FAS and idiopathic pulmonary fibrosis: In another study, in lung fibroblasts derived from IPF patients, IL6 contributed to resistance against Fas-induced apoptosis by increasing the expression of the anti-apoptotic protein BCL-2, whereas normal lung fibroblasts became more sensitive to Fas-induced apoptosis, which was mediated by the increased expression of the pro-apoptotic protein Bax when exposed to IL6 (Moodley et al., 2003a).