The induction of epithelial cell death using an antibody that activates the death receptor, Fas (CD95) [8, 9], or transgenic approaches encompassing diphtheria toxin, or diphtheria toxin receptor targeting bronchiolar or type II epithelial cells [10], are sufficient to induce pulmonary fibrosis in rodents. The gene discussed is FAS; the disease is pulmonary fibrosis.