CST7 and Alzheimer disease: By the addition of purified cystatin F dimer protein to cultured monocytes to mimic the high concentration of cystatin F in the plasma of AD patients, we found that the uptake of Aβ42-AlexaFluor 647 by the monocytic cell line THP-1 gradually decreased with increasing concentrations of the cystatin F dimer via FCM analysis (Fig. 4A).