IDO1 and inflammatory bowel disease: In agreement with studies carried out in adenocarcinoma cell lines, we found similar upregulation of genes such as IDO1 [14], GBP1 [12], CXCL9, CXCL10, and CXCL11 [13] in response to IFN-γ (Figure 3A), all of which are also known to be upregulated in IBD patients.