Sensitization to Aspergillus fumigatus as a risk factor for bronchiectasis in COPD
Received 12 May 2017
Accepted for publication 5 July 2017
Published 31 August 2017 Volume 2017:12 Pages 2629—2638
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 2
Editor who approved publication: Dr Richard Russell
Stephanie Everaerts,1,2 Katrien Lagrou,3,4 Adriana Dubbeldam,5 Natalie Lorent,1 Kristina Vermeersch,2 Erna Van Hoeyveld,3 Xavier Bossuyt,3,4 Lieven J Dupont,1,2 Bart M Vanaudenaerde,2 Wim Janssens1,2
1Department of Respiratory Diseases, University Hospitals Leuven, 2Laboratory of Respiratory Diseases, Department of Clinical and Experimental Medicine, KU Leuven, 3Department of Laboratory Medicine, University Hospitals Leuven, 4Department of Microbiology and Immunology, KU Leuven, 5Department of Radiology, University Hospitals Leuven, Leuven, Belgium
Background: Bronchiectasis–chronic obstructive pulmonary disease (COPD) overlap presents a possible clinical phenotype of COPD, but it is unclear why it develops in a subset of patients. We hypothesized that sensitization to Aspergillus fumigatus (A fum) is associated with bronchiectasis in COPD and occurs more frequently in vitamin D-deficient patients.
Methods: This observational study investigated sensitization to A fum in an outpatient clinical cohort of 300 COPD patients and 50 (ex-) smoking controls. Total IgE, A fum-specific IgE against the crude extract and against the recombinant antigens and A fum IgG were measured using ImmunoCAP fluoroenzyme immunoassay. Vitamin D was measured by radioimmunoassay, and computed tomography images of the lungs were scored using the modified Reiff score.
Results: Sensitization to A fum occurred in 18% of COPD patients compared to 4% of controls (P=0.0110). In all, 31 COPD patients (10%) were sensitized to the crude extract and 24 patients (8%) had only IgE against recombinant antigens. A fum IgG levels were significantly higher in the COPD group (P=0.0473). Within COPD, A fum-sensitized patients were more often male (P=0.0293) and more often had bronchiectasis (P=0.0297). Pseudomonas aeruginosa and Serratia marcescens were more prevalent in historical sputum samples of A fum-sensitized COPD patients compared to A fum-non-sensitized COPD patients (P=0.0436). Vitamin D levels were comparable (P=0.2057). Multivariate analysis demonstrated that sensitization to recombinant f1 or f3 had a 2.8-fold increased risk for bronchiectasis (P=0.0030).
Conclusion: These results highlight a potential role for sensitization to A fum in COPD-related bronchiectasis.
Keywords: Aspergillus fumigatus hypersensitivity, recombinant antigens, ABPA, vitamin D
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