Patients with allergic bronchopulmonary aspergillosis (ABPA) respond well to standard treatments (oral corticosteroids and/or antifungals); however, approximately in half of the patients, the condition recurs during tapering or early after treatment discontinuation. To avoid the adverse effects of long-term treatment, biologics targeting immunoglobulin E (IgE), eosinophils, or type 2 immune responses have been used in refractory ABPA. Omalizumab, an anti-IgE antibody, as well as mepolizumab and benralizumab targeting eosinophils has been consistently shown to decrease co-morbid asthma exacerbation and dose of oral corticosteroids. Furthermore, mepolizumab and benralizumab effectively improved chest radiographic abnormalities, such as mucus plugs in the bronchi. Data on dupilumab and tezepelumab are limited; however, they may be effective in patients who are resistant to treatment with omalizumab/mepolizumab/benralizumab. Future studies examining the effects of these biologics in preventing the recurrences/exacerbations of ABPA are warranted.

Allergic bronchopulmonary aspergillosis/mycosis (ABPA/ABPM) is characterized by increased serum levels of total and fungi-specific immunoglobulin E (IgE) and eosinophilic mucus plugs in the airways. Its classification as either an allergic or eosinophilic disease remains controversial. In the present review, we explored this topic based on three clinical studies that analyzed the clinical characteristics of ABPA/ABPM using a cluster analysis, factor analysis, and comparison between ABPM caused by Schizophyllum commune and ABPA. We also compared therapeutic responses to biologics targeting either IgE (omalizumab) or eosinophils (mepolizumab/benralizumab) to elucidate the role of these components in the pathogenesis of ABPA/ABPM. Based on these analyses, eosinophilic mucus plug formation in the airways is considered a cardinal feature of the development of ABPA/ABPM, whereas IgE responses to fungi are important factors that modulate disease manifestation.

Severe asthma is a critical condition for patients with asthma, characterized by frequent exacerbations, decreased pulmonary function, and unstable symptoms related to asthma. Consequently, the administration of systemic corticosteroids, which cause secondary damage because of their adverse effects, is considered. Recently, several types of molecular-targeted biological therapies have become available for patients with severe asthma, and they have a capacity to improve the pathophysiology of severe asthma. However, several clinical reports indicate that the effects differ depending on the biological targets of asthma in individual patients. In this review, the molecular mechanisms and clinical impact of biologic therapies in severe asthma are described. In addition, molecules targeted by possible future biologics are also addressed. Better understanding of the mechanistic basis for the role of biologics in severe asthma could lead to new therapeutic options for these patients.

Treatment of allergic bronchopulmonary aspergillosis (ABPA) is challenging. Biological therapies have been reported as adjunctive treatments for ABPA, primarily in case series or case reports. This study aimed to analyze the efficacy of biologics for managing ABPA both qualitatively and quantitatively.

All articles on APBA published in October 2023 were searched in PubMed, Web of Science, ClinicalTrials.gov, and Embase databases. The effects of interest were the mean changes from baseline for outcomes, including exacerbation rates, oral corticosteroids usage (OCS), and total immunoglobulin E (IgE) levels. Reported outcomes were quantitatively synthesized by usual or individual patient data (IPD) meta-analyses. PROSPERO registration number: CRD42022373396.

A total of 86 studies were included in the systematic review including 346 patients. Sixteen studies on omalizumab were pooled for the usual meta-analysis. Omalizumab therapy significantly reduced exacerbation rates (- 2.29 [95%CI - 3.32, - 1.26]), OCS dosage (- 10.91 mg [95%CI - 18.98, - 2.85]), and total IgE levels (- 273.07 IU/mL [95%CI - 379.30, - 166.84]), meanwhile improving FEV1% predicted (10.09% [95%CI 6.62, 13.55]). Thirty-one studies on dupilumab, mepolizumab, or benralizumab were pooled to perform an IPD meta-analysis, retrospectively. Both dupilumab and mepolizumab significantly reduced exacerbation rates, OCS, and total IgE levels. Benralizumab showed a similar trend, but it was not statistically significant. Tezepelumab showed weak evidence of its effects on ABPA. All five biologics led to milder clinical symptoms (e.g., cough, wheezing) with serious adverse effects that happened once in omalizumab treatment.

