MMP1 and Parkinson disease: Concentrations of MIF (p = 0.002), MMP-1 (p = 0.005), CD30 (p = 0.030), Tweak (p = 0.040), and SDF-1 alpha (p = 0.042) were lower in PD (n = 58) as compared to control subjects (n = 71) (Fig. 3C, D).