PATIENT CHARACTERISTICS: Age: 2 to 55 Performance status: Not specified Life expectancy: More than 60 days Hematopoietic: Circulating blast count less than 10,000/mm3 (control with hydroxyurea or similar agent allowed) Hepatic: Bilirubin less than 1.5 mg/dL AST less than 1.5 times upper limit of normal (ULN) Must have no veno-occlusive liver disease Renal: Creatinine less than 2.0 mg/dL OR less than 1.5 times ULN for age Other: No active infection HIV negative No circulating antimouse immunoglobulin antibodies Must be able to tolerate diagnostic or therapeutic procedures (e.g., radiation isolation)