Analysis of the eosinophil-rich cell infiltrate in colonic polyps of patients with food allergy

CANZIANI K.; VACCARO J.; MUGLIA C.; DOCENA G.

Beijing

Congreso; 17th International Congress of Immunology, 19?23 October 2019, Beijing, China; 2019

Juvenile polyps (JP) lead to rectal bleeding and diarrhea in children. We characterized the allergicinflammatory cell infiltrate of the polyps in patients with food allergy and the origin of the highfrequency of eosinophils.Polyps were removed in 20 patients, along with a biopsy of the normal surrounding tissue (SCT). Theproduction of CCL26 and RANTES were assessed by qPCR and confocal microscopy. Additionally,Caco-2 and HMEC-1 cell lines were stimulated with IFN-g (10ng/ml) or IL-13 (10ng/ml) and theactivation of STAT-3 and STAT-6, and expression of chemokines were analyzed by immunoblottingand qPCR, respectively.We found a significant increase of eosinophils and eotaxin-3 expression in polyps compared to SCT(p< .05), which was mainly produced in the epithelial compartment. Lamina propria and endothelialcells of polyp tissue were also positive for CCL26 staining. The SCT showed a basal expression.Caco-2 and HMEC-1 cells stimulated with IL-13 rendered higher levels of eotaxin-3 transcriptscompared to cells incubated with medium or IFN-g (p< .02). The IL-13-dependent induction of CCL26secretion triggered the STAT-3 and STAT-6 pathway activation.In conclusion, we found that the epithelial compartment and endothelium were the main sources foreotaxin-3 secretion, being IL-13 responsible for STAT-3 and STAT-6 activation. These findings mayshed light on understanding the etiology of the eosinophil homing to the gut of patients with food allergy and may be critical to study the IL-13/STAT-3/6/CCL26 axis during the novel therapy withbiologics (Dupilumab or anti-IL4Ralpha) for patients with eczema and food allergy.