Abstract

It is a common experience that gastrointestinal symptoms urge us to differentiate inflammatory bowel disease (IBD) from functional disorders. Furthermore, in patients with proven IBD the disease activity has to be accurately monitored. Fecal markers of neutrophil influx into the mucosa are promising indicators of intestinal inflammation. Some neutrophil-derived proteins may be linked to pathogenesis of IBD due to their functions as damage associated molecular pattern molecules (DAMPs). Phagocyte-specific DAMPs of the S100 family are released from neutrophils or monocytes, followed by pro-inflammatory activation of pattern recognition receptors. The complex of S100A8/S100A9 was termed “calprotectin” and is in use as a fecal marker for already 10 years. More recently, fecal S100A12 has been reported to be an even more accurate fecal marker of inflammation. We review the biology of this novel group of molecules which can be used as surrogate markers directly linked to the molecular mechanisms of gut inflammation.