Individual fecal alpha 1-antitrypsin excretion reflects clinical activity in Crohn's disease but not in ulcerative colitis.

BACKGROUND/AIMS: The natural course of fecal alpha 1-antitrypsin (AAT) excretion was assessed in patients with inflammatory bowel disease (IBD) to evaluate its role in monitoring their clinical disease activity. METHODOLOGY: A prospective cohort pilot study was performed in 9 patients with Crohn's disease (CD) and 3 individuals with ulcerative colitis (UC). Subjects were investigated at regular monthly intervals for about one year for (a) parallel AAT stool and serum concentrations by standard immunonephelometry, and (b) for clinical disease activity by Crohn's Disease Activity Index (CDAI) in CD patients, and by Clinical Activity Index (CAI) in UC subjects. Absolute results during follow-up were each referred to individual findings at study entry as relative results. RESULTS: While absolute fecal AAT concentration did not correlate with disease activity indices (p > 0.26), relative fecal AAT concentration significantly correlated to concurrent relative CDAI score in CD patients (p < 0.001, r = 0.67), but not to relative CAI score in UC subjects (p = 0.92). Monthly intraindividual variation of fecal AAT excretion did not predict development of either disease activity index (p > 0.14). CONCLUSIONS: Individual fecal AAT excretion closely reflects clinical course in CD subjects, but not in UC patients. It does not predict symptomatic deterioration in these individuals, at least on a short-term basis.