Correlations of the baseline levels of plasma TACE activity with CSF tau (A, D), Aβ42 levels (B, E), and CSF Aβ42/tau ratios (C, F) in AD and MCI groups. A, D) The levels of plasma TACE activity showed a moderate positive correlation with CSF tau levels (rs = 0.347, 0.469, p < 0.05) in MCI and AD subjects. B, E) There were statistically negative correlations between the levels of plasma TACE activity and CSF Aβ42 levels (rs = −0.383, −0.351, p < 0.05) in MCI and AD groups. The levels of plasma TACE activity showed a negative correlation with CSF Aβ42/tau ratios (rs = −0.575, −0.476, p < 0.05) in MCI and AD groups.