Marked accumulation of fluorodeoxyglucose and inflammatory cells expressing glucose transporter-3 in immunoglobulin G4-related autoimmune hepatitis.

Immunoglobulin (Ig)G4-related autoimmune hepatitis (AIH) is a recently proposed subtype that responds well to steroid treatment; however, its pathogenesis remains unclear. We report here a 65-year-old Japanese woman with skin itching and lip swelling. She had liver injury with jaundice, which persisted despite stopping anti-allergic agents. Blood chemistry revealed highly elevated serum IgG and IgG4 (535 mg/dL) levels, and positive anti-nuclear antibody. The diagnosis of AIH was based on liver biopsy. Notably, the IgG4 /IgG cell ratio was 85%. On fluorodeoxyglucose (FDG) positron emission tomography/computed tomography, robust signal intensity was found in the liver, and in enlarged lymph nodes and salivary glands with confirmed IgG4 cell infiltration. Immunofluorescence analysis of the liver biopsy specimen indicated clear expression of glucose transporter-3 (Glut-3) in IgG4 inflammatory cells infiltrating into the portal area. This is the first report of simultaneous strong accumulation of FDG and Glut-3 expression in IgG4-related AIH, which might aid in elucidating the pathogenesis of this disease.