Immunoglobulin G4-associated autoimmune hepatitis with peripheral blood eosinophilia: a case report.

Background: Immunoglobulin G4 (IgG4) associated autoimmune hepatitis (AIH) has been recognized as a type of autoimmune disease that responds to corticosteroid. The diagnosis is based on elevation of the serum IgG4 level, abundance of IgG4 enhanced plasma cell infiltration in the portal region of the liver, and satisfaction of the criteria for "definite AIH" under the revised International Autoimmune Hepatitis Group (IAIHG) scoring system. However, the clinical course of the disease is unclear.

Case Presentation: A 65-year-old man with jaundice and peripheral blood eosinophilia. His IAIHG and simplified score was compatible with definite AIH and his IgG4 level was elevated. Magnetic resonance imaging did not reveal abnormalities in the hepatobiliary system or pancreas. A liver biopsy revealed interface hepatitis with IgG4 positive plasma cell infiltration in the portal region, without evidence of bile duct injury. He responded to 4-week period of induction prednisolone therapy and had no recurring symptoms under maintenance therapy of 5 mg prednisolone during the 3-year follow up.

Conclusions: This was a rare case that demonstrated an association between IgG4 associated AIH and the presence of peripheral blood eosinophilia.