PRIOR CONCURRENT THERAPY: No prior therapy for ALL except: Emergency therapy for blast crisis, superior vena cava syndrome, or renal failure due to leukemic infiltration Biologic therapy: Not specified Chemotherapy: Intrathecal cytarabine or methotrexate allowed at diagnostic lumbar puncture Induction therapy must begin within 72 hours after intrathecal injection Endocrine therapy: At least 1-2 months since prior prednisone, for less than 48 hours, for reactive airway disease Inhalational steroids allowed Radiotherapy: Not specified Surgery: Not specified