Fecal S100A12: A novel noninvasive marker in children with Crohn's disease

Background: The calcium-binding protein S100A12 is related to calprotectin, a protein shown to be a useful marker of gut inflammation. S100A12 levels are elevated in serum and mucosa of children with inflammatory bowel disease (IBD) and may be implicated in the pathogenesis of IBD. The aims of this study were to validate an immunoassay for the detection of fecal S100A12, to assess its value as a new noninvasive marker of gut inflammation, and to investigate S100A12 levels in feces of children with IBD at diagnosis and during treatment. Materials and Methods: Feces were collected from children with active IBD at diagnosis and during treatment for IBD and from normal healthy control subjects. Fecal and serum levels of S100A12 were measured by immunoassay. Results: A sensitivity of 96% and a specificity of 92% were observed when 10 mg/kg fecal S100A12 was used as a cutoff. S100A12 levels were evenly distributed throughout fecal samples and were stable for 7 days when stored at room temperature. Fecal S100A12 was elevated in children with IBD compared with healthy control subjects, with levels closely correlated to disease activity and other serum inflammatory markers, particularly lower gut involvement. Fecal S100A12 levels fell during therapy in children entering remission with normal C-reactive protein levels. Conclusions: Fecal S100A12 is a novel noninvasive marker that distinguishes children with active IBD from healthy control subjects with high sensitivity and specificity. Fecal S100A12 possesses characteristics that are desirable for a noninvasive disease marker and therefore is a suitable candidate marker for IBD. Further evaluation is required to examine this marker in additional contexts.