In laminar propria lymphocytes of inflammatory bowel disease patients, LIF-activated STAT4 inhibits activation of the STAT3-dependent Il17a/Il17f promoter, while in intestinal epithelial cells, LIF bypasses abnormally low STAT4 levels and induces YAP gene expression by activating STAT3 (Zhang et al., 2019). This evidence concerns the gene IL17F and inflammatory bowel disease.