Published online May 21, 2019. doi: 10.3748/wjg.v25.i19.2308
Peer-review started: March 8, 2019
First decision: April 11, 2019
Revised: April 13, 2019
Accepted: April 19, 2019
Article in press: April 20, 2019
Published online: May 21, 2019
IgG4-related disease (IgG4-RD) is a chronic-fibroinflammatory disorder affecting a wide range of organs. Elevation of serum IgG4 concentrations and abundant infiltration of IgG4-expressing plasma cells are key diagnostic features of this autoimmune disease. Although common organ involvement of IgG4-RD includes the salivary glands, pancreas, and bile duct, hepatic involvement is less well established. Recently, five studies identified a subtype of autoimmune hepatitis (AIH), called IgG4-associated AIH (IgG4-AIH). IgG4-AIH is diagnosed based on significant accumulation of IgG4-expressing plasmacytes in the liver in patients who met the diagnostic criteria for classical AIH. Although four of the five reports regarded IgG4-AIH based on hepatic accumulation of IgG4-positive cells alone, one report diagnosed IgG4-AIH based on both hepatic accumulation of IgG4-positive cells and elevated serum concentrations of IgG4. IgG4-AIH diagnosed based on the latter criteria may be a hepatic manifestation of IgG4-RD whereas IgG4-AIH diagnosed based on the former criteria may be a subtype of AIH. In this review article, we summarize and discuss clinicopathological features of IgG4-AIH.
Core tip: IgG4-associated autoimmune hepatitis (IgG4-AIH) is a new disease entity characterized by the accumulation of IgG4-expressing plasma cells in the liver. Recent studies diagnosed IgG4-AIH based on hepatic accumulation of IgG4+ cells alone or in combination with elevated serum concentrations of IgG4. Further studies are required to determine whether IgG4-AIH is a subtype of AIH or a hepatic manifestation of IgG4-related disease.