Autoimmune lymphoproliferative syndrome (ALPS) is a disorder of immune regulation characterized by non-malignant proliferation of lymphocytes with lymphadenopathy/hepatomegaly, increased double negative T (α-β DNT cells), impaired apoptosis of T cells, and increased circulating levels of FAS ligand (CD95L), IL-10, IL-18 (130, 131). The gene discussed is FASLG; the disease is autoimmune lymphoproliferative syndrome.