Background Elevated fecal calprotectin (FC) levels indicate activity in Crohn's disease (CD) and ulcerative colitis and are used as non-invasive biomarkers in these diseases. Gastrointestinal involvement of Behçet's syndrome (GIBS) shows clinical and endoscopic similarities to CD. A previous study suggested that FC may help to diagnose GIBS patients (1), but we are not aware of any studies addressing its role in identifying disease activity in such patients.
Objectives To determine whether FC helps to distinguish active GIBS patients from those in remission.
Methods We collected fecal and serum specimens before colonoscopy from 39 GIBS patients who agreed to participate (Table). Twenty-six patients were asymptomatic whereas 13 had abdominal pain and/or diarrhea. We also filled disease activity index for intestinal Behçet's disease (DAIBD) and Crohn's disease activity index (CDAI) in each patient. Active gastrointestinal (GI) involvement was defined as having ulcers on colonoscopy. We included 22 active and 25 inactive CD patients as controls. We used 150 μg/g as the cut-off for a positive FC level. None of the patients were receiving NSAIDs that could increase FC levels.
Results Among the 39 GIBS patients, 14 had active ulcers on colonoscopy (8/13 symptomatic and 6/26 of asymptomatic). FC level was >150 μg/g in 12/14 active GIBS patients and in 6/25 patients in GI remission (OR: 19, 95% CI: 3 to 110). The median FC and CRP levels were higher among active GIBS patients whereas serum calprotectin levels were not different (Table). Among CD patients, 16/25 active patients and 3/22 patients in remission had a FC level >150 μg/g (OR: 11, 95% CI: 11 to 49). There was a high correlation between FC and CDAI scores (r=0.64, p<0.001) and a very high correlation between FC and DAIBD scores (r=0.71, p<0.001), while FC was not correlated with serum calprotectin and CRP levels. Among the 6 GIBS patients who had high FC levels despite being in remission for GI involvement, 2 had active mucocutaneous lesions, 1 had concomitant macrophage activation syndrome (MAS), 1 had polycythemia vera with trisomy 8 and 2 were started high dose corticosteroids. Repeat FC levels could be obtained in 3 of these patients, after the resolution of MAS and mucocutaneous lesions, and were <150 in all 3.
Conclusions FC seems to be a useful non-invasive tool for identifying active GI involvement in GIBS patients. Whether the presence of other BS manifestations can cause false positive results in GIBS patients in remission remains to be studied. On the other hand, serum calprotectin levels do not seem to be useful in identifying active disease in GIBS patients.
Kim DH et al. J Gastroenterol Hepatol. 2016.
Disclosure of Interest None declared