Background: To make a distinction between organic and functional disease is essential for gastroenterologists in their daily practice, but it may be challenging, given the variety and aspecificity of gastrointestinal symptoms among the general population. The clinician aim is to avoid diagnostic delay and to restrict unnecessary invasive and expensive exams. Summary: Faecal markers, in particular faecal calprotectin (FC), have given proof of being reliable markers of intestinal inflammation with good clinical sensitivity. Calprotectin is useful in the differential diagnosis between inflammatory bowel disease and irritable bowel syndrome, as well as in the follow-up of inflammatory bowel disease patients and in predicting treatment response, with an excellent correlation with endoscopic activity. Its role in collagenous colitis and infectious colitis is less clear and still under investigation. Key Message: Despite the growing evidence supporting its use, many clinicians are uncomfortable in dosing FC, due to its low specificity and the variability of cut-off values. Indeed there are no clear guidelines about how to manage patients with intermediate levels of FC. The aim of this article is to review recent literature on calprotectin and its use. The strong points and the limits of FC measurement will be analysed, and a practical approach in the daily clinical routine will be proposed.

SummaryMacrophages play a critical role in intestinal wound repair. However, the mechanisms of macrophage-assisted wound repair remain poorly understood. We aimed to characterize more clearly the repair activities of murine and human macrophages. Murine macrophages were differentiated from bone marrow cells and human macrophages from monocytes isolated from peripheral blood mononuclear cells of healthy donors (HD) or Crohn's disease (CD) patients or isolated from the intestinal mucosa of HD. In-vitro models were used to study the repair activities of macrophages. We found that murine and human macrophages were both able to promote epithelial repair in vitro. This function was mainly cell contact-independent and relied upon the production of soluble factors such as the hepatocyte growth factor (HGF). Indeed, HGF-silenced macrophages were less capable of promoting epithelial repair than control macrophages. Remarkably, macrophages from CD patients produced less HGF than their HD counterparts (HGF level: 84 ± 27 pg/mg of protein and 45 ± 34 pg/mg of protein, respectively, for HD and CD macrophages, P < 0·009) and were deficient in promoting epithelial repair (repairing activity: 90·1 ± 4·6 and 75·8 ± 8·3, respectively, for HD and CD macrophages, P < 0·0005). In conclusion, we provide evidence that macrophages act on wounded epithelial cells to promote epithelial repair through the secretion of HGF. The deficiency of CD macrophages to secrete HGF and to promote epithelial repair might contribute to the impaired intestinal mucosal healing in CD patients.

Very-early-onset inflammatory bowel disease (VEO-IBD) is a heterogeneous phenotype associated with a spectrum of rare Mendelian disorders. Here, we perform whole-exomesequencing and genome-wide genotyping in 145 patients (median age-at-diagnosis of 3.5 years), in whom no Mendelian disorders were clinically suspected. In five patients we detect a primary immunodeficiency or enteropathy, with clinical consequences (XIAP, CYBA, SH2D1A, PCSK1). We also present a case study of a VEO-IBD patient with a mosaic de novo, pathogenic allele in CYBB. The mutation is present in~70% of phagocytes and sufficient to result in defective bacterial handling but not life-threatening infections. Finally, we show that VEO-IBD patients have, on average, higher IBD polygenic risk scores than population controls (99 patients and 18,780 controls; P < 4 × 10 −10 ), and replicate this finding in an independent cohort of VEO-IBD cases and controls (117 patients and 2,603 controls; P < 5 × 10 −10 ). This discovery indicates that a polygenic component operates in VEO-IBD pathogenesis.

Although the full primary structures of the alfa and beta subunits of reference r-hFSH-alfa and its biosimilars are identical, cell context-dependent differences in the expressing cell lines and manufacturing process can lead to variations in glycosylation profiles. In the present study, we compared the structural features of reference r-hFSH-alfa with those of five biosimilar preparations approved in different global regions outside Europe (Primapur®, Jin Sai Heng®, Follitrope®, Folisurge®, and Corneumon®) with respect to glycosylation, macro- and microheterogeneity, and other post-translational modifications and higher order structure. The mean proportion of N-glycosylation-site occupancy was highest in reference r-hFSH-alfa, decreasing sequentially in Primapur, Jin Sai Heng, Corneumon, Follisurge and Follitrope, respectively. The level of antennarity showed slightly higher complexity in Corneumon, Primapur and Follitrope versus reference r-hFSH-alfa, whereas Jin Sai Heng and Folisurge were aligned with reference r-hFSH-alfa across all N-glycosylation sites. Sialylation level was higher in Corneumon and Follitrope, but small differences were detected in other biosimilar preparations compared with reference r-hFSH-alfa. Jin Sai Heng showed higher levels of N-glyconeuramic acid than the other preparations. Minor differences in oxidation levels were seen among the different products. Therefore, in summary, we identified var ious differences in N-glycosylation occupancy, antennarity, sialylation and oxidation between reference r-hFSH-alfa and the biosimilar preparations analyzed.

Objective: Macrophages play a critical role in intestinal wound repair. However, the molecular pathways that regulate macrophage wound repair activities remain poorly understood. The aim of this study was to evaluate the role of GM-CSF receptor signaling in the wound repair activities of macrophages. Methods: Murine macrophages were differentiated from bone marrow cells and human macrophages from monocytes isolated from peripheral blood mononuclear cells of Crohn's disease (CD) patients. In vitro models were used to study the repair activities of macrophages. Results: We provide evidence that GM-CSF receptor signaling is required for murine macrophages to promote epithelial repair. In addition, we demonstrate that the deficient repair properties of macrophages from CD patients with active disease can be recovered via GM-CSF therapy. Conclusion: Our data support a critical role of the GM-CSF signaling pathway in the pro-repair activities of mouse and human macrophages.