FAS and idiopathic pulmonary fibrosis: We examined the expression of specific apoptotic markers in BALF macrophages of treatment-naive patients and control group, representing activation of the extrinsic (fas, fas ligand) and the intrinsic pathway (bcl-2, bax) and total expression of apoptosis, based on expression of Apoptag; a statistically significant difference was found between the IPF group and control group at presentation regarding expression of Apoptag.