Serum alpha-1 antitrypsin: a noninvasive marker of pouchitis.
Maneno muhimu
Kikemikali
BACKGROUND
Patients with ulcerative colitis undergoing total proctocolectomy with ileal pouch-anal anastomosis may develop pouchitis. Alpha-1-antitrypsin (AAT) is an acute phase reactant produced mainly by hepatocytes, but also locally in the gut. Data on noninvasive biomarkers of pouchitis are scarce.
METHODS
To identify biomarkers that correlate with pouch inflammation, ulcerative colitis pouch patients were prospectively recruited and underwent clinical, endoscopic, and histologic evaluations. The Pouchitis Disease Activity Index (PDAI) was calculated, and pouchitis was defined by a score ≥7. Serum and fecal AAT, C-reactive protein (CRP), fecal calprotectin, ferritin and albumin levels were measured.
RESULTS
Seventy-one ulcerative colitis pouch patients (mean age 43.8 ± 8.3 yr, 50.7% males) were included. The main indication for ileal pouch-anal anastomosis was intractable colitis (83.1%). Median serum AAT level (183.0 mg/dL, 155.1-232.0) was significantly higher in patients with a PDAI ≥7 compared with those with a PDAI <7 (167.6 mg/dL, 151.0-181.0) (P = 0.03). Serum AAT, CRP, and fecal calprotectin levels significantly correlated with PDAI scores: r = 0.583, P < 0.001; r = 0.584, P < 0.001; and r = 0.606, P = 0.001, respectively. Serum AAT and CRP levels correlated significantly (r = 0.650, P < 0.001), as did serum AAT and fecal calprotectin levels (r = 0.663, P < 0.001). Fecal AAT levels did not correlate with any tested biomarker. Receiver operating characteristic analysis demonstrated sensitivity, specificity, and positive predictive value of 55.6%, 100%, and 100%, respectively, for diagnosing pouchitis at a serum AAT cutoff level of 189 mg/dL.
CONCLUSIONS
Serum AAT is a specific noninvasive biomarker of pouchitis. AAT levels correlate with disease activity and CRP and calprotectin levels.
