Augmentation of CML cell colony formation by bcr-abl–specific CD4⁺ T-cell clones. (A) The numbers of CFU-GM and BFU-E generated from bone marrow cells of various patients in the absence (□) and presence of b3a2-specific CD4⁺T-cell clones, MY-1 (▪), and TO-1 (▧) are shown. (B) The numbers of CFU-GM and BFU-E generated from bone marrow cells of a patient with HLA-DRB1*0901-positive b3a2 CML which had been untreated or treated with anti–HLA-DR MoAb and cultured without (□) or with MY-1 (▪) and TO-1 (▧) are shown. (C) The numbers of CFU-GM and BFU-E generated from bone marrow cells of various patients with CML in the absence (□) and presence of MY-1 (▪) and TO-1 (▧) culture supernatant are shown. Cells in triplicate wells were cultured and the data are expressed as mean colony counts ± standard deviation. *, P< .05; **, P < .01.