title: Fecal alpha 1-antitrypsin clearance as a marker of clinical relapse in patients with Crohn's disease of the distal ileum.
abstract: BACKGROUND
  Crohn's disease (CD) shows a chronic relapsing course but no marker of relapse is currently available. However, fecal alpha 1-antitrypsin (alpha 1-AT) clearance (alpha 1-ATCl) is an indicator of protein loss and increases during active inflammation. We assessed the usefulness of fecal alpha 1-ATCl in predicting clinical relapse in patients with inactive ileal CD.
  
  
  METHODS
  In a prospective longitudinal study, 26 patients with inactive ileal CD (Crohn's disease activity index (CDAI) < 150) (18 males, mean age 43 +/- 10, range 23-58) were enrolled. Fecal alpha 1-ATCl and concentration, daily stool weight and serum alpha 1-AT were measured at baseline (visit 1), after 1 week (visit 2) and 3 weeks (visit 3) in 24/26 patients (two drop-outs) (short-term study). In six of these 26 patients, fecal alpha 1-ATCl was also measured every 3 months for 1 year (long-term study). All patients were clinically assessed every 3 months for 1 year and every 6 months for 2 years. Ten healthy volunteers were tested as controls.
  
  
  METHODS
  Serum and fecal alpha 1-AT concentration was quantified by radial immunodiffusion.
  
  
  RESULTS
  The median fecal alpha 1-ATCl value at baseline was higher in inactive patients undergoing clinical relapse (CDAI > 200) in the next 6 months than in those remaining in remission at 6 months (P = 0.03). Fecal alpha 1-ATCl showed a 75% sensitivity, 85% specificity, 50% positive predictive value and 94% negative predictive value in predicting CD relapse in the next 6 months. In the long-term follow-up, fecal alpha 1-ATCl values increased at 12 months compared with both baseline and 6 month values (P = 0.005; P = 0.009). Fecal alpha 1-ATCl was higher in patients with raised C-reactive protein (P = 0.039).
  
  
  CONCLUSIONS
  Results from our study suggest that fecal alpha 1-ATCl is an indicator of clinical relapse in patients with CD of the distal ileum under regular surveillance.
authors.affiliation: Cattedra di Gastroenterologia, Dipartimento di Medicina Interna, Università degli Studi di Roma Tor Vergata, Rome, Italy. biancone@med.uniroma1.it
authors.forename: Livia
authors.initials: L
authors.lastname: Biancone
authors.forename: Massimo
authors.initials: M
authors.lastname: Fantini
authors.forename: Claudio
authors.initials: C
authors.lastname: Tosti
authors.forename: Rosamaria
authors.initials: R
authors.lastname: Bozzi
authors.forename: Piero
authors.initials: P
authors.lastname: Vavassori
authors.forename: Francesco
authors.initials: F
authors.lastname: Pallone
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D002097:C-Reactive Protein / Q000378:metabolism; D003424:Crohn Disease / Q000175:diagnosis* / Q000378:metabolism; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012008:Recurrence; D012680:Sensitivity and Specificity; D000515:alpha 1-Antitrypsin / Q000032:analysis*
chemical_list: D015415:Biomarkers; D000515:alpha 1-Antitrypsin; D002097:C-Reactive Protein