Concentrations of NDEV P-T181-tau were significantly increased (p < 0.001) with respect to controls in mild-to-moderate (CD81-adjusted levels: 44.28 pg/ml) and advanced AD (CD81-adjusted levels: 59.21 pg/ml), and did not show significant severity-related differences in AD cases (Fig. 1c). Here, CD81 is linked to Alzheimer disease.