Aspergillus serology and clinical outcomes in patients with bronchiectasis: data from the European Bronchiectasis Registry (EMBARC)

Aspergillus sp. cause diverse clinical manifestations in bronchiectasis including Allergic bronchopulmonary aspergillosis (ABPA), Aspergillus sensitization (AS) and raised IgG indicating exposure or infection with Aspergillus. What is the prevalence and clinical significance of Aspergillus-associated conditions in individuals with bronchiectasis? Bronchiectasis patients enrolled into the EMBARC registry from 2015 to 2022 with laboratory testing for Aspergillus lung disease (total IgE, specific IgE to Aspergillus or Aspergillus skin test, IgG to Aspergillus and blood eosinophil counts) were included for analysis. Modified-ISHAM-ABPA working group criteria (2021) were used to define ABPA. 9953 patients were included. 608 (6.1%) were classified as having ABPA, 570 (5.7%) showed Aspergillus sensitization, 806 (8.1%) had raised Aspergillus-specific IgG without sensitisation, 184 (1.8%) were both sensitised to Aspergillus and had raised Aspergillus-specific IgG and 619 (6.2%) had eosinophilic bronchiectasis (elevated eosinophil counts without evidence of Aspergillus lung disease). The remaining 72.0% had negative Aspergillus serology. Patients with ABPA, Aspergillus sensitization, and raised Aspergillus-specific IgG had more severe disease, with worse lung function and more frequent exacerbations at baseline. During long-term follow-up, patients with raised Aspergillus-specific IgG had higher exacerbation frequency and more severe exacerbations. Aspergillus sensitization associated with increased exacerbations and hospitalisations only in patients not receiving inhaled corticosteroids. Aspergillus lung disease is common in bronchiectasis. Raised IgG to Aspergillus is associated with significantly worse outcomes while ABPA and Aspergillus sensitization are associated with severe disease and exacerbations with a risk that is attenuated by inhaled corticosteroid use.