FASLG and chronic obstructive pulmonary disease: Takabatake and colleagues described significantly higher TNF-α and sTNF-R55 and R75 levels in the circulation of COPD patients, while serum levels of soluble Fas ligand (sFas-L), an inducer of apoptosis, and plasma levels of the soluble Fas receptor (sFas), an inhibitor of apoptosis, were not increased in COPD patients.