In light of the existing literature, IFN‐γ (encoded by IFNG) and T‐bet (encoded by TBX21) have been regarded as the most essential proinflammatory cytokine for the homing of autoreactive T lymphocytes to liver and the crucial transcription factor for T helper (Th) 1 cells differentiation in the development of AIH [34, 35, 36, 37]. The gene discussed is IFNG; the disease is autoimmune hepatitis.