 asthmatic subjects) was 37.0% (95% CI, 27.9-46.6). Multivariate meta-regression identified studies published from India (odds ratio, 1.11; 95% CI, 1.01-1.23) as the only factor associated with higher ABPA prevalence. There was presence of significant statistical heterogeneity and publication bias.

CONCLUSIONS

We found a high prevalence of ABPA in adult asthmatic subjects, underscoring the need for screening for ABPA in all asthmatic subjects seeking tertiary care.

Eosinophilic Lung Diseases

The eosinophilic lung diseases may manifest as chronic eosinophilic pneumonia, acute eosinophilic pneumonia, or as the Löffler syndrome (generally of parasitic etiology). The diagnosis of eosinophilic pneumonia is made when both characteristic clinical-imaging features and alveolar eosinophilia are present. Peripheral blood eosinophils are generally markedly elevated; however, eosinophilia may be absent at presentation. Lung biopsy is not indicated except in atypical cases after multidisciplinary discussion. The inquiry to possible causes (medications, toxic drugs, exposures, and infections especially parasitic) must be meticulous. Idiopathic acute eosinophilic pneumonia may be misdiagnosed as infectious pneumonia. Extrathoracic manifestations raise the suspicion of a systemic disease especially eosinophilic granulomatosis with polyangiitis. Airflow obstruction is frequent in allergic bronchopulmonary aspergillosis, idiopathic chronic eosinophilic pneumonia, eosinophilic granulomatosis with polyangiitis, and hypereosinophilic obliterative bronchiolitis. Corticosteroids are the cornerstone of therapy, but relapses are common. Therapies targeting interleukin 5/interleukin-5 are increasingly used in eosinophilic lung diseases.

Aspergillus Sensitization and Allergic Bronchopulmonary Aspergillosis in Asthmatic Children: A Systematic Review and Meta-Analysis

Background: The prevalence of aspergillus sensitization (AS) and allergic bronchopulmonary aspergillosis (ABPA) in asthmatic children remains unclear. Objective: To systematically review the literature to estimate the prevalence of AS and ABPA in children with bronchial asthma. Methods: We searched the PubMed and Embase databases for studies reporting the prevalence of AS or ABPA in pediatric asthma. The primary outcome was to assess the prevalence of AS, while the secondary outcome was to evaluate the prevalence of ABPA. We pooled the prevalence estimates using a random effects model. We also calculated the heterogeneity and publication bias. Results: Of the 11,695 records retrieved, 16 studies with 2468 asthmatic children met the inclusion criteria. Most studies were published from tertiary centers. The pooled prevalence of AS in asthma (15 studies; 2361 subjects) was 16.1% (95% confidence intervals [CI], 9.3-24.3). The prevalence of AS was significantly higher in prospective studies, studies from India, and those from developing countries. The pooled prevalence of ABPA in asthma (5 studies; 505 children) was 9.9% (95% CI, 0.81-27.6). There was significant heterogeneity and publication bias for both outcomes. Conclusions: We found a high prevalence of AS and ABPA in asthmatic children. There is a need for community-based studies from different ethnicities using a standard methodology to ascertain the true prevalence of AS and ABPA in pediatric asthma.

Chronic Occupational Mold Exposure Drives Expansion of Aspergillus-Reactive Type 1 and Type 2 T-Helper Cell Responses

Occupational mold exposure can lead to Aspergillus-associated allergic diseases including asthma and hypersensitivity pneumonitis. Elevated IL-17 levels or disbalanced T-helper (Th) cell expansion were previously linked to Aspergillus-associated allergic diseases, whereas alterations to the Th cell repertoire in healthy occupationally exposed subjects are scarcely studied. Therefore, we employed functional immunoassays to compare Th cell responses to A. fumigatus antigens in organic farmers, a cohort frequently exposed to environmental molds, and non-occupationally exposed controls. Organic farmers harbored significantly higher A. fumigatus-specific Th-cell frequencies than controls, with comparable expansion of Th1- and Th2-cell frequencies but only slightly elevated Th17-cell frequencies. Accordingly, Aspergillus antigen-induced Th1 and Th2 cytokine levels were strongly elevated, whereas induction of IL-17A was minimal. Additionally, increased levels of some innate immune cell-derived cytokines were found in samples from organic farmers. Antigen-induced cytokine release combined with Aspergillus-specific Th-cell frequencies resulted in high classification accuracy between organic farmers and controls. Aspf22, CatB, and CipC elicited the strongest differences in Th1 and Th2 responses between the two cohorts, suggesting these antigens as potential candidates for future bio-effect monitoring approaches. Overall, we found that occupationally exposed agricultural workers display a largely balanced co-expansion of Th1 and Th2 immunity with only minor changes in Th17 responses.

Role of Aspergillus fumigatus-Specific IgE in the Diagnosis of Allergic Bronchopulmonary Aspergillosis

INTRODUCTION

Allergic bronchopulmonary aspergillosis (ABPA) has been regarded as a rare disease in China due to the lack of quantitative detection of Aspergillus fumigatus-specific IgE (sIgE). We compared the diagnostic rate of ABPA among asthma patients with or without A. fumigatus-sIgE screening tests to evaluate the benefit of the tests in diagnosing ABPA.

