Colorectal polyps in children with cow milk´s allergy

MUGLIA, CECILIA; CANZIANI, KARINA EVA; ALTAMIRANO, EUGENIA; BALCARCE, NORMA; GARCÍA, MARCELA ; GUZMAN, LUCIANA; NANFITO, GABRIELA; ZANUZZI, CAROLINA ; DE LA FUENTE, MARJORIE; LANDSKRON RAMOS, GAUBEN; DÍAZ JIMENEZ, DAVID; HERMOSO RAMELLO, MARCELA; DOCENA, GUILLERMO

Medellín

Congreso; Inmunocolombia 2015; 2015

ALAI - ACAAI

Cow milk´s allergy (CMA) is the most common food allergy amongst infants, affecting 2-5 % of children. Our preliminary studies showed that 70 % of patients older than 1 year old, with rectal bleeding and colorectal polyps had high levels of serum cow?s milk protein (CMP) specific IgE. These polyps are routinely removed as part of the treatment. When milk was avoided no recidivant polyps were observed. In this work we studied the cellular components of these benign colonic polyps. Patients attending La Plata´s Children Hospital for rectal bleeding were subject to colonoscopy. When polyps were present they were resected and studied. Blood IgE levels were simultaneously determined and children were routinely studied for allergy. Resected polyps from 30 patients were analyzed. Immunohistochemistry and confocal microscopy using anti-IgE, anti-CD138, anti-IL33 and anti-ST2 conjugated antibodies were performed. Besides, cytokine and transcription factor mRNA expression were analyzed by RT-qPCR. Cytokine levels were evaluated using CBA bead assay and ELISA. Serum ST2 levels were measured by ELISA. Finally T cell lines were established form peripheral blood and lamina propria of polyps to study their specificity using proliferation assays (3HThymidine and CFSE). We found that 25 patients had serum CMP-specific IgE. The stroma of polyps showed a cellular infiltrate composed of mononuclear cells, eosinophils, mast cells, and plasmatic cells as observed by haematoxylin/eosin staining, immunohistochemistry and confocal microscopy. We confirmed the presence of IgE secreting plasma cells. ST2+ and IL-33+ cells were also observed, confirming a Th2 infiltrate in polyps. Biopsies from mucosae near the polyps showed mononuclear cell infiltrate but no eosinophils and a fewer number of IgE+ cells (30 ± 15 cells vs 2 ± 3 in 600 X fields). We found a higher expression of il-4, il-5, ST2s (P