What is the pathophysiology of mold-related allergic bronchopulmonary aspergillosis (ABPA)?

Updated: Sep 18, 2017
  • Author: Shih-Wen Huang, MD; Chief Editor: Harumi Jyonouchi, MD  more...
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Answer

This is a well-recognized form of hypersensitivity pneumonitis, with nearly every case occurring in patients with previously diagnosed asthma or cystic fibrosis (CF).

ABPA rarely occurs in the absence of clinical asthma. The pulmonary immune system responds to a saprophytic fungus present in bronchial mucus, leading to bronchial wall widening (bronchiectasis) and distal small-airway fibrosis (bronchiolitis obliterans). It is characterized by clinical, immunologic, radiologic, and pathologic findings that range from mild asthma to end-stage fibrotic lung disease.

Children with CF are susceptible to ABPA with mucoid impaction of Aspergillus species. A fumigatus is the most frequent Aspergillus species to infect humans. Spores are 2-3.5 µm, which permits penetration to smaller airways. ABPA is the result of types 1, 3, and 4 hypersensitivity reactions.


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