MAPT and Alzheimer disease: Thus, Shi et al. published, in 2011, quantified p-tau, t-tau and Aβ42 levels in saliva from 21 AD patients and 38 control group participants using immunoprecipitation (IP), two mass spectrometers (MS) (Applied Biosystems, Foster City, CA, USA and Thermo Fisher Scientific Corp, San Jose, CA, USA), and a Luminex assay (Qiagen, Valencia, CA, USA) [19].