IDENTIFICATION OF PERIPHERAL BLOOD AND COLONIC LAMINA PROPRIA IGE + MEMORY B CELLS

MANUELA ILID; JULIÁN VACCARO; MARÍA BELEN POLO; LORENA MENENDEZ; PAULA BAROBIA; CECILIA ZUBIRI; ANABELA ZOSI; LUCIANA GUZMÁN; VIVIANA BERNEDO; MARCELA GARCÍA; RENATA CURCIARELLO; CECILIA ISABEL MUGLIA; GUILLERMO DOCENA

Ciudad Autónoma de Buenos Aires

Congreso; 14th Latin American and Caribbean Congress of Immunology; 2024

ALACI y SAI

Given the rising incidence and severity of allergic manifestations and the critical role of IgE as a therapeutic target, it is imperative to investigate the mechanisms underlying the synthesis, secretion, and regulation of IgE. Our group studied colorectal juvenile polyps (JP) from atopic pediatric patients with proctorrhagia received at the Children’s Hospital of La Plata. These patients show elevated total and specific IgE to food allergens in peripheral blood (PB) and JP, with type 2 inflammatory infiltrate dominated by IgE-producing plasma cells and sensitized eosinophils. JP showed active germinal centers where IgE is synthesized. There is no in vivo evidence of IgE+ memory B cells (LBmem) generation in humans. We propose that the inflamed colonic mucosa of allergic patients is a site of differentiation of IgE+ memory B cells. This work aims to detect IgE+ memory B cells in polyps of food allergen-sensitized pediatric patients.Our work involved a comprehensive analysis of PB and JP from IgE-sensitized patients by flow cytometry using a range of antibodies including a polyclonal (IgE Bv711) and a monoclonal (Omalizumab A488) anti-IgE in a panel of antibodies (a-CD45 PerCP, a-CD19 V500, a-CD27 APC, a-CD138 PE, a-IgD SB600).We identified IgE+ memory B cells, with the monoclonal antibody, in 4 JPs (1,12%, 2,94%, 2,97%, and 5,05%) and their respective PB (0,04%, 1,36%, 5,62% and 0,39%), while the polyclonal anti-IgE antibody was useful for IgE+ cell quantification in PJs(1,09%, 5,67%, 16,96%, and 13,64%) and PB (0,10%, 1,91%, 16,02% and 2,36%).In conclusion, we detected IgE+ memory B cells in human colonic tissue, being essential to continue delving deeper into the pathology and severity of IgE-mediated inflammatory disorders related to food antigens.