Cystic fibrosis transmembrane conductance regulator gene mutations: Do they play a role in the aetiology of allergic bronchopulmonary aspergillosis?

Background: Previous work suggests that cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations may be implicated in the aetiology of allergic bronchopulmonary aspergilosis (ABPA). Objective: To compare the frequency of CF gene mutations in asthmatics with ABPA of varying severity with asthmatics who were skin prick test (SPT)-positive to Aspergillus fumigatus (Af) without evidence of ABPA and asthmatics SPT-negative to Af. Methods: Thirty-one Caucasian patients with ABPA were identified, together with asthmatics SPT positive to Afwithout evidence of ABPA (n = 23) and SPT negative to Af(n = 28). Genomic DNA was tested for 16 CF mutations accounting for approximately 85% of CF alleles in Caucasian New Zealanders. Results: Four (12.9%) ABPA patients were found to be carriers of a CF mutation (ΔF508 n = 3, R117H n = 1), one (4.3%) asthmatic SPT positive to Af without ABPA (ΔF508), and one (3.6%) asthmatic SPT negative to Af(R117H). All patients with a CF mutation had normal sweat chloride (< 40 mM). There was no significant difference between the frequency of CF mutations in the ABPA patients and asthmatics without ABPA. However, the frequency of CF mutations in the ABPA patients was significantly different (P = 0.0125) to the expected carrier rate in the general population. Conclusion: These results lend further support to a possible link between CF mutations and ABPA.