Fas

Why all the fuss about Fas? Fas seems to be essential for killing off the immune response before it goes out of control. Mice bearing spontaneous loss-of-function mutations in Fas and FasL have enlarged spleens and lymph glands, and some mouse strains have a form of autoimmunity, due to a defect in the elimination of activated lymphocytes. Mutations in Fas have also been described in children with autoimmune lymphoproliferative syndrome (ALPS). Fas is now also thought to be involved in cell death outside the immune system, especially in cancer and other noninfectious diseases.