title: Serum and mucosal S100 proteins, calprotectin (S100A8/S100A9) and S100A12, are elevated at diagnosis in children with inflammatory bowel disease.
abstract: OBJECTIVE
  Various markers characterize the complex inflammatory processes seen in chronic inflammatory bowel disease (IBD) including calprotectin, a complex of two S100 proteins, which has been evaluated and validated as a faecal marker of inflammation. However, the systemic and mucosal expression patterns of calprotectin and related S100 proteins are not well characterized in this disease. The objective of this study was to assess serum and mucosal levels of calprotectin, S100A12 and soluble receptor for advanced glycation end products (sRAGE), a putative S100 ligand, in a paediatric population with IBD.
  
  
  METHODS
  Children were enrolled at diagnosis of IBD, along with groups of children without IBD. Standard inflammatory markers and disease activity scores were collated. Calprotectin, S100A12 and sRAGE levels in serum and biopsy culture supernatants were measured by ELISA and tissue distribution of S100 proteins was investigated by immunohistochemistry.
  
  
  RESULTS
  Serum and mucosal calprotectin and S100A12 levels were increased in children with IBD as compared with non-IBD controls. Serum calprotectin levels correlated with S100A12 levels and with disease activity scores in children with IBD. sRAGE levels were not increased in IBD. S100A8, S100A9 and S100A12 were abundantly expressed throughout the lamina propria and epithelium in inflamed mucosa. In contrast, these proteins were present in the lamina propria, but not the epithelium, in non-inflamed mucosa.
  
  
  CONCLUSIONS
  Serum calprotectin and S100A12 are increased in children with IBD and indicate disease activity. Elevated levels of these proteins are present in the colonic mucosa and may contribute to the pathogenesis of IBD. Furthermore, an imbalance between sRAGE and S100A12 may contribute to inflammatory changes present in IBD.
authors.affiliation: School of Women's and Children's Health, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Steven T
authors.initials: ST
authors.lastname: Leach
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yang
authors.forename: Isabella
authors.initials: I
authors.lastname: Messina
authors.forename: Changjie
authors.initials: C
authors.lastname: Song
authors.forename: Carolyn L
authors.initials: CL
authors.lastname: Geczy
authors.forename: Anne M
authors.initials: AM
authors.lastname: Cunningham
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Day
mesh_terms: D000293:Adolescent; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D004848:Epithelium / Q000737:chemistry; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000473:pathology*; D007413:Intestinal Mucosa / Q000737:chemistry; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis* / Q000097:blood; D008297:Male; D009092:Mucous Membrane / Q000737:chemistry; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000097:blood; D009418:S100 Proteins / Q000032:analysis* / Q000097:blood; D000067616:S100A12 Protein
chemical_list: D039841:Leukocyte L1 Antigen Complex; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; D009418:S100 Proteins; D000067616:S100A12 Protein; C090441:S100A12 protein, human