ADCC activity of PBMCs from myeloma patients according to clinical stages. PBMCs from healthy donors or untreated (○), treated (•), or post PBSCT (▪) myeloma patients were compared as effector cells against RPMI 8226 cells at an E/T ratio of 50 in the presence of 1 μg/mL humanized anti-HM1.24 MoAb. Horizontal bars represent the mean values of each group. The shaded area represents the mean ± 2 SD of ADCC activity of PBMCs from healthy donors.