[p-ANCA and ASCA antibodies in the differential diagnosis between ulcerative rectocolitis and Crohn's disease].

UNLABELLED: Anti-Saccaromyces cerevisiae antibodies (ASCA) seem to be associated with Crohn's disease (CD), while anti-neutrophil cytoplasm antibodies (p-ANCA) seem to be a recognised marker for ulcerative colitis (UC). AIM: Of our study was to determine whether the presence of ASCA and p-ANCA antibodies could differentiate CD from UC and IBD from aspecific chronic colitis (ACC).
METHODS: Serum samples were obtained from 23 patients with CD and 32 with UC, and from 13 patients with aspecific chronic colitis. Diagnosis was established on clinical findings, endoscopy and histology. Determination of ASCA and p-ANCA antibodies was performed using indirect immunofluorescence technique and ELISA, respectively.
RESULTS: 20% CD patients against 50% UC patients expressed p-ANCA (p < 0.05). Vice versa 61% CD patients against 16% UC patients expressed ASCA (p < 0.05). The combination of positive ASCA and negative p-ANCA determined a sensibility, specificity and positive predictive value of 45%, 91% and 75% respectively, for diagnosis of CD. The combination of positive p-ANCA and negative ASCA determined a sensibility, specificity and positive predictive value of 44%, 95% and 94% respectively, for diagnosis of UC.
CONCLUSION: Our results indicate that ASCA are principally expressed in patients with CD, by contrast p-ANCA seem to be strongly associated with UC. The combination of these two tests can be useful in evaluating patients with indeterminate colitis, distinguishing UC from CD.