In one of the studies, it was demonstrated that the mice infected with the lethal H5N1 strain had higher amounts of plasmacytoid DCs (pDCs) expressing the Fas ligand (FasL), which caused the death of CD8+ T cells specific for influenza via a Fas-FasL-mediated pathway; the mice inoculated with the non-lethal H5N1 strain did not exhibit this [106]. This evidence concerns the gene FASLG and influenza.