FASLG and Alzheimer disease: Both in vitro and ex vivo studies have shown that Th1 cells exhibit greater susceptibility to AICD than Th2 cells, a difference largely attributed to more efficient Fas ligand surface expression in Th1 cells, which in turn contributes to the Th2-biased immune profile observed in AD (Oberg et al., 1997; Akdis et al., 2003).