characterization of CFTR function and expression in nasal primary cells collected from patients with cystic fibrosis in comparison to their parents, healthy heterozygotes and healthy controls

3 groups of subjects are enrolled CF subjects according to their genotypes (aiming to enroll patients carrying 2 CF causing mutations with no CFTR expression/function, and patients carrying at least 1 mutation with residual function, such R117H) Parents or siblings of the CF subjects, as healthy hétérozygotes healthy controls All these subjects experience nasal brushings. From these nasal brushings,nasal cells are expanded, and cultured in air liquid interface to obtain polarized epithelium. This epithelium is then studied in Ussing chamber experiments to characterize the level of cAMP dependant Chloride transport and Sodium reabsorption. Apical expression of CFTR is assessed by immunofluorescence.

Results will allow to define the variability of CFTR function and expression criteria in subjects with the same genotype. Such data are crucial for interpretation of the effect of CFTR modulators.

Inclusion Criteria:

• patients with Cystic Fibrosis with 2 mutations in CFTR
• healthy heterozygotes with 1 mutation in CFTR
• healthy subjects with no familial history of Cystic Fibrosis and no symptoms suggesting Cystic Fibrosis

Exclusion Criteria:

• smoking

patients with Cystic Fibrosis with 2 mutations in CFTR

• healthy heterozygotes with 1 mutation in CFTR
• healthy subjects with no familial history of Cystic Fibrosis and no symptoms compatibel with Cystic Fibrosis