Serologic testing of a panel of five antibodies in inflammatory bowel diseases: Diagnostic value and correlation with disease phenotype

The aim of the present study was to evaluate the diagnostic value of five serological antibodies, perinuclear antineutrophil cytoplasmic antibody (pANCA), anti-Saccharomyces cerevisiae antibodies [ASCA; ASCA-immunoglobulin (IgG)and ASCA-IgA], Escherichia coli outer membrane porin C antibody (anti-OmpC) and CBir1 flagellin antibody for detection in inflammatory bowel diseases. Whether the antibody status correlated with the disease phenotype was also evaluated. Sera from 71 patients with Crohn's disease (CD), 41 patients with ulcerative colitis (UC), 78 patients with other gastrointestinal diseases and 31 healthy control subjects were investigated. Clinical data were gathered at the time of serum sampling and enzyme-linked immunosorbent assay was used to determine titers of the above mentioned five antibodies. The pANCA test exhibited a sensitivity of 53.7% for UC and the ASCA test had a sensitivity of 66.2% for CD. The prevalence of anti-OmpC was significantly higher in CD than in intestinal tuberculosis (TB), indicating that anti-OmpC may be a serologic marker distinguishing CD from TB. The pANCA⁺/ASCA- exhibited the best specificity for differentiating between CD and UC. In UC, the presence of pANCA was greater in the patients with moderate to severe activity than in those with mild activity. ASCA was more positive in ileal CD. Furthermore, positive ASCA-IgG or anti-OmpC implied that complicated CD and pANCA was associated with colonic CD. Seropositivity of anti-CBir1 was lowest in colonic CD.