For example, IL-18 deficient mice were shown to have increased mortality, lung injury, and leukocyte infiltration in the BAL in response to bleomycin challenge compared to wild-type mice, and prophylactic treatment of wild-type mice with IL-18 prior to bleomycin challenge reduced lung injury and fibrosis suggesting that IL-18 plays a protective role against bleomycin-induced lung fibrosis [172]. This evidence concerns the gene IL18 and pulmonary fibrosis.