Further we again omitted the depressed control subjects (9.64 / 7.00 – 13.13 pg/ml) and compared serum IL-8 levels with these of AD patients (6.14 / 2.38–10.24 pg/ml) and observed the same difference as when the depressed control subjects were included (p = 0.02) (Additional file 1: Figure S1D). Here, CXCL8 is linked to Alzheimer disease.