Prevalence, clinical features, and laboratory predictors of autoimmune hepatitis in systemic sclerosis: A retrospective single-center cohort study

Autoimmune hepatitis is a rare overlap syndrome in systemic sclerosis that occurs independently of clinical phenotype. Routine monitoring of liver transaminases, particularly ALT, provides a reliable non-invasive screening tool. Clinicians should consider ALT elevations > 34.5 U/L as a trigger for further AIH evaluation, even in patients with prior MTX exposure. Key Points • Autoimmune hepatitis (AIH) represents a clinically significant overlap in systemic sclerosis (SSc), with a prevalence of 7.2% in this cohort, indicating that it may be more common than previously reported when systematic screening is implemented. Biochemical screening rather than biopsy-only evaluation improves detection. • The development of AIH in SSc patients appears to be independent of disease subtype (limited vs. diffuse), specific autoantibody profiles (Anti-Scl70, ACA), or major organ involvement, such as interstitial lung disease. • An ALT threshold of > 34.5 U/L provides a practical "red flag" for clinicians, offering high sensitivity and specificity to prompt further diagnostic evaluation, including liver-specific autoantibody testing and liver biopsy when indicated. This threshold should be interpreted cautiously in patients with prior methotrexate (MTX) exposure, as mild ALT elevations may also reflect drug-related hepatotoxicity. • An ALT threshold of > 34.5 U/L provides a practical "red flag" for clinicians, offering high sensitivity and specificity to prompt further diagnostic evaluation, including liver-specific autoantibody testing and liver biopsy when indicated. • Because AIH can develop across the full spectrum of SSc regardless of systemic disease severity, routine monitoring of transaminases is essential for early detection and timely initiation of immunosuppressive therapy.