Cystic Fibrosis: More Questions than Answers

Cystic fibrosis transmembrane regulator (CFTR) is shown as one member of a developmental cascade required for normal secretory epithelium development. Included in this pathway are other cytokines, possibly MRP8/14(CF antigen). During normal development, the presence of CFTR feedback mechanisms either completely inhibit or at least decrease the expression of these developmentally active cytokines. In contrast, a lack of CFTR function during development would lead to incomplete differentiation of secretory cells. The failure of secretory cell differentiation would lead to the constitutive expression of the developmental cytokines. Once the immune system matures postnatally, these same cytokines would assume a proinflammatory role, leading to chronic inflammation and fibrosis.