Enteric protein loss as a marker of intestinal inflammatory activity in Crohn's disease: comparability of enteric clearance and stool concentration of alpha-1-antitrypsin?

Intestinal alpha 1-antitrypsin (alpha 1-AT) clearance has been shown a reliable index of intestinal inflammatory activity in Crohn's disease (CD). For reasons of practicability, it has been repeatedly suggested to replace alpha 1-AT clearance by alpha 1-AT concentration in random stool samples. In 60 controls and in 70 patients with CD, in 21 patients before and after treatment, fecal alpha 1-AT concentration and the ratio of stool and serum alpha 1-AT concentration were compared with alpha 1-AT clearance. In 11 patients alpha 1-AT clearance, fecal concentration and stool/serum alpha 1-AT concentration ratio were compared with 51Cr-albumin clearance. alpha 1-AT clearance (104 +/- 14 vs. 17.5 +/- 2 ml/d, p < 0.0001) as well as fecal alpha 1-AT concentration (155 +/- 21 vs. 30 +/- 3 mg/100 ml, p < 0.0001) and stool/serum alpha 1-AT concentration ratio (45 +/- 6 vs. 12 +/- 1) were significantly higher in CD patients than in controls. alpha 1-AT clearance (60 +/- 9 vs. 37 +/- 4 ml/d, p < 0.01), fecal alpha 1-AT concentration (113 +/- 21 vs. 59 +/- 8 mg/100 ml, p < 0.01) and the stool/serum alpha 1-AT concentration ratio (27 +/- 4 vs. 18 +/- 2) decreased after treatment, but fecal alpha 1-AT concentration and the stool/serum alpha 1-AT concentration ratio failed to parallel the course of alpha 1-AT clearance in 33% and in 24% of patients, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)