Spondyloarthritis (SpA) is often complicated with subclinical gut inflammation. This study was aimed at searching for biomarkers discriminating SpA patients with and without intestinal symptoms. A group of 29 SpA patients and 33 healthy volunteers (control) were included in the study. Based on clinical evaluation, the patient cohort was subdivided into two groups: 1) SpA accompanied by various intestinal symptoms suggesting gut inflammation (group 2, n = 14) and 2) without such complications (group 1, n = 15). Serum concentrations of interleukins (IL) (IL-10, IL-17A/F, IL-22, IL-23), tumour necrosis factor (TNF), bone-homeostasis-related factors (osteoprotegerin - OPG and Dickkopf-1 - DKK-1), and the concentrations of selected gut inflammation-associated factors (intestinal fatty acid binding protein - iFABP, claudin 3 - CLDN3 and calprotectin) in samples of sera and/or urine or stool, respectively, were measured by specific ELISA. Serum concentrations of tested factors were similar in SpA patients and control. Faecal calprotectin level was higher in patients but did not discriminate between group 1 and 2. Compared to group 1, group 2 was characterized by elevated erythrocyte sedimentation rate (ESR), higher serum CLDN3 and DKK-1 levels. In SpA patients, serum DKK-1 concentrations correlated with systemic inflammation markers (R = 0.6, p < 0.01), while serum CLDN3 was found to be an independent risk factor (OR = 4.5, p = 0.021) for the occurrence of intestinal symptoms. We conclude that in SpA patients, up-regulated circulating levels of CLDN3 seem to be related to intestinal complication, while the quantity of circulating DKK-1 reflects the intensity of systemic inflammation.

中文翻译：

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患有和没有肠道症状的脊柱关节炎患者-寻找有区别的生物标志物。

脊柱关节炎（SpA）通常并发亚临床肠道炎症。这项研究的目的是寻找能够区分有或没有肠道症状的SpA患者的生物标志物。一组29名SpA患者和33名健康志愿者（对照组）被纳入研究。根据临床评估，将患者队列分为两组：1）SpA伴有多种肠道症状，提示肠道炎症（第2组，n = 14）和2）无此类并发症（第1组，n = 15）。血清白细胞介素（IL）（IL-10，IL-17A / F，IL-22，IL-23），肿瘤坏死因子（TNF），骨稳态相关因子（骨保护素-OPG和Dickkopf-1-DKK） -1），以及所选肠道炎症相关因子的浓度（肠道脂肪酸结合蛋白-iFABP，通过特异性ELISA测量血清和/或尿液或粪便样品中的claudin 3-CLDN3和钙卫蛋白。SpA患者和对照组的血清测试因子浓度相似。患者的粪便钙卫蛋白水平较高，但在第1组和第2组之间没有区别。与第1组相比，第2组的特征是红细胞沉降率（ESR）升高，血清CLDN3和DKK-1升高。在SpA患者中，血清DKK-1浓度与全身炎症标志物相关（R = 0.6，p <0.01），而血清CLDN3被发现是肠症状发生的独立危险因素（OR = 4.5，p = 0.021）。 。我们得出结论，在SpA患者中，CLDN3的循环水平上调似乎与肠道并发症有关，