Fig. 3

Correlation of CSF QC activity (mU/L) with levels of Aβ (pg/ml) and Tau peptides (pg/ml) and Aβ40–Aβ42 correlation. a Aβ38, b Aβ40, c Aβ42, d Tau, e ptau and f Aβ40–Aβ42 correlation. Different diagnosis groups are colour coded (green: control, blue: mild AD, red: moderate AD). Pearson’s correlation coefficient with p values given for each parameter and group. Ellipses give 95% CI of the scatter for each group. Width and sloop of ellipses give a visual impression of strength of correlation: slim ellipses with sloops clearly different from 0 or 1 characterize high correlation of both parameters whereas wide ellipses with sloops narrow to 0 or 1 indicate less or no correlation. AD Alzheimer’s disease, QC glutaminyl cyclase (Colour figure online)