This project holds great promise for defining a robust molecular phenotype for CF lung disease, which relates to prognosis, and new targets for therapy. By using a large and well-defined population of deltaF508 homozygotes who also have whole genome single nucleotide polymorphism (SNP) data, and by studying gene expression across the whole transcriptome in a large number of samples of two relevant tissues (respiratory epithelium and transformed lymphocytes), we will be uniquely positioned to develop an integrated view of molecular mechanisms underlying CF lung disease severity.