The value of serum CD48 (sCD48) as an indication of inflammation and fibrosis in autoimmune hepatitis (AIH) type 1 was investigated in the study. ELISA was used to detect the levels of sCD48 in an exploratory cohort. In this cohort, sCD48 levels were higher in AIH (12.81 ng/mL) than in healthy controls (4.90 ng/mL, P<0.0001), primary biliary cholangitis (7.32 ng/mL, P<0.0001), and non-alcoholic fatty liver disease (7.76 ng/mL, P<0.0001), and were associated with histological inflammation and fibrosis. sCD48 was also an independent predictor of severe inflammation (G3-4) and advanced fibrosis using multivariate logistic regression analysis (S3-4). For identifying severe inflammation and progressive fibrosis, two prediction scores based on sCD48 were developed (sCD48-AIH-SI and sCD48-AIH-AF, respectively). Predictive skills were tested and validated using these data as a foundation in a validation cohort. The area under the receiver operating characteristic curves for substantial inflammation in the exploratory cohort for sCD48 and sCD48-AIH-SI were 0.748 and 0.813, respectively.

Furthermore, from the start of immunosuppression through the re-evaluation biopsy, sCD48 levels declined in lockstep with aspartate transaminase, total serum IgG, and fibrosis-4 score. sCD48 could predict severe fibrosis in AIH patients in a re-evaluation biopsy cohort (S2-4). Furthermore, according to immunohistochemistry, hepatic CD48 expression was higher in AIH patients and decreased following treatment. Finally, histological inflammation and fibrosis in AIH-1 were predicted by sCD48 and sCD48-based prediction scores. Therefore, detecting sCD48 could help treat AIH in the clinic.