title: Distinct patterns of immunoglobulin classes and IgG subclasses of autoantibodies in patients with inflammatory bowel disease.
abstract: OBJECTIVE
  The pathophysiological significance of autoantibodies in inflammatory bowel diseases (IBD) is still unclear. To assess specific immunological abnormalities we examined the distribution and restriction of immunoglobulin classes and subclasses of anti-neutrophil cytoplasmic antibodies (ANCAs) in ulcerative colitis and of antibodies to pancreatic juice (APJs) in Crohn's disease.
  
  
  METHODS
  We tested 62 sera of patients with ulcerative colitis and 184 sera of patients with Crohn's disease for their immunoglobulin class and IgG subclass distribution of ANCAs (in ulcerative colitis patients) and APJs (in Crohn's disease patients) by fluorescence isothiocyanate (FITC)-labelled anti-human antibodies in an immunofluorescence assay with human granulocytes or pancreas as substrate. Twenty-five patients with Wegener's granulomatosis were used for comparison.
  
  
  RESULTS
  In ulcerative colitis ANCAs were found in 74% of the patients. They were predominantly of the IgG (96%) and IgA class (37%). In Crohn's disease APJs (present in 28% of the cases) were of the IgG (98%) and IgA class (71%). ANCAs in ulcerative colitis were of the IgG1 (73%) and IgG3 (5%) subclasses, APJs in Crohn's disease of the IgG1 (94%), IgG2 (20%) and IgG3 (2%) subclasses. The immunoglobulin class and IgG subclass distributions of ANCAs and APJs resembled the changes in total immunoglobulin classes and IgG subclasses in ulcerative colitis or Crohn's disease.
  
  
  CONCLUSIONS
  The immunoglobulin classes and IgG subclasses of autoantibodies in ulcerative colitis and Crohn's disease differ from each other and from the distribution of autoantibodies in vasculitic diseases (Wegener's granulomatosis, microscopic vasculitis, systemic lupus erythematosus). These alterations reflect specific pathophysiological features of ulcerative colitis and Crohn's disease.
authors.affiliation: Department of Internal Medicine I, University of Regensburg, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Müller-Ladner
authors.forename: V
authors.initials: V
authors.lastname: Gross
authors.forename: T
authors.initials: T
authors.lastname: Andus
authors.forename: H
authors.initials: H
authors.lastname: Gschwendtner
authors.forename: M
authors.initials: M
authors.lastname: Roth
authors.forename: I
authors.initials: I
authors.lastname: Caesar
authors.forename: J
authors.initials: J
authors.lastname: Schölmerich
authors.forename: B
authors.initials: B
authors.lastname: Lang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000032:analysis*; D001323:Autoantibodies / Q000032:analysis*; D003093:Colitis, Ulcerative / Q000097:blood / Q000276:immunology; D003424:Crohn Disease / Q000097:blood / Q000276:immunology; D005260:Female; D014890:Granulomatosis with Polyangiitis / Q000097:blood / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D015212:Inflammatory Bowel Diseases / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies; D007074:Immunoglobulin G