Characterization of the mucosal infiltrate of colorectal polyps in children with cow milk´s allergy

MUGLIA CECILIA; CANZIANI KARINA; ALTAMIRANO EUGENIA; BALCARCE NORMA; BOROBIA PAULA; GARCIA MARCELA; GUZMAN LUCIANA; NANFITO GABRIELA; ZANUZZI CAROLINA; DE LA FUENTE MARJORIE; LANDSKRON GLAUBEN; DÍAZ GIMENEZ DAVID; HERMOSO RAMALLO MARCELA; DOCENA GUILLERMO H.

Medellin

Congreso; Inmunocolombia 2015 XI Congreso Internacional de la Asociación Latinoamericana de Inmunología (ALAI) y X Congreso de la Asociación Colombiana de Asma, Alergia e Inmunologia; 2015

ALAI

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. When milk was avoided as treatment 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, anti-ST2s and anti-ST2l conjugated antibodies were performed. Besides, cytokine and transcription factor expression were analyzed by RT-qPCR. Cytokine levels were evaluated using CBA bead assay and ELISA. Finally T cell lines were established form peripheral blood and lamina propria to study their specificity by 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. CD4+ST2l+ 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