Next, the CX3CL1–CX3CR1 axis has been shown to be required for optimal production of IL-10 by intestinal mφ 56 and finally, CX3CR1-deficiency has been reported to lead to decreased numbers of intestinal mφ 107,108 as well as altering susceptibility to chemically induced colitis. This evidence concerns the gene CX3CL1 and colitis.