C9 and Alzheimer disease: The literature included herein showed a significant increase in complement effector proteins (Bb, C3b, C1q, C4b, C5b, C5b-C9 TCC, and Factor D) and a significant decrease in complement regulatory proteins (DAF, CD46, CD59, and CR1) in plasma NDsEVs and ADsEVs of patients with AD, which had moderate diagnostic value when used independently.