METHODS

We reviewed the detection rate of A. fumigatus-sIgE and the diagnostic rate of ABPA in 1842 asthma patients in the First Affiliated Hospital of Zhejiang University from 2014 to 2016. Additionally, we collected 144 asthma cases from November 2016 to March 2017 to detect the total serum IgE, A. fumigatus-sIgE and sIgE against mixed mold extract, the ABPA diagnostic rate of these patients was then compared with the total cohort. Total serum IgE, A. fumigatus-sIgE and sIgE against mixed mold extract were also tested in 30 patients identified with Aspergillus-positive sputum culture to analyze the incidence of ABPA.

RESULTS

Among the 1,842 asthma cases, 566 were inspected for total IgE; 308 (55.40%) were total IgE-positive and 58 (10.43%) had total IgE > 1,000 IU/mL. In contrast, only 126 cases were tested for A. fumigatus-sIgE (6.84%), and 28 had A. fumigatus-sIgE > 0.35 kUA/L (22.22%). Eleven patients were finally diagnosed with ABPA. Of 1,842 asthma patients, only 0.6% were diagnosed with ABPA if the A. fumigatus-sIgE was not detected at first. Moreover, among the 144 asthma cases that were selected for total IgE, A. fumigatus-sIgE, and sIgE against mixed mold extract screening tests, 12 had total IgE > 1,000 IU/mL (8.33%), 11 had A. fumigatus-sIgE > 0.35 kUA/L (7.64%), and 14 had sIgE against mixed mold extract > 0.35 (9.72%); 7 of these patients were confirmed as having ABPA according to the ISHAM guidelines (4.86%) but only 2 without A. fumigatus-sIgE screening test were diagnosed with ABPA (1.39%) (p = 0.000). Of the 30 Aspergillus-positive sputum culture cases, 4 had A. fumigatus-sIgE > 0.35 kUA/L (13.33%), but none was diagnosed with ABPA.

CONCLUSIONS

Routine A. fumigatus-sIgE screening for asthma patients can significantly improve the diagnostic rate of ABPA.

The Multifaceted Role of T-Helper Responses in Host Defense against Aspergillus fumigatus

The ubiquitous opportunistic fungal pathogen Aspergillus fumigatus rarely causes infections in immunocompetent individuals. A healthy functional innate immune system plays a crucial role in preventing Aspergillus-infection. This pivotal role for the innate immune system makes it a main research focus in studying the pathogenesis of aspergillosis. Although sometimes overshadowed by the innate immune response, the adaptive immune response, and in particular T-helper responses, also represents a key player in host defense against Aspergillus. Virtually all T-helper subsets have been described to play a role during aspergillosis, with the Th1 response being crucial for fungal clearance. However; morbidity and mortality of aspergillosis can also be partly attributed to detrimental immune responses resulting from adaptive immune activation. Th2 responses benefit fungal persistence; and are the foundation of allergic forms of aspergillosis. The Th17 response has two sides; although crucial for granulocyte recruitment, it can be involved in detrimental immunopathology. Regulatory T-cells, the endogenous regulators of inflammatory responses, play a key role in controlling detrimental inflammatory responses during aspergillosis. The current knowledge of the adaptive immune response against A. fumigatus is summarized in this review. A better understanding on how T-helper responses facilitate clearance of Aspergillus-infection and control inflammation can be the fundamental basis for understanding the pathogenesis of aspergillosis and for the development of novel host-directed therapies.

Eosinophilic Lung Diseases

Eosinophilic lung diseases especially comprise eosinophilic pneumonia or as the more transient Löffler syndrome, which is most often due to parasitic infections. The diagnosis of eosinophilic pneumonia is based on characteristic clinical-imaging features and the demonstration of alveolar eosinophilia, defined as at least 25% eosinophils at BAL. Peripheral blood eosinophilia is common but may be absent at presentation in idiopathic acute eosinophilic pneumonia, which may be misdiagnosed as severe infectious pneumonia. All possible causes of eosinophilia, including drug, toxin, fungus related etiologies, must be thoroughly investigated. Extrathoracic manifestations should raise the suspicion of eosinophilic granulomatosis with polyangiitis.

Allergic bronchopulmonary aspergillosis in an adult with Kartagener syndrome

Allergic bronchopulmonary aspergillosis (ABPA) is a pulmonary disorder resulting from immune responses directed against inhaled Aspergillus fumigatus antigens. It manifests with poorly controlled asthma, fleeting pulmonary opacities and structural lung damage in the form of bronchiectasis. Initially defined in individuals suffering from bronchial asthma and cystic fibrosis, it has also been described in patients with other structural lung disorders such as chronic obstructive pulmonary disease, pulmonary tuberculosis, idiopathic bronchiectasis and others. Kartagener syndrome is a manifestation of primary ciliary dyskinesia characterised by the presence of dextrocardia, bronchiectasis and chronic sinusitis. We report a case of ABPA in an adult suffering from Kartagener syndrome. We also performed a systematic review of the literature on the association between Kartagener syndrome and ABPA.