The complement system is an extremely pivotal component of the innate immune system with the ability to identify and clear infectious challenges that invade the central nervous system through damaged blood-brain barriers, which has an essential property in the defense of the host to ultimately maintain the homeostasis of the brain, and multiple complement proteins have been identified to be co-localize with amyloid plaques in AD patients, indicating a role of the in AD [11, 12]. This evidence concerns the gene VTN and Alzheimer disease.