C9 and prion disease: In T2 vs. T1 group, the most downregulated protein was complement component C9 in Complement and coagulation cascades, Systemic lupus erythematosus, Prion diseases, and Amoebiasis pathways with complement C1q subcomponent subunit C (C1QC) in Staphylococcus aureus infection pathway, Ig gamma-1 chain C region (IGHG1) in pathways of Phagosome, Dilated cardiomyopathy, Primary immunodeficiency, Fc gamma R-mediated phagocytosis, and Hematopoietic cell lineage.