--Disease Characteristics-- Advanced Parkinson's disease Hoehn-Yahr stage IV or worse during "off" periods Hoehn-Yahr stage III or better during "on" periods Predictable motor fluctuations with at least 20% of waking day in the "off" stage No atypical parkinsonism or secondary parkinsonism --Prior/Concurrent Therapy-- Biologic therapy: Not specified Chemotherapy: Stable doses of levodopa/carbidopa or any other antiparkinson therapy for 2 months prior to study Surgery: No previous intracranial/neurosurgical procedures --Patient Characteristics-- Renal: Creatinine clearance at least 70 mL/min or creatinine no greater than 1.8 mg/dL Protein no greater than 300 mg/dL Other: Not pregnant or nursing Adequate contraception required of fertile patients Prior history of good response to levodopa No sensitivity to cyclosporine Not HIV positive (e.g., HIV I or II) No human T-cell leukemia/lymphoma virus (HTLV-1) No tremors interfering with stereotactic surgery No clinically significant medical, neoplastic or infectious disease No clinically significant laboratory abnormality No dementia that precludes signing informed consent or score of less than 24 on Mini-Mental status examination