In autoimmune diseases, the gut microbiota can influence disease progression by affecting the function of antigen-presenting cells, and it has been found that secondary bile acids modulate dendritic cell function via the TGR5-cAMP-PKA pathway to reduce the severity of experimental autoimmune uveitis (EAU) in mice and that this alteration correlates with the composition of the gut microbiota in EAU mice (Hu et al. 2021). This evidence concerns the gene GPBAR1 and autoimmune disease.