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 (Figure 6). This evidence concerns the gene TNFSF13 and Parkinson disease.