[Diagnostic role of anti-saccharomyces cerevisiae and antineutrophil cytoplasmic autoantibodies in inflammatory bowel disease].

OBJECTIVE: To determine the accuracy of the assay using perinuclear antineutrophil cytoplasmic antibody (pANCA) and anti-saccharomyces cerevisiae antibodies (ASCA) in diagnosing ulcerative colitis (UC) and Crohn's disease (CD) and whether the presence of ASCA and pANCA antibodies could differentiate either CD from UC, or inflammatory bowel disease (IBD) from normal controls.

METHODS: Serum samples were obtained from 34 patients with CD and 29 with UC, and from 25 normal volunteers. Diagnosis was established on clinical findings, X-ray or endoscopy and histology. Determination of ASCA and pANCA antibodies was performed using indirect immunofluorescence technique.

RESULTS: 47.1% patients with CD against 69.0% patients with UC expressed pANCA (P < 0.05). Vice versa 58.6% patients with UC against 11.8% patients with CD expressed ASCA (P < 0.05). The sensibility, specificity and positive predictive value of combination of positive ASCA and negative pANCA to diagnosis CD was 0, 89.7% and 0 respectively, and those of combination of positive pANCA and negative ASCA to diagnosis of UC was 20.7%, 64.7% and 33.3% respectively.

CONCLUSIONS: The positive of either ASCA or pANCA are not enough sensible to screen the IBD, but useful to diagnosis IBD. The combination pANCA and ASCA can not be as a serum differential diagnosis marker for IBD.