FASLG and acute respiratory distress syndrome: Similarly, in acute lung diseases such as acute respiratory distress syndrome (ARDS), the degree of the epithelial injury and the loss of alveolar epithelial cells due to Fas-ligand–mediated apoptosis is an important predictor of outcome.11, 12, 13 In some cases of ARDS, a marked fibroproliferative response is associated with bad outcome.14 Therefore, a therapy that promotes epithelial repair and inhibits epithelial–mesenchymal transition (EMT) could be useful in both acute and chronic respiratory disease, but only if it was not also a stimulus for fibro-poliferation.