Applicability of International Autoimmune Hepatitis Group (IAIHG) Scoring System for Autoimmune Hepatitis in Pediatrics

Simple Summary Autoimmune hepatitis (AIH) is a difficult liver disease to diagnose, and researchers developed the International Autoimmune Hepatitis Group (IAIHG) scoring system to aid the diagnosis of AIH. The scoring system was originally designed for adult patients; thus, we aim to evaluate the performance of this scoring system in children for accurately diagnosing AIH. We found liver biopsies were an essential component of the IAIHG score system and that specific liver biopsy features including interface hepatitis and predominant plasma cells were significantly associated with AIH. Incorporating liver biopsy data improves the performance of the IAIHG scoring system. Although, the degrees of importance of each specific biopsy feature are more distinct in the children population compared to those of the adult population. Overall, we determined that the IAIHG score is effective at diagnosing AIH in children, but could be improved. Introduction: Many hepatologic pathologies mimic autoimmune hepatitis (AIH). Researchers developed the International Autoimmune Hepatitis Group (IAIHG) scoring system to compensate for the lack of specific diagnostic tests for AIH. The scoring system was not designed with pediatric patients in mind, so there are limits to its pediatric use. Additionally, there is limited information on the value of a liver biopsy in conjunction with its use. Methods: In this retrospective study, we evaluated the effect of liver biopsy scores on the IAIHG scoring system in patients that were 0-18 years old with suspected AIH. We also analyzed demographic data and laboratory values associated with a final AIH diagnosis. Results: We found that interface hepatitis and predominant plasma cells found during the biopsy were significantly associated with a final AIH diagnosis. We also found that abnormal laboratory values were associated with an AIH diagnosis. We found that IAIHG scores calculated post-liver biopsy showed a greater area under the receiver operating characteristic curve (AUROC) of 0.95, which was compared to 0.88 for the scores calculated before a liver biopsy. Including biopsy metrics lowered the optimized cutoff score and test specificity. Conclusion: Incorporating liver histopathological features improved the performance of the IAIHG scoring system. Further studies to identify other potential elements in liver histology may improve the performance metrics of the IAIHG test in the pediatric population.