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

Bronchiectasis Severity Index and FACED scores in patients with allergic bronchopulmonary aspergillosis complicating asthma: do they correlate with immunological severity or high-attenuation mucus?

BACKGROUND

The utility of two disease-severity indices, namely bronchiectasis severity index (BSI) and FACED score in allergic bronchopulmonary aspergillosis (ABPA) remains unknown.

OBJECTIVE

To correlate the BSI and FACED scores with immunological parameters (serum IgE [total and A. fumigatus-specific], A. fumigatus-specific IgG, blood eosinophil count), and high-attenuation mucus on chest computed tomography in ABPA. The secondary objectives were to evaluate the correlation between BSI and FACED scores and correlate the BSI/FACED scores with the bronchiectasis health questionnaire (BHQ) and Saint George's Respiratory Questionnaire (SGRQ).

METHODS

We included treatment-naïve ABPA subjects with bronchiectasis in a prospective observational study. We computed the BSI and FACED scores for each subject before initiating treatment. The subjects also completed two quality-of-life questionnaires (BHQ and SGRQ).

RESULTS

We included 91 subjects. The mean (standard deviation) BSI and FACED scores were 3.43 (3.39) and 1.43 (1.27). We found no correlation between BSI or FACED with any immunological parameter or high-attenuation mucus. There was a strong correlation between BSI and FACED scores (r = 0.76, p < 0.001). We found a weak correlation between BSI and BHQ/SGRQ and FACED and SGRQ.

CONCLUSION

We found no correlation between BSI and FACED with immunological parameters in ABPA. However, we found a significant correlation between BSI and FACED and a weak correlation between SGRQ and BHQ. ABPA likely requires a separate disease-severity scoring system.

Aspergillus-sensitized asthma in children

BACKGROUND

Asthma is the most common chronic respiratory disease in childhood. Aspergillus fumigatus sensitivity may be involved in the pathogenesis of asthma by leading to different clinical presentations.

OBJECTIVE

To investigate the demographic, clinical, laboratory, and radiological characteristics of A. fumigatus sensitivity in childhood asthma and identify associated risk factors and diagnostic parameters.

METHODS

A total of 259 children with asthma were included in the study, 7 (2.7%) with allergic bronchopulmonary aspergillosis (ABPA), 84 (32.4%) with A. fumigatus-sensitized asthma (Af-SA), and 168 (64.9%) with A. fumigatus-unsensitized asthma (Af-UA).

RESULTS

Aspergillus sensitivity was associated with early asthma onset and longer asthma duration. Total IgE level and asthma severity are highest in ABPA and higher in Af-SA. Absolute eosinophil count was higher, and FEV1 was lower in Af-SA and ABPA. Aspergillus fumigatus was associated with greater odds of being male (odds ratio [OR], 2.45), having atopic dermatitis (OR, 3.159), Alternaria sensitivity (OR, 10.37), and longer asthma duration (OR, 1.266). The best cut-off values for detecting A. fumigatus positivity were 363.5 IU/mL for total IgE and 455 cells/μL for absolute eosinophil count. In Af-SA compared to Af-UA, centrilobular nodules and peribronchial thickening were more common, and the bronchoarterial ratio was higher.

CONCLUSIONS

Aspergillus sensitivity is a strong allergic stimulus in asthma, leading to laboratory, structural, clinical, and functional consequences. Af-SA is a distinct asthma endotype independent of ABPA that is characterized by increased risk of severe clinical presentations and impaired lung function.

Bayesian analysis suggests independent development of sensitization to different fungal allergens

Background

Fungi are known for their ability to cause allergies, but data on individual sensitization to them are insufficient. The purpose of the study was to carry out a comprehensive analysis of the fungal allergens' sensitization profile in the Ukrainian population and to determine both population and individual sensitivity to these allergens.

