In conclusion, the current study provides evidence that five genes (PTGIR, PTGER4, ZBTB40, NFKB1 and SLC39A11) associated with IBD susceptibility are also involved in, directly or indirectly, the control of the expression of calprotectin genes S100A8 and S100A9. This evidence concerns the gene NFKB1 and inflammatory bowel disease.