BAX and idiopathic pulmonary fibrosis: In a subsequent study, IL-6 induced the resistance of IPF lung fibroblasts to Fas-induced apoptosis due to the increased expression of the anti-apoptotic protein BCL-2, in contrast to IL-6 stimulated normal lung fibroblasts, which were more sensitive to Fas-induced apoptosis due to the increased expression of the pro-apoptotic protein Bax (Moodley et al., 2003a).