It is stimulated by diverse factors such as the tumor necrosis factor (TNF) superfamily (TNFR1, Fas/CD95, and TRAIL-R), Toll-like receptors (TLR3 and TLR4), interferon-γ (IFN-γ), lipopolysaccharides (LPS), pathogen infection and various drugs [7,8]. Here, FAS is linked to infection.