Els van de Vijver

14 Table 2: Faecal markers of inflammation (8, 9) Faecal marker Molecular function/cellular source Number of articles in paediatric literature (1990 - June 2019) Lysozyme Released with degranulation of Paneth cells, macrophages and granulomas 20 Polymorphonuclear elastase Released with degranulation of polymorfonuclear granulocytes; plays a role in the first-line host defence 43 Myeloperoxidase Cytotoxic lysosomal protein released with degranulation of activated neutrophils 47 Metalloproteinase-9 Protein involved in neutrophil migration process, released by a variety of cell types, including activated neutrophils 3 Neopterin Synthesized by activated macrophages; serves as marker of cellular immune-system activator 23 Lactoferrin Cytoplasmic iron binding glycoprotein secreted by neutrophils and mucosal epithelial cells 21 Calprotectin (S100A8/S100A9) Cytoplasmic calcium binding protein released by neutrophils, monocytes and epithelial cells 154 All substances listed in Table 2 are found in abundance in the faeces of patients with active IBD, and concentrations are significantly lower in patients in remission.(5, 10) Calprotectin has been studied more extensively in children than any other faecal marker, and this biomarker test is now readily available in clinical laboratories. Chapter 1