IgG4-AIH with multiple inflammatory pseudotumors and decreased OATP1B3 expression

Area of Science:

• Hepatology
• Immunology
• Gastroenterology

Background:

• Autoimmune hepatitis (AIH) is a chronic liver inflammation driven by an autoimmune response.
• A subset of AIH cases is associated with immunoglobulin G4-related disease (IgG4-RD), termed IgG4-AIH.
• IgG4-AIH is rare, characterized by IgG4 plasma cell infiltration and elevated serum IgG4.

Purpose of the Study:

• To report a unique case of IgG4-AIH.
• To investigate the association between IgG4-AIH, inflammatory pseudotumors (IPTs), and OATP1B3 expression.

Main Methods:

• Case report detailing clinical presentation and histopathological findings.
• Analysis of IgG4-positive plasma cell infiltration in the liver.
• Assessment of serum IgG4 levels.
• Evaluation of organic anion transporting peptide (OATP) 1B3 expression in hepatic tissue.

Main Results:

• The case presented with IgG4-AIH associated with multiple hepatic inflammatory pseudotumors (IPTs).
• A decrease in OATP1B3 expression was observed.
• This decrease in OATP1B3 expression occurred without the typical lymphoplasmacytic and fibroblastic accumulation seen in IPTs.

Conclusions:

• IgG4-AIH can present with hepatic IPTs.
• IgG4-related inflammation may play a role in regulating OATP1B3 expression in the liver.
• Further research is needed to elucidate the mechanisms linking IgG4-RD, IPTs, and OATP1B3 dysfunction in AIH.