CCL2 and Parkinson disease: Patients with PD have been observed to display heightened levels of several inflammatory molecules (IL-1β (Interleukin-1 beta), IL-6 (Interleukin-6), INF-γ (interferon-γ), MCP-1 (Monocyte chemoattractant protein-1) and TNF-α (Tumor necrosis factor-α)) in their bloodstream, cerebrospinal fluid (CSF), and brain [106].