CLINICAL RESEARCH CORE Parkinson?s disease (PD) is the second most common neurodegenerative disorder. While current treatments mitigate the symptoms and disability associated with PD, no treatments slow or reverse the neurodegenerative process. Recent work points to a significant role for inflammation in PD pathogenesis. In work supported by the P20 Exploratory Project (NS09530), we found evidence for activation of innate immunity in animal models of PD, and obtained preliminary data implicating immunomodulation in human samples. Expanding this research to a more complete study of inflammatory changes in human subjects with PD is essential to define the role of inflammation in human disease and thus aid in the development of potential immunomodulatory disease modifying therapies. The primary goal of the Clinical Research Core is to establish a well-characterized cohort of early stage, idiopathic PD subjects for longitudinal study with regard to neuroinflammation. This cohort will provide clinical data, biospecimens, and imaging data that will directly support the three research projects proposed under the P50 grant. The Core will recruit, clinically assess, and follow annually 60 age- and sex- matched controls and 60 subjects with early stage, untreated, idiopathic PD at UAB. CSF, plasma, and peripheral blood mononuclear cells (PBMCs) will be collected at baseline, and plasma and PBMCs will be collected at annual follow-up visits. [18F]DPA-714 PET imaging will be performed on this cohort at baseline to assess central inflammation in early stage, idiopathic PD. All participant data will be submitted to the Data Management Resource (DMR) under the NINDS? Parkinson?s disease Biomarker Program (PDBP), and approved biospecimens will be sent to the NINDS repository BioSEND. In conjunction with Columbia University, the Core will also recruit LRRK2 G2019S carriers with PD (n=20) and without PD (n=20), and LRRK2 G2019S NON- carriers with PD (n=20) and without PD (n=20). Biospecimens and clinical data from patients previously genotyped for mutations in LRRK2 will feed directly into Project 3.