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Differences in IgE mediated basophil degranulation induced by proteic fractions from whole flea body extract in patients with papular urticaria by flea bite and healthy controls

Omar Dominguez-Amorocho12, Silvia Duarte1, Elizabeth Garcia3*, Evelyne Halpert3, Adriana Cuellar4 and Adriana Rodriguez5

Author Affiliations

1 Facultad de Medicina, Universidad Militar Nueva Granada, Bogotá, Colombia

2 Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia

3 Sección de Alergia y Dermatología Pediátrica, Fundación Santa Fe de Bogotá, Carrera 9 Nº 117-20, oficina 205, Bogotá, DC, Colombia

4 Grupo de Inmunobiología y Biología celular, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia

5 Centro de Investigaciones Odontológicas, Facultad de Odontología, Pontificia Universidad Javeriana, Bogotá, Colombia

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World Allergy Organization Journal 2013, 6:10  doi:10.1186/1939-4551-6-10

Published: 16 May 2013

Abstract

Background

Papular urticaria by flea bite (PUFB) is a chronic inflammatory disease in children. The aim of this study was to assess the functional activity of IgE to protein fractions from flea body extract, through basophil degranulation in PUFB patients and controls.

Methods

Basophil degranulation, measured by overexpression of CD63 surface molecules, was evaluated by flow cytometry in samples from patients and controls. Cell stimulation was performed with three fractions with different molecular weight from flea body extract using a Basotest® modified protocol. Mann–Whitney U-test was used for comparisons.

Results

Specific IgE from PUFB patients and healthy controls induced basophil degranulation to flea body extract with no significant differences between them (16.2 ± 3.1% vs 13.6 ± 2.8% p = 0.77). However, when flea extract was analyzed in fractions with proteins ranging different molecular weights, significant differences were observed on the response from patients compared with controls to <50 kD (14.9 ± 5.1% vs 9.7 ± 2.1% p = 0.0058) and 50–100 kD proteic fractions (8.3 ± 3.2% vs 2.8 ± 1.6% p = 0.0021).

Conclusion

In this study, was established that the differential response by IgE, in PUFB, depends from the molecular weight of the antigens contained in the flea extract. These antigens may be related to 30–35 kD proteins previously described as major allergens.

Keywords:
Basophil degranulation; CD63; Flea allergy; Papular urticaria; Basophil degranulation test