Aspergillus Serologic Findings and Clinical Outcomes in Patients With Bronchiectasis

Background: Aspergillus species cause diverse clinical manifestations in bronchiectasis including allergic bronchopulmonary aspergillosis (ABPA), Aspergillus sensitization (AS), and raised IgG indicating exposure to, or infection with, Aspergillus. Research Question: What are the prevalence and clinical significance of Aspergillus-associated conditions in individuals with bronchiectasis? Study Design and Methods: Patients with bronchiectasis enrolled into the European Bronchiectasis Registry from 2015 through 2022 with laboratory testing for Aspergillus lung disease (total IgE, IgE specific to Aspergillus or Aspergillus skin test, or IgG specific to Aspergillus and blood eosinophil counts) were included for analysis. Modified International Society for Human and Anima Mycology ABPA working group criteria (2024) were used to define ABPA. Results: Nine thousand nine hundred fifty-three patients were included. Six hundred eight patients (6.1%) were classified as having ABPA, 570 patients (5.7%) showed AS, 806 patients (8.1%) showed raised Aspergillus-specific IgG without AS, 184 patients (1.8%) showed both AS and had raised Aspergillus-specific IgG levels, and 619 patients (6.2%) demonstrated eosinophilic bronchiectasis (elevated eosinophil counts without evidence of Aspergillus lung disease). The remaining 72% showed negative Aspergillus serologic findings. Patients with ABPA, AS, or raised Aspergillus-specific IgG demonstrated more severe disease, with worse lung function and more frequent exacerbations at baseline. During long-term follow-up, patients with raised Aspergillus-specific IgG experienced higher exacerbation frequency and more severe exacerbations. AS was associated with increased exacerbations and hospitalizations only in patients not receiving inhaled corticosteroids. Interpretation: Aspergillus lung disease is common in bronchiectasis. Raised IgG levels to Aspergillus were associated with significantly worse outcomes, whereas ABPA and AS were associated with severe disease and exacerbations with a risk that is attenuated by inhaled corticosteroid use.