Biomarker Assessments of Leukine During Treatment of Parkinson's Disease

First, the investigators will determine the safety of a 36 month regimen of Leukine administered as a weight-based dose at 3 µg/kg/day for 5 days (week), followed by a 2-day holiday (weekend). This 36 month (n=10) pilot study will extend the prior 2 month observation tests towards the goal of assessing the safety of Leukine for treatment of Parkinson's disease (PD). Clinical signs and symptoms will be measured by personal well-being, physical, and neurological examinations (UPDRS Parts I, II, III, and IV assessments) and blood tests (CBC with differential, total T cell count, and a comprehensive metabolic sera panel). Second, we will assess regimen tolerability administered in a dose reduction, from 6 µg/kg/day without interruption, to 3 µg/kg/day with 2 day drug holidays. The investigators will examine over a time of 36 months, effects of treatment on defined adaptive immune deficits in PD as measured by analysis of peripheral blood mononuclear cells collected before, during, and after cessation of Leukine administration. Individual T cell parameters will be assessed and will include links between T cell function and subset analyses and clinical neurological signs and symptoms. In addition, the functional stability of the immune deficits will be assess in PD by examining T cell subsets in PD patients in this study against prior results. The investigators will also determine whether the immune deficits of PD are consistent during baseline data collection, and the potential Leukine-induced motor control and mobility improvements will be determined by UPDRS part I, II, III, and IV scores off treatment and on treatment.

Primary Objectives: There are three study goals. First, the investigators will determine the safety of a 36 month regimen of Leukine administered as a weight-based dose at 3 µg/kg/day for 5 days (week), followed by a 2-day holiday (weekend). This 36 month (n=10) pilot study will extend the prior 2 month observation tests towards the goal of assessing the safety of Leukine for treatment of Parkinson's disease (PD). Clinical signs and symptoms will be measured by personal well-being, physical, and neurological examinations (UPDRS Parts I, II, III, and IV assessments) and blood tests (CBC with differential, total T cell count, and a comprehensive metabolic sera panel). Second, the investigators will assess regimen tolerability administered in a dose reduction, from 6 µg/kg/day without interruption, to 3 µg/kg/day with 2 day drug holidays. The lowered dose was chosen based on known tolerability and parallel-linked immune reconstitution seen in cancer-associated disease treatments. Due to fragility of the patient population and prior recorded adverse events the proposed dose reductions are justified. Secondary Objectives: Over a course of 36 months, the effects of treatment on defined adaptive immune deficits in PD as measured by analysis of peripheral blood mononuclear cells collected before, during, and after cessation of Leukine administration will be examined. Individual T cell parameters that include links between T cell function and subset analyses and clinical neurological signs and symptoms will be examined. These immune parameters will be serially examined as they may contribute to the immune deficits in PD. Thus, timed analyses of changes in T cell phenotypes and/or function will be completed. In addition, the investigators will assess the functional stability of the immune deficits in PD and will determine whether the immune deficits of PD are consistent during baseline data collection. The potential Leukine-induced motor control and mobility improvements will be determined by assessing UPDRS part I, II, III, and IV scores off treatment and on treatment. Specifically, over the course of this six-month treatment study, various biomarkers will be assessed including: T cell markers of immune activation, DNA methylation status, and B cell and bone marrow progenitor cell markers. We hope to uncover the time course of Treg induction, as well as link the pharmacokinetics of Leukine treatment (not previously recorded) to changes in specific biomarkers. Additionally, changes in the humoral response following extended Leukine treatment will be assessed by measuring the presence of antibodies against Leukine and alterations in B cell frequencies.