Study of the Neuro-protective Effect of Granulocyte-colony Stimulating Factor on Early Stage Parkinson's Disease

Inclusion Criteria: * Hoehn \& Yahr stage I\~III * Patients with idiopathic Parkinson's disease(PD), who meet the United Kingdom Parkinson's Disease Society Brain Bank diagnostic criteria, with a good response to levodopa * The onset of PD symptoms must be occurred \> = 40 years of age (to exclude YOPD), and the patient must have been diagnosed with idiopathic PD \> =40 years of age * Patients may have symptoms of wearing OFF and/or levodopa induced dyskinesia * Patients must rate between Hoehn \& Yahr stage I to III, when in an OFF medication state * Patients must in their optimal medication treatment state, and will not changing their medications within 3 months before and after enrollment Exclusion Criteria: * Patients who are proved to be Young Onset Parkinson's Disease (YOPD) and/or genetically related (e.g. Parkin). * Women of child-bearing potential, pregnant or lactating. * Patients who are proved to have tumor growth and/or malignancy. * Patients with a past (within one year) or present history of psychotic symptoms requiring anti- psychotic treatment. * Patients with active symptoms of major depression with suicidal ideation or suicide attempt. * Patients with previous brain surgery (including pallidotomy and deep brain stimulation). * Patients with significant cognitive impairment ( Mini-Mental State Examination, MMSE \< 24). * Patients who do not sign the inform consent,