CCL8 and Parkinson disease: In PD subjects from the subset with matching serum and CSF, the CSF:serum ratios for CD30 (p = 0.002), MCP-2 (p = 0.010), and APRIL (p = 0.021) were lower, while Eotaxin was higher (p = 0.030) compared to the control (Fig. 4) before multiple comparison adjustment.