STAT1 and Alzheimer disease: Strikingly, expression of some genes including Th1 signature genesIfng andTbx21 by IL-21 are differentially regulated by STAT1 and STAT3, and IL-21-induced expression ofIFNG andTBX21 is enhanced in CD4+ T cells from AD-HIES patients and also modestly increased in CD4+ T cells from STAT1 gain-of-function patients28.