It was noted that these DEGs contained several pro-inflammatory cytokines, such as interleukin 18 receptor accessory protein (IL18RAP), interleukin 1 beta (IL1B), interleukin 1 receptor type 2 (IL1R2), and C-C motif chemokine 4 (CC4), that were significantly up-regulated in PD, accompanied by a significantly elevated matrix metallopeptidase 10 (MMP10) (Fig. 3a). The gene discussed is CCL4; the disease is Parkinson disease.