CCL2 and Parkinson disease: In contrast, PD mice treated with EV-GDNF showed a significant decrease (*) in secretion of IFN-γ and MCP-1 when compared to PD mice treated with saline, and a significant decrease ($) in IL-4, IL-6, IP-10, and TNF-α, when compared to PD mice treated with saline and sham EVs, similar to WT mice, or even lower.