Beginning at either days 14 (during the development of fibrosis9) or 30 (when fibrosis is established9) after IPF fibroblast injection (line S117A), C.B-17SCID/bg mice received PBS, IL13-PE, scrambled siRNA (n/s), or siRNA targeting either mouse or human MAP3K19 by intranasal delivery every other day until day 60 after human fibroblast injection. This evidence concerns the gene IL13 and idiopathic pulmonary fibrosis.