Auto-immune hepatitis (AIH) and primary biliary cholangitis (PBC) are increasing in prevalence in the Asia-Pacific region and have a spectrum of clinical presentation. Co-existing auto-immune conditions are common (25-40%) and diagnosis of both conditions is dependent upon a typical liver test pattern, auto-antibody profile and liver histology.
Of note, acute severe AIH may lack specific auto-antibodies and have atypical histology with central peri-venulitis and necrosis. Initial AIH treatment consists of corticosteroids with prednisolone; doses <0.5mg/kg appear to be as efficacious compared to higher doses for inducing remission with less side-effects. Budesonide is an effective alternative (in the absence of cirrhosis) with azathioprine (1-2mg/kg) used as steroid sparing therapy. Dosing guided by thiopurine metabolites may lead to higher rates of biochemical remission. Outcomes of COVID infection in AIH appear comparable to other causes of chronic liver disease.
PBC may present with fatigue and pruritis with additional symptoms related to sicca complex and osteoporosis. Fibroscan is accurate at staging fibrosis whereas the GLOBE and UK-PBC scores predict transplant free survival after one year of ursodeoxycholic acid. Whilst ursodeoxycholic acid (13-15mg/kg) remains first line treatment, 25% will have an inadequate biochemical response defined by serum alkaline phosphatase and bilirubin levels. Obeticholic acid and bezafibrate have both been demonstrated to improve biochemical cholestasis as add-on therapy. OCA increases risk of pruritis whereas bezafibrate has been demonstrated to have anti-pruritic properties. Additional phase 2 studies examining PPAR agonists show promise as second line therapies.