From the Guidelines
The diagnostic workup for autoimmune hepatitis requires a comprehensive approach combining laboratory tests, imaging, and often liver biopsy, as recommended by the 2020 American Association for the Study of Liver Diseases (AASLD) practice guidance and guidelines 1. The initial evaluation should include liver function tests (elevated AST, ALT, alkaline phosphatase, and bilirubin), complete blood count, and serological markers.
- The most important serological tests include:
- Antinuclear antibodies (ANA)
- Anti-smooth muscle antibodies (ASMA)
- Liver-kidney microsomal type 1 antibodies (anti-LKM1)
- Immunoglobulin levels, particularly IgG which is typically elevated Additional tests should include:
- Viral hepatitis serologies (hepatitis A, B, C)
- Ceruloplasmin
- Alpha-1 antitrypsin
- Iron studies to exclude other liver diseases Abdominal ultrasound or other imaging is necessary to assess liver morphology and rule out biliary obstruction or malignancy.
- A liver biopsy remains the gold standard for diagnosis, revealing characteristic features such as interface hepatitis, lymphoplasmacytic infiltration, and hepatocyte rosetting. The International Autoimmune Hepatitis Group scoring system, which incorporates clinical, biochemical, serological, and histological findings, can help establish the diagnosis, as described in the 2004 consensus statement from the committee for autoimmune serology of the International Autoimmune Hepatitis Group 1. Early diagnosis is crucial as prompt immunosuppressive therapy with prednisone (starting at 30-60 mg daily) alone or combined with azathioprine (50-150 mg daily) can prevent progression to cirrhosis and liver failure, as supported by the 2013 review article on the management of autoimmune hepatitis beyond consensus guidelines 1.
From the Research
Diagnostic Workup for Autoimmune Hepatitis
The diagnostic workup for autoimmune hepatitis involves a combination of clinical, laboratory, and histological features. The following are the key components of the diagnostic workup:
- Clinical presentation: Autoimmune hepatitis can present with a wide range of symptoms, from asymptomatic to acute hepatitis, cirrhosis, and acute liver failure 2.
- Laboratory tests:
- Increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels 2.
- Elevated serum IgG concentration 2.
- Presence of autoantibodies, such as anti-nuclear (ANA) and/or anti-smooth muscle antibodies (SMAs) for type 1 AIH, and anti-liver kidney microsomal antibody type 1 (LKM-1) and/or anti-liver cytosol type 1 (LC-1) for type 2 AIH 3.
- Histological findings: Interface hepatitis is a characteristic histological feature of autoimmune hepatitis 2.
- Diagnostic scores: The International Autoimmune Hepatitis Group (IAIHG) has established diagnostic scores, including the revised and simplified diagnostic scores, to help diagnose and classify autoimmune hepatitis 4, 5, 6.
- Autoantibody detection: Autoantibody detection is mandatory for the diagnosis and classification of autoimmune hepatitis, and should be performed according to the IAIHG guidelines 3, 4.
Classification of Autoimmune Hepatitis
Autoimmune hepatitis can be classified into two main types:
- Type 1 AIH: Characterized by the presence of ANA and/or SMA autoantibodies 3.
- Type 2 AIH: Characterized by the presence of LKM-1 and/or LC-1 autoantibodies 3. Other autoantibodies, such as perinuclear anti-nuclear neutrophil antibody (p-ANNA) and anti-soluble liver antigen (SLA) antibodies, can also be present in autoimmune hepatitis 3.