Methods

We utilized a set of ALEX allergy test data from 20,033 inhabitants of 17 regions of Ukraine from 1 to 89 years conducted in 2020-2022. A complex of programs in the Python language was developed and Bayesian network analysis was applied to determine the sensitivity combinations in individual patients to various fungal components.

Results

Sensitivity to Alt a 1 dominated and was observed in 79.39% of patients, and 62.17% of them were sensitive solely to Alt a 1. Exclusive sensitivity to Mala s 6 was second in individual patient profiles with a frequency of 4.06%. Combined sensitivity to Alt a 1 - Asp f 3 was third with a share of 3.28%. Pen ch and Cla h extracts stimulated the production of the lowest median sIgE levels. The highest median sIgE levels were for Alt a 1, Mala s 11 and Asp f 6, respectively. Median sIgE levels increased in adults compared to children for all components of Aspergillus fumigatus, as well as for Mala s 5 and Mala s 11. In the rest of the cases, they decreased in adults compared to children. The sensitization rates to fungi in general and specifically to Alternaria were lower in the western parts of Ukraine, especially in the Carpathian region, situated within the Broad-leaved Forest zone. The results of Bayesian modeling revealed that in the case of Alt a 1, the simultaneous absence of sensitivity to Cla h 8, Mala s 11, Mala s 5 and Mala s 6 molecules could condition the presence of sensitization to the major Alternaria allergen with a probability of 92.42%. In all other cases, there was a high probability of absence of sensitivity to particular allergen against the background of absence of sensitivity to other ones, which may indicate the independent development of sensitization to different fungal allergens.

Conclusions

Sensitivity to Alt a 1 dominated in the studied population with a lower rate in the western regions. The highest median sIgE levels were induced by Alt a 1, Mala s 11 and Asp f 6. Bayesian Analysis suggest a high probability of the independent development of sensitization to different fungal allergens. The idea that sensitization to one allergen may be protective against sensitization to another one(s) requires further clinical study.

Pediatric asthma comorbidities: Global impact and unmet needs

Real-world data on the range and impact of comorbid health conditions that affect pediatric asthma are scant, especially from developing countries. Lack of data hinders effective diagnosis, treatment, and overall management of these complex cases. We, hereby, describe the common pediatric asthma comorbid conditions in terms of evidence for association, potential mechanisms of impact on asthma control, and treatment benefit. Obesity, upper airway allergies, dysfunctional breathing, multiple sensitizations, depressive disorders, food allergy, and gastro-esophageal reflux are common associations with difficult-to-treat asthma. On the other hand, asthma symptoms and/or management may negatively impact the well-being of children through drug adverse effects, worsening of anaphylaxis symptoms, and disturbing mental health. Awareness of these ailments may be crucial for designing the optimum care for each asthmatic child individually and may ultimately improve the quality of life of patients and their families. A multidisciplinary team of physicians is required to identify and manage such comorbidities aiming to mitigate the over-use of asthma pharmacotherapy. Asthma research should target relevant real-world difficulties encountered at clinical practice and focus on interventions that would mitigate the impact of such comorbidities. Finally, policymakers and global healthcare organizations are urged to recognize pediatric asthma control as a healthcare priority and allocate resources for research and clinical interventions. In other words, global asthma control needs support by compassionate scientific partnership.

Revised ISHAM-ABPA working group clinical practice guidelines for diagnosing, classifying and treating allergic bronchopulmonary aspergillosis/mycoses

BACKGROUND

The International Society for Human and Animal Mycology (ISHAM) working group proposed recommendations for managing allergic bronchopulmonary aspergillosis (ABPA) a decade ago. There is a need to update these recommendations due to advances in diagnostics and therapeutics.

METHODS

An international expert group was convened to develop guidelines for managing ABPA (caused by Aspergillus spp.) and allergic bronchopulmonary mycosis (ABPM; caused by fungi other than Aspergillus spp.) in adults and children using a modified Delphi method (two online rounds and one in-person meeting). We defined consensus as ≥70% agreement or disagreement. The terms "recommend" and "suggest" are used when the consensus was ≥70% and <70%, respectively.

