The team evaluated the value of anti-Saccharomyces cerevisiae antibodies (ASCA) and perinuclear antineutrophil cytoplasmic antibodies (pANCA) to increase diagnostic accuracy in categorizing indeterminate colitis (IC).
The findings of the study were published in the May issue of Gastroenterology.
In the absence of pathognomonic markers for Crohn's disease (CD) and ulcerative colitis (UC), the diagnosis of inflammatory bowel disease depends on a compendium of clinical, radiographic, endoscopic, and histologic criteria that bears imperfect specificity to the individual disorders.
In 10% of cases of colitis, no differentiation can be made between CD and UC; these patients are diagnosed with IC.
From 1996, 97 patients with IC from 3 centers (Belgium, France, and Austria) were enrolled in the trial.
Each was analyzed for pANCA and ASCA, and followed up prospectively.
A definitive diagnosis was reached for 31 of 97 patients (32%).
|49% of IC patients did not show antibodies against ASCA or pANCA.
| Gastroenterology |
In these patients, ASCA+/pANCA- correlated with CD in 8 of 10 patients. On the other hand, ASCA-/pANCA+ correlated with UC in 7 of 11 patients.
The remaining 4 cases became CD, clinically behaving as UC-like CD.
Almost half of the patients (47 of 97) were negative for ASCA and pANCA. Some 40 patients remain diagnosed with IC to date.
Only 7 seronegative cases (15%) became CD or UC, compared with 48% (24 of 50) of seropositive patients.
Sofie Joossens, from Leuven, Belgium, said on behalf of her colleagues, "Results so far show that ASCA+/pANCA- predicts CD in 80% of patients with IC, and ASCA-/pANCA+ predicts UC in 64%."
"Interestingly, 49% of patients do not show antibodies against ASCA or pANCA.
"Most of these patients remain diagnosed with IC during their further clinical course, perhaps reflecting a distinct clinicoserological entity," she concluded.