Title: The value of serologic markers in indeterminate colitis: A prospective follow-up study
Abstract: Background & Aims: 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 indeterminate colitis (IC). We evaluated the value of anti–Saccharomyces cerevisiae antibodies (ASCA) and perinuclear antineutrophil cytoplasmic antibodies (pANCA) to increase diagnostic accuracy in categorizing IC. Methods: Since 1996, 97 patients with IC from 3 centers (Leuven, Lille, and Vienna) were enrolled, analyzed for pANCA and ASCA, and followed up prospectively. Results: A definitive diagnosis has been reached for 31 of 97 patients (32%). In these patients, ASCA+/pANCA− correlated with CD in 8 of 10 patients, whereas 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 [48.5%]) were negative for ASCA and pANCA, and 40 remain diagnosed with IC to date. Only 7 seronegative cases (14.9%) became CD or UC compared with 48% (24 of 50) of seropositive patients (P < 0.001). Conclusions: Results so far show that ASCA+/pANCA− predicts CD in 80% of patients with IC and ASCA−/pANCA+ predicts UC in 63.6%. Interestingly, 48.5% 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.GASTROENTEROLOGY 2002;122:1242-1247