Cystic fibrosis (CF) is a recessive genetic disorder caused by mutations in CF transmembrane conductance regulator (CFTR) gene. CF has multi-organ involvement, but respiratory disease is the major cause of morbidity and mortality. The median age of survival in CF is only 37 years, but there is a broad range of disease severity in the lung, even among patients with identical CFTR genotypes, including deltaF508 homozygotes.