Serum Immunoglobulin G Levels Predict Biochemical and Histological Remission of Autoimmune Hepatitis Type 1: A Single-Center Experience and Literature Review

Autoimmune hepatitis (AIH) is characterized by interface hepatitis, elevated serum alanine aminotransferase and aspartate aminotransferase levels, circulating autoantibodies, and elevated predominantly immunoglobulin G (IgG) levels. The goal in the treatment of autoimmune hepatitis (AIH) is complete disease remission. Here we took advantage of a large cohort of AIH patients to clarify predictors associated with biochemical and histological remission. Of 705 patients with complete follow-up, 569 (80.7%) patients achieved complete biochemical remission. Lower IgG levels (17.8 vs. 25 g/L, p < 0.001) and less liver cirrhosis (19.3% vs. 33.1%, p < 0.001) at diagnosis were observed in these patients. They also had lower serum IgG levels (13 vs. 18.9 g/L, p < 0.001) after 3 months of treatment. Histological remission was achieved in 69.4% of 160 patients with complete biochemical remission after 3 years of treatment. Patients with histological remission had lower IgG levels (16.2 vs. 20.1 g/L, p = 0.006) and Ishak fibrosis scores (3.4 vs. 4.1, p = 0.010) at diagnosis, and they appeared to achieve biochemical remission more rapidly (1 vs. 3 months, p < 0.001). Of note, patients with histological remission had higher frequency of fibrosis regression than those with persisting histological activity (87.5% vs. 60%, p = 0.004). In conclusion, lower serum IgG levels, less fibrosis in liver histology at diagnosis, and rapid response to immunosuppressive therapy are reliable predictors of biochemical and histological remission. Our study underscores the importance of early diagnosis and appropriate treatment.