Numerous studies have shown that KLRG1 expression is increased on NK and T-cell subsets in patients with a variety of autoimmune diseases, including primary biliary cholangitis (PBC), IBM, systemic lupus erythematosus (SLE), and experimental autoimmune encephalomyelitis (EAE) [18, 56, 79–81] but is reduced in NK cells in the peripheral blood of patients with SLE [15] and is lacking in the peripheral blood of patients with autoimmune lymphoproliferative syndrome (ALPS) [56]. The gene discussed is KLRG1; the disease is autoimmune lymphoproliferative syndrome.