Peptídeo ligante à proteína catiônica de eosinófilo no diagnóstico da esofagite eosinofílica e seu potencial terapêutico na alergia

Abstract

Eosinophilic esophagitis (EoE) is an inflammatory condition of the esophagus characterized by the presence of a large number of eosinophils. Currently, EoE diagnosis is based on invasive endoscopic procedures for histopathological examination. Non-invasive biomarkers would be valuable for diagnosis and monitoring of EoE. Our aim was to select and validate peptides with potential to be used for EoE detection. We performed a comparative proteomics analysis using LC-MS/MS of esophageal biopsies from pediatric patients with eosinophilic esophagitis, gastroesophageal reflux disease and control individuals. Then, Phage Display technology was used to select peptides against up-regulated protein from patients with EoE. Twelve phage clones were selected after three biopanning rounds, and the best phage clone reactivity was evaluated in a phage- ELISA assay using patient mucus samples. Mass spectrometry showed that eosinophil cationic protein (ECP) was up-regulated in EoE patients. A high reactive ECP- binding peptide (E5) was able to distinguish mucus of eosinophilic esophagitis patients from gastroesophageal reflux disease and healthy individuals by ELISA in 94 pediatric patients, achieving sensitivity of 84.62, specificity of 82.72, a positive likelihood ratio of 4,896, and an area under the curve of 0.84. This is the first study to demonstrate the detection of eosinophil cationic protein using peptides identified phage display. The peptide presented herein could be a useful diagnostic tool for the detection of EoE patients. Furthermore, in the therapeutic approach, peptide (E5) has been shown to be able to decrease an IgE-independent degranulation. The alignment of the peptide with some proteins, especially from mast cells, reinforce the possibility of peptide mimetic the receptors important for a degranulation of mast cells. After mass spectrometry (LC-MS/MS) analysis of the supernatant of the IgE-independent degranulation condition, we found 79 unique proteins, which provide important information for a better understanding of mast cell-mediated allergy, as well as study of biological targets that serve as diagnostic and/or therapeutic strategies in the future.