Although others have shown that overexpression of CFTR was not detrimental to airway epithelial cell integrity in vitro and in vivo [21],[22], we had anticipated that Fsk-stimulated Cl− secretion would exceed that of non-CF HAE since CF ciliated cells significantly overexpressed CFTR, i.e., CF HAE would be “supercorrected.” That CF HAE overexpressing CFTR exhibited identical anion secretion as measured in non-CF HAE with endogenous CFTR levels suggested that the ceiling for anion secretion rates was not solely related to the absolute quantity of CFTR present in ciliated cells. Here, CFTR is linked to cystic fibrosis.