The production of MCP-1 increased 5-fold in the brains (Figure 2A), 2-fold in the livers (Figure 2B), 4-fold in the kidneys (Figure 2C), and 3-fold in the spleens (Figure 2D) of PD mice treated with saline, compared to the results for the healthy (wild-type) animals. Here, CCL2 is linked to Parkinson disease.