A. Viability of OSU-CLL either untreated (media), treated with vehicle control (DMSO), or increasing doses of chlorambucil (A), fludarabine (B) and dexamethasone (C) for 48 hours determined by MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. D. Viability at 48 hours in response to the indicated therapeutic antibodies was determined by AnnexinV/ propidium iodide (Ann/PI) staining. Antibodies were used as a concentration of 10 µg/mL in the presence of 50 µg/mL anti-Fc crosslinking antibody. Abbreviations: Trastuzumab (Tras, HER2), Rituximab and Ofatumumab (Ritux and Ofa, CD20) and Alemtuzumab, (Alem, CD52). All results shown are representative of 4 independent experiments.