Transcriptional profiling of HIOs has indicated that many genes, such as indoleamine 2,3-dioxygenase 1 (IDO1) and guanylate binding protein 1 (GBP1), are up-regulated after IFN-γ stimulation, consistent with the results of biopsy tissue from IBD patients (75). The gene discussed is GBP1; the disease is inflammatory bowel disease.