Crosstalk between the gut and the liver via susceptibility loci: Novel advances in inflammatory bowel disease and autoimmune liver disease.

Inflammatory bowel disease (IBD) is an autoimmune disorder characterized by chronic, relapsing intestinal inflammation. Autoimmune liver disease (AILD) may be involved in IBD as an extra-intestinal manifestation (EIM). Epidemiologic and anatomic evidence have demonstrated an intimate crosstalk between the gut and the liver. In this review, we briefly introduced nine groups of susceptibility loci shared by inflammatory bowel and autoimmune liver disease for the first time. The genome-wide association studies (GWAS) evidence of pathways involving crosstalk between the gut and the liver is clarified and explained. It has been found that HNF4-α, GPR35, MST1R, CARD9, IL2/IL21/IL2R, BACH2, TNFRSF14, MAdCAM-1, and FUT2 are the genes involved in tight junction formation, macrophage function, T helper cell or Treg cell cycle and function, TNF secretion, lymphocyte homing or intestinal dysbiosis, respectively. The intimate crosstalk between the gut and liver in immunity is also highlighted and discussed in this review.