RESULTS

We recommend screening for A. fumigatus sensitisation using fungus-specific IgE in all newly diagnosed asthmatic adults at tertiary care but only difficult-to-treat asthmatic children. We recommend diagnosing ABPA in those with predisposing conditions or compatible clinico-radiological presentation, with a mandatory demonstration of fungal sensitisation and serum total IgE ≥500 IU·mL-1 and two of the following: fungal-specific IgG, peripheral blood eosinophilia or suggestive imaging. ABPM is considered in those with an ABPA-like presentation but normal A. fumigatus-IgE. Additionally, diagnosing ABPM requires repeated growth of the causative fungus from sputum. We do not routinely recommend treating asymptomatic ABPA patients. We recommend oral prednisolone or itraconazole monotherapy for treating acute ABPA (newly diagnosed or exacerbation), with prednisolone and itraconazole combination only for treating recurrent ABPA exacerbations. We have devised an objective multidimensional criterion to assess treatment response.

CONCLUSION

We have framed consensus guidelines for diagnosing, classifying and treating ABPA/M for patient care and 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.

Gaps in asthma diagnosis and treatment in low- and middle-income countries

Low- and middle-income countries (LMICs) contribute to a major proportion of asthma morbidity and mortality globally, even though the prevalence is higher in high income countries. Mortality due to asthma is avoidable and patients should be able to live a near normal life. There are factors that influence overall disease prevalence and poor health outcomes due to asthma in LMICs. This article summarizes the gaps in asthma diagnosis and management in LMICs. The gaps are diverse. Each challenge needs to be addressed through policy decisions, upgrade of infrastructure, knowledge and skills for early diagnosis and correct management among health care providers, both clinicians and paramedics. Healthcare accessibility and affordability are genuine challenges, and the public healthcare system needs to be geared up to address these at primary and tertiary levels. Mass education of the population through national level government initiatives is needed to help bridge the sociocultural gaps.

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.

Abnormal adenosine metabolism of neutrophils inhibits airway inflammation and remodeling in asthma model induced by Aspergillus fumigatus

BACKGROUND

Neutrophils consume a large amount of energy when performing their functions. Compared with other white blood cells, neutrophils contain few mitochondria and mainly rely on glycolysis and gluconeogenesis to produce ATP. The inflammatory site is hypoxic and nutrient poor. Our aim is to study the role of abnormal adenosine metabolism of neutrophils in the asthmatic airway inflammation microenvironment.

METHOD

In this study, an asthma model was established by intratracheal instillation of Aspergillus fumigatus extract in Ecto-5'-Nucleotidase (CD73) gene-knockout and wild-type mice. Multiple analyses from bronchoalveolar lavage fluid (BALF) were used to determine the levels of cytokines and chemokines. Immunohistochemistry was used to detect subcutaneous fibrosis and inflammatory cell infiltration. Finally, adenosine 5'-(α, β-methylene) diphosphate (APCP), a CD73 inhibitor, was pumped subcutaneously before Aspergillus attack to observe the infiltration of inflammatory cells and subcutaneous fibrosis to clarify its therapeutic effect.

RESULT

PAS staining showed that CD73 knockout inhibited pulmonary epithelial cell proliferation and bronchial fibrosis induced by Aspergillus extract. The genetic knockdownof CD73 significantly reduced the production of Th2 cytokines, interleukin (IL)-4, IL-6, IL-13, chemokine (C-C motif) ligand 5 (CCL5), eosinophil chemokine, neutrophil IL-17, and granulocyte colony-stimulating factor (G-CSF). In addition, exogenous adenosine supplementation increased airway inflammation. Finally, the CD73 inhibitor APCP was administered to reduce inflammation and subcutaneous fibrosis.

CONCLUSION

Elevated adenosine metabolism plays an inflammatory role in asthma, and CD73 could be a potential therapeutic target for asthma.