Etiology and Diagnostic Criteria
The disease belongs to the group of autoimmune liver disorders, which also includes primary biliary cholangitis and primary sclerosing cholangitis. The exact etiology remains unknown. Genetic predisposition plays a significant role: more than half of patients test positive for the HLA-B8 antigen.
Diagnosis is based on serological and immunological data. A mandatory condition is negative testing for viral hepatitis markers. Laboratory findings show elevated serum IgG levels and the circulation of various autoantibodies:
- Antinuclear antibodies (ANA).
- Liver-kidney microsomal antibodies (LKM).
- Liver-specific protein antibodies (LSP).
- Anti-smooth muscle antibodies (SMA).
Based on the antibody profile, 3 types of the disease are distinguished, though their histological picture is identical.
Clinical Presentation and Course
The condition typically progresses continuously from the onset of initial symptoms to a fatal outcome (if untreated).
Only in 10% of cases does the manifestation mimic acute hepatitis. In the vast majority of patients, the onset is insidious and gradual. Due to this subclinical course, 10–20% of patients already exhibit signs of decompensated liver cirrhosis at the time of diagnosis.
During exacerbations, the clinical presentation becomes prominent. Patients report anorexia, abdominal pain, and fever. Physical and lab findings include:
- Jaundice.
- Hemorrhagic diathesis.
- Hepatomegaly (enlarged liver).
- Splenomegaly (enlarged spleen, not always present).
Pathological Anatomy (Morphology)
The histological picture corresponds to severe chronic hepatitis. Changes involve all structural elements of the hepatic tissue.
Hepatocyte Changes Liver cells exhibit marked polymorphism. Severe degenerative changes develop, including hydropic and ballooning degeneration. Signs of regeneration are visible, manifested by binucleated and multinucleated hepatocytes. In zone 1 of the hepatic acinus, cells form specific rosette-like structures («rosettes»).
Parenchymal Necrosis The picture is characterized by frequent focal (spotty) necrosis, as well as periportal (piecemeal) necrosis.
Inflammatory Infiltrate and Stroma A lymphomacrophage infiltrate accumulates within the portal tracts. Its key feature is the admixture of a large number of plasma cells. Lymphoid follicles and macrophage granulomas may also form here. Fibroblast proliferation and sclerosis are observed in the stroma. In some cases, cholestasis and bile duct proliferation are noted.
Interface Hepatitis (Interface hepatitis) The inflammatory infiltrate is not restricted to the portal tracts: it breaches and destroys the limiting plate, spreading into zone 1 of the acinus.
Outcomes and Prognosis
Autoimmune hepatitis is characterized by high aggressiveness. The active course of the inflammatory process inevitably leads to the development of micronodular liver cirrhosis.
Notably, the frequency of progression to cirrhosis is significantly higher in this pathology, and the overall prognosis is much more serious compared to chronic viral hepatitis.