FOLR2 and peripheral arterial disease: The PE fragments then are secreted into the cytosol, where they inhibit protein synthesis by elongation factor-2, leading to apoptosis.36–37 Because FRβ is expressed exclusively on activated macrophages in atherosclerotic lesions, FRβ immunotoxin could be capable of mediating macrophage apoptosis in patients with ischemic heart diseases and peripheral arterial diseases thorough its specificity and cytotoxicity.