POS1008 THE ROLE OF SERUM CALPROTECTIN IN THE DIAGNOSIS OF INFLAMMATORY BOWEL DISEASE IN PATIENTS WITH ANKYLOSING SPONDYLITIS
Authors: P. Kulakova, G. Lukina, E. Alexandrova, A. Novikov, A. Klimets, N. Savenkova, A. Kovshik, E. Volnukhin
Journal: Annals of the Rheumatic Diseases (2021)

Background: Аnkylosing spondylitis (AS) and inflammatory bowel diseases (IBD) have many common features. Approximately one in two patients with axial spondyloarthritis have subclinical (histologically confirmed) inflammation of the intestine, and 5-10% of subclinical inflammation turns into Crohn’s disease (CD) or Ulcerative colitis (UC) [1]. Colonoscopy is usually used to diagnose IBD, but this procedure is invasive. Laboratory biomarkers, as fecal calprotectin (FC) and serum calprotectin (SC) can used to diagnosis of IBD. But there is no consensus regarding SC clinical utility. SC is exposed to proteolytic enzymes, but its level also increases with inflammation in the intestine and is associated with a higher disease activity [2]. SC levels positively correlate with CRP, ESR, disease activity in AS, but not as obvious as with FC [3,4]. Objectives: The aim of this study was to evaluate the possibility of using SC in the diagnosis of IBD in patients with AS. Methods: In the analysis were included 50 patients with AS, fulfilling the modified New York criteria, among them man -36 (72%), woman -14 (28%), mean age of patients was 42.5 ±9.9, mean disease duration – 13.4±8.7 years. All patients were examined with ESR, CRP, FC (range: 100-1800 µg /g), esophagogastroduodenoscopy, colonoscopy and quantitative analysis of the SC level using ELISA (BUHLMANN MRP8/14 ELISA, range: 0.4-3.9 µg /ml). Results: All patients had a high disease activity, mean BASDAI was 5.3 ± 1.8, mean ASDAS CRP 3.7 ± 1.01, mean ASDAS ESR 3.6 ± 1.01. 80 % patients had high FC level (more than 100 µg / g), while only 18% patients had an increase of SC level. IBD were diagnosed in 11 cases: 6 patients (12 %) with CD and 5 patients (10 %) - UC, in the remaining cases (78%) was no intestinal pathology. Only 2 patients with IBD had a high SC level. SC level was more correlated with ESR (r=0.5) and CRP (r=0.5) (p &lt;0.05) levels, than with FC level (r=0.4) (p &lt;0.05). Conclusion: The results showed that there is currently insufficient data to assess the possibility of using SC in the diagnosis of IBD in patients with AS. There is a significant association between the SC, CRP and ESR, but not fecal calprotectin. Potentially SC may be more representative of systemic inflammation than an intestinal inflammation. References: [1]Klingberg, E., Strid, H., Stahl, A.et al. A longitudinal study of fecal calprotectin and the development of inflammatory bowel disease in ankylosing spondylitis. A longitudinal study of fecal calprotectin and the development of inflammatory bowel disease in ankylosing spondylitis. Arthritis Res Ther 2017. 19(1):21 [2]Kalla R, Kennedy NA, Ventham NT, Boyapati RK, Adams AT, Nimmo ER, Visconti MR, Drummond H, Ho GT, Pattenden RJ, Wilson DC, Satsangi J. Serum Calprotectin: A Novel Diagnostic and Prognostic Marker in Inflammatory Bowel Diseases. Am J Gastroenterol. 2016 Dec;111(12):1796-1805 [3]Hu H, Du F, Zhang S, Zhang W. Serum calprotectin correlates with risk and disease severity of ankylosing spondylitis and its change during first month might predict favorable response to treatment. Mod Rheumatol. 2019 Sep;29(5):836-842. [4]Azramezani Kopi T, Shahrokh S, Mirzaei S, Asadzadeh Aghdaei H, Amini Kadijani A. The role of serum calprotectin as a novel biomarker in inflammatory bowel diseases: a review study. Gastroenterol Hepatol Bed Bench. 2019;12(3):183-189. Disclosure of Interests: None declared.