Development of a New Murine Model of Type 2 Autoimmune Hepatitis Using a Human Liver Protein.

Autoimmune hepatitis (AIH) is a chronic inflammatory condition of the liver characterized by parenchymal destruction, hypergammaglobulinemia, specific autoantibody production, and hepatic fibrosis and necrosis. Murine models of AIH have been described; however, little is known about the immunologic mechanisms of tissue destruction. In this study, a new murine model of type 2 AIH was developed using recombinant human cytochrome P450 (CYP) 2D6 emulsified with complete Freund's adjuvant (CFA). BALB/c mice were immunized with 2 µg/mL i.p. of CYP2D6 in CFA. The control group received CFA or phosphate-buffered saline alone. Alanine aminotransferase activity, autoantibody production, IgG concentrations, histologic damage, and specific T-cell response were evaluated. Persistent AIH, characterized by cellular infiltration, hepatic fibrosis, elevated alanine aminotransferase, and the production of anti-liver kidney microsomal antibody type 1 developed in CFA/CYP2D6-immunized mice. These mice presented high levels of IgG and its subclasses IgG1, IgG2a, and IgG2b against liver self-proteins. Interestingly, IL-2+ and interferon γ-positive Cyp2d6-specific T cells were present in greater concentrations in mice immunized with CFA/CYP2D6 compared with control. Immunization with CFA, in combination with a natural human autoantigen like CYP2D6, was demonstrated to break tolerance, resulting in a chronic form of autoimmune-related liver damage. This murine model of type 2 AIH is expected to be instrumental in understanding the immunologic mechanisms of the pathogenesis of this autoimmune liver disease.

Elevated circulating levels of IL-21 and IL-22 define a cytokine signature profile in type 2 autoimmune hepatitis patients.

UNLABELLED:  Background and aims. Autoimmune hepatitis (AIH) is a chronic inflammatory condition of the liver in which the immunological mechanisms involved in tissue destruction and/or repair are still unclear. Different pro-inflammatory cytokines have been shown to play a determinant role in AIH pathogenesis. Here, we aim to compare the circulating levels of pro- and anti-inflammatory cytokines such as IL-6, TNF-?, IL-17A/F, IL-21, IL-22, IL-23, and IL-10 in patients with type 2 AIH compared to patients with type 1 AIH and healthy controls (HC). Fourty-six Mexican patients with AIH were recruited in our study. Patients were classified as type 1 or 2 AIH based on immune serological markers. Fourty-four serum samples from healthy individuals were included as controls. Serum cytokine levels were determined by ELISA technique. RESULTS: Compared to healthy controls, serum levels of IL-17F, IL-21, IL-23, IL-10, IL-6, and TNF-?, but not IL-17A and IL-22, were significantly increased in AIH patients. When patients were grouped by aminotransferase activity, a biomarker of active disease, a positive correlation between serum IL-17F and alanine transaminase (rs: 0.4739; P = 0.0009) and aspartate transaminase (rs: 0.4984; P = 0.0004) levels was found. A cytokine signature profile associated with type 2 AIH was characterized by high serum IL-21 (type 1 AIH: 0.66 pg/mL; type 2 AIH: 331.1 pg/mL; P = 0.0042) and IL-22 (type 1 AIH: 0.1 pg/mL; type 2 AIH: 55.26 pg/mL; P = 0.0028) levels. CONCLUSIONS: We show for the first time, differential regulation of certain pro-inflammatory cytokines associated with disease progression and AIH type in Mexican patients.