Although we demonstrated both apoptosis of the alveolar epithelium via TUNEL analysis and the up regulation of Fas and FasL in situ in alveolar epithelium and in cells of the inflammatory infiltrate, modulation of reovirus 1/L-ALI/ARDS was not linked to the inhibition of the Fas/FasL pathway suggesting the involvement of additional apoptosis pathways [9]. This evidence concerns the gene FAS and acute respiratory distress syndrome.