With these data in mind, we note that primary biliary cirrhosis (PBC) is characterized by the presence of high titers of circulating antimitochondrial antibodies (AMAs), innate immune system activation [5–7], and liver-infiltrating autoreactive CD4 and CD8 T lymphocytes [8–10], leading to the progressive destruction of small intrahepatic bile ducts [11, 12]. The gene discussed is CD4; the disease is primary biliary cholangitis.