Furthermore, in order to clarify whether the expansion of Tregs is a characteristic finding of chronic viral hepatitis, we examined Foxp3 expression in liver biopsies of patients with other hepatic diseases, including nonalcoholic fatty liver disease (NAFLD), autoimmune hepatitis, primary biliary cirrhosis, and liver-toxicity induced by methotrexate. Here, FOXP3 is linked to primary biliary cholangitis.