CD8A and autoimmune hepatitis: In AIH, it has been proved that a signaling pathway mediated by hydrocarbon receptor (AhR) was necessary for ongoing AIH-like pathology, and Lactobacillus reuteri could release an AhR ligand, indole-3-aldehyde (I3A), thus promoting the differentiation of CD8 T cells in vitro and AIH-like pathology in mice [69].