The expression frequency of Tim‐3 on the surface of CD4+ T cells in human peripheral blood tested by flow cytometry was lower in the AIH group (23.4 ± 4.5) than in the control group (32.4 ± 2.0; Fig. 1A,B), indicating that the reduction in Tim‐3 expression is associated with AIH. Here, CD4 is linked to autoimmune hepatitis.