The importance of epithelial IL-8 production in CF is highlighted by two distinct animal models: 1) naïve sterile human lung grafts in severe combined immunodeficiency mice secrete IL-8 and recruit neutrophils to the CF lungs causing tissue damage [36]; 2) delta F508 cystic fibrosis mice raised in a pathogen-free environment spontaneously have increased levels of lung lavage fluid neutrophils and MIP-2, a mouse analog to human IL-8 [37]. Here, CXCL8 is linked to severe combined immunodeficiency.