Abstract
Objective: To investigate the expression of programmed death-1 (PD-1) in liver tissue and its association with liver pathology in patients with autoimmune hepatitis (AIH). Methods: A total of 54 AIH patients (38 in the active stage and 16 in the remission stage) were enrolled, and 9 healthy volunteers were enrolled as control group. Immunohistochemistry combined with quantitative image analysis was used to measure the expression of PD-1 in liver tissue. The t-test, rank sum test, one-way analysis of variance, least significant difference t-test, Mann-Whitney U test, and Pearson relation analysis were used for statistical analysis of different types of data. Results: The AIH group had a significantly higher positive rate of PD-1 in liver tissue than the control group (13.57%±6.84% vs 2.22%±0.66%, P < 0.01), and the patients in the active stage of AIH had a significantly higher positive rate of PD-1 in liver tissue than those in the remission stage (16.53%±7.72% vs 6.56%±3.16%, P < 0.01). The positive rate of PD-1 in liver tissue was 6.56%±3.16% in G0 group, 14.33%±5.08% in G1-2 group, and 19.23%±5.41% in G3-4 group (P < 0.01), but there was no significant difference in the positive rate of PD-1 between S0, S1-2, and S3-4 groups (P > 0.05). In AIH patients, the positive rate of PD-1 in liver tissue was positively correlated with the levels of total bilirubin, alanine aminotransferase, aspartate aminotransferase, and IgG (r = 0.665, 0.721, 0.711, and 0.813, all P < 0.01). Conclusion: AIH patients have regulated PD-1 expression in liver tissue, which is closely associated with liver inflammation and is not associated with fibrosis degree, suggesting that PD-1 is involved in the development and progression of inflammation in AIH patients.