title: Age of diagnosis influences serologic responses in children with Crohn's disease: a possible clue to etiology?
abstract: BACKGROUND
  Crohn's disease (CD) is often associated with antibodies to microbial antigens. Differences in immune response may offer clues to the pathogenesis of the disease. The aim was to examine the influence of age at diagnosis on the serologic response in children with CD.
  
  
  METHODS
  Data were drawn from 3 North American multicenter pediatric inflammatory bowel disease (IBD) research consortia. At or shortly after diagnosis, pANCA, ASCA IgA, ASCA IgG, anti-ompC, and anti-CBir1 were assayed. The results were compared as a function of age at CD diagnosis (0-7 years versus 8-15 years).
  
  
  RESULTS
  In all, 705 children (79 <8 years of age at diagnosis, 626 >or=8 years) were studied. Small bowel CD was less frequent in the younger group (48.7% versus 72.6%; P < 0.0001), while colonic involvement was comparable (91.0% versus 86.5%). ASCA IgA and IgG were seen in <20% of those 0-7 years old compared to nearly 40% of those 8-15 years old (P < 0.001), while anti-CBir1 was more frequent in the younger children (66% versus 54%, P < 0.05). Anti-CBir1 detected a significant number of children in both age groups who otherwise were serologically negative. Both age at diagnosis and site of CD involvement were independently associated with expression of ASCA and anti-CBir1.
  
  
  CONCLUSIONS
  Compared to children 8-15 years of age at diagnosis, those 0-7 years are more likely to express anti-CBir1 but only half as likely to express ASCA. These age-associated differences in antimicrobial seropositivity suggest that there may be different, and as yet unrecognized, genetic, immunologic, and/or microbial factors leading to CD in the youngest children.
authors.affiliation: Division of Pediatric Gastroenterology, North Shore, LIJ Health System, New Hyde Park, New York, USA. jmarkowi@nshs.edu
authors.forename: James
authors.initials: J
authors.lastname: Markowitz
authors.forename: Subra
authors.initials: S
authors.lastname: Kugathasan
authors.forename: Marla
authors.initials: M
authors.lastname: Dubinsky
authors.forename: Ling
authors.initials: L
authors.lastname: Mei
authors.forename: Wallace
authors.initials: W
authors.lastname: Crandall
authors.forename: Neal
authors.initials: N
authors.lastname: LeLeiko
authors.forename: Maria
authors.initials: M
authors.lastname: Oliva-Hemker
authors.forename: Joel
authors.initials: J
authors.lastname: Rosh
authors.forename: Jonathan
authors.initials: J
authors.lastname: Evans
authors.forename: David
authors.initials: D
authors.lastname: Mack
authors.forename: Anthony
authors.initials: A
authors.lastname: Otley
authors.forename: Marian
authors.initials: M
authors.lastname: Pfefferkorn
authors.forename: Ron
authors.initials: R
authors.lastname: Bahar
authors.forename: Eric
authors.initials: E
authors.lastname: Vasiliauskas
authors.forename: Ghassan
authors.initials: G
authors.lastname: Wahbeh
authors.forename: Gary
authors.initials: G
authors.lastname: Silber
authors.forename: J Antonio
authors.initials: JA
authors.lastname: Quiros
authors.forename: Iwona
authors.initials: I
authors.lastname: Wrobel
authors.forename: Justin
authors.initials: J
authors.lastname: Nebel
authors.forename: Carol
authors.initials: C
authors.lastname: Landers
authors.forename: Yoanna
authors.initials: Y
authors.lastname: Picornell
authors.forename: Stephan
authors.initials: S
authors.lastname: Targan
authors.forename: Trudy
authors.initials: T
authors.lastname: Lerer
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Hyams
mesh_terms: D000293:Adolescent; D000367:Age Factors; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D003424:Crohn Disease / Q000097:blood* / Q000209:etiology; D005260:Female; D005408:Flagellin / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010641:Phenotype; D018272:Porins / Q000276:immunology*; D011379:Prognosis; D011446:Prospective Studies
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; C502160:CBir1 flagellin; D007070:Immunoglobulin A; D007074:Immunoglobulin G; C113724:OmpC protein; D018272:Porins; D005408:Flagellin