Aspergillus SP. Positive Airway Samples in People With Non-CF Bronchiectasis is Associated With Higher Biomarkers of Systemic TH2 Inflammation, Allergic Airway Disease, and Airway Co-infection
Abstract Introduction: Non-Cystic Fibrosis Bronchiectasis (NCFB) is an obstructive pulmonary disease associated with structural lung disease, altered mucociliary clearance, hyper mucus secretion, recurrent infection, and airway inflammation that results in significant morbidity and mortality. Aspergillus sp (Asp) is a common fungi isolated in respiratory specimens of those with lung disease and is associated with both infectious and allergic pulmonary diseases such as Asthma and Cystic Fibrosis. Despite individuals with NCFB having similar phenotypes as these conditions, the impact of Asp on this population is poorly understood. Methods: We performed a cross-sectional retrospective analysis from the US Bronchiectasis and NTM Research Registry (BRR). NCFB patients without a history of lung transplant who had at least one respiratory Asp culture were included. We compared patients with no history of Asp grown from respiratory culture to those with at least one positive respiratory culture for Asp during the available period. Patient demographics, bacterial culture history, lung function, comorbidities, modified Bronchiectasis Severity Index (mBSI), and sputum parameters were analyzed descriptively. Comparisons between groups were conducted using Kruskal-Wallis, independent sample t-tests, and chi-square tests for continuous and categorical variables as appropriate. Results: 3985 people with NCFB met inclusion criteria. 3359 (84.3%) individuals were Asp culture negative compared to 626 (15.7%) individuals with Asp. There were notable differences in race, showing higher proportions of non-Hispanic white (90.4 vs 82.2%) in this population. While the frequency of Chronic Obstructive Pulmonary Disease and Primary Ciliary Dyskinesia were similar, there were more individuals with Asthma (31.3 vs 24.7%, p<0.001) and Allergic Bronchopulmonary Aspergillosis (ABPA) (6.4 vs 2.4%, p<0.001) in the Asp positive group (Figure 1A). The Asp positive group had higher blood eosinophils (150.0 vs 124.0 cells/uL, p=0.026, Figure 1B), had nominally lower lung function (73.5 vs 75.3% ppFEV1, p=0.089), and were more likely to have at least one or more positive bacterial cultures (62.9 vs 51.9%, p<0.001, Figure 1C). There was no significant difference in sex, age, exacerbations, Pseudomonas aeruginosa or NTM positive cultures, sputum volume, or mBSI. Conclusion: Individuals with NCFB and history of one or more positive Asp cultures were more likely to be non-Hispanic white, have a diagnosis of Asthma and/or ABPA, higher blood eosinophils, and more positive airway bacterial cultures. Further work is needed to better understand how Asp contributes to bronchiectasis progression. More expansive analysis and multivariant modeling is underway to better understand the impact of Asp in people with NCFB.