A24 mAb directed against the surface transferrin receptor induced apoptosis of ATL cell lines or primary ATL cells in vitro (201, 202) Alemtuzumab (Campath-1H), a chimeric humanized antibody that binds to the CD52 glycoprotein, led to promising, but short overall response rates in acute, chronic and lymphoma ATL (203). Here, CD52 is linked to lymphoma.