Background/Purpose: The fecal calprotectin (FC) is widely used as a non-invasive method for identifying patients with active Crohn’s disease (CD) and ulcerative colitis. Gastrointestinal involvement of Behçet’s syndrome (GIBS) shows clinical and endoscopic similarities to CD. A previous study in a small number of Behçet’s syndrome (BS) patients with mainly mucocutaneous lesions showed serum calprotectin levels did not differ between active and inactive patients (1). Another study suggested FC may help to diagnose GIBS patients (2). We are not aware of studies addressing whether FC helps to distinguish active GIBS patients from those in remission. Therefore, we aimed to determine whether FC helped to predict active disease in GIBS patients.

Methods:  We collected fecal specimens and serum from 23 GIBS (11 M, 12 F and mean age 44±9 yrs) patients before colonoscopy. The reasons for colonoscopy were assessing active disease in patients presenting with abdominal pain (with or without diarrhea) (n=9) or confirmation of a remission in asymptomatic patients (n=14). Seven of these patients had active GI involvement and the remaining 16 were inactive, based on colonoscopic findings. We also included 22 active and 25 inactive CD patients as controls. We used 150 µg/g as the cut-off for a positive FC level. We also looked at the correlations between FC and serum calprotectin and CRP levels, Crohn’s disease activity index (CDAI) and disease activity index for intestinal Behçet’s disease (DAIBD) scores.

Results: FC was >150 µg/g in all of the 7 GIBS patients with ulcers compared to 4/16 of GIBS patients without ulcers (OR: 42, 95%CI: 2 to 888). The median FC of active GIBS patients (n=7) was significantly higher than among inactive GIBS patients (n=16) (325 µg/g (IQR: 187-1800) vs 44 µg/g (IQR: 30-154); p=0.002). The mean serum calprotectin level was also higher among the active GIBS patients, however the difference was not significant (173.0 ± 273.7 µg/g vs 102.0 ± 135.4, p=0.13). There was a very low correlation between FC and serum calprotectin levels (r=0.08, p=0.72), a moderate correlation between FC and serum CRP levels (r=0.66, p=0.76), a moderate correlation between FC and CDAI scores (r=0.55, p=0.006) and very low correlation between FC and DAIBD scores (r=0.01, p=0.96). Among CD patients, 16/25 of the active patients and 3/22 of the patients in remission had FC level >150 µg/g (OR: 2.6, 95%CI: 3 to 49). Among the 4 GIBS patients who had high FC levels despite being in remission for gastrointestinal involvement, 1 had active mucocutaneous lesions, 1 had concomitant macrophage activation syndrome, and 1 had polycythemia vera with trisomy 8. None of the patients were receiving NSAIDs that could increase FC levels.

Conclusion: With further work FC may turn out to be a useful non-invasive tool for ruling out active GI lesions in asymptomatic GIBS patients. A high FC level demands caution for the presence of active ulcers especially in symptomatic patients while whether the presence of other BS manifestations can cause false positive results remains to be studied.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/fecal-calprotectin-level-is-useful-in-identifying-active-disease-in-behcets-syndrome-patients-with-gastrointestinal-involvement-a-controlled-study/