More recently, differences in the expression of cytokines have been identified between inflamed and non-inflamed bowel tissue in the same patient with Crohn’s disease, including chemokine ligand 1 (CXCL1, a chemokine with neutrophil attracting activity), chemokine ligand 20 (CCL20), C4b binding protein (C4BBP, a protein that controls the complement cascade) and interleukin 1 receptor antagonist (IL1RN) [54,55,56]. The gene discussed is IL1RN; the disease is Crohn disease.