IL21 and autoimmune hepatitis: Prednisone + Lactobacillus could significantly improve the levels of IL-21 and Tfh cells in PBMCs of AIH patients and reduce the expression of IL-21, Bcl-6, and CXCR5 mRNA in the liver in mice.222 In summary, Tfh cells may be an indicator to predict the progression and treatment of AIH, but more studies are necessary to analyze Tfh cells and the functions of Tfh cell subsets (Tfh1, Tfh2, and Tfh17) in the liver of AIH patients.