Fecal S100A12 as a Biomarker in Behcet’s Disease

Background: Gastroinestinal involvement in Behcet’s disease impacts morbidity and mortality. The diagnosis of gastrointestinal disease requires comprehensive evaluation with endoscopic and radiologic examinations which is costly and impractical. A biomarker is essential for non-invasive detection. Fecal S100A12 is an established biomarker in gastrointestinal inflammatory diseases and its serum levels are known to increase in Behcet’s Disease. In this study, we aimed to tests fecal S100A12 levels in Behcet’s patients, its relation with gastrointestinal symptoms to its potential as a biomarker in gastrointestinal involvement. Methods: We prospectively enrolled 48 cases of Behcet’s disease patients fulfilling International Study Group criteria from a university hospital. We excluded patients with other autoimmune conditions, active or recent infection, using NSAIDs and antibiotics. Control group was selected from volunteers who had applied to the rheumatology outpatient clinic. Patients with BD were categorized into 5 groups according to organ involvement. Also we evaluated and recorded disease activity with the BDCAF 2006. Fecal S100A12, fecal calprotectin and acute phase reactants were also collected. Results: Fecal calprotectin levels were six-fold higher in BD than controls (p<0.0001). Fecal S100A12 was also two-fold higher albeit without statistical significance (p=0.132). Fecal calprotectin and fecal S100A12 levels were positively correlated (r:0.530, p<0.0001). Both fecal calprotectin (138.1 μg/g vs 50.1 μg/g, p=0.006).) and fecal S100A12 (48.3 ng/mL vs 19.4 ng/mL, p=0.023) were higher in Behcet's patients with gastrointestinal symptoms compared to those without. Fecal calprotectin and fecal S100A12 levels were not correlated with total BDCAF score, CRP and ESR levels. Conclusion: Fecal S100A12 is correlated with fecal calprotectin and higher in Behcet’s patients with gastrointestinal involvement. This is the first study of fecal S100A12 in Behcet’s disease and its potential use in Behcet’s disease patients with gastrointestinal symptoms.