The Predictive Value of Autoantibodies in Determining Autoimmune Hepatitis (AIH) Severity

Background: The presence of autoantibodies is a prerequisite for the diagnosis of autoimmune hepatitis (AIH). However, most autoantibodies are not disease-specific, and serological overlap between AIH and other chronic liver diseases is common. Since the prognostic parameters of AIH are limited, this study aimed to investigate the relationship between histopathological findings on liver biopsy with different types of autoantibodies associated with AIH and how autoantibodies can predict the severity and extent of disease. Methods: The present study was performed on 30 patients with a definite diagnosis of AIH according to the International Autoimmune Hepatitis Group (IAIHG) criteria. Pediatric AIH patients underwent liver tissue examinations at the time of diagnosis at accession, which confirmed characteristic histological changes. AIH-related serologic major and minor autoantibodies were measured using indirect immunofluorescence assays and ELISA kit (EUROIMMUN, Germany), respectively, and were compared within all patients, and the results were recorded. Finally, the obtained data were analyzed using SPSS V25 software. Results: Out of 30 patients, 17 (56.66%) were female, and the age range of patients was 17-11 years (8.46±6.95). Anti-nuclear antibody (ANA) (73.3%), smooth muscle antibody (SMA)-anti-smooth muscle actin antibody (ASMA) (70%), perinuclear anti-neutrophilic cytoplasmic antibodies (p-ANCA) (63%), and liver kidney microsomal (LKM) (43.3%) were the most common autoantibodies found in children with AIH. There was a significant relation between the severity of histological findings and the presence of LKM antibodies (P<0.05). The highest sensitivity for predicting severe AIH based on histopathological findings was ANA autoantibody positivity and the presence of at least two primary autoantibodies (LKM and SMA-ASMA). On the other hand, positive LKM antibodies had the highest specificity and positive predictive value (PPV) in AIH severity prediction. Conclusion: The results of the present study suggested that there might be a significant correlation between the presence of primary LKM autoantibodies and biopsy results, so it can possibly act as an accurate autoantibody for predicting the severity of AIH, while other AIH-related autoantibodies did not seem to have a significant correlation with biochemical and histological findings.