S100A8 and inflammatory bowel disease: For example, S100A8 and S100A9 (calprotectin) constitute ~45% of the cytoplasmic content of neutrophils and is used as a non-invasive faecal biomarker for assessing colonic inflammation in IBD.24 We therefore tested if neutrophil numbers vary following C. rodentium infection of C57 and C3H mice.