title: Molecular cloning reveals nearly half of patients with Crohn's disease have an antibody to peroxiredoxin 6-like protein.
abstract: OBJECTIVE
  Crohn's disease (CD) is a chronic inflammatory bowel disease (IBD) of unknown etiology. We aimed to identify the etiological agent of CD using a molecular cloning strategy that was particularly focused on identifying agents causing immune abnormalities and infectious agents.
  
  
  METHODS
  We constructed a cDNA library derived from the inflamed intestinal tissue of a CD patient, and screened 1.5 million clones in this library with the serum from another typical CD patient. The expressed cDNA clones that positively reacted with the serum were then expressed as fusion proteins with glutathione S-transferase, and western blotting was performed using the sera of 22 CD, 13 ulcerative colitis (UC), and 16 non-IBD patients.
  
  
  RESULTS
  We identified nine positive clones that did not contain any viral or bacterial genomic DNA. Of these, we selected one clone (clone 50) with which the typical CD patient's serum most strongly reacted. Clone 50 is highly homologous to the antioxidant protein peroxiredoxin 6. In western blotting, the sera of 47.6% CD patients (small intestine type 80%, large and small intestine type 43%, large intestine type 0%) showed strong reactivity to clone 50, none of the UC patients were reactive to clone 50, and 18.8% of non-IBD patients were very weakly reactive to it. We also found that the expression of peroxiredoxin 6 was significantly increased in inflamed intestinal epithelia of CD.
  
  
  CONCLUSIONS
  The present study first showed that some CD patients have an antibody against peroxiredoxin 6-like protein, which may be involved in the pathogenesis of CD.
authors.affiliation: Akita Health Care Center, Akita Red Cross Hospital, Akita University School of Medicine, Akita, Japan. maiizuka@woody.ocn.ne.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iizuka
authors.forename: Osamu
authors.initials: O
authors.lastname: Nakagomi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nanjo
authors.forename: Mitsuro
authors.initials: M
authors.lastname: Chiba
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Fukushima
authors.forename: Akira
authors.initials: A
authors.lastname: Sugita
authors.forename: Shiho
authors.initials: S
authors.lastname: Sagara
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Horie
authors.forename: Sumio
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001323:Autoantibodies / Q000097:blood* / Q000235:genetics; D015415:Biomarkers / Q000097:blood; D015153:Blotting, Western; D003001:Cloning, Molecular; D003093:Colitis, Ulcerative / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D003424:Crohn Disease / Q000201:enzymology / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D005260:Female; D015723:Gene Library; D006801:Humans; D007150:Immunohistochemistry; D007422:Intestines / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D008297:Male; D008969:Molecular Sequence Data; D054465:Peroxiredoxin VI / Q000032:analysis; D054464:Peroxiredoxins / Q000032:analysis / Q000276:immunology*; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; C576982:peroxiredoxin 6-like protein, human; C515977:PRDX6 protein, human; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins