The significance of combined assays of anti Saccharomyces cerevisia antibody and perinuclear antineutrophil cytoplasmic antibody on differentiatial diagnosis of inflammatory bowel disease

Objective To assess the value of combined assays of anti Saccharomyces cerevisia antibody (ASCA) and perinuclear antineutrophil cytoplasmic antibody (pANCA) in differential diagnosis of inflammatory bowel disease (IBD). Methods Nineteen patients with IBD, including 9 patients with Crohn's disease(CD) and 10 patients with ulcerative colitis(UC), and 18 healthy subjects were enrolled into study. Serum levels of pANCA and ASCA (IgG and IgA) were measured by indirect immunofluorescence technique and a standardized ELISA, respectively. Results The serum levels of ASCA IgG and ASCA IgA in CD patients (18.51± 6.38 and 11.74 ± 5.46 ) were significantly higher than those in UC patients ( 6.98 ± 5.24 and 3.88 ± 3.52 ) and healthy subjects( 5.90 ± 4.12 and 4.62 ± 3.21 )respectively (P 0.05 ). The sensitivity of pANCA in diagnosis of UC was 80%, and no case was positive in both CD patients and healthy controls. Conclusion The present study indicated that ASCA and pANCA had diagnostic specificity in patients of CD and UC. It was conceivable that ASCA as a marker correlated with CD while pANCA as an immunological index related to UC. The combination of ASCA and pANCA test had the differential diagnostic value in IBD patients.