Treatment of Autoimmune Hepatitis

Introduction to Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is characterized by the presence of specific antibodies, with type 2 AIH often accompanied by anti-liver kidney microsomal type 1 (anti-LKM1) and anti-liver cytosol type 1 (anti-LC1) antibodies, and usually absence of antinuclear antibodies (ANA) and smooth muscle antibodies (SMA) is not typical for type 2, affecting children and young adults, with up to 25% presenting with acute liver failure, and often associated with other autoimmune conditions 1
The American Association for the Study of Liver Diseases recommends using a simplified diagnostic scoring system for AIH, which includes points for ANA or SMA ≥1:40, IgG levels, liver histology, and absence of viral hepatitis, with a score of ≥7 indicating definite AIH and ≥6 indicating probable AIH 1

Elevated aminotransferases, positive SMA, elevated IgG levels, and compatible histology on liver biopsy are key diagnostic features of AIH, with 80% of diagnoses occurring within three months of detecting positive SMA 1
A clinically significant level of positivity in adults starts at a dilution of 1/40, and in children and adolescents (up to age 18), positivity at dilutions of 1/20 for ASMA is clinically relevant due to lower background prevalence 2
The most specific pattern for AIH is the "T pattern" (tubular) or "VGT pattern" (vessel, glomerular, tubular) on rodent kidney tissue by indirect immunofluorescence, and higher titers generally correlate with greater specificity for AIH 2
ASMA is a key serological marker for type 1 autoimmune hepatitis (AIH-1), which accounts for approximately 75% of AIH cases, and targets cytoskeletal elements, particularly F-actin, and are found in high titers in AIH patients 3, 2
ASMA can be detected in primary biliary cholangitis (8-77% of patients) and primary sclerosing cholangitis (up to 83% of patients), as well as in drug-induced liver injury, highlighting the importance of interpreting SMA positivity in the context of the complete clinical picture 4, 5

The initial treatment for patients with type 2 autoimmune hepatitis should be prednisolone (or prednisone) combined with azathioprine, with prompt initiation upon diagnosis to prevent disease progression and liver failure, starting with prednisolone 30-40 mg/day and azathioprine 50-100 mg/day (approximately 1 mg/kg/day) 3
The European Association for the Study of the Liver recommends a standard regimen of prednisone/prednisolone with azathioprine for AIH treatment, with an initial dose of 30-40 mg/day of prednisolone and 50-100 mg/day of azathioprine 6
Alternative regimens, such as budesonide with azathioprine, may be used, but budesonide is contraindicated in cirrhosis or acute severe AIH, as it can lead to portal vein thrombosis and reduced efficacy 6

Treatment should continue for at least 2 years and for at least 12 months after normalization of transaminases, with monitoring of liver enzymes (ALT, AST) every 1-2 weeks initially, assessment of IgG levels periodically, evaluation for side effects of immunosuppression, and consideration of liver biopsy to confirm histological remission before considering any treatment changes 3
Patients should receive calcium and vitamin D supplementation with DEXA scanning every 1-2 years while on steroids 3

Early referral to a liver transplant center should be considered in cases with liver failure, bridging necrosis on biopsy, or jaundice with MELD score not rapidly improving on treatment 3
For prednisolone intolerance, consider budesonide (only in non-cirrhotic patients), and for azathioprine intolerance, use prednisolone alone at higher doses or consider prednisolone with mycophenolate 3
For treatment failure, consider increasing azathioprine to 2 mg/kg/day while maintaining prednisolone at 5-10 mg/day, and for refractory cases, consider calcineurin inhibitors (cyclosporine, tacrolimus) under expert guidance 3
Patients with cholestatic features should be evaluated for AIH-PBC or AIH-PSC overlap, and antimitochondrial antibodies (AMA) should be checked, with consideration of cholangiography 1

Hepatitis A and B vaccination should be performed early in susceptible patients 3
Lifelong clinical and biochemical monitoring is mandatory even after treatment withdrawal 3
With appropriate treatment, 80% of AIH patients achieve remission, but untreated moderate-to-severe AIH has a poor prognosis, and long-term immunosuppression is typically required, with only a minority achieving sustained remission after withdrawal 1