OBJECTIVES: I. Evaluate the antileukemic effects of humanized anti-CD33 monoclonal antibody M195 (HuM195) against minimal residual disease in patients with acute promyelocytic leukemia (APL) by using a reverse transcription-polymerase chain reaction for the mutated retinoic acid receptor-alpha to detect changes in minimal residual disease. II. Assess the disease free and overall survival of patients with APL receiving HuM195 for minimal residual disease. III. Evaluate the safety and toxicity of HuM195 in these patients. IV. Evaluate whether HuM195 elicits a human anti-human antibody response, including anti-idiotype antibody responses, in patients with APL.