Characterization of the Th2 environment and local IgE production in colorectal polyps of allergic patients

CANZIANI, K.; VACCARO, J.; PUCCI MOLINERIS, M.; BALCARCE, N; DÍAZ JIMENEZ D; GUZMAN, L; GARCÍA M; ALTAMIRANO E; MEIER, D; HERMOSO RAMELLO M; MUGLIA C.I.; DOCENA, G.

Cancún

Congreso; Immuno Mexico 2018; 2018

Latin American Association of Immunology and Mexican Society of Immunology

Juvenile polyps are common in children. They occur mainly singly and typically at the rectosigmoid. The most frequent presentation is painless rectal bleeding. JP contain proliferative lamina propria cells with abundant connective tissue, and a chronic cellular infiltration of eosinophils. However, the aetiology of JP still remains largely unknown and few reports have characterized the stroma of colorectal polyps in atopic patients. We previously showed that 70 % of patients older than 1 yo, with rectal bleeding and JP had high levels of serum IgE specific to cow milk proteins (CMP). This finding prompted us to study the relation between the aetiology of polyps and the atopic condition of patients.Patients attending La Plata´s Children Hospital for rectal bleeding were subject to colonoscopy. Polyps (PT) and biopsies from surrounding mucosae (SCT) were resected and studied. Blood IgE levels were simultaneously determined and children were routinely studied for allergy. Resected polyps from 18 patients were analyzed. Immunohistochemistry and confocal microscopy using anti-IgE, anti-CD138, anti-CD20, anti-ki67, anti-CD57, anti-AID, anti-IL33 and anti-ST2 conjugated antibodies were performed. Besides, cytokine mRNA expression of Ccl5, Ccl26, Il-17a, Ifn-γ, Il-13, Il-6, Il-4, Il-33, St-2s and St-2l were analyzed by RT-qPCR. Cytokine levels of different T helper profile were evaluated using CBA bead assay and ELISA. Germinal centers were isolated by dissection laser and analyzed by PCR to study the immunoglobulin class switching. We found that 12 patients had serum CMP-specific IgE. The stroma of polyps showed a cellular infiltrate composed of mononuclear cells, mast cells, plasmatic cells and eosinophils with high levels of Ccl26 mRNA expression. IgE was found in plasma cells (30 ± 15 cells in 600 X fields) and eosinophils in P but SCT only showed a mononuclear cell infiltrate with IgA plasma cells but no eosinophils and a fewer number of IgE+ cells (2 ± 3 cells in 600 X fields). ST2+, IL-33+ and TSLP+ cells were also observed, confirming a Th2 infiltrate in polyps. Serum ST2 levels were higher in patients with polyps compared to control population (94 ± 15 vs 1233 ± 425 pg/ml, p