CST3 and Alzheimer disease: As shown in Fig 2, increased estimated levels of β2 microglobulin (+47,584.4 ng/mL; P = .029), PAI-1 (+3,432.9 ng/mL; P = 1.1 × 10−5), and cystatin C (+31,691 ng/mL; P = 4.0 × 10−5) were found in AD patients, while TIMP-1 levels (−370.7 ng/mL; P = 7.5 × 10−4) were decreased.