Marked accumulation of fluorodeoxyglucose and inflammatory cells expressing glucose transporter-3 in immunoglobulin G4-related autoimmune hepatitis: Expression of FDG and Glut-3 in IgG4-related AIH

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 (535mg/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.