title: Antibodies to CBir1 are associated with glycogen storage disease type Ib.
abstract: OBJECTIVE
  : Glycogen storage disease (GSD) type Ib is a congenital disorder of glycogen metabolism that is associated with neutropenia, neutrophil and monocyte dysfunction, and an inflammatory bowel disease (IBD) that mimics a Crohn disease phenotype. The enteric microflora is implicated in the pathogenesis of IBD; however, its role in the development of GSD-associated IBD is unknown. Antibody reactivity to Saccharomyces cerevisiae antibodies (ASCA), Escherichia coli outer membrane porin C (anti-OmpC), and bacterial flagellin (anti-CBir1) have been associated with Crohn disease in the general population, but they have an undetermined association in children and adults with GSD-Ib. Our goal was to examine the association of ASCA, anti-OmpC, and anti-CBir1 with the clinical features of GSD-Ib enterocolitis.
  
  
  METHODS
  : A retrospective review identified 19 patients with GSD-Ib with or without a known diagnosis of enterocolitis. Radiographic, endoscopic, and serologic data were collected and assays for ASCA, anti-OmpC, and anti-CBir1 obtained.
  
  
  RESULTS
  : Seven patients had combined radiographic, endoscopic, and histologic evidence of intestinal inflammation; the majority had ileocolonic involvement. Seventeen of 19 (89%) patients had elevated anti-CBir1 levels (6/7 in the IBD group and 11/12 in the no clinical evidence of IBD group). Thirteen of 19 (68%) had elevated anti-OmpC levels (5/7 in the IBD group and 8/12 in the no clinical evidence of IBD group). Eleven of 19 (58%) patients had elevated ASCA IgA levels (4/7 in the IBD group and 7/12 in the no clinical evidence of IBD group).
  
  
  CONCLUSIONS
  : Nearly all of the patients with GSD-Ib had elevated anti-CBir1 levels. The antibody did not differentiate those with and without a diagnosis of GSD-Ib-associated IBD. Seroreactivity to flagellin may represent immune dysfunction rather than active enterocolitis in this patient population. Long-term follow-up of the group without known IBD is required to determine whether these antibodies can predict intestinal inflammation.
authors.affiliation: Division of Pediatric Gastroenterology, Department of Pediatrics, USA.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Davis
authors.forename: John F
authors.initials: JF
authors.lastname: Valentine
authors.forename: David A
authors.initials: DA
authors.lastname: Weinstein
authors.forename: Steven
authors.initials: S
authors.lastname: Polyak
mesh_terms: D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000097:blood*; D001426:Bacterial Proteins / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004760:Enterocolitis / Q000150:complications / Q000235:genetics / Q000276:immunology*; D005260:Female; D005408:Flagellin; D005953:Glycogen Storage Disease Type I / Q000150:complications / Q000175:diagnosis / Q000276:immunology*; D006801:Humans; D015994:Incidence; D007223:Infant; D015212:Inflammatory Bowel Diseases / Q000150:complications / Q000235:genetics / Q000276:immunology*; D007422:Intestines / Q000276:immunology* / Q000382:microbiology; D008297:Male; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000906:Antibodies; D001426:Bacterial Proteins; C502160:CBir1 flagellin; D005408:Flagellin
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