These results indicate the clinical benefit of omalizumab, dupilumab, and mepolizumab in patients with ABPA. Further randomized, controlled studies with a larger sample size and longer follow-up are needed to confirm these findings.

Pulmonary manifestations in patients with allergic bronchopulmonary aspergillosis (ABPA) and nontuberculous mycobacterial-pulmonary disease (NTM-PD) include bronchiectasis and mucus plugging. A 68-year-old woman, treated with antibiotics and inhaled corticosteroids for NTM-PD and asthma, presented with fever and wheezing. ABPA was diagnosed based on laboratory findings (elevated peripheral blood eosinophil counts and serum total IgE levels and positive Aspergillus-specific IgE and IgG) and imaging observation of a high-attenuation mucus plug. Systemic prednisolone was avoided to prevent NTM-PD progression. Dupilumab, a monoclonal antibody that blocks IL-4/13, was introduced to improve the clinical findings. Herein, we discuss the pathophysiological mechanisms underlying this rare comorbidity.

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.

Mucus plugs are associated with airway obstruction in severe asthma and are involved in the formation of activated eosinophils. Benralizumab, an anti-interleukin-5 receptor antibody, markedly reduces not only peripheral blood eosinophils but also airway eosinophils; however, its effects on mucus plugs have not been clarified. In this study, we examined the efficacy of benralizumab on mucus plugs using computed tomography (CT) imaging.

Twelve patients who were administered benralizumab and underwent CT before and approximately 4 months after the introduction of benralizumab were included in this study, and the number of mucus plugs before and after benralizumab administration was compared. The correlation between the clinical background and treatment effect was also examined.

The number of mucus plugs significantly decreased after the introduction of benralizumab. The number of mucus plugs was correlated with sputum eosinophil percentage and eosinophil cationic protein in the sputum supernatants and inversely correlated with forced expiratory volume in 1 s (FEV1). Benralizumab induction resulted in a marked decrease in blood and sputum eosinophil levels and a significant improvement in asthma symptoms, quality of life scores, FEV1, and exacerbation frequency. Furthermore, there was a significant correlation between the reduction in mucus plugs and changes in the symptom score or FEV1.

These data suggest that benralizumab may have the potential to improve symptoms and respiratory function in patients with severe eosinophilic asthma by reducing mucus plugs.

Biologics targeting the molecules associated with type 2 inflammation have significantly improved the outcomes of patients with severe eosinophilic asthma and chronic rhinosinusitis with nasal polyps (CRSwNP). Chronic eosinophilic airway/lung diseases including chronic eosinophilic pneumonia, allergic bronchopulmonary aspergillosis/mycosis, eosinophilic bronchitis, and eosinophilic granulomatosis with polyangiitis share clinical features with eosinophilic asthma and CRPwNP, which are mostly adult-onset and may develop simultaneously or consecutively. These eosinophilic airway/lung diseases respond well to initial treatment with systemic corticosteroids, but often recur when the corticosteroids are tapered. The management of these "refractory" cases is an unmet need for clinicians. We first reviewed the standard treatments for these chronic eosinophilic airway/lung diseases, followed by the definition and prevalence of refractory diseases and the role of biologics in their management. The available evidence varies from case reports and case series to randomized control trials, depending on the type of disease; however, these studies provide not only a direction for clinical practice, but also insights into the pathophysiology of each disease. Physicians should discuss the efficacy and costs of biologics in patients with refractory eosinophilic airway/lung diseases to minimize not only the current symptoms, but future risks as well.