CD81 and Alzheimer disease: Results showed a significant neurite density decrease in neurons treated with AEVs from AD, compared to the control participants (p = 0.02); the difference was not observed in the NEV-treated (p = 0.891) or CD81 + EV-treated neurons (p = 0.252) (Figure 2), suggesting a greater neurodegenerative potential for AEVs, compared to NEVs or CD81 + EVs.