LTF and Parkinson disease: Specifically, lactoferrin levels (PD: 1003.383 μg/g vs. HS: 748.077 μg/g, FDR < 0.01; Figure 2A) and calprotectin (PD: 143.863 μg/g vs. HS: 106.368 μg/g, FDR < 0.01; Figure 2B) were significantly elevated in the PD group.