IgE and IgG4 binding to lentil epitopes in children with red and green lentil allergy

Background: The consumption of lentil is common in the Mediterranean area and is one of the causes of IgE-mediated food allergy in many countries. Len c 1 is a well-defined allergen of lentil and approximately 80% of the patients with lentil allergy recognize the purified Len c 1 protein. We sought to identify IgE and IgG4 sequential epitopes of Len c 1 in patients with red and/or green lentil allergy. We also aimed to determine IgE and IgG4 binding differences between those patients who had outgrown or remained reactive to lentil. Methods: Children with IgE-mediated lentil allergy were included in the study. We applied a microarray immunoassay to determine the characterization of positive IgE and IgG4 binding to Len c 1 epitopes in the patients’ sera. Results: The peptides specifically recognized by IgE and IgG4 antibodies were mainly detected between peptides 107 and 135 of Len c 1. The signal intensities of positive epitopes were significantly greater in reactive patients than tolerant ones (P =.008 for IgE and P =.002 for IgG4). Moreover, IgE and IgG4 antibodies bound largely the same sequential epitopes in patients who remained reactive or outgrew their allergy. Conclusion: IgG4-binding epitopes in lentil allergy were identified and IgE and IgG4 binding to epitopes in both red and green lentils was compared. Our data regarding signal intensity differences between reactive and outgrown patients and overlap binding of IgE and IgG4 antibodies may be important for the development of more accurate diagnostic tests and understanding of natural tolerance development.