In addition, elevated serum IL‐21 levels are positively associated with immunoglobulin levels, whereas decreased serum IL‐10 levels are inversely associated with immunoglobulin levels, which might regulate immunoglobulin production.25, 26 Taken together, our data revealed the pathogenic significance of altered TFR/TFH cell balance in AIH. Here, IL21 is linked to autoimmune hepatitis.