title: Faecal and serum levels of eosinophil cationic protein in a healthy paediatric population.
abstract: BACKGROUND
  Eosinophil cationic protein (ECP) has been regarded as an excellent marker of eosinophil activation in various diseases where eosinophil-mediated inflammation plays a role. Recently, it has been suggested as a faecal marker of intestinal inflammation in several immune-mediated diseases with gastrointestinal expression. Owing to the scarcity of information at paediatric age, the establishment of reference values is necessary before further clinical studies.
  
  
  OBJECTIVE
  To determine faecal and serum ECP levels in healthy children and their association with other biological parameters, thereby providing background additional validation data for this age group.
  
  
  METHODS
  Faecal and serum ECP levels were available from healthy Caucasian children recruited at a regular outpatient clinic. Exclusion criteria were: chronic illnesses, acute illness, mucosal bleeding and recent pharmacological medication. Faecal and serum ECP levels and faecal a1AT were determined by commercial radioimmunoassay and serum IgE by fluoroenzyme immunoassay Uni-CAP.
  
  
  RESULTS
  Mean and median faecal ECP levels were 1.93 microg/g and 1.20 microg/g, respectively (range 0.41-22.20),while the corresponding serum ECP levels were 13.50 microg/L and 9.54 microg/L, respectively (range 0.20-74.8). The cut-offs found were 2.80 microg/g and 16.89 microg/L for faecal and serum ECP, respectively. A significant (p=0.001) increase in serum, but not in faecal, ECP levels was found among patients with high peripheral eosinophil blood count. Neither faecal nor serum ECP levels were influenced by serum IgE levels.
  
  
  CONCLUSIONS
  Faecal and serum ECP levels, as determined in the present study, add background information concerning reference levels at paediatric age for further studies indifferent clinical settings.
authors.affiliation: Paediatric Department, University Hospital de Santa Maria, Lisbon, Portugal. anacristinacardososilva@gmail.com
authors.forename: A C
authors.initials: AC
authors.lastname: Silva
authors.forename: L
authors.initials: L
authors.lastname: Levy
authors.forename: J C
authors.initials: JC
authors.lastname: Trindade
authors.forename: P
authors.initials: P
authors.lastname: Mendonça
authors.forename: C
authors.initials: C
authors.lastname: Silva
authors.forename: A I
authors.initials: AI
authors.lastname: Lopes
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D047150:Eosinophil Cationic Protein / Q000032:analysis* / Q000097:blood*; D004804:Eosinophils / Q000737:chemistry / Q000166:cytology; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D007958:Leukocyte Count; D008297:Male; D012016:Reference Values; D044465:White People; D000515:alpha 1-Antitrypsin / Q000032:analysis
chemical_list: D000515:alpha 1-Antitrypsin; D007073:Immunoglobulin E; D047150:Eosinophil Cationic Protein; C479220:RNASE3 protein, human