C9 and Alzheimer disease: Two studies compared differences between NDsEVs and ADsEVs in patients with AD in the same indicators [44,46], finding that levels of Aβ42, p-Tau181, p-S396-Tau, sAPPα, sAPPβ, BACE-1, γ-secretase, TNF-α, C5b-C9 TCC, C3d, C4b, Bb, Factor B, and Factor D in ADsEVs were significantly higher than those in NDsEVs.