All but two of the proteins in clusters 2, 3 and 4 significantly differentiate IBD from IBS, most profoundly CXCL9, IL-17 A and TNFRSF9 (p < 0.0001), as well as CCL28 and CXCL10 (p < 0.001). Here, TNFRSF9 is linked to irritable bowel syndrome.