People with cystic fibrosis (pwCF), a disease caused by mutations in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein, are at increased risk of allergic bronchopulmonary aspergillosis, a chronic form of pulmonary aspergillosis characterised by Th2 responses in the airway and bronchiectasis [6–10]. The gene discussed is CFTR; the disease is cystic fibrosis.