OBJECTIVES: I. Determine the toxicity of high-dose busulfan followed by interleukin-2 (IL-2) and sargramostim (GM-CSF) activated autologous/syngeneic peripheral blood stem cell (PBSC) transplantation, sequential IL-2 and GM-CSF therapy, and interferon alfa in patients with chronic myelogenous leukemia. II. Determine engraftment potential of IL-2/GM-CSF activated PBSC followed by sequential IL-2/GM-CSF therapy in this patient population. III. Assess the time to cytogenetic and/or morphologic relapse, overall event-free survival, and overall survival in these patients treated with this regimen.