Background/Purpose: Fecal calprotectin (FC) is a well bio-marker related to mucosal inflammation. Digital chromo-endoscopy (DCE) with magnification is a technique to identify microscopic inflammation. The objective of the study is to establish the association between FC levels and DCE/histology for the detection of early bowel lesions related to structural inflammatory changes in patients with SpA without IBD (inflammatory bowel disease)

Methods: In total, 180 patients with SpA fulfilling ASAS classification criteria were assessed by rheumatologist. Of them, 42.2% met the selection criteria and 48.7 % had an indication by a gastroenterologist to perform DCE for colon e ileum plus histological analysis. FC, CRP, and HLA-B*27 were performed. The association between FC levels and CDE/histological and clinical parameters were evaluated using Chi-square or Fisher’s exact test with multivariate evaluation by principal components analysis (PCA)

Results: The average age of the patients included for DCE was 45,1±10.3 years, 56.8% were men, 40.9% were HLA-B*27:05 positive and 89.2% had axial involvement and 91.9% inflammatory back pain. Positive levels of FC (PFC >120ng/mL) and high levels (HFC) >250ng/Ml, were observed in 27% and 16% respectively. BASDAI >4 was found in 54.1% of patients and ASDAS-PCR >2.1 in 78.4%. High levels of PFC were associated with BASFI >4 (p = 0.036), BASDAI >4 (p = 0.047). More than 70% of these patients a loss of the vascular pattern in the ileum (LVPI) was observed (p = 0.005). Moreover, 77% of the patients having PFC with abdominal bloating, simultaneously had LVPI (p = 0.020) in addition to villous atrophy and microscopic inflammation in 66.7% (p = 0.012). In those patient having PFC plus abdominal pain the presence of LVPI was observed in 75% (p= 0.007). The HFC associated with alterations at the level of the ileum mucosa (p= 0.009), with LVPI (p= 0.001). At microscopic analysis, the HFC levels were associated with inflammation (p= 0.046) and a chronic pattern (p = 0.014) in 83.3%. Overall, 27.3% of patients had HFC and diarrhea, associated with LVPI and presence of erosions in ileum (p=0.026) and (p=0.031), respectively. Microscopically, ileum chronic inflammation was observed in 25% (p=0.037). All patients having increased HFC levels and ASDAS-CRP >2.1,the following findings were observed: alteration of ileum mucosa (p = 0.09), request for vascular pattern (p = 0.001) and villous atrophy reflected microscopically as a chronic pattern (p=0.014) in 66.7%. The PCA with Kaiser normalization of 0.642 and Bartlett test (p=0.0001), showed three factors:1) Micro and macroscopic changes of chronic inflammation and HFC (CC = 0.837, 2),increased CRP and microscopic acute inflammation (CC = 0.792) and 3) clinical activity scores ASDAS-PCR and BASDAI (CC = 0.914)

Conclusion: FC levels were significantly higher in patients with SpA group in which CDE showed LVPI as main finding with associations with disease activity score.FC levels may be used to guide patient management in SpA and further investigation is required. The presence of villi atrophy may suggest a shared immune pathway related to chronic damage in the intestinal tissue when the joint manifestations are active

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/elevated-calprotectin-levels-reveal-loss-of-vascular-pattern-and-atrophy-of-villi-in-ileum-using-digital-chromo-endoscopy-and-magnification-colonoscopy-in-patients-with-spondyloarthritis-without-infla/